From: Epplin John A Subject: COZY: Slaved Gyro Date: Tue, 4 May 1999 07:58:32 -0500 Am planning an all electric panel, had bad experiences with cheap vacuum pumps and lost a friend do to a situation that started with a vac pump failure in IMC. Will have redundant system, 2 batteries, 2 alternators and monitoring systems. My goal is to have a comfortable IFR airplane. Now my question: Has anyone installed a compass system such as a Collins PN101 or King KCS55 in a Cozy? I have made provisions in the end of the strake for the flux valve but nothing so far for the electric gyro. I don't think there is room in the spar but it may fit between the aft landing gear bulkhead and firewall. This would be a little aft of the CG, don't know if this is desirable as far as the gyro is concerned. I realize I still need the Whiskey compass as a last ditch backup. Thanks for any insight into this. John Epplin Mk4 #467 N100EP From: Epplin John A Subject: RE: COZY: gyros Date: Tue, 4 May 1999 09:15:37 -0500 I read you loud and clear! Maybe I am just gadget crazy or something. Consider this though, The PN101 replaces 2 instruments in the panel, panel is too small already as you allude to. The cost of a direct reading DG and vor converter/indicator is still less than the HSI, but you get much more. I am pricing these things on the used market and they are not out of reach. As you say, the volts can be fixed, also need 400 Hz for the gyro so a little transformer-rectifier will produce the 24 VDC easy enough. As an aside, when this thing is all sorted out my next project will be a complete autopilot system based on PC technology. This gives me a part of that John E... > -----Original Message----- > From: vaatk@flash.net [SMTP:vaatk@flash.net] > Sent: Tuesday, May 04, 1999 8:36 AM > To: cozy_builders mailing list > Subject: COZY: gyros > > I went through 2 vacuum pumps in 5 years. I got rid of them in 1992 > and replaced with all electric gyros. A lighter weight system and > more reliable also. > the Collins PN101 is the best for the money, it is a VERY reliable > system but is designed to run on 24 volts. The volts can be > overcome. This is a lot of gyro for our class of plane. In the jets > the pictorial nav is all we have but because of weight and space I > only have the standard electric gyros which have worked quite well. > With 1200 hours on the COZY I only have maybe 10 or so hours of actual > IFR, the planes are just not designed to carry all the crap that's > needed to do a good job flying in weather. Vance Atkinson > N43CZ From: "Wilhelmson, Jack" Subject: RE: COZY: Slaved Gyro Date: Tue, 4 May 1999 10:22:48 -0400 John: I have a flux coil driven remote magnetic compass in my airplane. The sensing unit is mounted in the nose as far forward as possible. The unit is a kit that I built quite a few years ago. I think I got it out of the CS newsletter. It really works great and is much more stable and accurate than the whisky compass. I consider it a good backup for the gyro compass. Carbon vane vac. pumps last about 500 hrs. Have them overhauled at about 300 hrs if you fly a lot of serious IFR. Make sure that the rebuilder replaces the rotor and bushings in the pump as well as the vanes. Some of these shops only replace the vanes and call them rebuilt. This causes premature failure due to the fact that the vanes are too loose in the rotor slots. I learned these things the hard way. Jack Wilhelmson N711CZ > -----Original Message----- > From: Epplin John A [SMTP:EpplinJohnA@jdcorp.deere.com] > Sent: Tuesday, May 04, 1999 8:59 AM > To: cozy_builders@canard.com > Subject: COZY: Slaved Gyro > > Am planning an all electric panel, had bad experiences with cheap vacuum > pumps and lost a friend do to a situation that started with a vac pump > failure in IMC. Will have redundant system, 2 batteries, 2 alternators > and > monitoring systems. My goal is to have a comfortable IFR airplane. Now > my > question: > > Has anyone installed a compass system such as a Collins PN101 or King > KCS55 > in a Cozy? I have made provisions in the end of the strake for the flux > valve but nothing so far for the electric gyro. I don't think there is > room > in the spar but it may fit between the aft landing gear bulkhead and > firewall. This would be a little aft of the CG, don't know if this is > desirable as far as the gyro is concerned. > > I realize I still need the Whiskey compass as a last ditch backup. > > Thanks for any insight into this. > > John Epplin Mk4 #467 N100EP From: cdenk@ix.netcom.com Date: Tue, 4 May 1999 17:29:17 -0500 (CDT) Subject: Re: COZY: Slaved Gyro Several items to consider: 1: THE FAR 91.205 for IFR flight says "Gyroscopic direction indicator (directional gyro or equivalent)". I would get the substitution in writing from the FAA. 2: Canadian IFR requires "a gyroscopic direction indicator or gyromagnetic compass" 3: If going all electric, I would consult heavily with Vance, as to where the power and backup power is coming from and the necessary circuits to be true backup. 4: I have on order (from Kansas) an autopilot vacuum directional gyro. My existing one is presessing and due for service. I plan to couple it with Porcine Assoc. DG coupler to the Navaid autopilot to give me heading hold independent of the GPS coupling. I agree that vacuum pumps aren't the most reliable thing (I seem to have more problems with certified equipment), but I like the idea of the electric T&B as old reliable backup. Did have vacuum pump quit on IFR flight plan on a Sunday, lost 2 hours while I replaced the pump in Georgia. Did loose an alternator belt, was close to flyin at Butler, a local gave me a ride to the NAPA store and bought a new one. And this last Sunday the GPS quit (probably a dead internal battery) while on a 200 mile flight to dinner VFR. COntinued the flight using pilotage, the 2 VOR's, and ADF to verify position, no big issue. Same flight one of the EGT probes went out causing a few concerning minutes untill crosschecking CHT's and static RPM, felt comfortable to continue journey. Use great respect when deviating from the usual, there are reasons its the usual. From: cdenk@ix.netcom.com Date: Tue, 4 May 1999 18:36:02 -0500 (CDT) Subject: Re: COZY: Slaved Gyro A further note I found in the Canadian "Air Navigation ORDER Series V, No. 22/CRRc.