Date: Mon, 04 Jan 1999 18:57:19 From: "Robert L. Nuckolls, III" Subject: COZY: Re: alternator/regulator wiring >I have recently started having an electrical problem - within a few >(5-15) seconds after turning alternator switch on, the voltage slowly >rises to 16+ volts (at which point I turn alternator switch off to avoid >frying battery & avionics). I would just conclude the regulator has >gone bad, but I first noticed this after I had repaired (perhaps >incorectly?) a broken ground wire on the regulator. The regulator has >five wires, rather than the three I expected: Red->alternator switch on >panel, Green->"F" terminal on alternator, Yellow->"N" terminal on >alternator, Orange->taped off/no connection, Black->ground(this is the >wire I (re?)attached to ground when I found it broken). Voltage >regulator is labeled "TRANSPO F7078". >Anyone familiar with this regulator & know if it is wired correctly? Runaway voltage, particularly the creepy kind you describe is invariably the voltage regulator. The broken wire may have toasted its innards in some way. I'd replace it. You might consider an automotive aftermarket replacment for a 1980s Ford regulator. Standard Autoparts p/n VR166 is one good choice. It's all solid state and sells for $10 to $15 in auto parts stores. However, this, like ANY regulator should be teamed with overvoltage protection . . . if you don't have ov protection, you were very lucky to have noticed the failure before it lunched your electo-goodies. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < If you continue to do > < What you've always done > < You will continue to be > < What you've always been. > ================================= Date: Tue, 05 Jan 1999 10:30:35 From: "Robert L. Nuckolls, III" Subject: COZY: Re: RV-List: Wire terminals >A builder recently opined: >In my humble opinion and experience, everything >at Radio Shack is of the lowest possible quality. > Actually, you can buy a broad range of product capabilities at Radio Shack, and many other stores like them. I hear that Radio Shack parts went to Mars on the last lander mission. The trick is to understand what you want the parts to do and which ones are suited to the task. To put a wet blanket (or a warm one for that matter) on any single supplier's hardware may not be very useful in terms of offering advice. Some parts at R-S are indeed low cost and not very sturdy, but many others are from the same name-brand suppliers such as National, Motorola, AMP, Molex, etc. as the upscale suppliers. If we design our airplanes for failure tolerance, then absolute quality is less an issue . . . one may try a component in any location and upgrade it if its maintenance history is unsatisfactory. The process can be more comforting if we educate ourselves with respect to what's needed and compare it with what's offered . . . Date: Wed, 02 Dec 1998 16:59:22 From: "Robert L. Nuckolls, III" Subject: COZY: RE: Electric cable installation Tail, battery >Yes, sure I've been aware engines usually are rubber-mounted on their >mounts, and of course ground straps between engine block and mount have >always been common practice. > >What I've been wondering about, however, was the remark that, as I >understood it, the actual structure of the mount itself should never be used >as ground lead. Is that true, or is it just a matter of not defining things >precisely enough? The advise against using engine mounts for ground paths is based on several relatively minor points. First, the mount is generally tubular steel, not nearly the quality of conductor that a copper ground strap. There are a myriad of joints and attaching hardware involved in the grounding path each of which contributes a small amount of resistance in the milliohm or sub milliohm level. Engine mounts attach to the airframe in generally 4 or more places which causes currents from the mount to flow across the firewall sheet from a variety of directions. Fasteners designed for adequate mechanical performance may or may not be good also for electrical performance . . . given that having an engine fall off is more stressful than having poor electrical system performance, efforts to optimize mechanical integrity tend to prevail. Any one of these considerations by itself is relatively minor but if anyone has read my articles on grounding will know that the sum total of these effects can add up to significant performance losses and/or noises. The obvious solution is let the engine mount hold the engine on and let a ground strap carry the electrons to and from a single ground point on the firewall. BOTH may be optimized for their respective tasks without compromising the other. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < If you continue to do > < What you've always done > < You will continue to be > < What you've always been. > ================================= From: lschuler@cellular.uscc.com Date: Tue, 05 Jan 1999 16:13:30 -0600 Subject: Re: COZY: Re: RV-List: Wire terminals Bob Nuckolls wrote: >... >I hear that Radio Shack parts went to Mars on >the last lander mission. The trick is to >understand what you want the parts to do and >which ones are suited to the task. To put a >wet blanket (or a warm one for that matter) on >any single supplier's hardware may not be very >useful in terms of offering advice. .. >If we design our airplanes for failure >tolerance, then absolute quality >is less an issue . . . one may try a >component in any location and upgrade >it if its maintenance history is >unsatisfactory. The process can be more >comforting if we educate ourselves with >respect to what's needed and compare it >with what's offered . . . Having an electronics background and understanding reliability issues related to a transistor or an IC chip better than I do a steel bolt or a heavy glass lay-up, it's too tempting to pass up.... Seems to me Bob has some solid reasoning applicable to other suppliers of airplane parts/supplies, such as Wicks, ASS, Harbor Freight, Featherlite, Aerocad, Brock, Wright-LCC (EZ-Lift), B&C, the local NAPA store, and so on. Also seems to me that we each must arrive at a compromise somewhere between building in "fault tolerance", and our individual tolerance for faults... For example, we could buy a "mirroring" hard drive for our home PCs (or two engines for the plane) at additional cost or choose to tolerate an occasional head crash on a single drive (or occasional engine-out in the plane). As Nat Puffer so eloquently pointed out when I got concerned about air pockets in the lay-up of my fiberglass nose strut: "Worry about the important stuff". Trick, of course, in applying Nat and Bob's reasoning is knowing what's important at an appropriate point (pre-fatal-failure) in our airplane-building learning curve... ..Regardless of the supplier, or part. Larry Date: Thu, 21 Jan 1999 07:41:07 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Antenna problems >I was doing a continuity check on the coax for my comm. The coax >is OK; but, I tried doing a continuity check from the center pin at the >comm down to the tip of the antenna. When I checked the whip >antenna, I got no continuity. Since I know nothing about this stuff, I >have this question. Should there be continuity from the center pin in >the connector on the antenna and the tip of the antenna? If there >should be, I have a break somewhere in the antenna. I would check with the manufacturer of the antenna. Radio frequency energy can be piped through a lot of components not the least of which is capacitors . . . they do not conduct DC current. The other way to check is to push some energy into the antenna with a transmitter and check standing wave ratio or you can use a device like the antenna analyzer shown in the tools section of our website catalog. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < If you continue to do > < What you've always done > < You will continue to be > < What you've always been. > ================================= From: cdenk@ix.netcom.com Date: Fri, 22 Jan 1999 16:15:17 -0600 (CST) Subject: Re: COZY: % POWER SOLUTION On 01/22/99 07:15:01 you wrote: > >Why don't you guys check out this little gem.... > >http://www.technologykitchen.com/digital.htm > >This instruments eliminates the guess work no matter what engine / prop >combo you have. > >Gary Hunter >EAA Technical Counselor > > Nice information, but limited use in flight for an EZ. Panel space is a premium, added weight, looks like could be 2 lbs. With fixed pitch prop, there is a limited number of RPM/Manifold pressure combinations. A small amount of work after a little experience will define common power limits you will use. From: cdenk@ix.netcom.com Date: Tue, 26 Jan 1999 18:12:37 -0600 (CST) Subject: RE: COZY: % POWER SOLUTION Someone wrote me privately >This instrument replaces - tachometer, manifold pressure guage, OAT, and if >you really want to press it... the altimeter and it reports density >altitude. WOW !! > >Knowing how much power you have on take-off is pretty nice feature too.> I dug more into their web site, and found more info. Neat, weight OK. only improvements I see, is a remote sensor for the manifold pressure, more flexibility in oatside air temp sensor mounting AND check the visibility in the sun light! The altitude is only for backup, with over 200' possible error. What was the size, 2.25" or 3.125" opening? Date: Thu, 28 Jan 1999 08:26:14 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Aircraft noise in comm radio. >I had originally located the mic and phone jacks to the comm radio to the cage structure behind the pilot's left shoulder, using a pair of insulated adel clamps to attach the simple angle bracket.. This turned out to be a nuciance, and reminded me uncomfortably of John Denvers problem. So I decided to move the jack assembly to a more convenient position, which turned out to be at the rear of the seat back rail tab. I simply drilled a hole in the angle and used a slightly longer bolt to mount the seat rails. > >The next time I turned on the radio, planning to go flying and test a trim change, I heard the unmistakable noise of the aircraft alternator in the head set. Not only that, I discovered that there was suddenly an interaction between the strobe lights and the Apollo SL60 nav/comm, and that the nav display blinked on and off in response to the strobe flashes! > >It was apparent that I had unintentionally picked up a lot of ground currents in the shield of the headset cable, and introduced some undesirable coupling to other parts of the electrical system. Mounting the headset jack bracket on a standoff solved the problem, and my radios are once again quiet. I've reposted this item to several list-servers . . . including some of the plastic airplanes interest groups. It's important to avoid any local "grounding" of headset and microphone jacks, even to a metal instrument panel in a composite airplane. Hard paper extruded washers are available to provide insulation of the jacks from their mounting plate, or you can mount the jacks on a thin sheet of glass-epoxy like etched circuit boards. We stock the washers too @ $1 per jack, postage paid. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < A mind abhors a vacuum . . . > < When deprived of facts, > < our fantasies are generally > < much worse than reality. > ================================= From: cdenk@ix.netcom.com Date: Wed, 17 Feb 1999 16:25:40 -0600 (CST) Subject: COZY: Electrical safety rules Ten Commandments of Electrical Safety (1) Beware of the lightning that lurks in an undischarged capacitor lest it cause thee to be bounced upon thy backside in a most ungainly manner. (2) Cause thou the switch that supplies large quantities of juice to be opened and thusly tagged, so thy days may be long on this earthly vale of tears. (3) Prove to thyself that all circuits that radiateth and upon which thou worketh are grounded lest they lift thee to high-frequency potential and cause thee to radiate also. (4) Take care thou useth the proper method when thou taketh the measure of high-voltage circuits so that thou doth not incinerate both thee and the meter, for verily though thou hast no account number and can be easily replaced, the meter doth have one and as a consequence bringeth much woe upon the supply department. (5)Tarry thee not amongst those who engage in intentional shocks for they are surely non-believers and are not long for this world. (6) Take care thou tampereth not with interlocks and safety devices, for this incureth the wrath of thy seniors and bringeth the fury of the safety officer down upon thy head and shoulders. (7) Work thee not on energized equipment, for if thou doeth, thy mates will surely be buying lunch without thee and thy space at the table will be filled by another. (8) Verily, verily I say unto thee, never service high-voltage equipment alone, for electric cooking is a slothful process, and thou might sizzle in thy own fat for hours on end before thy Maker sees fit to end thy misery and drag thee into His fold. (9) Trifle thee not with radioactive tubes and substances lest thou commence to glow in the dark like a lightning bug. (10) Commit thee to memory the works of the prophets, which are written in the instruction books, which giveth the straight info and which consoleth thee, and thou cannot make mistakes. -From Orbit, the Journal of the Rutherford High Energy Laboratory, Didcot, England (31 January 1965) p Date: Thu, 18 Feb 1999 23:49:44 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Auto Fuse Failure Light >One of the things that I have heard people say, is that auto fuses would be >OK most of the time, but you don't have an easy way to identify which fuse >blows while in flight. I had been thinking about ways to wire up a failure >indicator LED when I happened to notice the solution hanging on the rack in >the auto fuse section of a TRAK auto store. What value is there in knowing that a fuse has blown? The reasons that some device in your airplane fails to function range from simple disconncts to end of life (bulb burns out, brushes worn, etc.). Very few system failures result in opened circuit protection. So what value is there in knowing that something doesn't work because the fuse is opened or that it's some other problem that didn't open the fuse? In either case, the system doesn't work and plan-B has to be implemented. What is the first indication pilots have that something is amiss? You flip a switch and the expected thing doesn't happen. A flag drops on an instrument. A pointer goes to zero . . . considering ALL the things that will produce the same dead system, why is is useful to know that a fuse is popped? And if it were popped, do you really want to replace it in flight? I wonder if the annunciator panel recently added to the EXP-Bus hasn't fueled new anxiety amongst our fellow builders. First the product offers to replace electro-mechanical breakers having lots of parts with solid state breakers having only one part. Good . . . parts count down, reliablity up and cost is down. Now it adds an annunciator system to show when a circuit is functioning. Parts count up, added cost, and light bulbs can lie. Consider how many C,B or P single engine airplanes have an indicator light to show that the landing light is on? Fuel pump running? Pitot heat on? None that I've flown. How do we know if those things are working? Ammeter goes up, runway is visible, fuel pressure is up. If the system dies, does the annunciator light go out? No, it powers up from the same souce as the device . . . flip the switch, the annunciator light comes on and something MAY work. Suppose any of those devices is bad, the annunciator is still on. Or in the case of your suggestion about the fuse annunciators, the fuse is still good. So the question remains, what value is there in annunciating breakers popped, fuses good, or power switch closed when there are failure modes that the annunciation doesn't catch. I'll suggest you're better off using system performance results to tell if things are working than to waste time, money and misplaced confidence in any form of annunciation that has no way to make your experience any safer. Worse yet, it may detract from safety by being a distraction or providing misleading information. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < A mind abhors a vacuum . . . > < When deprived of facts, > < our fantasies are generally > < much worse than reality. > ================================= Date: Sun, 21 Feb 1999 17:57:07 From: "Robert L. Nuckolls, III" Subject: COZY: Re: bolder batteries At 11:00 PM 2/18/99 -0500, you wrote: >Have you given any thought to these new Bolder thin metal film >batteries? See them at www.boldertmf.com. They are the size of a >grapefruit and put out 350 amps for starting but have limited amp hour >capacity (1 Amp for two hours, 50 amps for 85 sec). >I have considered using one as a starting power source but I >would also like to have an adequate dual battery setup for a >dual electronic ignition. These batteries have been around in various forms for about two years at least. Bill had an array of the little "jelly-roll" batteries in his shop just before OSH 97. He demonstrated a 300 amp dump ability for enough time to get an engine started. I looked at the Bolder batteries and they don't show a cell connection worthy of hundreds of amps current flow. Bill's battery had welded intercell connectors and soft, braided lead wires to attach the battery into a system. Bill's interest in this product was to offer a light weight battery good for one start to airshow performers who like to leave their big battery on the ground during a show but might need to start the engine after a stopage in flight. >What do you think of the combination of an 18 AH motorcycle >battery and the bolder battery, switchable so that either >battery can power either ignition? Do you think that's >too dicey with the limited AH capacity of the Bolder battery? Don't see the advantage of this combination. There are lots of 18 a.h. batteries that will crank an engine very handily without the assitance of the 2 a.h. Bolder battery (or it's market equal). If you were going to install a 2 a.h. battery as a short-term backup for ignition only, then there are some much less expensive devices that could be used since you don't need cranking capability from the little guy. For dual electronic ignition, I think I'd still recommend a pair of equal sized batteries with one battery a year shuffle as I've described in my articles. If you want to get weight down, how about a pair of 10 or 12 a.h. batteries used together for cranking? A pair of 10's would be about the same weight as the 18 and 2 combo you were proposing and cost less to maintain. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < A mind abhors a vacuum . . . > < When deprived of facts, > < our fantasies are generally > < much worse than reality. > ================================= Date: Mon, 01 Mar 1999 23:38:46 From: "Robert L. Nuckolls, III" Subject: COZY: Downloadable VLM-14 Manual Many of you have written to me over the past several months to tell me about a broken link from one of our website catalog pages. I've just finished the preliminary issue of the instruction manual for installation and use of our VLM-14 volt/loadmeter and low voltage warning system. Interested individuals are invited to get their very own copy at . . . http://www.aeroelectric.com/Catalog/instrmnt/9021_704.pdf Bob . . . //// (o o) ===========o00o=(_)=o00o========= < A mind abhors a vacuum . . . > < When deprived of facts, > < our fantasies are generally > < much worse than reality. > ================================= From: "Paul Stowitts" Subject: COZY: Alternator Fuse Size Date: Sun, 7 Mar 1999 21:09:14 -0800 I am working on wiring and I have been getting differing opinions regarding the fuse size for my alternator. I plan on mounting the fuse in the rear so I don't need to bring the heavier gauge wire to the panel and back. The plans show a 35 amp fuse for the alternator. I have the B&C 60 amp alternator so I figured I should install a 60 amp fuse with #8 wire. At least two others have told me I should install a higher rated fuse (80 to 90 amp). It seems to me that I would then have to increase the wire size as well. Can anyone shed some light on this topic? Thanks in advance. Paul Stowitts Cozy Mark IV #200 Date: Mon, 08 Mar 1999 09:35:25 From: "Robert L. Nuckolls, III" Subject: Re: COZY: Alternator Fuse Size At 09:09 PM 3/7/99 -0800, you wrote: >I am working on wiring and I have been getting differing opinions regarding >the fuse size for my alternator. I plan on mounting the fuse in the rear >so I don't need to bring the heavier gauge wire to the panel and back. The >plans show a 35 amp fuse for the alternator. I have the B&C 60 amp >alternator so I figured I should install a 60 amp fuse with #8 wire. When an alternator is cool and charging a dead battery, it will put out 10-20% more current than it's rated for. This is why the 60 amp breaker on 60 amp alternators in most single engine Cessnas and Pipers nuisance trips . . . > At >least two others have told me I should install a higher rated fuse (80 to >90 amp). It seems to me that I would then have to increase the wire size >as well. Can anyone shed some light on this topic? Thanks in advance. 80 is appropriate for a 60 amp alternator. We offer a kit for an 80-amp b-lead fuse that includes terminals for #4AWG wire (to keep the wire size commensurate with the fuse size). See http://www.aeroelectric.com/Catalog/ckrtprot/ckrtprot.html#bleadfuse Bob . . . //// (o o) ===========o00o=(_)=o00o========= < A mind abhors a vacuum . . . > < When deprived of facts, > < our fantasies are generally > < much worse than reality. > ================================= From: cdenk@ix.netcom.com Date: Mon, 8 Mar 1999 16:09:12 -0600 (CST) Subject: Re: COZY: Alternator Fuse Size Stowitts ?? The function of the fuse or circuit breaker is to protect the wire from overheating and causing a fire. First size the wire to the maximum amperage expected, then select a breaker or fuse that is NO MORE than the wire is allowed amperage, AND NEVER MORE. The wire allowable amperage is published in many places. Check the Mechanics handbook, or accepted practices book. There are examples there. The alternator should be sized for more than your maximum continuous load by (If I remember correctly) 15%. From: "james leturgey" Subject: Re: COZY: Chap. 22 - Battery info Date: Wed, 17 Mar 1999 05:57:26 PST Marc: I would recommend one of those trickle chargers that most motorcyle buffs use. Maybe borrow one although they are quite inexpensive. The regular chargers they sell at Walmart for cars might be a little risky. Jim >From: "Marc J. Zeitlin" >Reply-To: "Marc J. Zeitlin" >To: Cozy Builders Mailing List >Subject: COZY: Chap. 22 - Battery info >Date: Wed, 17 Mar 1999 00:27:53 -0500 > >People; > >Handy tip: if you leave your battery master solenoid on for two days, you >will drain your battery. > >I have a Concorde 25 Amp-Hour battery - does anyone know if it's OK to use >a standard car battery charger to recharge this thing, or do I need >something fancy and expensive that is only used for airplane batteries? > >-- >Marc J. Zeitlin mailto:marcz@ultranet.com > http://www.ultranet.com/~marcz/ > Get Your Private, Free Email at http://www.hotmail.com Date: Wed, 17 Mar 1999 07:55:17 From: "Robert L. Nuckolls, III" Subject: Re: COZY: Chap. 22 - Battery info >>From: "Marc J. Zeitlin" >>Reply-To: "Marc J. Zeitlin" >>To: Cozy Builders Mailing List >>Subject: COZY: Chap. 22 - Battery info >>Date: Wed, 17 Mar 1999 00:27:53 -0500 >> >>People; >> >>Handy tip: if you leave your battery master solenoid on for two days, >you >>will drain your battery. >> >>I have a Concorde 25 Amp-Hour battery - does anyone know if it's OK to >use >>a standard car battery charger to recharge this thing, or do I need >>something fancy and expensive that is only used for airplane batteries? RG batteries require no "special" treatment for charging. They are a liquid sulphuric acid and lead system just like we've been using in cars and airplanes for years. While the RG battery is an exemplar performer in almost every category, they are limited in the amount of water they carry and after the battery reaches full charge, continued charging disassociates water into H2-O2 and pressure builds inside the cell. IF the pressure exceeds the venting value of hte valves, some of these gases will be lost and the battery's performance will suffer. Any charger with an "automatic shutoff" is probably fine. Use a voltmeter to check that after the charger has been in place long enough for its ammeter to go to near zero or it's little "charged" led to come on, then see what the voltage is. 13.8 to 14.2 you can leave on forever at room temperature. 14.3 to 14.8 is not a serious threat to the battery but I wouldn't leave it attached for continuous support . . . there's no really good reason to leave a charter on an RG battery for storage support, the self discharge rate on these devices is on the order of .1 to .2 percent per day . . . charge 'em with anything you have and then disconnect the charger. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Go ahead, make my day . . . > < show me where I'm wrong. > ================================= From: CRSAFFORD@aol.com Date: Wed, 17 Mar 1999 14:39:46 EST Subject: Re: COZY: Chap. 22 - Battery info Marc - check out www.westmarine.com, click on "The West Advisor" button, then "electrical", then "smart charging" - more than you ever wanted to know about charging flooded cell and gel cell batteries. From: "Nat Puffer" Subject: COZY: Battery Date: Wed, 17 Mar 1999 18:34:55 -0600 Builders., I have one of Bill Bainbridges "new technology" batteries, and can't speak highly enough about it. It is not lead-acid, and not gel-cel (Bill hasn't explained what it is). All I can say is that I have had it for 7 years now. It has been completely flat at least 4 times, and still takes a full charge. It is completely sealed, and very compact. It turns my 0-360 with perfect compression over like crazy. My airplane wasn't used for over 6 months, and it still had the power to turn my engine over and start it, not once, but twice. I would never consider a Concord again, or an auto battery, or any other lead-acid battery. It costs a little more, but worth about 4 or 5 lead acid batteries. Regards, Nat Date: Wed, 17 Mar 1999 22:41:48 -0500 From: Bulent Aliev Subject: Re: COZY: Chap. 22 - Battery info I'm sure you have it in reverse Larry: The gell batteries must be charged at 14.1V-14.2V and wet ones at 13.8V. The auto alternators and chargers are set for 13.8V. I have installed many gell cell systems ad they recommend for the alternators to have external adjustable regulators set to 14.1V-14.2V and external chargers with the same voltage. This way you will have the gell's charged to their full capacity. There is more to it but these are the basics in my opinion. Bulent lschuler@cellular.uscc.com wrote: > > Marc, > > Not familiar with Concord specifically, but here's a rule of thumb: > > if it's a gell cell, 13.8 volts to charge; typical slow (trickle level) > from 'some' car chargers will work (or at least be close). If it's a > standard lead-acid style, charge at 14 to 14.2 volts, which is standard car > stuff (and therefore OK). > > Slow charge is always better than trying to 'zap' it with heavy charge > current. If the thing is as dead as it sounds, the initial current may be > relatively high due to it's condition, but should taper to trickle level as > it comes up to charge. > > Hope it helps. > > Larry Date: Sun, 21 Mar 1999 12:56:27 From: "Robert L. Nuckolls, III" Subject: COZY: Fusible Links A reader on one of the lists writes: >The concept is that a 4 inch length of wire, at least 4 wire sizes smaller >than the wire being protected, will work as a fusible link by heating and >opening before the protected wire is damaged. Damage is limited to melting of >the insulation on the fusible link plus heating of anything touching it, so >try to isolate the link and/or insulate it with a fiberglass sleeve. Fusible >links may be purchased at auto parts stores or made from pieces of tefzel wire >using crimp terminals. Fusible links are apparently used in cars to protect >certain areas of wiring from screwdrivers dropped into the works. I recommend that fusible links for aircraft be limited to the 24AWG and 22 AWG sizes for supplying some of the always-hot feeds to thing like the essential bus alternate feed, electronic ignitions in any form, electronic controlled fuel injection, and ammeter shunts. These feeds are generally limited to 5 amps or so max continuous demand. I just got home from a fire-fighting trip to CA for Raytheon and I found a good buy on silicone impregnated fiberglas sleeving in a size 12 . . . it fits inside the insulation support barrel on a 22-18 AWG (red) PIDG terminal. We'll be offering 24 and 22 AWG fuselinks from our website catalog as soon as I can get the .html files revised. They will be p/n S905-xx-y where xx is either 22 or 24 for the wire size and y is 6 for #6 screw stud, 8 for #8, 10 for #10, 25 for 1/4", 31 for 5/16", 38 for 3/8" or 50 for 1/2" ring terminal. The other end is fitted with a PIDG butt splice for continuing on with the wire that's getting protected. >In my installation I wanted the breakers in the panel but this left the wires >between the master relay and the breakers (including the panel connectors) >unprotected. I added a fusible link to protect these wires, unlikely as a >failure here is. Of course, since the link is about 25A and the panel >connectors are rated at 15A per pin, a connector meltdown is still possible if >a short occurs in the panel.... Fuses, breakers, and/or fusible links are not needed in the location cited . . . I have had a lot of builders suggest "master breakers" to protect against bus shorts . . . check your installation and see what might CAUSE the short you are guarding against. Once you find that failure, eliminate it, don't protect against it. The trip I just got home from was to help debug a system that was so worry-driven about finding and annunciating every conceivable fault that system complexity grew by 20-50 times what it should have been for this very critical application. The end result was that the system was over budget by 10X and unusable . . . Take care lest unjustified worries drive complexity up and reliablity down. >Another fusible link was added between the alternator's regulator and the >capacitor. These links replace the high current fuses called for in Europa's >diagram. I added fusible links on the wires controlling the master and >starter relays for the same reason. All fusible links are on the engine side >of the firewall (to avoid smoke in the cockpit) and are positioned to be >easily accessed. I wouldn't suggest that you take these out . . they don't hurt anything but I wouldn't recommend that other folks put them in either. Some are not needed due to absence fault that would cause them to operate, others are not needed because your system should be designed to eliminate the probability of faulting. Take a look at the wiring diagrams which are downloadable at http://www.aeroelectric.com/errata/z8.pdf If you don't find a fusible link on those diagrams where you think one might be useful or necessary, let's talk about it. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < A mind abhors a vacuum . . . > < When deprived of facts, > < our fantasies are generally > < much worse than reality. > ================================= Date: Wed, 24 Mar 1999 14:00:48 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Europa_Mail: Fusible Links At 11:13 AM 3/24/99 EST, John Moran wrote: >In a message dated 99-03-21 13:59:03 EST, you write: > ><< I recommend that fusible links for aircraft be limited to the > 24AWG and 22 AWG sizes for supplying some of the always-hot > feeds to thing like the essential bus alternate feed, electronic > ignitions in any form, electronic controlled fuel injection, and > ammeter shunts. These feeds are generally limited to 5 amps or > so max continuous demand. > >> > > >Hi Bob, > >In conflict with your response to my note on the Europa net, I note that your >drawing Z-7 shows a fusible link of #16 wire in the upper right corner. I am >unclear on whether you have changed your philosopy since Z-7 was published or >this is a misprint. John, you are of course, correct. The image that came to mind when I saw the word "alternator" was the bigger brothers to the Rotax and LOM PM machines . . . Fusible link technology is indeed appropriate for protection of the alternator feed to the bus. I think it's a stretch to go after 40-100 amp b-leads on the big guys . . . a cartridge fuse is much cleaner. >Also, would you please publish the fuse points for the various sizes of tefzel >insulated wire - the only reference I found indicated that #25 bare wire fuses >at 30A in free air; I assume that insulated wire fuses at a lower current due >to heat retention by the insulation but cannot find published figures. While >knowing that a link 4 sizes smaller will protect the wire, it would also be >useful at times to know the expected fuse point. I'll see if I can find some data on this. You're correct that insulation and environment can have a marked effect on the fusing constant for any conductor . . . the -4AWG rule is intuitively valid, the weakest link in the chain can be guaranteed to fail first, irrespective of the conditions that drive fusing constant. >While your analysis indicated that I have used more fusible links than >required, I am comfortable with them since they seem extremely reliable and >are certain to prevent damage to wire bundles which could possibly be damaged >otherwise. I thank you heartily for this elegant concept. And I appreciate >your taking the time to critique my electrical system design - as a first time >builder, I need all the help I can get. Very good. I'm pleased that you took the time to study the data and arrive at a comfortable conclusion for yourself based on the physics. Norm Doty wrote: are we really sure we want fusable links? i would think that anything that heats up to the point of burning thru itself isnt a good idea, mabey we can protect the things surrounding them from the heat today but everything ages/weakens/rots and we know no one checks everything everytime. A good question. Keep in mind that fuses burn through every time they're called upon to act. Fuse manufacturer's design the product so that the burning happens in a restricted space and doesn't propogate damage to the rest of the sytem. The fusible link does the same thing . . .it's a bit more spectacular because there is some smoke but contining the relatively small conductor inside a piece of fiberglas sleeving prevents propogation of damage. Fuselinks have one VERY attractive feature . . . unlike the breakers and/or fuses they replace, the parts count is VERY low. The parts are made from ordinary wiring and terminals that may be expected to perform as well 20 years from now as they do today. That's difficult to say for fuseholders and circuit breakers. Fusible links are especially useful in situations where the need to protect is very unlikely but the need to have reliable connection is strong . . . like electronic ignition and essential bus alternate feeds. I've pitched about $100 worth of inline fuse holders I used to sell because my builders are having trouble with them after only a few years. From: cdenk@ix.netcom.com Date: Wed, 24 Mar 1999 17:31:56 -0600 (CST) Subject: COZY: Alternator noise What is the filter capacitor value for the power out terminal on an alternator to antenuate the noise in the head sets? I'm thinking 22 MFD, 35 volt. Date: Thu, 15 Apr 1999 10:01:01 From: "Robert L. Nuckolls, III" Subject: COZY: Re: wire harness and busses >Bob, why do you recommend fuses over circuit breakers for aircraft use? >With a military aviation background I instinctively expect to array my >panel with C/Bs for individual equipment, Main Buss A, Main Buss B, and >Essential Buss. That's mostly because military airplanes are war machines. Any form of failure is a distraction to a pilot that could happen while he's being shot at . . . further, the equipment and design philosophies prevalent in military aircraft and flowed down to air transport category airplanes is deeply rooted in aviation antiquity. Institutional inertia in both military and commercial aircraft almost assures us that change will be slow in coming and lag a decade or more behind the advancements we enjoy in our automobiles and consumer electro- goodies. > >I'm thinking access when something surges, being able to power off >busses (down to Essential) when electrical fire threatens, power >removal for maintenance, etc. Read the articles referenced or reprinted on my website. Look at downloadable power distribution diagrams from the back of our book. All of those concerns are easily addressed with simple, inexpensive and pilot-friendly hardware and design philosophies . . . breakers, magnetos, carbs, ADFs, VORs, and iron gyros of the 1950s are replacable with more reliable, lower cost equipment that place an RV light-years ahead of a brand new C172 for 1/3 the dollars. > >Fuses seem limited for aviation use. Granted _I've_ never had to pop >or reset a C/B in my civilian flying yet (knock, knock, knock) but...? What is generally the first clue that a breaker has opened in flight? Somthing has quit working or you threw a switch and the expected thing didn't happen. Now, suppose you look at the breaker panel and a breaker is out . . . what do you know? Something is sufficiently wrong with the system to warrant disconnection to avoid fire in the airplane. Now, suppose something isn't working and NO breakers are popped. What do you know? The thing that didn't work is STILL not working. Given that failures which do NOT pop fuses generally outnumber the ones that do pop fuses by 10:1 and given that resetting an OVERLOADED circuit in flight may be foolhardy, what then is the value of having a breaker on the panel? Probability that replacing a fuse or resetting a breaker will get your equipment back on line SHOULD be slim to zero . . . granted, there are numerous cases where breakers in certified iron will NUSIANCE trip . . . a condition tolerated only in the holy-water sprinkled airplanes 'cause it's so damned difficult to correct a certfied mistake. Not so with your home built. If you experience nusiance tripping, replace the protection and feedline with the next larger size . . . there is no reason for an amateur built owner to expect anything but the best performance from his/her airplane and modifications toward achieving that goal are only a toolbox away. Our brothers flying the certified iron are not so fortunate. Did you know that the majority of single engine airplanes have at least one breaker DESIGNED to nusiance trip? Besides, what single piece of equipment is going into your airplane that is essential to your comfortable completion of flight? If you have such equipment, why are you worried about breakers/fuses? There are LOTS of ways electro-goodies crap that don't involve breakers/fuses. Therefore I'll suggest that worrying about how you protect critical circuits isn't very productive. Planning for BACKUP to critical devices is much more useful. Does your flight bag have a handheld GPS and COM radio? Do you have a single-lamp panel-flood feedable from the hot side of the battery contactor? Do you have ACTIVE notification of altenrator failure? Are you going to maintain your battery to the extent that it will support minimum essential equipment for duration of fuel on board? If you have dual electronic ignition, are you planning for dual batteries? I'll suggeset that issues of FLIGHT SYSTEM RELIABILITY have little to do with what kind of hardware you use rather how you wire it up and having PLAN B operating procedures that turn ANY failure into a ho-hum event. Recall the L-1011 that went into the Florida swamp a few years back? The whole cockpit crew was busy trying to figure out why a gear down indicator light wasn't illuminated. Intent upon mechanic's duties in flight, they ignored a/p disconnect tones and other warnings while a perfectly good airplane full of people went into the mud. Never happen to me? I wouldn't bet on it . . . unless I observe the simple rule that one wears a pilot's hat in the air and save the mechanic's hat for on the ground. Design your system to be FAILURE TOLERANT, not in-flight maintainable. Modern hardware and design philosophies unencumbered by institutional dogma and government "assistance" allows us to built the best airplanes ever. Date: Mon, 26 Apr 1999 13:23:48 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Shielded Wire > ><< How do I go about grounding the braid on "shielded wire"? >> > > Try this old trick a Boeing tech showed me about 35 years ago while I was hammering on a B-52 . . . Strip away the outer jacket to expose the braid underneath. Bunch the braid up slightly and use an awl to open a pathway in the side of the braid close to the end of the outer jacket. Bend the wire/braid over 180 degrees and pull the center conductor out of the open hole. Tug the braid out straight to close the hole. Now you have two leads which may be terminated as needed. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurassic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Mon, 26 Apr 1999 13:07:59 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Battery contactor temperature >During a tech counselor inspection, we discovered that my battery contactor >felt pretty warm when its master switch was on (engine not running - don't >have one yet). I later measured it at 135 F, regardless of load on the >battery. After moving the battery to the other contactor, it also measured >135 F after being on for about 10 minutes. (I have dual batteries, >contactors, and master switches.) These contactors are Stancor 70-914, with >nominal coil resistance of 16 ohms at 12 volts, rated at 80 amps continuous. >Voltage measurements across the contactor coil, master switch, and wiring >indicate there's about 0.8 amps flowing, which is about what I think it >should be. > >So my questions are: 1) Has anybody else measured contactor temperature? >and, 2) Should I be worried about this? A battery contactor is a continuous duty rated device and as you have observed, dwill draw about .8 amps at 14 v which translates to something on the order of 10 watts. It is NORMAL for all devices of this class to run warm. Starter contactors will draw about 4 amps or 50 WATTS which would make them toast in a vew minutes. This is why they are INTERMITTANT rated devices. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurassic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Mon, 26 Apr 1999 14:01:25 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Transponder antenna gnd plane At 01:07 AM 4/23/99 EDT, you wrote: >I recall a discussion on the size of the x-ponder ground plane. Believe >was around 5.20 inches dia. (some number times the antenna length). >Does anyone recall this number? 2 times the seated height of the antenna which is 2.6" > Location away from the pilot/co-pilot is also >recommended but over ten feet requires a different cable. Yes?? I was >thinking about locating it aft of the pilot in the baggage area. Is that >distance safe? A totally bogus recommendation. A few years back, someone observed that their transponder was rated for 200 watts output . . . 1/3rd that of the family microwave. Our hero was immediately concerned for preservation of the family jewels and proceeded to line the bottom of his composite seat pan with aluminum foil. What he failed to understand was that his RF coffee warmer and popcorn popper was rated in continuous watts while the transponder was in peak watts. The average power output from a transponder is less than 1 watt . . . BTW, the eyes are about 100 times more sensitive to the effects of microwave heating than are any deep organs . . . you'll go blind you quit making babies. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurassic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Wed, 28 Apr 1999 15:25:45 From: "Robert L. Nuckolls, III" Subject: COZY: Re: source of large in-line fuses >I was looking for large in-line fuses and discovered a surprising source: >mobile audio suppliers. Seems that the proliferation of multi-hundred watt >amplifiers popular with cars that go boom-booming around town has created a >market for large in-line fuses. Fuses in the range of 10A-100A and holders >that accommodate 8awg and 4awg wire are common for this type of >installation. > >So if you want to use an in-line fuse instead of a fusable link somewhere, >this may be a useful place to look. I have been watching some of these products and even ordered a few items to looke them over. To date, I have no positive recommendations for products I've seen. The lower current fuses are large, tubular glass cartridges that require holders with large area, low pressure contacts. I'm skeptical of the "gold" finish on many of these parts as to it's value in maintaining low contact resistance. Wire attachement on many of the high-power mobil audio accesories is by driving a screw laterally into a bundle of stranded wire . . . okay for solid house wire but not Mil-W-22759 bizillioin strand aircraft wire. You can buy an automotive encarnation of the ANL series current limiters which mount on threaded studs and attach wires using conventionally applied ring terminals. I'l consider these for use in airplanes. If anyone has some experience or engineering data in support of specific products, I'd be pleased to hear about it. For the moment, the majority of what I've seen in catalogs and hanging on the racks in stores wasn't very exciting. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurassic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Thu, 29 Apr 1999 22:34:54 From: "Robert L. Nuckolls, III" Subject: COZY: Re:Shielded Wire (Explaination Needed) I've prepared a picture tutorial on preparation of shielded wire for termination to other electro-goodies in your airplane. Interested individuals are invited to click on . . . http://www.aeroelectric.com/articles/shdlwire Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurasic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Thu, 29 Apr 1999 23:02:37 From: "Robert L. Nuckolls, III" Subject: COZY: Shielded Wire? >Bob, >So what about the capacitor. Will it help reduce any noise in the >intercom, radio, etc, system if we install one. A friend of mine >recommended that I install a capacitor in the system along with the >shielded wire from the alternator. A builder called me about ten years ago and spent several minutes outlining all the shielding, filtering, prepositioning of harware in the airplane all in the name of eliminating electrical noise. All in all, several dozens of hours, pounds of hardwrae and no small sum of cash. I was a bit astonished and asked what kind of noise proplem he was having. "Oh," sez he, "I don't have a noise problem, the airplane is not yet ready to fly." My advice is generally this: Put shielded wire on magneto p-leads, spark plug wires -and- on any appliances where the manufacturer recommneds it and describes how it is to be hooked up. Then, if a noise problem presents itself, you need to identify the source, propogation mode and victim and plan the best way to handle that particular problem by filtering at source, breaking the propogation mode or filtering at the victim. Given that there are dozens of possible combinations, you can easily spend the time and dollars represented by our hero's precautions and still not assure yourself of a noise free airplane. Begin with good basic installation practice and whip each problem as it presents itself . . . it's generally not hard to do . . . Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurasic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Thu, 29 Apr 1999 22:48:55 From: "Robert L. Nuckolls, III" Subject: COZY: Re: OOPS, incomplete URL (was Shielded Wire Explaination Sorry, Left out the last slash which is important . . . http://www.aeroelectric.com/articles/shldwire/ Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurasic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com From: SWrightFLY@aol.com Date: Fri, 30 Apr 1999 08:10:20 EDT Subject: Re: COZY: Re:Shielded Wire (Explaination Needed) I'm sure I speek for many others by saying we truly appreciate the ongoing education you deliver to us by your weekly bits of knowledge and explaniton of how all this elusive electical stuff works and how to safely install electrical systems. I am in the process of upgrading the electrical installation procedures of my Nose Lift as a result of your teachings. Steve Wright Wright Aircraft Works LLC Stagger EZ N9700 Date: Mon, 03 May 1999 00:09:24 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Recombinant Gas (RG) Sealed Batteries >A) Is there an industry standard as to terminal > configuration, i.e. 5/16 or 3/8 threaded stud?? > >B) If I were to buy the battery early for wiring and > installation reasons, would I risk deterioration > while it sat on the shelf for X months?? > >For CG reasons, battery installation is normally last, >yet I would like to have the wiring in place, which >means correctly sized terminations. Any reasonable >answers accepted. If a "standard" exists, it's only because all of the 24-32 a.h. flooded batteries for airplanes have used 5/16" terminals. In the modern RG batteries, you'll find terminals of 1/4" to 5/16" . . . Buy your flying battery the week you intend to fly. Use an el-cheepo boat or tractor battery to check things out in the shop. Some builders are taking advantage of a plug-in-the-wall power supply we offer that will run a full-up airplane electrical system on the ground. See . . . http://www.aeroelectric.com/Catalog/catalog.html Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurasic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com From: "Ugolini, Nick J" Subject: RE: COZY: Re:Low-cost landing lights/flasher Date: Mon, 3 May 1999 14:42:16 -0400 When I wired my LongEZ, I set it up as follow A toggle switch selects the landing lights to either flash (day) or steady state (night) One relay ($4 steady on type) is for steady on night time operations One relay ($6 flashing type used for turn signals) is used for pulsing day time operations One micro switch is used to turn the system on when the landing light moves out of the housing ground -----light micro switch---- Toggle Sw--|Flash Relay ----pwr for relay coil -|Steady relay ---- pwr for relay coil ground-------light------ |Flash Relay ----pwr for contacts |Steady relay ---- pwr for contacts this setup allows the pilot to select day/night landing operations, and keeps the high currents away from switch (the toggle switch only grounds one of the relays) and routes the high current through the relays. It reduces the amount of #16 wire and it automatically switches on the landing light when extended.... best of all it only cost me about $10 or 15 bucks.... Nick -----Original Message----- From: SWrightFLY@aol.com [mailto:SWrightFLY@aol.com] Sent: Monday, May 03, 1999 1:43 PM To: cozy_builders@canard.com; CANARD-AVIATORS@canard.com Subject: COZY: Re:Low-cost landing lights/flasher I just got a recent copy of the JC Whitney catalog and on page 104 and 105 I see the blue glow halogen lights which are very compact. On the opposite page were two types of flasher systems. One was $54.00 handles up to 20 amps and has solid state circuity. Would this combination work? What is the quality of these items? I recall seeing a similar flasher system at OSH and this system turned the lights on and off slowly which "extended" the life of the bulbs and it cost several hundred $. Will the JC Whitney system do this? I plan to resess the wing root (standard Long-EZ wing) about 12" and install them. Thanks in advance Steve Wright From: "Wilhelmson, Jack" Subject: RE: COZY: Re:Low-cost landing lights/flasher Date: Mon, 3 May 1999 15:15:55 -0400 Steve: I have not seen these products, so I can not comment on them. Are you talking about flashing the main landing lights as the only beacon or just as a added safety feature? The problem with the canard aircraft and the rotating/flashing beacon is that the FARs require a angle of viewability from above/below front/rear that is hard to satisfy with only one beacon/flashing or strobe light. That is why most canards use one on each wing tip mounted in conjunction with the red/green running lights. The landing lights in the wing root have some disadvantages: 1. It takes two instead of one to get forward coverage. 