-48" [This is a part of my Canadian permission for IFR]. "No person may operate an aircraft in IFR flight within northern domestic airspace unless it is equipped with an approved, servieable gyroscopic direction indicator and a means of establishing direction that is not dependent on a magnetic source." Kind of seems like double talk to me, but there are areas of Canada (as well as the States)(18 degrees North of Duluth, Minn.) that have considerable magnetic disturbance. I think they are saying, they want the ability of the pilot to make manual adjustments to one direction reference device. Maybe someone can enlighten us, or better yet, get the Canadians interpetation. From: cdenk@ix.netcom.com Date: Tue, 4 May 1999 21:04:55 -0500 (CDT) Subject: Re: COZY: Slaved Gyro Was asked I think the way to go for backup vacuum is a unit that uses engine vacuum. Its available (I don't know where) for certified aircraft for around $300 US. From: cdenk@ix.netcom.com Date: Tue, 4 May 1999 21:26:42 -0500 (CDT) Subject: Re: COZY: Magnetic compass On 05/04/99 20:35:42 you wrote: > >Question; > >The (VFR) FARs require a "magnetic compass". Can this be an electronic >Flux Gate type? It is magnetic, but not as reliable as the whiskey types. >How about GPS? It is more accurate but gives no reading if the plane is >not moving, power is lost or the antenna breaks. > >FYI a recent thread referenced a 24 volt requirement for an instrument. I >carry a DC to DC converter whose output is +/- 0.050 volts at 24 volts with >an input of 8 to 18 volts. > >Bill T. >N29EZ > > The FAR's say for VFR (and therefore required for everywhere) "magnetic compass". I believe vertical card compasses are allowed as this. A flux gate compass requires electric power and is much more complicated. I believe the non-powered is a good practice and probably the FAA interpets it that way. The Canadians say "A direct reading magnetic compass" for IFR. I interpet that to allow only whiskey glass compasses. I think thats a making a statement against vertical card compasses. I have seen advertisements for a Pegasus whiskey glass compass. It appears that it is easier to read than the usual airpath unit. Summing my thoughts: 1: A whiskey glass is a must. 2: The fluxgate is heavy, don't think it can drive an autopilot. Don't think its a replacement for a DG. 3: Separate power supplies are a must for gyros. I prefer vacuum, the pumps aren't that bad, require respect when cleaning the engine not to contaminate. 4: Going to try vacuum gyro and Porcine heading hold interface to Navaid autopilot. 5: Possibly going to add Porcine's GPS heading hold/intercept, then I'll have a backup to heading hold if the autopilot stays on line. 6: I stay away from heavy IFR, always leaving an out within easy fuel range. From: sdbish@juno.com Subject: Re: COZY: Slaved Gyro Date: Wed, 05 May 1999 01:32:26 EDT Was asked I think the way to go for backup vacuum is a unit that uses engine vacuum. Its available (I don't know where) for certified aircraft for around $300 US. Engine vacuum has it's limitations, as it varies with throttle position. An analysis which I did a number of years ago, and unfortunately is not as fresh in my memory as I'd like, I seem to recall that under certain throttle or power conditions the intake manifold vacuum would be marginal as a back up vacuum source. Consider what readings you get on the manifold pressure gage, which is a measure of the vacuum, if properly converted. Marv Bishop ___________________________________________________________________ You don't need to buy Internet access to use free Internet e-mail. Get completely free e-mail from Juno at http://www.juno.com/getjuno.html or call Juno at (800) 654-JUNO [654-5866] From: cdenk@ix.netcom.com Date: Wed, 5 May 1999 04:15:48 -0500 (CDT) Subject: Re: COZY: Slaved Gyro On 05/05/99 07:45:08 you wrote: > >Where can we find an electric vacuum pump? Spruce had some standby vacuum stuff in their catalog. In another message someone questioned maybe could be mounted under passenger seat, fold down like landing light, when vacuum pump quits, extend it - ha ha - more weight and complex. If you want to fly heavy IFR, get a King AIr with backup everything and 2 pilots. Date: Wed, 05 May 1999 07:45:08 -0500 From: Carlos Leon Subject: Re: COZY: Slaved Gyro Where can we find an electric vacuum pump? Terry Pierce wrote: > What about a standby electric vacuum pump? It has to be cheaper than > electric gyros. > > -- > Terry Pierce <>< mailto:tpierce@ghg.net > Cozy Mark IV #600 > > Wilhelmson, Jack wrote: > > > > John: > > > > I have a flux coil driven remote magnetic compass in my airplane. The > > sensing unit is mounted in the nose as far forward as possible. > > The unit is a kit that I built quite a few years ago. I think I got it out > > of the CS newsletter. It really works great and is much more stable and > > accurate From: Epplin John A Subject: RE: COZY: Slaved Gyro Date: Wed, 5 May 1999 08:56:32 -0500 Sure getting a lot of good input from this question. I was looking at the possibility of the system described by Tom B. here. It would make a reasonable alternative but when I considered that I needed a redundant electrical system for the ignition anyway the decision was made to go with an all electric system. I won't get into the mag verses electronic ignition here except to say I am going dual electronic. Carl's post : 1: THE FAR 91.205 for IFR flight says "Gyroscopic direction indicator (directional gyro or equivalent)". I would get the substitution in writing from the FAA. 2: Canadian IFR requires "a gyroscopic direction indicator or gyromagnetic compass" I would assume the PN101 satisfies this requirement. I have seen many aircraft with flight directors etc that always have the gyro itself remote mounted, if fact this is normal. This does not eliminate the whisky compass or at least some sort of stand alone compass as a last ditch backup. I want to thank all that responded, gives a bit more insight into the system. John epplin... Mk4 #467 N100EP > -----Original Message----- > From: Tom Brusehaver [SMTP:tgb@cozy.core.wamnet.com] > > > >Engine vacuum has it's limitations, as it varies with throttle position. > > We have one in our clubs 172. There is a chart on the panel, altitude > vs. throttle setting. Yes, you cannot run full throttle at 12K and > get any vacuum from this device. It is an emergency only device, but > it works! > > You would be in limp mode to use it, but it would be a whole lot > better to be going slow, than not have it. Besides you'll probably > have enough stress, having more time to deal with things would be a > good thing. From: alwick@juno.com Date: Wed, 5 May 1999 21:32:24 -0700 Subject: Re: COZY: Slaved Gyro I'm going to try using engine vacuum augmented with a few electric vacuum pumps normally used to control your automobile cruise control. Haven't heard of anyone doing this, but worth a try. An unproven idea, something to consider. May not have enough volume, but I've got 7 of these pumps! I'll have computer monitor instrument vacuum and activate pump if needed. -al On Wed, 5 May 1999 08:29:57 -0500 (CDT) Tom Brusehaver writes: > >>Engine vacuum has it's limitations, as it varies with throttle >position. >> An analysis which I did a number of years ago, and unfortunately >is >>not as fresh in my memory as I'd like, I seem to recall that under >>certain throttle or power conditions the intake manifold vacuum would >be >>marginal as a back up vacuum source. Consider what readings you get >on >>the manifold pressure gage, which is a measure of the vacuum, if >>properly converted. > >We have one in our clubs 172. There is a chart on the panel, >altitude >vs. throttle setting. Yes, you cannot run full throttle at 12K and >get any vacuum from this device. It is an emergency only device, but >it works! > >You would be in limp mode to use it, but it would be a whole lot >better to be going slow, than not have it. Besides you'll probably >have enough stress, having more time to deal with things would be a >good thing. -al wick Canopy Latch System guy. Artificial intelligence in Cockpit Cozy sn 389 driven by stock Subaru 2.5 ltr.92% complete. ___________________________________________________________________ You don't need to buy Internet access to use free Internet e-mail. Get completely free e-mail from Juno at http://www.juno.com/getjuno.html or call Juno at (800) 654-JUNO [654-5866] Date: Thu, 06 May 1999 17:11:38 -0500 From: Michael Link Subject: Re: COZY: Slaved Gyro Terry Pierce wrote: > What about a standby electric vacuum pump? It has to be cheaper than > electric gyros. > > -- > Terry Pierce <>< mailto:tpierce@ghg.net > Cozy Mark IV #600 Terry, It all depends on how you figure costs. Short term, you are probably correct ; long term costs are a different story. Electric gyros last longer than vacuum gyros. ( R.C. Allen Co. says at least 3 times as long, and as much as 10 times longer). You also won't have to replace or rebuild a vacuum pump every 300 to 500 hrs., not to mention vacuum filters,vacuum regulators,vacuum guage, etc. A back-up rechargable battery that will run the gyros for a couple of hrs. costs less than $30.00. From: cdenk@ix.netcom.com Date: Sun, 15 Aug 1999 10:59:00 -0500 (CDT) Subject: COZY: Thermocouple, ?? If type K thermocouples have quick disconnect connections that are subject to changing temps, (say calibration at 70F, and now at 150F) how is the calibration affected? Is there a connector available that will minimize this affect? From: "John Rippengal" Subject: COZY: [Eze-solo] Thermocouple, ?? Date: Sun, 15 Aug 1999 19:17:39 +0300 ----- Original Message ----- From: >If type K thermocouples have quick disconnect connections that are subject to changing temps, (say calibration at 70F, and now at 150F) how is the calibration affected? Is there a connector available that will minimize this affect?