2. They are not adjustable for taxi, takeoff and landing as is the plans light. 3. The landing light door can be used as a way to get more air flow(adjustable in the cockpit.) 4. The wiring is simpler and less and the electrical load is also less. My landing light is a halogen off road polycarb. housing type.(very light). Other wise it is per plans. It is one of the things that I would not change if I ever build another COZY. Jack Wilhelmson N711CZ > -----Original Message----- > From: SWrightFLY@aol.com [SMTP:SWrightFLY@aol.com] > Sent: Monday, May 03, 1999 1:43 PM > To: cozy_builders@canard.com; CANARD-AVIATORS@canard.com > Subject: COZY: Re:Low-cost landing lights/flasher > > I just got a recent copy of the JC Whitney > catalog and on page 104 and 105 I see the blue glow halogen lights which > are > very compact. On the opposite page were two types of flasher systems. One > was > $54.00 handles up to 20 amps and has solid state circuity. Would this > combination work? What is the quality of these > items? I recall seeing a similar flasher system at OSH and this system > turned the > lights on and off slowly which "extended" the life of the bulbs and it > cost > several hundred $. Will the JC > Whitney system do this? I plan to resess the wing root (standard Long-EZ > wing) about 12" and install them. > > Thanks in advance > Steve Wright From: "astrong" Subject: Re: COZY: Re:Low-cost landing lights/flasher Date: Mon, 3 May 1999 13:27:44 -0700 Hi!, Steve. Check out the innovations link, "Landing and Taxi lights" in my homepage www.canard.com/trim for my installation. I have just completed mounting the nose lift and will keep you updated. Regards Alex -----Original Message----- From: SWrightFLY@aol.com To: cozy_builders@canard.com ; CANARD-AVIATORS@canard.com Date: Monday, May 03, 1999 10:57 AM Subject: COZY: Re:Low-cost landing lights/flasher >I just got a recent copy of the JC Whitney >catalog and on page 104 and 105 I see the blue glow halogen lights which are >very compact. On the opposite page were two types of flasher systems. One was >$54.00 handles up to 20 amps and has solid state circuity. Would this >combination work? What is the quality of these >items? I recall seeing a similar flasher system at OSH and this system >turned the >lights on and off slowly which "extended" the life of the bulbs and it cost >several hundred $. Will the JC >Whitney system do this? I plan to resess the wing root (standard Long-EZ >wing) about 12" and install them. > >Thanks in advance >Steve Wright > Date: Wed, 02 Dec 1998 08:07:39 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Shielding the "P" leads At 08:41 PM 5/3/99 -0500, you wrote: >A question about shielding. > >The manual says the P-leads should be shielded at the switch end only. I >have noticed production aircraft that have the shield grounded at the mag >(to the case itself). I know not to ground at both ends or else one may >produce a ground loop, but is there a reason to use one method over another? . . . I recommend that the ignition switch shields be used to produce a ground for the ignition switch and that the shield be grounded to airframe at the magneto or ignition box. Two reasons for this: (1) it insures that no ground loop currents flow in the shield conductor which degrades its performance as a nose attenuator. (2) should your crankcase jumper become disconnected and/or you forget to hook it back up after maintenance -AND- you try to crank the engine, the starter will seek a ground through ANY wires that might close the path between battery(-) and crankcase. If this happens to be your p-lead (or any other shields/grounds) then you get instant smoke and foul smells from under the instrument panel. Had two mechanics generate a lot of work for themselves while I owned the airport at Benton, KS about 10 years ago . . . not a pleasant sight. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurasic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Wed, 02 Dec 1998 08:16:40 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Wire Splice Trick >Anyone that has ever taken a "butt splice" apart that >has been exposed to the weather will remember the GREEN WIRE. RIGHT? > >Any way for the trick, dig out your old Hot Glue Gun, a >Glass of Water, and Squirt a 1/6" +or- string into the water. > >The next time you want to make a water tight "butt splice", >do the but splice as normal but put a 2" long piece of Heat >Shrink Tube on the wire first. Then cut a 2" long piece of the >glue (Dry not with water) slide the tube over the but >splice , insert the glue string, and heat. > >Not only do you have a water tight "butt splice" but >you also have a splice that is less likely to pull apart. > > >Heat Shrink can be had at any Radio Shack. This is a pretty fair appoximation of a series of double-wall heat-shrinks offered by most manufacturers of such products. We stock 1/2" double walled product with a melting sealant for the inner wall. Complete encapsulation of the joint from a "string" of hot glue might be a bit shakey if the heatshrink is a thinner variety that puts to little force on the shrink or tends to split if you have to heat it too strongly or for too long. This technique will work best with the heavier/ stiffer heatshrinks . . . I'll look into getting a variety of double-wall heatshrinks and offer them from our website catalog. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurasic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Mon, 03 May 1999 23:29:56 -0400 From: "Andreas P. Christou" Subject: COZY: Re: [c-a] Re:Low-cost landing lights/flasher At 09:38 PM 5/3/99 -0400, SWrightFLY@aol.com wrote: >[The Canard Aviators's Mailing list] > >I just got a recent copy of the JC Whitney catalog and on page 104 and >105 I see the blue glow halogen lights which are very compact. On the >opposite page were two types of flasher systems. > >One was $54.00 handles up to 20 amps and has solid state circuitry. >Would this combination work? > >What is the quality of these items? I recall seeing a similar flasher >system at OSH and this system turned the lights on and off slowly which >"extended" the life of the bulbs and it cost several hundred $. Will the >JC Whitney system do this? I plan to recess the wing root (standard >Long-EZ wing) about 12" and install them. > Steve, I used low voltage (12V) 75W sealed units normally driven through a transformer and found in Kitchen ceilings for my landing light. The units resemble the type of bulb found in overhead projectors. They are available with a variety of light beam angular divergence, from pencil beam at 2.5 degrees to over 30 degrees wide angle. I made a pop up type unit that resembles a car head lamp which has a wide angle and a pencil beam unit. The complete assembly is inside the battery hatch cover and is controlled by a beldon cable from the cockpit. One caution, these units run hot! (the light bulb holder is ceramic) and for that reason, I made the unit from aluminium. I would recommend that you use special care to insulate the halogen bulbs from the foam and fiberglass in the wing. The bulbs have survived over 200 flight hours and about 160 landings so far without breaking the filaments. Good luck! Andreas P. Christou VariEze N13VB , |______< >______| __\"/__ v From: Burton.Donald@orbital.com Date: Tue, 4 May 1999 07:13:47 -0400 Subject: COZY: Re: [c-a] Re:Low-cost landing lights/flasher I recall a Bob Nuckolls article which had a diode which does what you describe. My memory says that with this component in the circuit there is always some power to the bulb (kind of warming the elements) and when you turn it on they will have less tendency to shock the filament. I think these are about as costly as a resistor at radio shack. It draws very little current. It is detailed very nicely in the Aero Electric Connection (Bobs publication on aircraft wiring). Since I haven't got to the wiring yet, but plan to include this cheap circuit. His web site is http://www.aeroelectric.com/ Perhaps some one who is not electrically challenged (like myself) could explain it better without me having to go home to get the book. db SWrightFLY@aol.com on 05/03/99 09:38:27 PM To: cozy_builders@canard.com, CANARD-AVIATORS@canard.com cc: (bcc: Donald Burton/ORBVA) Subject: [c-a] Re:Low-cost landing lights/flasher [The Canard Aviators's Mailing list] I just got a recent copy of the JC Whitney catalog and on page 104 and 105 I see the blue glow halogen lights which are very compact. On the opposite page were two types of flasher systems. One was $54.00 handles up to 20 amps and has solid state circuitry. Would this combination work? What is the quality of these items? I recall seeing a similar flasher system at OSH and this system turned the lights on and off slowly which "extended" the life of the bulbs and it cost several hundred $. Will the JC Whitney system do this? I plan to recess the wing root (standard Long-EZ wing) about 12" and install them. Thanks in advance Steve Wright \ ->>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>-|- / -For details on sponsors of this list, copyrights, and how to remove -yourself from this list, please visit: http://www.canard.com/ca-ending.html (c) 1997,1998, 1999 Canard Aviators. support@canard.com / -|-<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< \ Date: Wed, 05 May 1999 22:27:29 -0400 From: John B Vermeylen Subject: COZY: Re: [c-a] Noise from strobes Hi John, I was reviewing the archives and would like to ask you more about intercom interference with the strobe power pack. My strobe power comes from the breaker panel mounted on the instrument panel. I'm not sure if you would get noise in your intercom if the intercom is also powered from the breaker panel mounted on the instrument panel. I seem to be more concerned with the high energy wires going out to the strobes themselves. The strobe wiring instructions doesn't call for shielded wires running through the wings from the power pack to the strobes. But I would think a high energy line like that would radiate out an interacting magnetic field possibly affecting the com antenna. What do you think? John Vermeylen N69CZ From: cdenk@ix.netcom.com Date: Wed, 5 May 1999 22:03:04 -0500 (CDT) Subject: Re: COZY: Re: [c-a] Noise from strobes The Whelan strobes I have came with shielded wire for the strobes, what brand do you have. I have an ice cube (1" cube) automotive relay at the power supply which is within 6" of my battery, all on top the spar. There is a fuse to the relay power, and a short wire to the power supply. There is a healthy capacitor grounded to the power supply case which is thru bolted to the stainless firewall which is also well grounded to the engine. The position and dress (position) of its wires is critical and strictly trial and error. Stumbled on the winner, can't describe how. The relay control (coil power) comes from a switch on the instrument panel which is protected by a circuit breaker along with other small electrical loads. Without the capacitor there was noise in the Bose headsets. Date: Thu, 06 May 1999 08:35:36 From: "Robert L. Nuckolls, III" Subject: COZY: Re:Low-cost landing lights/flasher At 07:13 AM 5/4/99 -0400, you wrote: >I recall a Bob Nuckolls article which had a diode which does what you describe. >My memory says that with this component in the circuit there is always some >power to the bulb (kind of warming the elements) and when you turn it on they >will have less tendency to shock the filament. There are two ways to mitigate the inrush current to a lamp filament at turn on. One is to keep some amount of current flowing in the lamp filament equal to about 1-2% of it's full operating power at all times. This keeps the filament above the bittle/ductile transition temperaure (more resistant to vibration) and elevates the resistance of the filament so that application of full power has a lower inrush value. The "keep warm" power can be from a small DC-DC converter that puts out about 3 volts which can be diode distributed to all of the aircraft's lighting circuits. The other technique involves the use of resistors in parallel with the control switch of each lighting circuit such that a small but significant amount of current flows to the lamps even when the switch is open or OFF. The other technique involves incorporation of an inrush limiter in series with the lamp. These are educated resistors that have a significant resistance value when cold (.2 to .5 ohms) and drop to an in-significant value (.005 to .01 ohms) when warm. When operated in series with the lamp, their cold resistance keeps the inrush to a lower, more desired value but a few seconds after application of power to the lamp, their resistance drops due to the warming effect of lamp current flowing in the device. NEITHER of these techniques is particularly significant in terms of lamp life for wig-wagged landing lights. This is because the lamp filament doesn't have time to cool off between flashes so after the inrush current for second and subsequent flashes is MUCH lower than the first. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurasic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Thu, 06 May 1999 08:23:03 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Wire Splice Trick >The latest issue of Sport Aviation has an article >on wire termination. He recommends crimp and solder. >The crimp for mechanical, and solder for the electrical. For the life of me, I cannot understand why folks recommend this practice. The companies that make solderless devices and take the time to get them Mil-Spec'ed and/or certified would be equally confused. There have been hundreds of thousands of airplanes and bizillions of cars built with nary a solder joint in the electrical system and they hang together just fine. IF one is using poor tools then solder might be useful, but if you're going to solder, why not forget the crimp tools and solder everything? Save some $. >I thought solder caused a point of possible fatigue, >and was not the best way to go. Both crimp AND solder have ways of putting stress risers into a group of wire strands making them more likely to fail right at the connection than anywhere else along the wire. This is why crimp terminals have TWO places to grab the wire . . . the ELECTRICAL joint where the stranding is mashed into a homogenous mass and the INSULATION GRIP where the wire is supported to keep vibration stresses off the electrical joint. Soldered joints need heat shrink over the joint for impoved support of the final assembly. In terms of overall reliablity, there is NO difference between a properly soldered joint and a crimped joint. The crimped joints are prefered in a factory environment 'cause crimp tools don't burn holes in the carpet and they require less craftsmanship to operate than a soldering iron. The folk who tout one over the other or recommend BOTH as some sort of reliability enhancement simply don't understand the physics of the matter. >Good quality terminals are a must. I use only "AMP" >brand on the airframe. There are probably others out >there that are good quality also, but I listened to >my radio shop, and I haven't had any problems yet >with my wiring, just the certified equipment connected. Another myth propogated by folk who simply don't take the time to understand the products they use or recommend. AMP makes a full range of terminals from open barrel, uninsulated el-cheapos up through Plasti-Grip (automotive/ hardware store stuff) and topped off with the pre-insulated diamond grip (PIDG) terminals which have been standards of comparison for decades. Dozens of other terminal manufacturers make similarly scaled products in order to satisfy the needs of a very large market. You can buy terminals UN-SUITED for use in airplanes from AMP or anybody else. Bad or poorly supported advice is no substitute for an understanding of how things work and why we choose to use them. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurasic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Thu, 06 May 1999 17:56:43 -0500 From: Michael Link Subject: Re: COZY: Strobe noise Nat Puffer wrote: > Builders, > My Whelen power pack is located in the centersection spar as shown in the > plans, with no special electrical provisions like shielding or capacitors > and I have no noise. I like the simplest installation that does the job. > Nat I also have the same installation that Nat describes--with no noise. Michael Link Date: Thu, 06 May 1999 20:42:05 -0500 From: David Domeier Subject: Re: COZY: Re: [c-a] Noise from strobes John, I ran the strobe wires from the center section mounted power unit out to the wing tip in the same hole as contains the Com antenna leads. The power switch is on the instrument panel with the CB....no noise that I can hear. dd MKIV N10CZ (3.5 hours on a newly OH'd engine and running mightly smooth...CHT and Oil Temp are higher than with the old engine but seem to be coming down as the engine breaks in. Yesterday the oil temp hit 220°, OAT was 81°. Today it topped out at 190° although OAT was 61°. Note on using speed brake - yesterday I had to fly a high approach to accomodate ATC and other traffic and extended the board on downwind for a diving turn to the runway. At about 100' turbulence necessitated an increase in speed which required adding some power. It wasn't much and didn't last more than 30 seconds but it sure caused the CHT and Oil Temp to go up quick, 420°/232° respectively on taxiway....I'd forgotten the board was out. I think I will stop using it unless the runway is made for sure with no power. On a go around with the board out, the engine would probably be fried in about 2 minutes) Date: Fri, 07 May 1999 09:09:58 -0500 From: Ken Reiter Subject: Re: COZY: Strobe noise I also have the setup like Nat's, but with a relay mounted next to the strobe power pack on in spar and then just the control line for the relay up to the panel. - No strobe noise! Ken From ???@??? Fri May 07 20:52:11 1999 Return-Path: owner-cozy_builders@betaweb.com Received: from twc2.betaweb.com (majordomo@betaweb.com [206.43.209.18]) by acestes-fe0.ultra.net (8.8.8/ult/n20340/mtc.v2) with ESMTP id RAA13211 for ; Fri, 7 May 1999 17:54:41 -0400 (EDT) Received: (from majordomo@localhost) by twc2.betaweb.com (8.8.5/8.8.5) id QAA02961 for cozy_builders-list; Fri, 7 May 1999 16:30:13 -04From ???@??? Fri May 07 20:52:11 1999 Return-Path: owner-cozy_builders@betaweb.com Received: from twc2.betaweb.com (majordomo@betaweb.com [206.43.209.18]) by acestes-fe0.ultra.net (8.8.8/ult/n20340/mtc.v2) with ESMTP id RAA13211 for ; Fri, 7 May 1999 17:54:41 -0400 (EDT) Received: (from majordomo@localhost) by twc2.betaweb.com (8.8.5/8.8.5) id QAA02961 for cozy_builders-list; Fri, 7 May 1999 16:30:13 -0400 X-Authentication-Warning: twc2.betaweb.com: majordomo set sender to owner-cozy_builders@betaweb.com using -f Received: from dfw-ix7.ix.netcom.com (dfw-ix7.ix.netcom.com [206.214.98.7]) by twc2.betaweb.com (8.8.5/8.8.5) with ESMTP id QAA02953 for ; Fri, 7 May 1999 16:30:09 -0400 From: cdenk@ix.netcom.com Received: (from smap@localhost) by dfw-ix7.ix.netcom.com (8.8.4/8.8.4) id QAA01478; Fri, 7 May 1999 16:20:32 -0500 (CDT) Date: Fri, 7 May 1999 16:20:32 -0500 (CDT) Received: from ely-oh4-30.ix.netcom.com(206.216.59.158) by dfw-ix7.ix.netcom.com via smap (V1.3) id rma001415; Fri May 7 16:20:24 1999 To: ken@quickturn.com To: mglink@bellsouth.net To: cozy@extremezone.com Cc: cozy_builders@canard.com Message-Id: <199957171942641@ix.netcom.com> Subject: Re: COZY: Strobe noise X-Mailer: Netcomplete v4.0, from NETCOM On-Line Communications, Inc. MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: owner-cozy_builders@betaweb.com Precedence: bulk Reply-To: cdenk@ix.netcom.com X-UIDL: 0db9d05d81a0903dcc4b2ecaabc187e3 wAS SAID > Not every installation is the same, wires not same material, routed the same, and of course different brands, models, ond optional equipment. For all I know its the Bose headsets, intercom, or rhe man in the moon. There was noise and the capacitor solved it. Date: Tue, 11 May 1999 10:40:51 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Wire Splice Trick At 01:44 PM 5/10/99 -0500, you wrote: > >Paul - > >Both NASA and the Military use soldered connectors. > >J.H. > True . . . and the argument isn't whether solder is better or worse than crimped. The thing that's missing from the article is an acknowledgment of the need for insulation support behind EITHER soldered OR crimped joints. The article also fails to direct the reader to low cost tools that do adequate tasks on terminating wires. The article also speaks of terminal strips . . . devices I've never needed in the design of an electrical system. The value of the article needs to be deduced in the answer to the following question: "Suppose someone who knows nothing about wiring reads this article . . . what information does it contain that will help anyone do a good job?" Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurassic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Tue, 11 May 1999 13:59:02 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Chap. 22 - Battery info >>I have a Concorde 25 Amp-Hour battery - does anyone know if it's OK to >>use a standard car battery charger to recharge this thing, or do I need >>something fancy and expensive that is only used for airplane batteries? > > >Not familiar with Concord specifically, but here's a rule of thumb: > >if it's a gell cell, 13.8 volts to charge; typical slow (trickle level) >from 'some' car chargers will work (or at least be close). If it's a >standard lead-acid style, charge at 14 to 14.2 volts, which is standard car >stuff (and therefore OK). Gell cells don't exist any more . . . at least not in places you'd normally be shopping for an airplane battery. Virtually all of the batteries you see in the catalogs for portable and/or backup power are SLA (sealed lead acid) batteries that feature fully liquid electrolyte captured in fiberglas mats by capillary action. >Slow charge is always better than trying to 'zap' it with heavy charge >current. If the thing is as dead as it sounds, the initial current may be >relatively high due to it's condition, but should taper to trickle level as >it comes up to charge. In real life, dead batteries get recharged at whatever rate the alternator in the vehicle will stuff the electrons back into the chemistry . . . 