< If uncompensated the instrument would read 80F too low. Yes there are leads/plugs/sockets that overcome this effect but I don't know US source. However even engine side of firewall a variation of 80F seems unlikely; 20 to 40 is more likely. It's not too difficult to measure at normal running and the meter could be re-calibrated to the mean. Is the absolute temperature of exhaust gas to within say 30F really that important as opposed to the relative change when leaning?? Do you really care whether it is 1350 or 1380 as long as you can see the trend? John Rippengal Date: Sun, 15 Aug 1999 13:47:02 -0400 From: Rob Cherney Subject: COZY: Re: [Eze-solo] Thermocouple, ?? Carl: Omega Engineering sells a wide variety of compensating thermocouple connectors. They also have a fair amount of information on thermocouples. See: http://www.omega.com A PDF primer on thermocouples is at: http://www.omega.com/pdf/temperature/Z/pdf/z021-032.pdf Their temperature products is at: http://www.omega.com/toc_asp/section.asp?book=temperature§ion=g A PDF data sheet for their connectors is at: http://www.omega.com/Temperature/pdf/UST.pdf Rob- At 10:59 AM 8/15/99 -0500, cdenk@ix.netcom.com wrote: >If type K thermocouples have quick disconnect connections that are subject >to changing temps, (say calibration at 70F, and now >at 150F) how is the calibration affected? Is there a connector available >that will minimize this affect? > >_ >_\ >8=>====EZ Instruments =========|> >_/ > "eze-solo@canard.com" Canard Aircraft Electronic Instruments list > http://www.canard.com/ezi > > for help on how to get off this list, > send the following to: majordomo@canard.com > > unsubscribe eze-solo your@emailaddress.com +------------------------------------------------------------------+ |Robert Cherney Home Phone: (410)465-5598 | |Ellicott City, Maryland e-mail: cherney@home.com | +------------------------------------------------------------------+ From: alwick@juno.com Date: Sun, 15 Aug 1999 11:08:23 -0700 Subject: Re: COZY: Thermocouple, ?? You can easily determine this for yourself by calibrating with the suspect connection. To calibrate using ASTM procedure just place ice cubes in glass. Fill with water (distilled preferred, but not signif). Let it sit for few minutes with your thermocouple in glass. Use boiling water to determine your other calibration point(may have to consider elevation). I think you'll find that the junction is not significant and is linear. -al wick Canopy Latch System guy. Artificial intelligence in Cockpit Cozy sn 389 driven by stock Subaru 2.5 ltr 101% complete. On Sun, 15 Aug 1999 10:59:00 -0500 (CDT) cdenk@ix.netcom.com writes: > If type K thermocouples have quick disconnect connections that are > subject to changing temps, (say calibration at 70F, and now > at 150F) how is the calibration affected? Is there a connector > available that will minimize this affect? > ___________________________________________________________________ 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: Sun, 15 Aug 1999 18:57:55 -0400 From: "John R. Gleason" Subject: COZY: TC Connectors The materials in the QD connectors are made of the same alloy as the TC. Therefore, there is no "couple" at the connection. It is important to use the right connectors with the TC in use. In most cases they are color coded (yellow - type K, Black - type J, etc.) The insulation on the wires is also usually color coded. As I said several months ago, Omega has an excellent book on the subject that they send out FREE. Go to their web site at www.omega.com Click on the free lierature box. If everyone had a copy of their handbook we could probably eliminate TC questions.


JRG " Highland Dragon Rider" COZY # 772 (Making Hardware)


At 10:59 AM 8/15/99 -0500, you wrote:
>If type K thermocouples have quick disconnect connections that are subject
>to changing temps, (say calibration at 70F, and now
>at 150F) how is the calibration affected? Is there a connector available
>that will minimize this affect?
>
 From ???@??? Sun Aug 29 01:42:11 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 SAA00613 for ; Sun, 22 Aug 1999 18:42:12 -0400 (EDT) Received: (from majordomo@localhost) by twc2.betaweb.com (8.8.5/8.8.5) id NAA28945 for cozy_builders-list; Sun, 22 Aug 1999 13:36:58 -0400 X-Authentication-Warning: twc2.betaweb.com: majordomo set sender to owner-cozy_builders@betaweb.com using -f Received: from DTC.NET (DTC.NET [206.242.217.15]) by twc2.betaweb.com (8.8.5/8.8.5) with ESMTP id NAA28940 for ; Sun, 22 Aug 1999 13:36:53 -0400 Received: from bob (P7.TS1.DTC.NET [205.183.130.7]) by DTC.NET (8.9.1/8.9.1) with SMTP id WAA19383; Sun, 22 Aug 1999 22:08:58 GMT Message-Id: <3.0.1.16.19990822170837.858f7090@dtc.net> X-Sender: nuckolls@dtc.net X-Mailer: Windows Eudora Light Version 3.0.1 (16) Date: Sun, 22 Aug 1999 17:08:37 To: (Recipient list suppressed) From: "Robert L. Nuckolls, III" Subject: COZY: Re: Turn coodinatro shielding In-Reply-To: <199908222002.NAA27180@matronics.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Sender: owner-cozy_builders@betaweb.com Precedence: bulk Reply-To: "Robert L. Nuckolls, III" X-UIDL: d4b5755461d14a31fd1937e30cf28b60 >Well I have this really neat instrument panel all designed for my RV-4, but >may have a problem. I have the compass planned to be mounted on the panel >near the turn coordinator. But on the bench, the TC swings the compass >greatly. I know the easy solution is to move the compass, but I was hoping >the retain this design. Is it possible to shield the TC in some manner? The IDEAL material to reduce stray magnetic fields around both potential antagonists -and- victims is a stuff called Mu-Metal . . . not easy to get and not easy to work with. You can try an experiement to see if it's worth the trouble. Get some ordinary galvanized sheetmetal that comes in rolls about 8" wide and used for valley sheeting between roofs. Cut a strip wide enough to cover the depth of the turn coordinator and long enough to wrap around the outside case about three layers deep. The metal is soft, thin and pretty easy to work with. Hold the sheet-metal cocoon in place with several fat rubber bands or some wraps of tape. Now, see what effect the T/C has on the compass. If you're lucky, the sheet metal you've put on does the trick and you can slip this shield off to be replaced later after the T/C is installed. Use Tie-Wraps or lacing string to hold it in the final installation. If you're not so lucky, you'll find that the effects are considerably reduced but still to strong to swing out when the compass is installed. In this case you may have to go for the high-dollar, finger slicing stuff. 