40-60 amps is not uncommon. SLA batteries tolerate these recharge rates quite well. The trick is to know when the battery is "full" . . . the charge voltage can be 13.8 to 14.6 volts depending on how fast you want to stuff the energy back in. When the recharge rate drops below an amp or so, it's time to quite charging it. Our next generation voltage regulators will schedule bus voltage based on measured recharge rate. We'll stuff at 14.4 or so and then drop the bus to 13.5 when the battery is full. 13.5 keeps the airplane's electro-goodies happy but absolutely stops charging the battery. I think this change in battery utilization will put a nice quantum jump upward in the life of an airplane's battery while keeping charging rates high enough to top of a battery in a 30-minute flight. >Hope it helps. > >Larry > Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurassic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Tue, 11 May 1999 08:39:49 From: "Robert L. Nuckolls, III" Subject: COZY: All electric panels; a list-server thread There was a list-server thread I participated in with a group of Grumman drivers a few weeks ago. I was going to delete the thread but after reviewing it, I decided to post it on our website. Interested parties may click on: http://www.aeroelectric.com/articles/allelect.html Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurassic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Tue, 11 May 1999 13:18:39 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Battery At 06:34 PM 3/17/99 -0600, Nat Puffer wrote: >Builders., >I have one of Bill Bainbridges "new technology" batteries, and can't speak >highly enough about it. It is not lead-acid, and not gel-cel (Bill hasn't >explained what it is). All I can say is that I have had it for 7 years now. >It has been completely flat at least 4 times, and still takes a full >charge. It is completely sealed, and very compact. It turns my 0-360 with >perfect compression over like crazy. My airplane wasn't used for over 6 >months, and it still had the power to turn my engine over and start it, not >once, but twice. I would never consider a Concord again, or an auto >battery, or any other lead-acid battery. It costs a little more, but worth >about 4 or 5 lead acid batteries. >Regards, >Nat This would be one of the recominant gas (RG) sealed lead acid batteries in Bill's inventory. This is the same technology as the Concord RG batteries. From the groans and moans I'm hearing from the field, Concord is still having some "bad battery days" but I will say this. If you have problems with a Concord product, email Skip Koss (their sales guru) directly at: mailto:"Skip Koss" . . . everyone I've talked to who has contacted Skip with a problem says he's quickly and fairly addressed their concerns. In the mean time, keep thinking RG, RG, RG when it comes to airplane batteries . . . they ARE the wave of the future. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurassic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Fri, 28 May 1999 13:13:15 From: "Robert L. Nuckolls, III" Subject: COZY: Recent Terminal Article in Sport Aviation I've been getting a lot of inquiries about an article that appeared recently in Sport Aviation. The letter below is exemplary of the questions I'm getting, so I thought I would share it with everyone . . . ----------------------------- >Last night I read an article in the latest "Sport Aviation" (the one with >that beautiful red Staggerwing on the cover) and saw that you "took some >heat" from another guy in the electrical business about your use of "spade" >lugs for aircraft electrical connections. > >I would be interested in your response to that article. I reviewed that article two years ago for Jack Cox and recommended that it not be published. The article was preachy, gave lots of "donts" without describing the alterative "dos" and offered advice that contradicted decades of industry standard practices. It completely ignored the physics involved in making vibration resistant wire connections suited for airplanes. Please be confident that terminals we sell and tools we supply for installing them are in step with aircraft industry practice and that much of what Mr. Burgher recommends is certain to produce inferior results. I will be publising a line-by-line critical review of the article soon. I will have my work reviewed by at least two other aircraft electrical engineers and include their comments should they care to contribute to the work. >BTW, I have purchased from you a complete set of spade connectors, and your >40-point "grounding lug" assembly which connects through the firewall. I >havent' gotten to that point of my restoration yet, so those parts are all >still "in the bag." > >On one hand, the continuous ring style lug seems less likely to come off >than a spade connector. On the other hand, my 1940-vintage "Ford" voltage >regulator has spade connectors which have NEVER come off in 10+ years of >flying . . . Ring terminals don't COME OFF, they GET LOOSE. A partial revolution of the threaded fastener kills the joint. Ring terminals are FINE devices, it's our techniques for attaching to them that sucks. I'll suggest that your observations are in line with recommendations I've published for years. Folks interested in further background topics touched on by Mr. Burgher are invited to check out articles at: http://www.aeroelectric.com/articles.html Look down the page for works on "big terminals" and "fast-on spade terminals". When the review is completed, I'll publish in on our website and let everyone know of its availability. I'm also going to regenerate and post an aritcle I did several years ago for another magazine on crimped terminals . . . much of the data for that article came right out of the AMP, Inc. engineering applications manual. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurassic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Fri, 28 May 1999 13:31:02 From: "Robert L. Nuckolls, III" Subject: COZY: Re: BATTERY >The first round of ventless batteries were known as gel cells. These have >mostly been replaced by RG batteries now with some still being available. > Both RG and Gel batteries are vented in that there is a cap designed to release at 1 to 2 psi of overpressure inside the cell. This is necessary to prevent bursting in the event of an severe overcharge. Paul is correct in that for normal operation, these batteries are closed off to the exchange of gasses and moisture with the atmosphere and are often referred to as "sealed". But you'll also see the acronymn "SVLA" used in conjuntion with modern batteries . . . this translates to "sealed, vented lead-acid" . . . If anyone is interested the very latest and greatest of battery developments is invited to check out: http://www.boldertmf.com If you have dual alternators (full electric panel and one alternator running vacuum pump pad) and two of these three-pound batteries to crank engine and stabilize alternator, it's now possible to have an electrical system (starter, batteries, AND alternators) whos total weight is LESS than the 24 a.h. battery that most people fly in their airplanes with an order of magnitude higher flight system reliability. I love this business!!!! Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurassic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Fri, 28 May 1999 22:04:27 -0400 From: "Marc J. Zeitlin" Subject: COZY: Chap. 22 - Battery Info Robert L. Nuckolls, III tried to post this, but because of the word "subscr*be" in the second line, majordomo thought it was an administrative request and bounced it (sometimes computers are complete idiots :-) ): >An oft repeated question on the various list servers to >which I subscr*be ask about the nature of RG batteries. >I've compiled a list of URL's that folk will find most >informative with respect to modern batteries. Click on >any or all of the following: > > http://www.hepi.com/drvolt.html > > http://www.boldertmf.com > > http://aeroelectric.com/rg_bat.html > >An especially descriptive document on batteries can be found >at: > > http://www.lifelinebatteries.com/marine/comps.htm > >(this one has yet another name for our RG friends, >"AGM" for absorbed glass mat . . .) > >Also, peek at: > > http://www.globalair.com/wilco/concord.htm > > http://www.aeroelectric.com/bat_thd.pdf > >and finally, this article by Steve Williams . . . > > http://www.sbw.org/sbw/home.nsf/index/SuctionBad > >While searching the web for these links, I note that more >often than not, the RG battery's connection to the outside >world is referred to as "valve regulated" and not >"vented" . . . > >I think it's reasonable to expect that the question will >arise again . . . keep this post handy for next inquiring >mind who wants to know . . . I'll duplicate this links >list on our website . . . > >Hope everybody has a nice weekend! -- Marc J. Zeitlin mailto:marcz@ultranet.com http://www.ultranet.com/~marcz/ Date: Mon, 31 May 1999 12:18:25 From: "Robert L. Nuckolls, III" Subject: COZY: Re: battery shelf life >I was in a rush the other day, so I didn't follow up properly. Would it >diminish an RG battery's service life to have it sit around for 6-9 months >before putting it in active use? How about hitting it with a brief >discharge/charge every couple months? Have you already purchased it? I'd rather see you run your system on a car or marine battery patched into the system . . . or with a ground power supply like those sold on our website. Wait until you're ready to fly before putting the "real" battery in place. If you already have the battery, a short stint on a charger every 90 days will suffice to keep it up . . . Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurasic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Thu, 17 Jun 1999 09:41:46 From: "Robert L. Nuckolls, III" Subject: COZY: Re: What fuse type for the essential bus feed line? >> Bob's drawings show a 15 amp fuse where the 14AWG wire comes off the upstream >> (battery side) master contactor. This fuse protects against a short between >> the always hot wire and the essential switch. What type fuse have people been >> using for this application? The essential bus alternate feed path needs to be sized to the loads on the bus. IF you're able to achieve the ultimate in system reliability and get e-bus running loads below 8 amps, then the recommended alternate feed architecture is shown in the latest encarnation of Appendix Z now downloadable from our website at http://www.aeroelectric.com/errata/z8_0299.pdf A 20AWG fuse link crimped into a 14AWG wire (for lower voltage drop when battery is rear mounted ) or 16AWG wire (if battery is up front) completes the interconnection along the alternate feed path. If you succumb to baser instincts and get an e-bus that's loaded heavier than 8 amps continuous, then go to a 10 or 15 amp fuse to protect a 14AWG alternate feedpath wire. I have some builders running a 3-amp continuous/7-amp intermittant e-bus using 22AWG fuselink and 18AWG feedline. If you DO need an inline fuseholder, the Bussmann HFB device is recommended . . . but I'd work really hard to avoid the need . . . anything over 5 amps for an e-bus load really cramps your ability to get where you want to go with a finite energy resource that may be of unknown quantity . . . Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurasic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Thu, 17 Jun 1999 10:04:11 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Electronic ignition, etc. At 03:06 PM 6/16/99 +0100, you wrote: >I like the concept of the Lasar system, but it has gotten only lukewarm >enthusiasm from The Aviation Consumer, and it's really expensive, even >with the rebate for the turned-in mags. From a purely engineering perpective, the Lasar system is a bad encarnation of two worlds never intended to live together . . . the result is a device with too many parts, too many places to quit working, too high a price and no better delivery on performance or flight system reliability than some lower cost alternatives. . . >Reading through some of my accumulated literature (while Mrs./Ms./Miss >Pheobe has me on otherwise on hold) I ran across a brochure from >Electroair, a Tennessee firm, advertising an electronic ignition system. >$785.00 FOB for a single unit, $1,350 for a dual unit. While the >literature doesn't say so, it implies that a single unit can be used >along side a conventional magneto. 95% of your performance increase will come with installing the first electronic ignition. Keep in mind also that fuel efficiency improvements come only at very low manifold pressure cruise . . i.e. carburetor engine running full throttle at 8,000 feet and up. Unless you PLAN to spend MANY hours at such lofty heights, your return on investment will be very slow if there's any return at all. The biggest leap forward will be starting performance since the electronic ignition delivers at low battery voltage and low rpm. If it were my airplane, I'd do this: Since you paid for some perfectly good mags with the engine when you bought it, I'd take one mag off and install one electronic ignition. When the mag finally craps (and it WILL), switch the electronic ignition to the other side and put the first magneto you removed back on. When THAT magento craps (and it WILL TOO), then put on a second electronic ignition. If you're really lucky, you'll be old enough by then to be in danger of loosing your medical and you can let the new owner of your airplane decide what the ignition system is going to look like. If you're not so lucky, then at least you will have received what ever value there was to get from the mags and you will have forstalled purchase of one electronic ignition for awhile . . . Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurasic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Fri, 09 Jul 1999 16:45:10 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Firewall electrical connectors >Many types of wire through ordinary bulkhead connectors are OK, but be sure >you don't put thermocouple leads into those connectors. The reason is that >the thermocouple junction consists of a bi-metallic joining of the two >different types of wire that make up the lead wires. If you cut the leads >and put pins on them and then into a bulkhead connector and out the other >side with the remainder of the leads wires, you have created another >bi-metallic junction at the connector location. This will prevent you from >obtaining reliable temperature measurements at the place you really want to >measure it. The thermocouple manufacturers do make bulkhead connectors that >allow you to carry the leads through the bulkhead--just be sure you don't >use an ordinary Cannon connectors or the like that are used for ordinary >power and signal voltages and currents.... Actually only half true . . . the part about creating new bi-metal junctions is true but consider that for every brass pin crimped to a thermocouple wire in a plug, there is an equal and opposing junction created in the mating plug. From an electrical performance standpoint, there is very little error added to thermocouples by taking them through a connector. However, it's NOT easy. Thermocouple wire alloys are much harder than brass/copper alloys found in wire and connector pins. It's difficult to get a sturdy, gas-tight joint on a thermocouple conductor by crimping a brass pin to it. It can be done rather well with machined-pins . . . solid barrels of brass closed onto the thermocouple conductor with a quad-squash die tool. Another more time consuming way works rather well. "TIN" the ends of your thermocouple conductors with silver solder and then SOLDER the tinned conductors into solder-cup type connectors. Only some TC alloys will solder at low temps with tin/lead solder but a coating of silver solder over the outside of the conductor will make it solderable with ordinary materials common to electrical connectors. Yes, there is still more "contamination" of the bi-metal measurement system but each lump in the line is offset buy a similar lump close by in the mating connector and overall errors introduced are insignificant. A technique that has been recommended by some manufacturers of TC instruments for hombuilts tell you to take TC wire through Molex or other open-barrel, sheet-metal pins on low cost plastic connectors . . . I don't recommend it. You can also purchase machined pins of the same alloy as the TC wire you're working with but believe me, you don't even want to know what they cost. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurassic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Sun, 11 Jul 1999 11:00:12 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Questions At 09:56 AM 6/30/99 +0200, you wrote: >Bob, >Thank you for your answers. There was one more question I forgot to ask: I've >been told that a good place to hook up the engine hour meter is to the >charging side of the alternator - that way the hour meter only works when the >engine is running (assuming the alternator is charging!).If this is the case, >where would I connect the hour meter on your Z3? Would I need an inline >Diode? Hour meters for airplanes run on 10-15 vdc. The raw output from your alternator is AC voltage. I've seen the technique you asked about accomplished with a bridge rectifier, resistor, capacitor and sometimes a zener diode for keeping the output voltage from becomming too high (the AC output is unregulated and quite high at cruise RPM). My preference is for using a single pole, double throw oil pressure switch as a combination hour meter and low oil pressure warning light driver. The hour meter runs directly from the battery through a 1-3A fuse and gets ground through the close on pressure side of the switch. A low oil pressure warning light powers from the essential bus (or main bus if you don't have a two-bus system) and gets ground through the close on no pressure side of the switch. This system will cause the hour meter to run even if the battery master is OFF. The low oil pressure warning serves two purposes. In addition to the obvious function, the light serves as a reminder to shut off the battery master switch before leaving the airplane. Some builders include a small buzzer in the system as a audible alert. If your airplane has an essential-bus/main-bus architecture, then driving the warning light from the e-bus monitors both the battery master -and- the e-bus alternate feed switches. A diagram describing this sytem may be downloaded from http://www.aeroelectric.com/oilpwarn.pdf We stock the double throw oil pressure switch as an S710-1 Oil Pressure Switch. Not in our website catalog yet but you can order one with a statement in the comments box that you'd like to have an S710-1 Switch. They're $7.50 plus postage. By the way, some browser's interface with Acrobat Reader can be flakey. One of four machines I use will not smoothly display a .pdf link accessed directly from the browser. Acrobat opens and the browser reports "document done" but the page is blank. If this happens, use your right mouse button to click on the link an direct your browser to "save link" to some spot on your hard drive. After the download is completed, use Acrobat as an independent application to open the .pdf file directly from your hard drive. Date: Wed, 28 Jul 1999 06:37:53 From: "Robert L. Nuckolls, III" Subject: COZY: Fusible Link Fabrication I've had quite a few questions about fabricating fusible links . . . I've published an illustrated technique at: http://www.aeroelectric.com/articles/fuselink Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurasic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Thu, 29 Jul 1999 16:45:57 From: "Robert L. Nuckolls, III" Subject: Re: COZY: Chap 22-23 - Alternator Brand >Date: Thu, 29 Jul 1999 16:44:50 >To: "DeFord, Brian" >From: "Robert L. Nuckolls, III" >Subject: Re: COZY: Chap 22-23 - Alternator Brand >In-Reply-To: > >At 11:58 AM 7/29/99 -0700, you wrote: >>I'm looking at perchasing an alternator for my IO-360 with ~60A capability. >>Anyone care to share what brand they use or would recommend? >> >>Thanks, >>Brian DeFord NIPON-DIENSO . . . preferably one modified by B&C to run with a real, aircraft alternator controller like their LR3B-14. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurassic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Wed, 28 Jul 1999 23:34:17 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Engine Instruments >I like both systems. I've heard of several guys who have had these systems >and had problems with them getting whacked(technical term) when they start >the engine from surges and EMI. I would recommend a avionics saver unit >from Control Vision.(. This unit will protect >delicate engine and avionic instruments from surges and automatically turn >off engine instruments and avionics when the starter is engaged. >I'm sure there are other ways to do this also but the unit is so cheap that >I don't think it's worth the time to do anything else. Folks, IF you are considering ANY device for your project that has the slightest hint of history for being "whacked" or anything else when installed in an otherwise normally operating airplane, you'd better check with the manufacturer of the device before you buy it. ASK, "Will your product meet or exceed all the requirements set forth in RTCA DO-160, Power Input conditions described in sections 16.0 through 20.0" Building products that meet these requirements is a piece of cake . . . I've been doing it for over 25 years. There's no excuse for anyone to bring a product into the marketplace that does NOT meet these requirements. "Delicate engine and avionic instruments" is a term that should be erased from the lexicon of airplanespeak . . . yes, I know there are plenty of folks out there who depend on fears and ignorance of the common folk in order to enhance the sales of their products. It works VERY well in the world of type certificated aircraft . . . even some degreed engineers at airplane plants still preach the gospel of "better safe than sorry." But please, Please, PLEASE don't propogate stories that invariably begin with, "I've heard of several guys who have had . . . " If anyone has a real name of a victim, and a product that failed to pass muster in his airplane I'd sincerely like to know name, rank and serial number of all parties and parts involved. I'll contact them and offer gratis services to identify the failure mode and offer ways to prevent it from happening again either by appropriate (and generally rudimentary changes to the electrical system) -OR- help the manufacturer with the relatively trivial task of hardening their product. Over the past 10 years, several dozen leads on "whacked", "fried" and "smoked" componts have failed to yield any real cases of design deficiencies . . in fact, of all the situations I've tried to identify, only two turned out to be real failures and both were induced by wiring errors during installation. You guys are building the best airplanes ever. Our collective skills can only get better if we extract ourselves out of the muck and mire of federally decreed ignorance that plagues our brothers who fly the heavy iron. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurasic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com From: cdenk@ix.netcom.com Date: Thu, 29 Jul 1999 19:31:38 -0500 (CDT) Subject: Re: COZY: Chap 22-23 - Alternator Brand I use a Delco (General Motors) CS-121, which puts out 74 amps. I made the 2 brackets , one from 1/4" x 1" steel, and the other from 1/8" x 1" steel. The adjusting bar, if I remember was the standard lycoming part. I use a B & C regulator. The unit has 700+ hours. With my IFR panel, heater blower, heated pitot my electic supply requirement is 58 amps. I can idle on the ground indefinately without discharging the battery with every thing on high. Date: Sat, 31 Jul 1999 13:26:31 -0500 From: Michael Link Subject: Re: COZY: Chap 22-23 - Alternator Brand "DeFord, Brian" wrote: > I'm looking at perchasing an alternator for my IO-360 with ~60A capability. > Anyone care to share what brand they use or would recommend? > > Thanks, > Brian DeFord > > Brian, I used a Mitsubishi Alt. off a Mazda RX-7. It is a 70 amp unit with a very good voltage regulator built in. There is an excitation lead so you can turn the alt. off if you wish. Do not get an older one with cooling blades built in behind the pulley (I believe they are only 50 amp. and are heavier) Use alternators off 1989 or later cars. If you luck out and find one that is off a '91 or later, they are REALLY light. I had a guy turn an Al pulley 3.75" in diameter in order to save weight and slow the alt down. Adapting it to the engine( 0-360) was easy. I have been using it for a year, and I highly recommend it. It puts out a steady 14.4 volts and has kept the electrical system in good shape. Regards, Michael Link Cozy MK-IV N-171-ML From: cdenk@ix.netcom.com Date: Sat, 31 Jul 1999 14:35:46 -0500 (CDT) Subject: Re: COZY: Chap 22-23 - Alternator Brand was said The Delco I commented about yesterday also came with a built-in regulator which I removed, I don't think it had overvoltage protection which is important to minimize frying of $10,000 in avionics. Generally the aviation useage, the shaft turns the wrong way, usually thats not an issue cooling, but the nut now unthreads instead of getting tighter from the torque on the pulley which is usually held only by friction from the nut. Generous Locktite is necessary, use some heat and a impact wrench to remove. Had to borrow a air wrench from local truck garage in the middle of the night to get one off a Bercut some years ago. From: "Jeff Murdock" Subject: Re: COZY: Chap 22-23 - Alternator Brand Date: Tue, 3 Aug 1999 11:23:44 -0700 Was said by nuckolls@aeroelectric.com: > NIPON-DIENSO . . . preferably one modified by B&C to run > with a real, aircraft alternator controller like their > LR3B-14. Bob, Were you referring to Nippondenso? I believe that they supply the alternator for one of the Katana models. Nippondenso has also changed their name to DENSO International. Their U.S. web page is www.denso-int.com. There isn't a lot of information (specifications) on their web page since they mostly deal with OEMs. DENSO also makes a very small and light weight starter for race cars, however, I am still trying to find information on the starter. Jeff jmurdock@ixpres.com Date: Tue, 03 Aug 1999 13:52:21 -0400 From: "Johnson, Phillip" Subject: COZY: Circuit Breakers and Fusible Links I was at Oshkosh last week and saw a neat switch panel that had ten switches, a master switch relay and a number of neat features all for the cost of about $250. The most obvious neat feature was a solid state circuit breaker that was built in. After talking with the vendor he told me that this device was a PolySwitch made by Raychem and could be purchased through DigiKey at www.digikey.com The PolySwitch is a device that is commonly used in applications such as automotive electric windows where the operator drives the window to a stalled state when fully opening or fully closing the window. Under these conditions the trip current is exceeded and the device turns to a high impedance state which it maintains until the supply current is released, whereafter the PolySwitch returns to its initial state ready for the next stalled condition. The devices are configured in series with the switch and the load such that if over current is encountered the PolySwitch turns to a high impedance condition, the small, (milliamperes) current that continues causes self heating of the device and maintains the "OFF" condition until such time as the circuit is broken by the switch. When the switch is opened the self heating stops and the PolySwitch returns to its low impedance condition necessary for normal operation. These PolySwitches can be placed in series individually with each of the avionics so that the internal switching on each of the avionics may be used to reset the device without the need for panel mounted breakers. The vendor of the switch panels described above also provides a monitor that lights a LED if one of the PolySwitches is activated. The neat thing about these devices is that they have indefinite life, auto resetting, are not mechanical, and cost between 75 cents and 125 cents each. Although not suited for all applications I can see a number of applications where these devices could be used with significant advantage over conventional breakers. Consider the electric nose lift. This could be configured with a momentary switch on the instrument panel with an up/off/down position, a relay to act as a no volt switch, and a PolySwitch to cause the motor to fully extend or retract to the stalled condition without risk of damage and without the need to precisely align limit switches. The gear would always either fully extend or retract. No adjustment. Continuous power is limited to 11 Amps max. DigiKey Part Numbers are RGE300-ND 3 Amp RGE500-ND 5 Amp RGE700-ND 7 Amp RGE900-ND 9 Amp RGE1100-ND 11 Amp Phillip Johnson From: "Paul Stowitts" Subject: RE: COZY: Circuit Breakers and Fusible Links Date: Tue, 3 Aug 1999 16:07:16 -0700 >The PolySwitch is a device that is commonly used in applications such >as automotive electric windows where the operator drives the window to >a stalled state when fully opening or fully closing the window. Under >these conditions the trip current is exceeded and the device turns to >a high impedance state which it maintains until the supply current is >released, whereafter the PolySwitch returns to its initial state ready >for the next stalled condition. Just a note of caution with these. When it gets hot outside, two of my car windows don't work until it cools down. This could be risky. Paul Stowitts Cozy Mark IV #200 From: cdenk@ix.netcom.com Date: Tue, 3 Aug 1999 19:58:42 -0500 (CDT) Subject: Re: COZY: Circuit Breakers and Fusible Links What is its failure mode? open or shorted? I much prefer a mechanical set of contacts to break (open), and yes on occasions they may weld themsellf together. Date: Wed, 04 Aug 1999 08:14:22 -0400 From: "Johnson, Phillip" Subject: RE: COZY: Circuit Breakers and Fusible Links > >Paul Stowitts Writes> > >Just a note of caution with these. When it gets hot outside, two of my car >windows don't work until it cools down. This could be risky. > >< > >Raychem have a web site for this PolySwitch and the thermal properties are >indicated on this site. Also included on this site is the power window design >criteria, quite interesting. The thermal characteristics for the PolySwitch >are little different to those of the more conventional mechanical breaker. In >the case of the power windows the device is designed to trip with every >operation so they have to be designed within a narrow operating range, >circuit breakers (PolySwitch or mechanical) are configured as an overload >protection device and offer more margin. > >Phillip Johnson Date: Wed, 04 Aug 1999 09:57:44 From: "Robert L. Nuckolls, III" Subject: COZY: RE: Circuit Breakers and Fusible Links >>Just a note of caution with these. When it gets hot outside, two of my car >>windows don't work until it cools down. This could be risky. >> >>< >> >>Raychem have a web site for this PolySwitch and the thermal properties are >>indicated on this site. Also included on this site is the power window design >>criteria, quite interesting. The thermal characteristics for the PolySwitch >>are little different to those of the more conventional mechanical breaker. In >>the case of the power windows the device is designed to trip with every >>operation so they have to be designed within a narrow operating range, >>circuit breakers (PolySwitch or mechanical) are configured as an overload >>protection device and offer more margin. Thermal characteristics of PolySwitches are considerably different . . . please look at the pieces I published about products using PolySwitches on our website. Suggest you click on: http://www.aeroelectric.com/expbusad.html http://www.aeroelectric.com/xpbusthd.html Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurasic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Wed, 04 Aug 1999 11:53:12 -0400 From: "Johnson, Phillip" Subject: RE: COZY: RE: Circuit Breakers and Fusible Links Bob Nuckles Wrote: > . . . please look at the pieces I published > about products using PolySwitches on our website. > Suggest you click on: > > >I read two web pages and I think that you are not comparing apples with >apples. The EX-Bus is equivalent to a set of breakers for those people who >want the benefits of breakers without throwing fuses down their throats. >There are two pannels offered, one with rocker switches and already set in a >panel and should be compared with the other switch panels on the market at >greater cost. The second option (less expensive) uses toggle switches that >may be remotely located at the builders whim. Both systems interface with a >$99 monitor that lights LED's in the event a PolySwitch turns open circuit >and includes an ammeter. There are a number of neat features that many >builders are uncomfortable in designing into their pannel without >supervision. > >For those fundementalists in the group they can make there own equivalent of >this panel since the PolySwitches run at an average cost of $1 compared with >$1.75 for a fuse block. > >Comparing apples with apples the PolySwitch wins in both cases. I'm sure >there are many other combinations that I have not considered but at the end >of the day it becomes a personal thing. I personally do not like fuses, >That's my personal thing and many share my view as many share your view. >Given that a builder shares my view on fuses/breakers then the PolySwitch or >EX-Bus is worth investigation. Those who do not share the view feel free to >ingore this discussion. > >Phillip Johnson Date: Thu, 05 Aug 1999 09:35:12 From: "Robert L. Nuckolls, III" Subject: COZY: RE: Circuit Breakers and Fusible Links >>I read two web pages and I think that you are not comparing apples with >>apples. The EX-Bus is equivalent to a set of breakers for those people who >>want the benefits of breakers without throwing fuses down their throats. >>There are two pannels offered, one with rocker switches and already set in a >>panel and should be compared with the other switch panels on the market at >>greater cost. The second option (less expensive) uses toggle switches that >>may be remotely located at the builders whim. Both systems interface with a >>$99 monitor that lights LED's in the event a PolySwitch turns open circuit >>and includes an ammeter. There are a number of neat features that many >>builders are uncomfortable in designing into their pannel without >>supervision. At the time I wrote those pieces, most of the features you're refering to did not exist in the EX-Bus . . . my reason for citing those pieces was in response to a discussion of the technical merits of the Polyswitch as a circuit protection component. >>For those fundementalists in the group they can make there own equivalent of >>this panel since the PolySwitches run at an average cost of $1 compared with >>$1.75 for a fuse block. Problem with Polyswitches is that they are a devices that range in size from a fat asprin to a fat quarter and have two solid wire leads that make connections. They are designed to be incorporated into a product, i.e. soldered to an etched circuit board like the EX-bus. Unless you purchase them in a manufactured assembly then you have to figure out how they will be used in the airplane . . . a labor and materials intensive activity compared to the fuse blocks which are ready to install and wire up in minutes. >>Comparing apples with apples the PolySwitch wins in both cases. I'm sure >>there are many other combinations that I have not considered but at the end >>of the day it becomes a personal thing. I personally do not like fuses, >>That's my personal thing and many share my view as many share your view. >>Given that a builder shares my view on fuses/breakers then the PolySwitch or >>EX-Bus is worth investigation. Those who do not share the view feel free to >>ingore this discussion. What is it with a fuse that you don't like? Are they unsafe? Do they pose a risk with respect to the probable outcome of any given flight? If your system is designed to eliminate nuisance trips (unlike many certified systems flying today) what value is there in doing any kind of fuse replacement while airborn? Would you cruise down the highway at 70 mph while fiddling with fuses under the dash? If not, why do it in your airplane? The design criteria that make fuses attractive in airplanes or any other vehicle is the notion that we, (as designers of airplanes unencumbered with government interference) will ELIMINATE nuisance tripping from any system's circuit protection. This leaves but ONE reason for a fuse to open . . . the system is BROKE. If there are systems that you depend on for comfortable completion of flight, then you'd better have BACKUPS for them. The ways that electro-goodies fail that DO NOT pop fuses outnumber the failures that DO pop fuses by 10:1 or more. If the goal is to increase flight system reliability, spending time worrying about inflight fuse maintenance on a critical system seems poorly spent. The most reliable systems are those that do not increase pilot workload in spite of failure of any single system. I'll grant that the Polyswitch is a device that will protect wiring in an overloaded condition. I and dozens of my contemporaries have been pondering these devices for use in certified aircraft since they were first introduced to us about 20 years ago. Given the rudimentary form of the device (designed to be a component part of an assembly) the additional work to package and install them as replacments for fuse holders or breakers (ready to use out of the box) makes them poor competition in the cost/performace ratio of all circuit protective devices. This leaves most builders a single option with respect to incorporation of Polyswitches in their airplane . . . buy them pre-installed in an assembly fabricated by someone else, i.e. the ex-bus or other product. Now, it becomes a decision as to choice of operational features and system architecture. If the relatiely fixed, off the shelf offering is perceived to be good value and something you would like to have, by all means, go for it. However, if you enjoy the flexibility of roll-your-own architecture that is easily modified in the future and readily repaired with spare parts from dozens of suppliers, then the individual switch circuit protected with a fuse (or breaker) has some cost/performance/ convenience value. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurasic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com From: mister@neesnet.com Date: Fri, 06 Aug 1999 07:56:03 -0500 Subject: Re: COZY: RE: Circuit Breakers and Fusible Links Regarding Breakers vs Fuses: My Cozy III was wired using Bob Nuckolls' philosophy with fuses and the essential bus concept. The only breaker I have is for the alternator field. The system was simple to wire, was inexspenive and has performed well and been trouble free. A blown fuse would be an inconvenience but wouldn't affect the outcome of the flight. I generally carry a handheld backup radio with nav capability and a simple backup handheld non database gps. These aren't critical but are more for convenience and peace of mind. I think the philosophy of using fuses instead of breakers in our airplanes is solid. Bob Misterka COZY III N342RM http://www.gis.net/~bmist From: "Ugolini, Nick J" Subject: RE: COZY: RE: Circuit Breakers and Fusible Links Date: Fri, 6 Aug 1999 08:09:02 -0400 > the cost/performace ratio of all circuit protective devices.< >I think you are clutching at straws and chasing shadows. >A 20-slot fuse block mounts in 5 minutes and wires up in 1/4 the time of a breaker panel for 1/10 the cost. Rather than "shadows and straws" I'll suggest it's rather rudimentary logic.> I wired my LongEZ using Bob's "Aero Connection" utilizing fuse blocks with a total of 30 fuses (block cost $15 + cost of fuses) and one breaker for the alternator (cost $5.) In the last 725 hrs of flying I have had exactly zero "nuisance" circuit failures. I don't believe circuits just "pop". If a circuit fails than there must be a real problem and I would never reset it while flying. Since everything in my plane has its own discrete fuse (from the starting relay to the panel lights to each radio) at most I would only lose one circuit. I can live with that. Nick Date: Thu, 05 Aug 1999 20:57:32 From: "Robert L. Nuckolls, III" Subject: COZY: RE: Circuit Breakers and Fusible Links At 01:31 PM 8/5/99 -0400, you wrote: Robert L. Nuckolls Writes> > the cost/performace ratio of all circuit protective devices.< > >I think you are clutching at straws and chasing shadows. Really? That's the first time I've been accused of that. Interesting. >I have worked as an engineer in the defence industry for more years than I >care to remember and in mission critical components there are no fuses, >except for where battle shorts are incorporated. (For the uninformed a battle >short allows the fuse to be overridden in a battle scenario. It's rather like >using a nail in the fuse socket.) Most of the equipment that is within my >jurestriction has no fuses and uses devices such as the PolySwitch to protect >the circuit. > >Phillip Johnson A myrid of breaker-popping stories ranging from the benign nuisance trip to the "dark and stormy night" variety have graced the pages of aviation journals for the past 40 years. MOST of the stories circulating around are too many tellings removed from the original experience and have gathered "new emphasis" with each telling. Virtually all of the stories would not be worth telling had the systems involved been engineered with a little imagination and an eye toward failure tolerance as opposed to a 10 to the minus 9 failure rate. How about designing an airplane in which there are NO mission critical components? I am truly sorry that your confidence in the design of failure tolerant, minimal pilot workload systems is so low. By all means, please use whatever parts in your airplane that offer you comfort. I must continue to suggest that builders consider that EVERY part they put in their electrical system is subject to failure and that if the part is critical it gets backed up. If it's not critical, the failure is ignored until safely on the ground. It's not difficult to do in a single engine light aircraft . . . Remember the L-1011 that went into the Everglades a few years back? The entire cockpit crew was playing system diagnostician to figure out why a light bulb was not illuminating . . . nobody was flying the airplane and a perfectly good airplane full of people hit the swamp. The FAA/DOD mentality for systems design has spooked many of our brothers into believing that every part must be of "aircraft quality" (whatever that means) and that we must strive to minimize failures of any part under all scenarios. An impossible task. I prefer to assume that any given part is going to fail at some point in time and then adjust system architecture and operating procedures so that it doesn't matter. Having achieved that, the mode of circuit protection is immaterial and can be selected for low parts count and convenience of installation. A 20-slot fuse block mounts in 5 minutes and wires up in 1/4 the time of a breaker panel for 1/10 the cost. Rather than "shadows and straws" I'll suggest it's rather rudimentary logic. From: mbeduhn@juno.com Date: Fri, 6 Aug 1999 21:00:57 -0500 Subject: Re: COZY: RE: Circuit Breakers and Fusible Links First, I want to say for the record that I also agree with Bob's philosophy of keeping it simple, and backing up critical circuits and elements. However, I had an interesting thing happen in my plane that applies to this discussion topic (fuses vs breakers). My plane was installed with both breakers and fuses. The theory was to use the breakers to keep the wires from burning up, and the fuses to protect my expensive radios and other electronic instruments. When I was flying off my initial 40 hours, I would periodically get a tripped breaker. I reset it in flight (while holding my breath and smelling for smoke), and it would be fine for awhile (sometimes hours), but then for an unknown reason it would trip again. One day the breaker seemed to trip on a fairly regular basis. In fact, every time I made a steep left turn it would trip!!! Once I noticed that pattern, it wasn't too hard to figure out the source of the problem. Here is what happened: When I built the plane, I installed a level switch in each tank to indicate that it was down to 5 gallons. A warning light illuminates on my alarm panel indicating which tank is low. As it turned out, the bulb indicating low fuel in the left tank was shorted, and the breaker tripped when I made steep left turns (I guess the turns weren't coordinated, or this theoretically wouldn't have happened). Interesting huh? I learned several things from this experience: 1) Resetting a breaker in flight is not necessarily a bad thing. 2) A breaker helped me diagnose this problem. 3) I never say a circuit will never fail. In this unusual case, being able to tell when the short occurred (watching the breaker pop) helped me solve the mystery. Had this circuit been protected with fuses, I don't know how I would have ever solved the mystery. However, in spite of this experience, if I were to do it over again, I would keep it simple and install only fuses. Mark Beduhn Cozy IV N494CZ (no popped breakers or blown fuses since this problem was solved). > I wired my LongEZ using Bob's "Aero Connection" utilizing fuse > blocks with a total of 30 fuses (block cost $15 + cost of fuses) and one breaker > for the alternator (cost $5.) In the last 725 hrs of flying I have had > exactly zero "nuisance" circuit failures. I don't believe circuits just "pop". > If a circuit fails than there must be a real problem and I would never > reset it while flying. Since everything in my plane has its own discrete > fuse (from the starting relay to the panel lights to each radio) at most I > would only lose one circuit. I can live with that. > > Nick Date: Sat, 07 Aug 1999 14:17:36 -0500 From: Michael Link Subject: Re: COZY: RE: Circuit Breakers and Fusible Links Hi Guys, I resisted commenting on the fuse-breaker controversy, but since the discussion kept going on, I find myself unable to resist putting in my 2 cents worth on the subject. Looking at the issue from the perspective of someone who has been in the electronics and avionics REPAIR business for more years than I care to admit, the choice is rather easy. While they are less expensive, lighter, and more compact, fuses and fuse holders/blocks are less reliable in the long run. I mentioned fuse holders and fuse blocks specifically because they tend to be the weakest part of the fuse system. As the contacts age, resistance develops, which leads to localized heating, which leads to greater resistance, more heat, etc. The fuse often fails as the result of the faulty holder/block. Again, I am not analyzing this problem from engineering test data, but from real world repair work. My experience has been that component  mean time between failure (MTBF) ratings and what happens in the field can be significantly different. Bottom line is that we experience far more fuse/holder failures than failed circuit breakers. Consider switch/breakers for a moment. Since you need a means to switch circuits as well as protect them, why not use one component that accomplishes both tasks. I have installed Airpax brand switch/breakers in my Cozy with very satisfactory results. They do not take much more room than standard toggle switches, so I was able to use 17 of them in the small offset area at the top of the Cozy panel. I found a surplus source for the 5amp units under $5.00 ea. Unfortunately other current ratings range from $14 to $20 ea. Remember though, you are replacing a switch and a breaker (or fuse). Like I said initially.....my 2 cents worth. Regards, Michael Link COZY MK-IV N-171-ML From: "Ugolini, Nick J" Subject: RE: COZY: Re: Circuit breakers and fuses Date: Mon, 9 Aug 1999 15:18:45 -0400 Brian, Don't be so worried about your plane electrical system. It will never get wet, the connectors are designed for corrosion, and the wire has a tin coating (use mil spec wire and connectors). You wont have any problems if you stick to standard aviation wiring techniques. What your eluding to in your email is really not very practical, and certainly not worth the effort to try and do..... Car have their wiring much more exposed, and the material involve are inferior to plane materials. I would not recommend comparing the two. After nearly 1000 hrs on my plane, electrical failure is not an issue. It has certainly been the only reliable system on the plane which has given me no problems at all..... Nick -----Original Message----- From: Brian Norquist [mailto:brian.norquist@usa.net] Sent: Monday, August 09, 1999 2:09 PM To: cozy_builders@canard.com Subject: COZY: Re: Circuit breakers and fuses Perhaps we should think of planes that operate near saltwater as flying boats (that don't normally land in the water). One might then assert that all circuitry should be sealed against moisture and salt. This would would take some effort, expense, add weight to the aircraft and depending upon how the sealing was done, it might restrict inspection. But it seems to be well worth the bother to me. All of dozen cars I've owned have developed electrical problems. I've lived where salt is used on the roads and that's a big part of it. The thought of an electrical problem in my future plane is very disturbing to me. I'm going to be spending a lot of time and money making sure the AF and PP are safe and reliable, it doesn't make sense to leave the electrical system unscrutinized. Toward this end I imagine my future in a resealable pressure-change-tolerant optically transparent water and air tight bag (maybe even with a vacuum value). The bag will be loose enough so that the circuit breakers can be actuated without opening the bag. Something like environmentally sealed keyboard that will be on the plane. In addition to that, on any exposed metallic electric/conducting wire or connection there will be a coating of Liquid Blank Tape ($5 at Home Depot) or something similar. ____________________________________________________________________ Get free e-mail and a permanent address at http://www.netaddress.com/?N=1 Date: Mon, 09 Aug 1999 15:10:16 From: "Robert L. Nuckolls, III" Subject: Re: COZY: Re: Circuit breakers and fuses At 12:08 PM 8/9/99 MDT, you wrote: >Perhaps we should think of planes that operate near saltwater as >flying boats (that don't normally land in the water). One might >then assert that all circuitry should be sealed against moisture >and salt. I've been there . . . to make a long story short, any attempt to provide environmental isolation between vulnerable components and evil things lurking in the air can actually make things WORSE. Any attempt to enclose and SEAL hardware away will work only if the enclosure is absolutely air tight (hermetic seal). Otherwise, tiny chinks in the armor provide a means ingress of contaminated liquid that now has to escape through the almost perfect sealing as a vapor. It's far better to leave things out in the open where the can be observed, occasionally cleaned, and never trapped in a less-than-perfect enclosure with the very antagonists you are trying to keep at bay. >Toward this end I imagine my future in a >resealable pressure-change-tolerant optically transparent water >and air tight bag (maybe even with a vacuum value). The bag will >be loose enough so that the circuit breakers can be actuated without >opening the bag. Something like environmentally sealed keyboard >that will be on the plane. > >In addition to that, on any exposed metallic electric/conducting wire >or connection there will be a coating of Liquid Blank Tape ($5 at Home >Depot) or something similar. Please don't worry about it. If you're local ambient is so antagonistic to electrical parts, I think your real worries will have more to do with aiframe and power plant components than with electro-goodies. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurasic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Sun, 08 Aug 1999 20:01:58 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Circuit Breakers and Fusible Links > >Here is what happened: > >When I built the plane, I installed a level switch in each tank to >indicate that it was down to 5 gallons. A warning light illuminates on >my alarm panel indicating which tank is low. As it turned out, the bulb >indicating low fuel in the left tank was shorted, and the breaker tripped >when I made steep left turns (I guess the turns weren't coordinated, or >this theoretically wouldn't have happened). > >Interesting huh? > >I learned several things from this experience: >1) Resetting a breaker in flight is not necessarily a bad thing. But did you KNOW that before you were on the ground and able to make a considered diagnosis? Knowing what you know now, would you take a similar situation in the future and choose to shift from pilot-mode to mechanic-mode in an effort to see if an inflight reset is a good idea? >2) A breaker helped me diagnose this problem. . . . and a popped fuse would not? >3) I never say a circuit will never fail. . . . which is why we have fuses and circuit breakers in the first place. >In this unusual case, being able to tell when the short occurred >(watching the breaker pop) helped me solve the mystery. Had this circuit >been protected with fuses, I don't know how I would have ever solved the >mystery. Why not? When chasing an intermittant short, how about rigging a light bulb in series with the bus to feed the affected circuit . . . you can wiggle and fiddle while watching the light . . . when the light is illuminated brightly, the short is in effect. When you're diagnosing the same kind of problem with a breaker, you can clip a lightbulb across the open breaker for the same diagnostic tool. This is NOT an unsual case at all . . . MANY faults present themselves initially with an intermittant condition . . . which is one of the reasons I don't think Polyfuses are such a good idea . . you might fly around with an impeding failure when it first manifests only an intermittant condition and not know it until it craps for good. >However, in spite of this experience, if I were to do it over >again, I would keep it simple and install only fuses. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurasic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Sun, 08 Aug 1999 20:21:19 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Circuit Breakers and Fusible Links >Looking at the issue from the perspective of someone who has been in the >electronics and avionics REPAIR business for more years than I care to admit, >the choice is rather easy. While they are less expensive, lighter, and more >compact, fuses and fuse holders/blocks are less reliable in the long run. I >mentioned fuse holders and fuse blocks specifically because they tend to be >the weakest part of the fuse system. As the contacts age, resistance >develops, which leads to localized heating, which leads to greater >resistance, more heat, etc. The fuse often fails as the result of the faulty >holder/block. Agreed, and breakers often fail for the same kinds of reasons. The ATC/ATO fuse blocks we recommend are very new designs that have eliminated many of the failure modes found in older, clip type fuse holders for cylindrical glass fuses. I had a guy walk up to me at Sun-n-Fun a few years ago and while turning one of our fuseblocks over in his hand remarked, "I never put a piece of $!@#$ like that in MY airplane . . . the salt air down here would eat it up in no time." I asked him if the salt air does NOT eat on breakers, wing skins, and most other airplane parts in addition to fuseblocks? Further, consider that the fuseblock with 20 protected circuits can be REPLACED as a preventive maintenance item, say every five years for a cost of about $35 plus a half hour's work. How many hours/dollars is involved in replacing all your breakers? He didn't answer . . . >Again, I am not analyzing this problem from engineering test data, but from >real world repair work. My experience has been that component mean time >between failure (MTBF) ratings and what happens in the field can be >significantly different. Bottom line is that we experience far more >fuse/holder failures than failed circuit breakers. Absolutly agreed . . . but are any of the failures less than say 10 years old? Have they suffered humidity and/or salt air damage? Are they modern blade type fuseholders with gas tight electrical connnections between holder and fuse? Unlike fuseholders of the past, I fully expect the majority of these modern devices to be in place the day the airplane is scrapped. >Consider switch/breakers for a moment. Since you need a means to switch >circuits as well as protect them, why not use one component that accomplishes >both tasks. I have installed Airpax brand switch/breakers in my Cozy with >very satisfactory results. They do not take much more room than standard >toggle switches, so I was able to use 17 of them in the small offset area at >the top of the Cozy panel. I found a surplus source for the 5amp units under >$5.00 ea. Unfortunately other current ratings range from $14 to $20 ea. >Remember though, you are replacing a switch and a breaker (or fuse). >Like I said initially.....my 2 cents worth. My objection to switch breakers is that you are forced to have an extra bus on the left side were most people put their switches. This in addition to fuses and/or breakers elsewhere. The nice thing about fuse blocks is that you fabricate NO busses. ALL busses are almost totally enclosed in the plastic insulation housing of hte holder. The fuse blocks have much LESS always hot metal exposed than any combination of switches, switch-breakers and breaker panels . . . and you don't have to fabricate a single bus bar. 17 switch-breakers? Then ALL of you power distribution what right on the same panel area as pilot operating controls for thing that did not need them . . . Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurasic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Sun, 08 Aug 1999 22:03:47 -0500 From: David Domeier Subject: Re: COZY: Re: Circuit Breakers and Fusible Links Bob, re "......pilot-mode to mechanic-mode in an effort to see if an inflight reset is a good idea?" I know of one major airline that has a policy of one inflight reset of any circuit breaker trip except those protecting a fuel pump. And that policy has been around since the days of the Connies. CB's have been tripping randomly since they were invented. If they trip a second time, it probably wasn't random dd Date: Mon, 09 Aug 1999 10:27:07 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Circuit Breakers and Fusible Links >> 17 switch-breakers? Then ALL of you power distribution what right >> on the same panel area as pilot operating controls for thing that >> did not need them . . . >I say again; Huh? > >Bob >This was a very confusing response. You seem a bit tired or prehaps emotionally >tied up in this issue. If I was listening to this instead of reading, I would >think you would have had a stroke. A little proof reading would help. Not trying >to critisize but just let you know how it looks from the outside. >Regards >Michael Amick Understand . . . the comment was looking at a condition where a field of 17 switch breakers also includes the 6-8 switches required to operate the airplane . . . consider ergonomic factors of sorting out pilot operating controls from a group of switches that don't need to be there. Probability for inadvertent operation of a switch/breaker is much greater. Thanks for the yank on the chain . . . Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurasic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com From: "John Slade" Subject: Re: COZY: RE: Circuit Breakers and Fusible Links Date: Wed, 11 Aug 1999 11:33:57 -0400 Bob, I've followed this thread with interest and learned a lot from it. Thanks. Last night I was having a discussion with an A&P who suggested what might be an exception to the "fuses are better than breakers" theory. A big jet over Seattle was having trouble getting the gear down. Selecting gear down would throw the breaker every time. Apparantly the pilot got the gear to go down, by holding the breaker in. Perhaps a breaker would be better for the gear. On the other hand, perhaps the emergency gear handle (in our case a trusty sears socket wrench) is better than the fire risk. Any thoughts? John Slade Cozy MkIV #757 From: cdenk@ix.netcom.com Date: Fri, 13 Aug 1999 15:45:41 -0500 (CDT) Subject: Re: COZY: RE: Circuit Breakers and Fusible Links On 08/11/99 11:33:57 you wrote: Apparantly the pilot got the gear to go down, by holding the breaker in THats only one failure mode, more current than the protection can handle, resulting from other issues, for one the motor itself can seize for numerous resons. From: cdenk@ix.netcom.com Date: Fri, 13 Aug 1999 21:19:28 -0500 (CDT) Subject: Re: COZY: RE: Circuit Breakers and Fusible Links Was said All circuits and devices should be tested before first flight! In this case, the lamp, if shorted, wouldn't light. When filling tanks first time, and at each annual (or preferably whenever a tank is run low) should be tested to determine what the remaining fuel is whe then warning lights. The effect of climb, decent, turns, skids and slips should be explored during the test flying period. Date: Mon, 16 Aug 1999 09:44:00 From: "Robert L. Nuckolls, III" Subject: COZY: Re: OV protection At 07:06 PM 8/15/99 EDT, you wrote: >Bob, > >Just looking at your drawing for putting OV protection into a charging system >with an internally regulated alternator. Why is the feed from the bus to the >crowbar module on a breaker instead of a fuse? Is there any particular >reason to put the battery master and alternator field on one switch? The crowbar circuit is the only one that I recomend using a breaker on. Two reasons. You may find yourself with a quirky regulator that overshoots on some loading conditions and resetting in flight is okay if you have a voltmeter on board and can verify that steady state output from your regulator/alternator is in limits. Second, you may want to conduct ground operations battery only where it's desireable to pull the alternator breaker to keep the alternator off line and loading the battery with it's field current (up to 4 amps!). Putting the battery and alternator together on a DC power master siwtch makes it impossible to leave the alternator ON line with the battery OFF line . . . most alternators are flakey without a battery on line. Further, there's no good reason to have the alternator OFF line while cranking the engine during pre-flight. Hence the move to a DC Power Master switch shown in all of our drawings. Please, don't use the classic split-rocker master switch unless it's your desire to use the matching rockers for all of your switching needs. Rockers are difficult to mount an they lock you into a single supplier for spares. Further, there is no MAGIC in the split rocker that was pioneered into TC aircraft back in the 60's for reasons that nobody really understood at that time. Date: Wed, 18 Aug 1999 09:29:01 From: "Robert L. Nuckolls, III" Subject: COZY: error in URL quotation . . . There was an error in the URL I quoted for the ov protection diagram for alternators with built in regulators . . . the correct url is: http://www.aeroelectric.com/articles/bleadov.pdf Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurasic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Tue, 17 Aug 1999 08:56:15 From: "Robert L. Nuckolls, III" Subject: COZY: Re: "Field" circuits >>O.k., I know that I should know this, but . . . >> >>How does one tell whether an alternator needs a field switch? Or >>do they all need a field switch? >> >>I have a new 0-320 that came with an alternator but no electrical >>schematic or directions to my knowledge. And I know only enough >>to get myself into trouble. >> >>I've had some planes with separate field switches and others that if >>they had one I overlooked it. ;-) >> >>Any clues? >> All alternators need some form of panel mounted pilot control for turning it OFF - they also need overvoltage protection. If the alternator has a built in regulator and you don't plan to modify it for an external regualtor, then you need to wire it as shown in http://www.aeroelectric.com/articles/bleadovm.pdf If your alternator uses and external regulator, then it can be wired in accordance with any of many classic wiring diagrams like those shown in the back of our book. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurasic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Wed, 18 Aug 1999 09:22:07 From: "Robert L. Nuckolls, III" Subject: COZY: Re: (Vision Microsytems comment) At 07:38 PM 8/17/99 -0700, you wrote: >--> RV-List message posted by: Blake Harral > >The screw connectors on the Vision Microsystems DPU do not >appear to be well-suited to stranded wire typical in aircraft >electrical systems. The screws are tightened, but the wire >strands flatten over time and the screws are then loose and the >connection questionable. > >I have avoided this problem somewhat by crimping a solderless >connector that terminates in about a 50 thousands pin, and >inserting that pin in the screw connectors on the DPU. > >Blake > I mentioned that to Ron when I spoke with him the first time about 5-6 years ago. Your idea for hardening up the wires before installing them in those terminal strips is a good one. I'd suggest that the open barrel molex pins for the smaller (.062") white plastic connectors be considered too . . . they have an insulation grip in addition to the wire grip . . . I really wish Ron had used D-sub connectors on the back of his gizmos . . . Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurasic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Fri, 20 Aug 1999 12:15:07 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Designing for Failure >Be aware that when you disconnect the battery from a vehicle or aircraft >fitted with a alternator a sudden surge may occur. This can damage the >alternator depending on the type of surge diodes fitted and can also in the >case of motor vehicles damage electronic control units. This rather generalized caveat has been floating around in various forms for decades in transportation industries where vehicles use battery/alternator DC power systems. Many folk have interpreted it to have applicability under all conditions, even when the engine is not running. Others have enlarged the meaning to include the attachment or disconnection of jumper cables between the vehicle's power supply and that of another vehicle or exernal power source. I'd guess that the basis for the statement comes from what we learned about alternator behavior when they first replaced generators on airplanes back in the early 60's. While a generator would willingly start up and provide stable, useful power even when there was no battery on line, the new fangled alternator would not. Depending on design of the alternator/regulator combination, power supplied by an alternator sans battery could be anything from barely satisfactory to wildly hazardous to the health of electro-goodies on the airplane. This lays foundation for the birth of the split rocker, battery master switch that found its way onto most of the single engine airplanes flying today. The idea of the split rocker was to prevent leaving an alternator on line unless the battery was also on line. However, it did allow leaving the alternator OFF until after engine start and for battery-only ground ops. Of course, it also allowed turning off the alternator in flight. This last fact raised a new issue. 60 amp alternators were standard equipment on most Cessnas . . . even the lowly Day/VFR training ships like the C-150. As the battery slid off toward oblivion, it's ability to stabilize an alternator degraded too . . . especially when the machine was a 60-amp, fire-breathing dragon. Some folks experimenting with the alternator switch in flight found that re-energizing the alternator at cruise RPM, low system loads and a soggy battery produced surge transients of wallet vacuuming proportions. Hence the placard you see on many single engine certified ships saying "DO NOT TURN ALTERNATOR OFF IN FLIGHT EXCPET IN AN EMERGENCY". Again, we find the certified side of the house "fixing" a design problem with increased training and pilot workload. It also shifts the blame for subsequent mishaps off onto the pilot when the happless chap fails to observe the placard. In conversations with a number of TC aircraft owners, I've suggested that they superglue the halves of their split rocker switches together if their airplane has a pullable field breaker. This prevents inadvertent operation of only the alternator side of the rocker switch but still allows battery only ground ops and/or disabling the alternator in flight should the situation warrant it. Our recommended wiring diagrams for amateur built aircraft show single operator, two pole switches for the DC power master switch and a pullable breaker for the alternator feeding the alternator field. Alternator and battery come ON and OFF together. Getting back to the original statement, we need to understand also that as long as there is a battery of reasonably good condition on the line (even if it's presently discharged), there is no risk from adding or disconnecing an external battery with or without the alternator on line and/or engine running. The risks associated with external power connection are from inadvertent reversal of polarity and/or connection of 28v ground power to a 14v airplane (unlike connectors on the wall of your house for 120 versus 240 volts, ground power connectors on airplanes are not mechanically different for 14 versus 28v). The last risk associated with ground power shows up on some TC aircraft where the pilot has no control from his seat over the application or removal of ground power from his aircraft's system. All three of these gotchas have been addressed in the recommended wiring we show for ground power jacks as published on our website. Bottom line is that there are valid reasons for people to hand down these little bits of hangar wisdom. However without an understanding of the physics and circumstances behind the statement, it becomes more folklore than fact. Educated pilots are much less likely to have a bad day - in the air or on the ground. Education by sound byte or excerpt can be worse than none at all. The politicians and news anchors prove it every day. Date: Sat, 21 Aug 1999 01:42:40 -0400 Subject: Re: [c-a] Re: COZY: Re: Electric gizmos.... From: Art Bianconi Some years ago I was fortunate to be able to work alongside engineers from Underwriters Laboratories (UL) during destructive testing of electrical devices. This was part of my apprenticeship as a designer for a major electrical manufacturer and it was during this period that I acquired an appreciation for the real world differences between AC and DC current and the impact those differences have on switch design and applications. I share this with you because I am concerned at the widespread lack of appropriateness many builders demonstrate when selecting switches for the cockpit environment. Each time a builder asks me to perform a pre-FAA inspection of the aircraft, I carefully examine the switches and, to date, over three-forths of the projects inspected have turned up AC rated or non-rated switches in DC circuits. "Current is current; what difference does it make DC or AC?" The differences between AC & DC load carrying capability are dramatically non-linear and are best appreciated by carefully inspecting a high-quality switch rated for both AC and DC usage. Typical of this is the roller and bar micro switch made by MICRO Corporation (part # DT- 2RV23-A7). Rated at 10 amps at 125 or 250 volts AC, the same switch can only carry 0.15 amps at 250 volts DC! In real terms, we have lost more than 98% of the original load carrying ability and all we did was go from AC to DC! The voltage stayed the same! "But I'm using 120 Volt AC switches with only 14 volts DC." It doesn't matter what the AC rating is. If the switch is being used in a DC circuit, it needs a DC rating. Those of you who can still remember the old Kettering coil ignition systems will recall that when the condenser in the distributor went bad, the points generally turned blue and melted down in just a few minutes. Cockpit switches don't have the benefit of condensers to absorb the electrical inertia present in a DC circuit and as a result, the gap temperatures get hot enough to weld contacts. That includes AC rated switches, even those made with exotic high temperature alloys. AC current changes directions 120 times a second in a 60 cycle circuit. Consequently, there are 120 times each second when there is no current flowing at all. The current actually helps turn itself off the moment it sees a gap and switch designers use this phenomenon to help reduce the cost of manufacturing AC switches. In DC circuits, however, the "push" is constant even when the points begin to open and the resulting flash or arcing is DC current's way of demonstrating it's resistance to termination. The impact this abuse has on DC switch design is considerable. "But won't my circuit breakers protect me?" No they won't. Fuses and circuit breakers provide overload protection and a welded set of contacts will not, by themselves, cause an increase in circuit load. What often happened during UL testing was that the points welded shut making it impossible to open the circuit. Cycling the switch to the open position was often misleading: yes the lever moved but inside the switch, the cam had separated from the welded points. While it appeared physically to have switched off the current, the circuit was in fact, still hot. If the device on that circuit was your fuel transfer pump or fuel boost pump and you thought it turned off when in fact it was still running, what would the consequences be? If it were a flap, elevator trim device or a landing gear motor, how would tripping a circuit breaker save you. If the activating switch is welded closed and the device it controls is in a mode other than what is required for safe flight or landing, what will the circuit breaker do to change that? A DC rated switch will cost you about 3 times more than an AC rated switch of identical current capacity. If your panel has 10 switches (which is not likely) the difference will be less than $40.oo. You've gotten this far. Is it worth jeopardizing your investment or your safety by cutting corners with even one cheap or improperly rated switch? Regards Arturo ___________________________________________________________________ Get the Internet just the way you want it. Free software, free e-mail, and free Internet access for a month! Try Juno Web: http://dl.www.juno.com/dynoget/tagj. Date: Sat, 21 Aug 1999 19:06:17 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Electric gizmos. . (switch ratings) >Some years ago I was fortunate to be able to work alongside engineers >from Underwriters Laboratories (UL) during destructive testing of >electrical devices. This was part of my apprenticeship as a designer for >a major electrical manufacturer and it was during this period that I >acquired an appreciation for the real world differences between AC and DC >current and the impact those differences have on switch design and >applications. >A DC rated switch will cost you about 3 times more than an AC rated >switch of identical current capacity. If your panel has 10 switches >(which is not likely) the difference will be less than $40.oo. You've >gotten this far. Is it worth jeopardizing your investment or your safety >by cutting corners with even one cheap or improperly rated switch? I ran across this piece (or one very close to it) in an issue of Van's Air Force about two years ago. I wrote a rebuttal piece that ran in Sport Aviation a few months later and has resided on our website since. You may get your own copy of the article at: http://www.aeroelectric.com/articles/swtchrat.pdf Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurasic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Sun, 22 Aug 1999 10:36:44 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Essential bus feed >I am using a Radio Shack Cat# 276-1185 rectifying diode array for >automatic isolation of my essential buss. My problem is that while smoke >testing the electrical system I noticed a 0.7 volt drop in voltage >across the diode array. This was a no load, engine off check and my >input voltage from the battery is 12.43 volts with 11.73 reaching the >essential buss. Is this OK? My gut says no. What you have observed is built into the physics of how diodes work. They are not perfect "switches" . . . while their reverse conduction is very tiny (this is what makes them good isolators to prevent backflow of energy) their forward conduction has a small but relatively fixed voltage drop. The very common silicon power rectifier may be expected to drop between .6 and .8 volts under normal operating conditions. It is possible to buy germanium diodes and special silicon diodes (schotky) with lower drops but for the application we're discussing, it's not necesary. Here's why. Consider that when the alternator is running, bus voltage is 13.8 volts or greater. If you feed your essential bus from the main bus through the recommended isolation diode, this puts your essential bus at 13.1 volts or greater. Is this a "bad" thing? Consider further that when the alternator is not running, battery only operations will be at 12.5 volts or LOWER. Under these conditions, everything on the essential bus is supplied with a voltage LOWER than when the alternator is running. If the goodies on the essential bus are EXPECTED to operate battery-only until the battery's useful energy is depleted (down to 10.5 volts) then I suggest that the 0.7 volt drop you've observed is nothing to be concerned about. The design task you need to complete is make sure that all goodies on the essential bus will indeed function in the battery-only mode. All products for TC aircraft must be functional at some performance level down to 9 volts! Some suppliers of hardware to the amateur built industry have not done their homework. I get several messages a year from folk who find that some shiny new gizmo on their panel won't work unless the bus is at normal, alternator working levels. This survey of goodies in your airplane has nothing to do with whether or not a diode is installed . . . even if you replaced the diode with a switch (bad idea), the electro-goody's shortcomings will still be there. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurasic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Mon, 23 Aug 1999 07:34:21 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Altinator >My alternator an internal regulator and your ov relay and crowbar. >The altinator has two 1/4 spade conectors on the back in the >form of a T. I am told that the verticle one if for 12v or ignition lead >and the other is for an idiot light. Can I connect only to the 12v and >forget the other? I was also told that I can connect the two terminals with >a 10w 10ohm resister. When I do that it gets very how when the altinator is >not running. Some alternators need the idiot light in the circuit in order to tell the internal regulator that it is okay to come on line. Try hooking up to the only the IGN or +12 termninal first. If the alternator doesn't come up, then add the resistor. 10 ohms is much too low a value and I understand why it would get hot! The lamp that normally connects to this terminal would draw about 100 milliampers . . . a 120 ohm resistor (1 watt) is more appropriate. In fact, I'm surprised that any systems with a 10 ohm resistor installed would survive . . . don't know why it doesn't smoke the lamp driver inside the regulator. Another alternative is to hook up the idiot light to a fixture on the panel. You DO plan to have low voltage warning of some kind? Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurasic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Thu, 26 Aug 1999 08:35:50 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Batteries > I did not quite understand how to identify a pending battery failure > when we discussed ignition systems a couple of months back. I have > the following questions: > > 1. Is low voltage a sure sign of impending failure (provided the rest > of the charging system is healthy)? Voltage alone is not a very good indicator of anything. The two conditions that voltage alone will call out are (1) if the alternator is running and the bus voltage where it belongs (13.8 to 14.6 volts) then the charging system is carrying all sytem loads with something left over to charge the battery. IF the battery is CAPABLE of storing a useful amount of energy for later use, it will do so under these conditions. (2) if the alternator is NOT working and the bus voltage is greater than 10.5 volts, then there is SOME energy still left in the battery. Again, the question goes to CAPACITY which I'll address below. > 2. How about specific gravity? Do the testers that float the little > balls work? Hydrometers have been around since the first acid was dropped between two lead plates to run the first electric cars. While they will yield some useful information about battery condition, they're totally useless in recombinant gas, sealed lead-acid batteries. Personally, given the outstanding performance of the RG/SLA batteries, I wouldn't even consider putting a wet battery into and airplane. I just replaced the wet battery in my GMC van with an RG battery. > 3. Just what are the 'load testers' used at the parts / tire stores > and how do they work? Where can I buy one of these? Load testing speaks mostly to the ability of a battery to deliver power fast enough to crank an engine . . . while loosely associated with battery condition, it's not a good measure of battery capacity. You "load test" your battery every time you successfully crank the engine. None-the-less, I'll suggest that 1/2 of all single-engine airplanes flying today have FAILED batteries aboard . . . if the alternator craps, there is insufficient energy stored in the battery to be a practical second source of power. None the less, the battery probably got the engine going . . . I'm doing some work on the AGATE program for Raytheon (Beech). I'm going to propose an automatic battery capacity tester be included on board the airplane so that the owner can make periodic tests of battery capacity and replace them based on good data as opposed to waiting until they no longer crank the engine. > My concern is having what I think are 2 healthy batteries, only to > find that they have only about 20% storage. This will not last long > with an EFI fuel pump sucking on it. This is why we developed the two battery, yearly swapout technique for electrically dependent airplanes. Install two, RG batteries of identical size in your airplane. Use "main" battery to power engine essentials during alternator out ops and the "aux" battery to power panel essentials. Swap out the main battery into the aux slot each annual and put a new battery into the main slot. Now, you always have one battery less than one-year old and no batteries more than two years old. The CAPACITY of your on-board energy storage system is proven and can be relied upon to get your wheels back on the ground with comfort. The goal is to make sure that batteries have 75-80% of original capacity before you go flying. > At this point I am in favor of 2 alternators unless I can be sure of > identifying a battery that is prepairing to die. But 2 batteries and > 2 alternators on what is a basically day VFR plane??? Sounds like to > much weight and complexity to me. Maybe 2 alternators and 1 battery > is a better idea. The idea of eliminating failure modes has several > permutations here, but I was not educated enough in our last visit on > this subject to make an informed decision. Two alternators is an excellent idea . . . especially IF you can deal with an all-electric panel. B&C has light weight alternators in the 8 and 20 amp class than fit on the vacuum pump pad of the engine. Wiring for these systems is shown in diagrams downloadable from http://www.aeroelectric.com/errata/Z8_0299.pdf I would still have two batteries so that each alternator runs it's own stand-alone electrical system . . . see drawings. However, you can comfortably run one alternator and two batteries as well if you're willing to remove "a perfectly good battery" from the aux slot every year . . . the $50-70 expense of this exercise is trivial compared to the total cost of airplane ownership and it affords a level of reliability that is unequaled in ANY single engine, type certificated airplane flying today. > > Maybe we can get enough info to start a folder like was done for fuel > systems. This is very important since many of us are planning to run > EFI, which has to have juice. It's not a big deal. The design criteria lend themselves very well to analysis of the energy needed to meet your mission requirements. You just need to think and act a little bit "outside the box" . . . your experiences with TC'd airplanes are best filled in the "how not to do it" category going instead with a considered, calculated and MAINTAINED approach to fabrication and operation of your airplane. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurasic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Thu, 26 Aug 1999 07:50:15 From: "Robert L. Nuckolls, III" Subject: COZY: RE: ACS/Gerdes key-type ignition switch >Gentleman, >If I can put my 2 cents in... The ACS Gerdes ignition switch is a great >switch but.... there is an AD on the switch and I would comply with the >AD if I were installing the switch in my airplane... It may help you >from making an emergency landing. >Bryan Files >Ever Fly Maintenance >Palmer, Alaska The AD against that switch is for replacment of the starter switch contacts and addition of a DIODE across the switch contacts . . . or one can add the diode across the starter contactor coil as shown in all of our wiring diagrams. If you have a new switch of any age, it's just fine. You need to be sure there's an arc suppression diode or MOV in the sytem to keep the switch contacts from burning on the starter contacts only. In any case, there are NO effects on the magneto switching. If you have an switch already installed, but NO diode on your starter contactor, and the start function is working okay, don't fiddle with the switch and simply add the diode. I don't understand why the Feds made this fix an AD . . . the probability of creating an inflight hazard is somewhere between very tiny and zero. If you haven't purchased an ignition switch, consider using two toggles and a push button to control mags and starter. It's less expensive, the switches look like they belong on the panel with all the other switches and you won't find yourself strapped in with the key still in your pocket. Key switches are a minor inconvenience to someone who wants to steal your airplane. Recall that once you have two engines, no TC airplane has a ring of keys dangling from the panel in flight much less two. You get inside the door on a twin and you've got the airplane (assuming you know how to fly it). The expense, panel space and inconveniences of a keyswitch are easily traded away with what has to be an infintesimal increase in the risk of theft. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurasic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Mon, 30 Aug 1999 22:47:46 -0500 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Battery Cables & Ground Straps At 09:20 AM 8/30/99 -0400, you wrote: >--> RV-List message posted by: pcondon@csc.com > > >I crimped my battery cables with a bottle jack ( or sissor jack ) , a sorta >sharp-angled piece of STEEL angle iron ( bed frame angle iron ) & #2 copper >lugs. I simply positioned the cable--stripped- into the copper lug, shimmed >under my car, found a stout frame member and placed the cable/copper lug between >the angle iron and the frame member of the car and jacked up to squash-- I mean >crimp- the assembly together. Took 5 minutes & cost nothing. I did this for a >friend a few weeks later but walked up the street & crawled under a truck to >jack-crimp the cable(the truck was much heaver & produced a perfect crimp). >Don't over jack to distort the copper lug.............happy crimping It's also very easy to solder large terminals onto fat wires . . . see: http://www.aereoelectric.com/articles.html and page down to "Big Connections" . . . Date: Sat, 28 Aug 1999 19:56:33 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Antenna Resistance >Darrel Morisse wrote: > >> I have a standard 3 hole comm antenna, Dorne and Margolin Model DMC63-1/A. >> A friend was fooling around with it using an ohm meter and said the antenna >> is no good because he wasn't getting any resistance between the ground and >> hot receptacle. He claimed it should be at least 30 ohms continuity. >> Is what he's saying true? >> Is this an effective way of proving an antenna is shot? >> He also said that if I used it I would burn up the transmitter on my radio. >> >> Any help out there? >> Darrel > >forgot to mention that the antenna imperdance (in ohm) can be inductive or >capasitive, ie. if you are using an ohm-meter on an inductive antenna you can >measure zero ohm! >If you are measuring a capacitive antenna you are measuring in an open circuit >with infinity resistance. This is a little bit of a short and practical >explanation as the antenna theory is very complex, but from a practical way of >view its ok. >To really check your antenna and feeder installation (coaxial cable) we use to >have a SWR (standing wave ratio) check, this check confirm that your antenna is >workin properly, cause in this way we can see that if all the power delivered >from the transmitter is radiated out through the antenna. >If you are using your transmitter without any antenna, your transmitter may >quit, also if you are transmitting with a grounded/shorted antenna same might >happend. >As you see, using a ohm meter does not prove the antenna is ok or bad. The last statement is true but not quite for the reasons mentioned . . . you can have both "inductive" and "capacitive" antennas that measure either infinite ohms or zero ohms or anywhere between with an ohmmeter . . . a device for measuring DC resistance. Antennas are characterized with an AC impedance value that does require equipment designed for radio frequency AC measurements. Betware of low cost SWR meters sold by Radio Shack and CB radio outlets. While "rated" for a wide range of frequencies, I've found a number of devices that showed an SWR reading of 1:1 (ideal) when in fact it was much different! The best device is an impedance meter like the one we rent from our website catalog. See . . . http://www.aeroelectric.com/Catalog/catalog.html Go down to "Tools and Test Equipment" and click on "Rental Antenna Analyzer." While you're checking out the device, you can click on "download operating instructions" to see how the thing is used. This tool costs about $250. You only need it for a short time when installing home made antennas so we decided to make one available for rent. Getting back to the original post . . . If you have a manufactured antenna that has not been badly beat up . . . it is 99.99% probability of being okay. Bolt that feller on and give it a try. If the system doesn't work after installation, and you suspect the feedline or antenna, buy, rent or borrow some test equipment equal to the antenna analyzer I just showed you and it will help you deduce the fault. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurasic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Tue, 31 Aug 1999 22:17:18 -0500 From: "Robert L. Nuckolls, III" Subject: COZY: Re: "full field test" At 07:02 AM 8/31/99 -0400, you wrote: >I am hav.ing trouble with my alternator, and I have heard of a 'full field >Test'. Can you tell me what this test is or where I can find a description >Of it? Yes sir! The "full field" test is a VERY useful tool in diagnosing charger system difficulties but it must be done with caution. Of course, it applies only to alternators with external regulators. It's also not applicable to alternators with permanent magnet fields (like Rotax and B&C SD-8 alternators). Fabricate a jumper harness from a toggle switch (or even a push button if it's good for 5 amps or so) and two lengths of 20AWG wire long enough to reach from pilot's seat and the rear of your alternator. Disconnect the small wire from the alternator's field terminal and attach one of wires of your test harness. Attach the other wire to the alternator's output terminal or b-lead. Start with the test switch OFF or open. Start your engine. Monitor bus voltage with a good voltmeter and it's also really nice if your airplane is equipped with an alternator loadmeter (alternator output amps). Start the engine. Bus voltage should be equal to battery voltage . . . something around 12.5 volts or below. Turn on landing lights and pitot heat if you have them. Turn all radios OFF. Operate engine at minimum RPM and close your test switch while watching bus voltage. If it rises above 14 volts, shut the switch off and go to plan-B. The only time this will happen is if your idle speed is pretty high and your alternator pulley ratio is pretty fast also. Most likely, you will not see any increase in bus voltage. Now, carefully increase RPM until bus voltage reads 14 volts. Now turn everything ON that you can load the bus with except radios. Increase RPM's again to get 14 volts. If you can get 14 volts at any RPM below cruise values, then your alternator is probably okay. Pull the throttle back to idle, turn your test switch OFF, turn off all electro-goodies in your airplane and then shut things down. Another, less tricky test uses an el-cheapo automotive voltage regulator (generic Ford aftermarket is a good one . . . they can be had for about $20 or less). Rig test leads on test regulator as follows: B-lead input wire goes to pins "A" and "S" on regulator. A ground lead goes to the regulator case. A field ouput wire goes to the regulator's "F" lead. Leave the "I" lead un-connected. Again, remove the existing field lead from the rear of your alternator. Make a temporary installation of the test regulator by attaching "A/S" wire to the alternator's b-lead terminal. Attach "F" wire to alternator field. Attach ground wire to alternator case. Start engine and watch bus voltage. If the alternator is okay, the system will come up to 14 volts and carry all system loads at some RPM below cruise. If the alternator is bad, then you're not going to get enough output to bring the bus up to 14 volts . . . maybe no output at all. The snap-in test regulator is an excellent test tool to isolate regulator/wiring problems from alternator problems. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurassic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Fri, 03 Sep 1999 09:45:36 -0500 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Instrument lite dimmers >Ok, all you electronic experts, here's my problem. I bought an aircraft >instrument panel dimmer unit (20 ohms, 20 watts) for use with my stack >and post lights. When I test it with a meter, it shows that the >resistance changes properly as I spin the control. However, when I >connect it to my post lights (or to any other lights), it does not dim >them: they stay full-bright regardless of control position. Any ideas >what I'm doing wrong?? The size of a RHEOSTAT for dimming lamps is dependent upon the CURRENT draw requirements of all the lamps in the circuit. The rheostat used on the single overhead panel flood in a Cessna 172 is tiny compared to the dimmer used on a panel full of postlights in a Cessna 310. The latter case uses up lots of room behind the panel and makes the panel get too hot to touch when lamps are dimmed to about half intensity. I suspect that your lighting loads are so small that the 20-ohm resistance offered by your rheostat simply doesn't drop the voltage by a significant amount. Modern dimming techniques get some electronics included that allow the dimming control knob to adjust VOLTAGE and not RESISTANCE. While electronic dimmers are rated for some MAX CURRENT, their dimming charateristics are independent of the number of lamps they control. Examples of these devices can be viewed in our website catalog at http://www.aeroelectric.com/Catalog/lighting/lighting.html#hdim I published an article in Sport Aviation a few years back describing the technique for rolling your own .7 amp dimmer. Rheostats are expensive, have poor dimming characteristics (lamps don't dim linearly with knob rotation) and are generall not available in EXACTLY the right resistance for your situation. Further, if you dof find one that's just right, adding any more lights (or taking some out) in the future, hoses up the dimmer system. Electronic dimming is predictable, uses only tiny potentiometers on the panel for control, and let you mount the parts that get warm off the panel and out of the way. IMNHO, the only way to go . . . Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurassic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Sat, 11 Sep 1999 14:44:02 -0500 From: "Robert L. Nuckolls, III" Subject: COZY: Alternator/Battery issues . . . >OK, A&P's and EE's, jump in here and correct my thinking. This could be the >case if you were talking about a car, but I'm not 100% sure about alt's in >aircraft. Automobile alt's have diodes in them, that when they go bad will >allow a battery to completely discharge back through the alternator. When the diodes in an alternator go "bad" they either open (do nothing) or short (lots of smoke) . . . actually, you have to fail a minimum of two of the six to eight diodes in an alternator to effect the reverse feed of energy from battery back into alternator and it will not be any whimpy current flow . . . we're talking HUNDREDS of amps. This is why your b-lead on the alternator has a circuit breaker or fuse in it . . . >. . . . . When >this happens, depending on how long the battery as sat (or discharged), you >may never get it to come back to life with just a battery charger. First, alternator diode failure is a VERY rare event. This is one of the reasons why I've recommended firewall mounted fuses in the alternator b-lead for homebuilts . . . if the fuse is properly sized to eliminate nuisance trips, then most likely it will NEVER trip for the lifetime of the airplane. > . . . To keep >things simple, think of batteries as having a "memory". When they lose it, >through complete discharge, they don't know which side is positive and which >is negative (and can't be recharged until pos and neg are established). One >way to overcome this (sometimes) is by simply hooking another battery to the >dead one, to reestablish neg and pos sides. Once this is done, the battery >"may" be able to be fully charged with a charger. Alternators can also be >checked to see if the diodes are bad. Again, whether or not this applies to >aircraft type or not...I don't know. The MEMORY effect alluded to was first improperly applied to liquid Ni-Cads used mostly in BIG airplanes. I could cite about a half dozen articles that appeared in various electronics journals over the past 15 years debunking the memory theory but suffice it to say here that "memory" doesn't happen in other batteries . . . and especially in lead acid ones. Lead acid batteries have a shelf life . . . meaning that once a battery has acquired a certain age, it's capacity has degraded to a non-useful level. The RATE at which a battery degrades to useless is a function of state of charge and where in the life cycle the battery presently resides. For example, a 3 year old battery that's down to 40% of capacity already may loose half of that by sitting in a totally dischaged for a week and become NON-recoverable. While a brand new battery can take that 20% whack and still appear to have "recovered" . . . . It's true that a totally discharged battery can be charged up reversed with some apparent capacity of a reverse polarity but it doesn't take another battery to properly "polarize" a totally discharged battery . . . just hook your charger to it in the normal manner and say a few kind words over it, . . and hope you get back some utility for having done so. If you have bad diodes in an alternator that are at risk of discharging the battery, you're going to know it in a hurry. If you have open diodes, you may NOT know it. I bought a used car a few years back with a crippled alternator. The car seemed to have a pretty noisy bus and I filtered the +14V lead going into my ham rig to control the noise. It wasn't until I got the a/c fixed and had the blower running on HI along with headlights at night that I discovered the alternator's output was insufficient to keep the battery charged. I must have driven the car six months or more with a funky alternator. If you have a 60 amp alternator and fly only day/vfr, you might fly for years with a half dead alternator and not know it. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurassic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Sat, 04 Sep 1999 14:26:10 -0500 From: "Robert L. Nuckolls, III" Subject: Re: COZY: battery location At 10:48 AM 9/4/99 -0500, you wrote: >Builders, >In a recent e-mail, Robert Nuckolls III answered a builder who asked about >battery location, but he suppressed the address and copy list. He said that >the battery was one accessory that you could locate anywhere. On the Cozy, >we located it at the firewall. In that location, the run to the starter and >engine ground is so short you can use #4 welding cable, without much >voltage drop or heating. On the other hand, if you locate it in the nose, >the run is so long, you have to use #2 cable to keep the voltage drop down. >It will take about 24 ft of #2 cable. That is a lot of unnecessary "dead" >weight, as well as adding more weight besides the battery to forward c.g. >Regards, >Nat No argument Nat . . . the original question was somewhat generic and I tried to make the answer generic too. The thrust of my statement was that since the battery tends to be HEAVY, it has a strong influence on w/b . . . given that some builders like to try new things and should one find that w/b needs adjustment, then the battery is the first candidtate for relocation to satisfy w/b requirements. If w/b is not the driving issue, then by all means, mount it as close to the engine as possible so that the 4AWG wiring will suffice. BTW . . there are some new, 3 pound SLA batteries coming over the hill that are capable of cranking an engine. IF a builder is interested in a total electric airplane so that a vacuum pump pad opens up, then a second alternator can be installed. With dual alternators, the battery's duties as STANDBY power go away and the battery can be downsized a LOT. We're looking at the possiblity of removing vacuum pump and plumbing, a 24 a.h. or larger battery, a classic Prestolite or Ford alternator and the classic Prestolite starter (about 65 pounds total) and replacing it with dual lightweight alternators, dual batteries and lightweight starter for a total system weight that is less than half the stuff we took out! I have to suppress the address and copy list on items of general interest . . . I post them to 9 different list servers and if I don't use the "blind carbon copy" feature in place of the To: address, it causes a real snowstorm of unnecessary messages . . . I'm not trying to be sneaky or anything sinister . . . Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurassic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com From: cdenk@ix.netcom.com Date: Sat, 4 Sep 1999 15:14:36 -0500 (CDT) Subject: Re: COZY: battery location Nuckolls said I fortunately didn't consider the battery nose location, the C.G. ended up forward, even with the battery setting on the centersection spar. As far as I can determine, the forward C.G. is a result of many little 2 or 3 pound items, like a heater/defroster that works, full IFR panel, nose mounted landing lights, and the list goes on and on. All the niceties that help make flying comfortable and enhancing safety are a compromise. Date: Sat, 04 Sep 1999 11:45:30 -0500 From: "Robert L. Nuckolls, III" Subject: COZY: Re: battery location >Is there any reason that you would want to put the battery in the rear of >the other than getting it away from the heat up front,will it effect >balance that much, or is it just personal preference. The battery is about the only accessory with any weight that is also endowed with optional locations for installation. If your configuration is very close to one that's already flying such that weight and balance issues are not in question, then duplicating the system that's flying presents you with no new problems. Some of my builders are doing automotive and/or otherwise untried engine configurations and I advise them to PLAN for battery installations both for and aft but wait until they're sure what the weight an balance looks like before deciding. I know several folk who reinstalled their battery after the first trip to the scales. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurassic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Sun, 05 Sep 1999 12:14:56 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Inst. lamp dimmers >I built the dimmer you designed, mentioned in the RV-List, some time ago. >It worked! I played around with an idea I had that would make the >instrument light level vary with ambient light intensity. By using a >photoresitor (RS part), I got the light to dim when the ambient light was >high, ie, daylight. This was the opposite of what I was looking for, so I >wired a 2N2222 transistor across the pot, controlled by the photoresistor. >This worked fairly well, dimming the instrument light as the ambient light >decreased. The pot still operated to trim the light level. I suppose with >more tinkering, I could install a trim pot to vary the response rate of the >photoresitor. Good for you! Autodimming has been with us for awhile. The Cessna 400 series radios and some of the earlier autopilots produced some of industry's first whacks at the problem. I think it was fairly successful . . . you will probably have to tinker with the resistors associated with the photoresistor to set min-max ratios . . . but you can do this on the bench using a wall-dimmer on an overhead bulb to simulate approaching darkness. Turn down ambient lighting down all the way and let your eyes dark adapt for about 5 min . . . bring lighting up until you can just read the panel with no additional lighting . . . this is the light level where panel lighting wants to be "max" . . . then dim room lighting to full dark and adjust the "min" to the right level. . . . doing this on the bench (or in the shop sitting in the cockpit) will get you in the ballpark making it unlikely that further fiddling will be needed later. >This is all just benchtop tinkering....It hasn't been installed in any >cockpit, so the variables of cockpit brightness, photoresistor location, >etc., would have to be worked out. I don't know if you could get ideal >automatic instrument light dimming, but I'm forwarding you this as food for >thought. Of course radios have photo-resistors right on their front panels . . . a bit of a pain in the whatsit since your hand shades the photodetector when you reach for controls . . . just when you most want to see what's going on, the lights on the device dim down! Your notion of finding a suitable photo detector location NOT on the panel is a sound one. Your efforts are a good example of ways amateur builders can provide bells and whistles that spam can drivers can only wish for. . . Let us know how it works out. Better yet, write up an article and share the knowledge. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurassic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Tue, 14 Sep 1999 10:31:54 -0500 From: "Robert L. Nuckolls, III" Subject: COZY: Ground Systems was: Main battery cable size >The point here is that ALL of the metal in the airplane should be at the >same potential. This includes wings, tail surfaces, ailerons, flaps, just >whatever is made out of metal. > >There is a current AD note on the Beech King Air series to install ground >straps on the rudder of the airplane. The reason for this is that static >electricity would build up charges on the rudder and then discharge to the >fuselage. In the process of doing this the hinges would become eroded. > >Now our little GStars are not in the same speed range, and will not be >flying through the same kinds of weather, but the point here is that you do >not want different parts of the airplane to be at different potentials. > >What Bob suggested earlier is a fine way to go about doing that, but I >suspect it is a bit of overkill. In our case we have a bonding strap that >runs from the engine to the cage to the wings to the vertical tail and to >the horizontal tail. To accomplish this a #2 copper wire runs from one of >the starter mounting bolts to the lower left side engine to cage mounting >bolt. The negative pole of the battery is grounded to the cage using a #2 >copper wire to the bolt that secures the cage to the shell underneath the >baggage compartment floor. Short pieces of braided strap ground the wings >to the cage and one long strap runs from the bolt under the baggage >compartment floor to the tail section of the airplane. Were talking about two different issues here. The "bond-everything- to-everything-else mania swept through the Ez crowd about 10 years ago. These efforts are to elminate and/or reduce noises in radios due to static build up on surface of aircraft that causes tiny currents to flow in not-so-well connnected joints like control surface hinges. I've yet to see any confirmed case where this was useful on a homebuilt and I doubt that it's going to show up on anything less than a Lancair or Glasair in the 200 kts range. The DC POWER DISTRIBUTION ground system is another thing all together. Here, we're trying to (1) reduce the resistance in the starter cranking pathways to the lowest practical value, (2) avoid running battery currents through structure . . . especially welded steel where unwanted magnetization can take place, and (3) avoid the fabrication of ground loops where alternator and/or battery currents flowing in airframe can induce noises in other systems not well thought out with respect to installation and grounding. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurassic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Wed, 15 Sep 1999 08:17:05 -0500 From: "Robert L. Nuckolls, III" Subject: COZY: Re: 14v vs. 28v >> I think the only place that wire size is an issue is the high amp >> portion of the system & then only because the large wire gets >> stiff & hard to route. This applies to systems with batteries in >> the fuselage, etc. On the other hand, all new airplanes are going >> to 28v systems, as far as I can tell. Most of all "new" airplanes have been 28v for decades, the type certificiated ones that is. The trend was started when Cessna observed that buying one kind of thing in one voltage version only was less expensive than buying the same thing in two versions. Even the lowly C-150 went to 28v. It had almost nothing to do with weight since all of the 28v hardware with the exception of wire was the same weight as the 14v stuff. It was 95% driven by purchasing economics. Many of my readers building big Glasairs and Lancairs would LIKE to go 14V but their engine came with EXPENSIVE 28V alternators and starters installed. EVERY voltage sensitive part they have to purchase is uniquely "aircraft" which will never be priced according to consumer driven economics nor will they experience the product improvements we enjoy in an unregulated, free market atmosphere . . . >> . . . . This will surely affect the >> future availability of avionics for replacements & etc. Remember, >> the avionics manufacturers can pack more "stuff" on 28v boards than >> they can 14v boards & can create smaller packages for transmitters. The differences in electro-goodies between voltages is trivial to none. The major drivers of volume and weight have to do more with packaging and human interface aspects. A transmitter, for example, can be quite tiny except for the need to get heat out of it. While a 28v transmitter may be a couple of percent more efficient than its 14v cousin, it's by only a very few percent . . . given that the output stages have similar efficiencies and output power, their size doesn't materially change with voltage. BTW, most small signal stuff in avionics needs to run a voltages much below 14v . . . this is good and bad . . . it allows for power conditioning to take all the noises and perturbations off DC power before it's applied to sensitive electronics . . . it also drives up parts count and volume of the system without much effect on its overall efficiency. >> The only items from the auto industry are the alternator & the >> battery & perhaps some lights. . . . . and relays, electronic controlled fuel injection systems, ignition systems, fuel pumps, blowers and fans, contactors, and most important LOW COST SEALED GAS RECOMBINANT LEAD ACID BATTERIES. . . . . .The voltage regulator is now mostly >> in the alternator. 28v alternators & batteries cost about twice as >> much. Even the emergency starting issue is perhaps not such a big >> deal as batteries can be hooked in series, even while in autos. >> This would require two autos, however. This is all about a dead >> heat right now, it seems to me, but don't forget that it is very >> easy to step down voltage for lights & etc., . . . not really. It's the same problem for lights as it is for radios . . . power conditioning of some type between the bus and the working parts of the product. More parts count and less efficiency. Your nav lights are the most energy consuming system on the airplane . . . while a starter takes a lot of POWER for 5 seconds (200A X 11V X 5S = 11K watt-seconds) the nav lights are 6A X 14V X 7200S = 604K watt-seconds for a two hour flight). Having a 30% efficient starter isn't nearly as bad as having an 80% efficient lighting system when you start tallying up the ENERGY budget required to utilize each system. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurassic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Thu, 16 Sep 1999 09:20:42 -0500 From: "Robert L. Nuckolls, III" Subject: COZY: LIVING aircraft batteries . . . (was 14 vs. 28v) >Twice in the last 20 years I have been stuck with a >dead battery. The first time happened at a middle-of-nowhere . . . > . . . .Because I was in airplanes with 14 volt systems, >their vehicles were able to provide jump starts which got me >home . . . A 28 volt airplane has far fewer rescue options. May I suggest that over half of all s.e. airplanes flying today departed with a FAILED battery? We tend to treat batteries in our airplanes like batteries in our cars . . . it gets replaced when it fails to crank the engine for perhaps the 4th or 5th time? This means that the battery has been useless as a source of backup energy for perhaps years before it finally gets replaced. RG batteries are going to make this situation worse, they maintain a lower internal resistance than their wet and gel cousins. They'll still get an engine started even futher down the slide toward the recycle bin. Please learn and observe some peventative maintenance techniques almost unheard of in certified aviation. KNOW (by measurement) or BE SURE (by periodic replacement) or DON'T CARE (with dual alternators) that the battery is capable of getting you home in the situations which you fly. You can find a lot of mechanics out there that curse batteries for their various faults but very few that understand how to live with them. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurassic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Fri, 24 Sep 1999 10:09:31 -0500 From: "Robert L. Nuckolls, III" Subject: COZY: Buss bar calculations . . . At 12:50 PM 9/23/99 -0700, you wrote: >> At 08:56 AM 9/23/99 -0700, you wrote: >> > Yesterday, I sat down to figure out if my busses were adequate. Current >> >plan is to use 1/2" strips of .031" silver. The busses are little and >> >short, so I was mostly worried about temperature rise, less about voltage >> >drop. Temperature rise and voltage drop go hand-in-hand . . . loss of energy due to voltage drop converts directly to heat. However, thin strips of bare metal have the BETTER heat rejection than insulated wires of the same cross section. Further, because the strip is bolted to the terminal posts of circuit breakers every inch or so, you can probably get by with a very thin foil . . . buss bars tend to be thick for the purpose of making them mechanically favorable to work with. >> Silver? Talk about overkill! Trust me, it isn't an issue. >> >*** Yeah, well, I was going to make them of copper ( "Gee", said my IA, "all >the busses in my Bonanza are copper" ) but the FSDO inspector wanted me to >put in inspection requirements for the copper. Something like > > "Inspect for corrosion at annual. If corrosion is found, remove bus and >burnish it off. Use Swiglet special tool PAQ-FIBS-1 for burnishing. Bus is >adequately burnished when it looks like new copper. Replace bus if, after >burnishing, it is less than 0.XX inches thick or less than 0.XX inches >wide." This statement probably grew out of a paragraph in AC43-13 wherein a suggestion is made for "periodic cleaning of buss bars for corrosion" or something like that. EAA asked me to comment on the rewrite of AC43-13 about two years ago, I pointed out that properly assembled hardware attaching bus bars to breakers uses multi-tooth lockwashers or at the least, properly torqued fasteners that create GAS TIGHT joints. If properly assembled, very corroded bus bars can have perfectly good electrical properties because the place where breakers and screws hit the bar are SEALED from environmental effects. Most copper production bus bars are tin or solder plated to retard corrosion of bare copper surfaces. However, when clean hardware is assembled with internal tooth lockwashers under properly torqued fasteners, that joint is good for a lot more years than you're going to own the airplane. The science of crimping terminals to wires calls on the same conditions for getting two pieces of metal into intimate contact with each other. None-the-less, after EAA comments were forwarded to the FAA, -and- the document went back to the techwriters for another two years worth of work, AC43-13 is still loaded with poorly crafted suggestions and requirements that receive further bastardization when invoked by ignorant people with power. > ...Since I used silver, I was able to say something more like > >"Since busses are solid silver, they should remain free of electrically >significant corrosion for the life of the airplane". Silver is about as reactive to atmospheric stresses as copper. Why would we need "silver polish" for the family heirlooms were it not so? However, assembled with proper hardware and techniques, a silver bus bar will perform no better or worse than its copper brothers. >...I had the silver sheet just lying around, anyway. My dad was an amateur >jeweler, and when he died, I got all his stuff. That silver has been in the >closet for 15 years. I'd kept it because I thought it might come in handy >for RF projects. I've got a couple of silver bars that I bought about 20 years ago to silver-plate the inside surfaces of VHF antenna duplexer cavities I was building out of copper clad etched circuit board material . . . here's where a few molecules of silver laid on top of the copper was really worth the effort. Don't anyone run out looking for silver strip to "update" your airplane's bus bars . . . anyone who suggests it's either necessary or useful simply doesn't understand the physics involved. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurassic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Sat, 25 Sep 1999 09:05:18 -0400 From: "John R. Gleason" Subject: COZY: Contactor Ident. Once again, I'm hoping the wisdom of the people on these lists can help me. I have two contactors that came from the part-built plane I bought. I expect that one is a battery (master) solenoid and the other a starter solenoid. Trouble is I'm not sure which is which. One has four poles and has the following markings "RBM Controls" "70-111221-5" The other has three poles and has the following marking "OR1464" Any clues which is which? Many thanks. Allan Aaron Allan, The four pole contactor is the momentary contact starter solenoid. You will only need three of the poles. One small pole and one large pole are tied together internally.That small terminal is the extra one and is for the ignition system start boost in an automotive system. Most automotive ignitions run on about eight volts through a dropping or ballast resistor. When you start the engine this solenoid bypasses the resistor and feeds the ignition straight from the battery. It ends up still being about eight volts because of the voltage being pulled down by the starter. This momentary bypass was developed to keep the coil voltage from dropping to about five volts on start. The three terminal solenoid is the master and is designed for continuous duty. JRG Highland Dragon Rider COZY 0772 Making Hardware Date: Sun, 26 Sep 1999 10:30:59 -0500 From: "Robert L. Nuckolls, III" Subject: Re: COZY: Re: [c-a] Contactors At 03:41 PM 9/25/99 PDT, you wrote: >Allan, > >The master solenoid has three lugs. (I have one sitting right here that >says W-R/RBM 70-111226-5 COIL 12 VDC CONT.) The key word here is CONT. as >in "continuous". > >The starter solenoid has four lugs. Be aware that "starter" contactors and "battery" contactors can come with ANY combination of lugs. They can also be pretty mysterious as to whether they are continuous duty or intermittant duty unless specifically marked. Using an ohmmeter, you can deduce a LOT of important information about contactors. It's pretty much a no-brainer that the FAT terminals carry the BIG currents but the SKINNY terminals can be used in a variety of ways. If you are holding a strange contactor in your hand for the first time, find the terminals that are on the ends of the coil first. It's a sure bet that if the contactor has only three terminals total, that the one skinny terminal is one end of the coil. Attach the ohmmeter there and look at the other two terminals with the other . . . if no is found to the fat terminals, check to the mounting base of the contactor. When you've discovered the coil ends, note the resistance reading. If below 10 ohms, it's a sure bet that the contactor is intermittant duty. A continuous duty contactor will measure 10 to 20 ohms. If greater than 20 ohms, you MIGHT have a 24 volt device. If you have a 4-terminal device -AND- one of the coil terminals includes the mounting base, then the 4th terminal is probably a "telegraph" contact used to signal other parts of the system that the contactor is closed. This feature is found most often in intermittant duty, starter contactors wherein the 4-therminal is used to bypass an ignition ballasting resistor on older cars. In airplanes, some builders use this to drive a "starter engaged" indicator light on the panel. The contactors illustrated in our website catalog are two examples that you can take a peek at. The continous duty contactor photo shows a 4-terminal device. You can see a recommended technique for installing a spike supression diode on this device and adding a jumper wire to make it applicable to battery contactor service. The intermittant duty device shown is also 4-terminal . . . However, in this case the BASE of the contactor is one side of the coil while the 4th terminal is the "telegraph" terminal I mentioned above. This contactor has a spike catcher diode built in. A gross count of terminals cannot be directly equated to the manner in which the contactor is wired -OR- the service to which it is applicable in the airplane. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurassic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com From: "scott christensen" Subject: COZY: Re: [c-a] Contactors Date: Sat, 25 Sep 1999 15:41:59 PDT Allan, The master solenoid has three lugs. (I have one sitting right here that says W-R/RBM 70-111226-5 COIL 12 VDC CONT.) The key word here is CONT. as in "continuous". The starter solenoid has four lugs. Scott Date: Sun, 10 Oct 1999 10:45:29 -0500 From: "Robert L. Nuckolls, III" Subject: COZY: Re: LIVING with aircraft batteries ------------------ >>>A few years back I did some research into batteries for an underwater >>>propulsion device and I learned that the number of cycles that you got >>>out of a battery decreased with the percent discharge of the cycles. So >>>I am wondering what the effect on battery life is when you discharge it >>>to 5-10% of its capacity. Is that the only way to test the battery? >> ------------------ bn: It's true that a battery's life is improved by limiting the bn: depth to which you discharge it on each cycle. ------------------ >So, then, what is different about the construction of a "deep-cycle" >battery, such as those marketed as such for use in golf carts? ------------------ Deep cycle batteries pack more chemistry into the plate structure . . . generally limiting the number of plates per volume and increased spacing between plates which translates into higher internal resistance and poorer performance at low temperatures. I suspect that as the battery technology evolves, the the gap between batteries optomized for deep cycle work and cranking service may narrow. Most sealed lead acid batteries sold are used in deep cycle applications (camcorders, cellphones, power tools, etc.) so I'm sure the industry is working hard to keep this performance arena working well. In larger batteries (10 a.h. and up) there is also a need for good cranking performance. One company in particular has gone the extra mile in optimizing cranking performance in VERY small cells (1.2 a.h.). See http://199.239.60.165/ These tiny cells combined with two alternators make it now possible to remove the pigs found on most aircraft engines for starters and alternators and to forego the classic 24 a.h. battery in favor of light weight alternators, starter, and itty-bitty batteries for a DUAL electrical system who's TOTAL weight is about equal to the original 24 a.h. battery! The only sealed batteries I'm aware of specifcally made for deep cycle service are true gel-cells offered by Sonnenschein and Johnson Controls (the old Globe line). I think B&C still offers a couple of gels for customers that like them but for my money, the RG battery is the only way to go for an airplane were deep cycle performance isn't an issue. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurassic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com