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, 24 Sep 1999 17:09:50 -0700 From: Eric Westland Subject: COZY: ASI Calibration David, Here's a link to a site I found helpful when checking my ASI. It uses GPS data from three legs flown at any heading and then crunches the numbers in an Excel spreadsheet. There is lots of other good stuff there as well. http://www.cyberus.ca/~khorton/rvlinks.html#PEC -eric Date: Tue, 05 Oct 1999 07:11:28 -0400 From: "Marc J. Zeitlin" Subject: COZY: Airspeed Indicator - arc speeds Brian DeFord tried to write (but majordomo cut him off at the knees due to the word "config" being the first word in the 9th line :-) : >Cozy MK-IV builders: > >I'm getting ready to order an airspeed indicator for my MK-IV and I can >specify arc ranges to customize it. In looking at the POH, I am a little >unsure at what range I should specify for all of the arcs. Can those flying >give me a rough estimate of what they are using? > >* White arc (typically the range is from Vso, power off stall in landing >config at max landing weight, to Vfe, max flap extension speed) > >Since no flaps, do you use max speed brake or gear down speed? What speeds >are best for Vso and Vfe? > >* Green arc (typically the range is from Vs1, power off stall at max takeoff >weight and gear up, to Vno, max crusing speed in smooth air) > >What speeds are best for Vs1 and Vno? > >* Yellow arc (starts at Vno and goes to Vne, never exceed speed) > >POH states 190kts is Vne > >So - to summarize and to make replies easy - please fill in the blanks :) > >Vso >Vfe (or equivalent) >Vs1 >Vno >Vne > >Thanks for your help! >Brian DeFord From: cdenk@ix.netcom.com Date: Tue, 5 Oct 1999 19:08:12 -0500 (CDT) Subject: Re: COZY: Airspeed Indicator - arc speeds Order an airspeed indicator without markings, knots as the major units, and MPH as the inner units from Mid Continent Instruments with the agreement they will add the range marks later. Then after you have flown, and know the exact minimum (equivalent of stall) speed, have the marks added. With next day delivery, should have back in less than week, including a fresh calibration. From: cdenk@ix.netcom.com Date: Tue, 5 Oct 1999 19:11:39 -0500 (CDT) Subject: Re: COZY: Airspeed Indicator - arc speeds Was said Interesting, both the 3 place and the Cosy Classic show 200 knots. From: "gdavis" Subject: Re: COZY: Airspeed Indicator - arc speeds Date: Thu, 7 Oct 1999 18:45:01 -0700 Mark, Call Howard Francis he has Air indicators with the proper arche as per nat at a great price. I think mine was about $95.00. Is new rebuildt right off the shelf. Gene Davis N42CZ From: "Nat Puffer" Subject: Re: COZY: UMA ASI Date: Mon, 11 Oct 1999 15:50:21 -0500 David, Howard Francis in Tempe sells rebuilt ASIs for half the cost and twice the accuracy. Nat ---------- > From: David Domeier > To: cozy_builders@canard.com; Canard mail list > Subject: COZY: UMA ASI > Date: Monday, October 11, 1999 5:36 PM > > About 2 weeks ago I posted a message regarding a very hard landing > in my Cozy MKIV that caused some cosmetic damage to farings and my ego. > This is a follow up to that message. > > I determined that the airplane pranged on (nose gear first) due to > lack of adequate airspeed while flying at a forward cg and heavier than > usual gw. And the reason the airspeed was inadequate was that the ASI > was indicating about 12-14 knots fast - IAS was 80 kts but CAS was > actually 68 kts or less. It took a while to prove this out, but based > on GPS ground speed runs and an inflight check with 2 other aircraft, I > believed it was so. > > I sent the airspeed indicator back to UMA with a letter explaining > what was wrong. (Wicks would not take it back even though it was just > six weeks old) I received a new indicator in about a week. I installed > it along with a back up ASI and flight tested it. I was very > disappointed to find it reading exactly what the previous one had - > about 12-14 knots fast!? > > At this point I was beginning to question whether all the previous > checks I had done were valid and perhaps I had a pitot/static problem. > I moved the static port and the pitot port temporarily and it proved > nothing except the indication was exactly the same. Why was this thing > indicating so much in error?? > > Today I went to a local Cessna dealer and borrowed an certified ASI > off their shelf. (both of mine are not certified) I hooked it up and > blasted off with 3 ASI's - one on the panel and 2 on the right seat. > With the Cessna indicator at 100 kts, the 20 year old back up was at 102 > kts, and the new UMA was at 115 kts! > > Conclusion - there are new ASI's being sold very much out of > calibration. I called UMA and the person I spoke to was very apologetic > and, yes, they would recalibrate the unit as soon as I returned it. > This time I will get a written report on what they find rather than a > new unit off the shelf. > > dd > MKIV N10CZ > > From: cdenk@ix.netcom.com Date: Mon, 11 Oct 1999 20:41:10 -0500 (CDT) Subject: Re: COZY: UMA ASI I had an episode, of several instruments I bought from a Trade A Plane advertiser that said they were a certified repair station, and then there was a notice in Sport Aviation that they were not certified. Sent the instruments back, got credit from Mastercard, and provided the FAA with copies of my paperwork. An accurate ASI is important when ATC asks for a specific airspeed. Its a lot easier to work with accurate instruments than when under the heat of battle try to remember what the calibration number is. Know who you are dealing with, buy certified equipment, there is a reason, the others are able to offer lower prices, they are cutting corners. From: FLYCOZY@aol.com Date: Tue, 12 Oct 1999 01:17:46 EDT Subject: COZY: Re; VM1000 Cozy builders I just finished a few weeks age installing the vision micro system 1000 system in the cozy I am building. The installation was quite simple I mounted the DPU ( display power unit) on top of the center spar by the battery all the wires from the senders come up the engine mount and through a rubber grommet in the firewall and then to the DPU. I found the installation manual EZ to follow and all the senders were included in the price. If I remember right I believe it was priced at $ 3100.00 this includes all the senders and the monitor. "Just one ribbon cable goes up to the instrument panel. If you order one remember to tell them its's going in a pusher . They need to supply you with a longer ribbon wire to the display unit".That might sound like alot of money but if you price all the same equipment individually you will be in the same price range. One thing I really like about the VM 1000 is that it has a memory of your last flight it remembers the highs and lows of each engine system so you don't have to right it down in flight, which allows more time to monitor other things. It also has AUTO TRACK this is just a push of a button and it remembers the setting , such as after you get to altitude and the aircraft stabilized you can touch this button it"s the the third button from the left and the unit will flash the area af concern if you get a noteable change in temperature or pressure. I have spent a considerable amount of time researching the best bang for the buck. In my opinion the vision micro system is a good value. The only thing I did'nt like was that when you wire the system into the light dimmer panel the VM has such a large face and tends to let off alot of light compared to the other lights in the panel . This could easily be remedied by 1. putting it on a seperate dimmer or 2. wire in a resistor in the dimmer line to cut down on the light voltage. Have fun; Dennis Oelmann N261DM cozy 3 N269DH co-builder N 66DK co builder N 92VT Mark IV Date: Mon, 11 Oct 1999 06:06:48 -0400 From: Jeff Russell Subject: COZY: Re: Cozy : VM 1000 mfacchinelli@sogei.it wrote: > Every comment about it from that pilots-builders who have installed and > used it is wellcome ? I do not like how small the read outs are. Hard for me to scan. I use separate gauges for oil temp/press, tach, engine EGT/CHT/volt/OAT, manifold, fuel flow/pressure. I can scan them much better. -- Jeff Russell/AeroCad Inc. Date: Tue, 12 Oct 1999 08:27:55 -0500 From: David Domeier Subject: Re: COZY: Re; VM1000 A BEST feature of the VM1000 is fuel management. The fuel flow count on my unit is very accurate. When fuel remaining reaches 10 gallons, REM starts flashing and doesn't quit until fuel is added. Of course it does not know which tank the fuel is in so fuel tank valve selector management is required.... dd Date: Mon, 11 Oct 1999 05:53:59 -0500 Subject: Re: COZY: VM 1000 Engine Monitor (of Vision Microsystem inc) From: mark w beduhn On Mon, 11 Oct 1999 11:18:39 +0200 mfacchinelli@sogei.it writes: > Canardians, > > Can someone help me to contact Vision Microsystem inc?.(E-mail > address or else) > I need all the info I can get about the VM 1000 Engine Monitor?.. > Are the probes included in the kit ? > Every comment about it from that pilots-builders who have installed > and used it is welcome ? > > CIAO from Italy > Massimo Bonicelli > > Phone: (360) 714-8203 Fax: (360) 714-8253 Address: Vision Microsystems 4071 Hannegan Suite T Bellingham, WA 98226 All probes and sensors come with the system. You will need to tell them the engine model number that it is being installed with, so they can customize the internal program to match the your engine specifications. I have been using one for 2 years with a Lycoming IO-360 and I like it a lot. Mark Beduhn Cozy IV N494CZ Date: Thu, 14 Oct 1999 13:44:21 -0500 From: David Domeier Subject: COZY: UMA responds.... This is a follow up to previous messages I have posted regarding a high airspeed reading using a UMA ASI. To recap, I purchased a new UMA indicator, Wicks part number AS-E/CZ, in August to replace a 20 year old unit I had salvaged from my LEZ. The new indicator was the one I was using when I made a very hard landing in the MKIV on September 17. After numerous flight checks it was determined the ASI was in fact reading some 12-14 knots fast. It error varied somewhat depending on speed. Instead of coming over the fence at 80 knots, the calibrated speed was 68 or less. I sent the unit back to UMA since Wicks would not accept it. About a week later I received another indicator and it had exactly the same error factor. The day before yesterday I sent it back with a polite letter explaining the situation and asking for a bench test and report on the indicator. This morning, just 48 hours after sending the unit, I got a phone call from UMA. The indicator was out of calibration as I reported, and the reason was a technician had misread the outer scale for MPH when calibrating the instrument. They sell ASI's with the scale MPH/KNOTS and KNOTS/MPH (outer/inner scale) and that's how it got calibrated in MPH instead of KNOTS. In fact, it happened twice. The first time when the unit was built and the second time when I sent it back for recalibration. The person who called was very honest about the calibration error, assured me it had been addressed by a quality control officer, and corrected. My ASI will be shipped tomorrow after an over night calibration process to read correctly in knots. UMA is OK. They want to do what's right. dd From: "Wilhelmson, Jack" Subject: RE: COZY: UMA responds.... Date: Thu, 14 Oct 1999 17:57:35 -0400 It is easy to bench check a ASI using some clear plastic tubing Taped to a ruler and a aquarium valve. The formula is a constant times Velocity squared for water head. I calibrate my own ASI when needed. The water head at 100 knots is about 14" (from memory which is very week). Jack Wilhelmson N711CZFrom ???@??? Fri Oct 15 06:01:18 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 JAA02470 for ; Fri, 15 Oct 1999 09:41:16 -0400 (EDT) Received: (from majordomo@localhost) by twc2.betaweb.com (8.8.5/8.8.5) id JAA30811 for cozy_builders-list; Fri, 15 Oct 1999 09:12:14 -0400 X-Authentication-Warning: twc2.betaweb.com: majordomo set sender to owner-cozy_builders@betaweb.com using -f Received: from hawk.prod.itd.earthlink.net (hawk.prod.itd.earthlink.net [207.217.120.22]) by twc2.betaweb.com (8.8.5/8.8.5) with ESMTP id JAA30799; Fri, 15 Oct 1999 09:12:07 -0400 Received: from earthlink.net (1Cust233.tnt10.chi5.da.uu.net [63.22.154.233]) by hawk.prod.itd.earthlink.net (8.9.3/8.9.3) with ESMTP id GAA08236; Fri, 15 Oct 1999 06:10:14 -0700 (PDT) Message-ID: <38072818.4DCE3D9B@earthlink.net> Date: Fri, 15 Oct 1999 08:11:53 -0500 From: David Domeier X-Mailer: Mozilla 4.61 (Macintosh; I; PPC) X-Accept-Language: en MIME-Version: 1.0 To: "Wilhelmson, Jack" CC: cozy_builders@canard.com, Canard mail list Subject: COZY: Pitot/static inst calibration.. References: <28C1D35F1A45D2119A4C0008C7FA56D20111016D@scra_nt1.scra.org> Content-Type: text/plain; charset=us-ascii; x-mac-type="54455854"; x-mac-creator="4D4F5353" Content-Transfer-Encoding: 7bit Sender: owner-cozy_builders@betaweb.com Precedence: bulk Reply-To: David Domeier X-UIDL: 9541097ce28ddcc8fc7d0aab1b95432d Jack, re "The water head at 100 knots is about 14" (from memory which is very week)." You must have a simpler procedure than the one I down loaded. The one I have was written by Russ Erb and requires 20 to 40 feet of clear vinyl tube. I stopped reading the report at that time 'cause I figured I could get what info I wanted quicker in the air using the GPS. Thanks for the info and maybe you could post a message on how you did it. The Russ Erb procedure was developed as a project at the USAF Academy and must have taken weeks to set up. dd From: "Reid Siebert" Subject: COZY: Airspeed calibration problems Date: Sat, 16 Oct 1999 09:23:02 -0500 Prior to flying your new bird for the first time the pitot and static systems should be certified by a calibrated test box. One of these boxes can be found at most avionics shops, and many better FBO's. This test box will find any air leaks, or instrument errors that exist in your installation, by comparing your instruments against a set of recently calibrated instruments. This test is required by F.A.R. for ANY aircraft that has an altitude reporting feature on its transponder, before that aircraft can fly in radar controlled airspace, and the test must be repeated every twenty four calendar months. The test can be done, by a technician, in a few hours, and eliminates all worries one might have about the quality of his work, or that of the instruments he purchased. When you talk to a shop about doing this ask for a Pitot & Static Test, along with a Transponder Altitude Readout Test. These test are the same ones mandated for IFR rated aircraft. It's money well spent for the peace of mind in knowing your are flying as fast as your instruments say you are. Reid Siebert A& P Mech., and Cozy Builder Date: Sun, 17 Oct 1999 19:47:55 -0400 From: bil kleb Subject: Re: COZY: Airspeed calibration problems Reid Siebert wrote: > > Prior to flying your new bird for the first time the pitot and static > systems should be certified by a calibrated test box. the way i read the regs (91.413, 43 Apnds E&F) that these boxes are made for, they don't test the pitot system: just the static. basically they make sure that your altimeter doesn't leak, is calibrated, and that your encoder /transponder pair is squawking the right code given the some simulated altitude. if you'd like to check your pitot, make a water manometer (a u-shaped tube partially full of water with a ruler strapped alongside) and have at it; dh = 0.5*rhoa*(v*n2m*5280/3600)^2/g/rhow*12 where (for typical conditions), dh = difference in water column height (inches) rhoa = density of air (0.002378 slugs/ft^3) v = speed (mph or kts according to n2m, see next item) n2m = conversion factor (1.152 for speed in knots or 1.0 for speed in kts) g = 32.19 ft/s^2 (gravitational acceleration) rhow = density of water (1.937 slugs/ft^3) or the inverse relation: v = 3600/5280/n2m*sqrt(2*rhow*g*h/12/rhoa) so you can generate a table like: knots inches 40. 1.04 45. 1.32 50. 1.63 55. 1.97 60. 2.35 65. 2.76 70. 3.20 75. 3.67 80. 4.17 85. 4.71 90. 5.28 95. 5.89 100. 6.52 105. 7.19 110. 7.89 115. 8.62 120. 9.39 125. 10.19 130. 11.02 135. 11.88 140. 12.78 145. 13.71 150. 14.67 155. 15.67 160. 16.69 165. 17.75 170. 18.85 175. 19.97 180. 21.13 185. 22.32 190. 23.54 195. 24.80 200. 26.08 -- bil Date: Sun, 17 Oct 1999 22:43:08 -0500 From: David Domeier Subject: Re: COZY: Airspeed calibration problems Reid, re "When you talk to a shop about doing this ask for a Pitot & Static Test, along with a Transponder Altitude Readout Test. These test are the same ones mandated for IFR rated aircraft." The Pitot & Static Test test for IFR certification does not mandate testing the ASI, only the altimeter. In fact, some instrument shops do not keep the ASI portion of the test equipment calibrated for that reason. My airplane is IFR certified, I have the test report in the log, and there is no reference to ASI. dd Date: Mon, 18 Oct 1999 06:48:52 -0400 From: bil kleb Subject: Re: COZY: Airspeed calibration problems bil kleb wrote: > > n2m = conversion factor (1.152 for speed in knots or 1.0 for speed in kts) oops: 1.0 for speed in mph > v = 3600/5280/n2m*sqrt(2*rhow*g*h/12/rhoa) and in this equation the "h" should be "dh". while i'm here, i might as well give units to the plain numbers: 3600 s/hr 5280 ft/mile 12 in/ft in case you want to play "cancel the units" to check things. these equations are simply equating the hydrostatic pressure of a gas/liquid (water in this case) given by [density X gravity X height] to the "dynamic pressure" (pressure due to speed) of a gas/liquid (air in this case) given by [1/2 X density X speed X speed]. also note that the order of multiplication/division is from left to right. for instance, in the equation above, you would divide 3600 by 5280 then divide that result by n2m and multiply by the square root for the result in parenthesis. (out of respect for our moderator's employer, the formulas are most easily used on an HP calculator using RPN (reverse polish notation).) see also jim weir's july 1989 kitplane's article, "here is a $3 method of calibrating your airspeed indicator", also available online as: http://www.rst-engr.com/rst/magazine/kp-89jul.zip -- bil From: "Reid Siebert" Subject: Re: COZY: Airspeed calibration problems Date: Mon, 18 Oct 1999 07:54:43 -0500 Every pitot and static test unit I have ever used has BOTH a calibrated altimeter, and a calibrated airspeed indicator, installed on the test box. If the FBO, or avionics shop, you are using does not have both, go someplace that is more professional. Reid Siebert Date: Mon, 25 Oct 1999 22:17:44 -0500 From: David Domeier Subject: COZY: Static pressure I've decided a static pressure test of the altimeter and airspeed indicator on the ground is not an indication of what the instruments will indicate in flight. This is because once air is set in motion, it is very difficult to accurately measure its static pressure. Bernoulii's Law is very true - as the speed of a fluid increases, dynamic pressure increases and static pressure decreases. The UMA ASI now installed in my MKIV, after recalibration in knots instead of mph, is much more accurate than it was but I still find a difference from calibrated to IAS in performing GPS TAS checks at 8,500'. It is apparent the reason is that static pressure as detected in flight is less than the true static pressure of the atmosphere, hence, the airspeed indicator is reading a few knots high due to low pressure on the static side of the instrument. I spoke with a guy today who was involved in the certification of a corporate jet. They found that static pressure measured out in front of the airplane was effected by the speed of the air going by the port. The faster they went the lower the pressure. (No big surprise, Bernoulii figured that out over 200 years ago) The problem of having an accurate airspeed and altitude indication was easily compensated for with a chip in the air data computer. All big jets have an air data computer these days and that's how they get very accurate IAS and altitude. In our little airplanes, at the speeds we fly, the error is not significant, but irritating. I have been searching for the perfect spot on the Cozy to pick up static pressure and there is none. I've tried 3 locations and they are about the same, even 6 inches below the fuselage. On some airplanes, the static port has been located far aft on the fuselage. Also, a small fence is located in front of the port to slow down the relative speed for a more accurate indication. I will be trying that this week. I've also tried a small bleed hole in the pitot tube side of the ASI. A 3/32 hole will reduce IAS about 6 knots at cruise speed. This stuff isn't monumentally important, but it is a bit interesting, at least to me. dd Date: Mon, 25 Oct 1999 23:19:29 -0600 From: James Russell Subject: Re: COZY: Static pressure Hi David: > The UMA ASI now installed in my MKIV, after recalibration in knots >instead of mph, is much more accurate than it was but I still find a >difference from calibrated to IAS in performing GPS TAS checks at >8,500'. It is apparent the reason is that static pressure as detected >in flight is less than the true static pressure of the atmosphere, >hence, the airspeed indicator is reading a few knots high due to low >pressure on the static side of the instrument. How much difference is there between the GPS and ASI? > > In our little airplanes, at the speeds we fly, the error is not >significant, but irritating. I have been searching for the perfect spot >on the Cozy to pick up static pressure and there is none. I've tried 3 >locations and they are about the same, even 6 inches below the >fuselage. On some airplanes, the static port has been located far aft >on the fuselage. Also, a small fence is located in front of the port to >slow down the relative speed for a more accurate indication. I will be >trying that this week. I've also tried a small bleed hole in the pitot >tube side of the ASI. A 3/32 hole will reduce IAS about 6 knots at >cruise speed. I know they're big , draggy, and ugly but do the gimbeled ( flight test ) pitot tubes have a better provision for static air? I know that we did alot of skin waviness mapping ( and paint thickness, too! ) around the staic ports ( for RVSM ) on Gulfstreams, Challengers, etc. And that is w/ at least two ADCs... and 4 static ports... > This stuff isn't monumentally important, but it is a bit >interesting, at least to me. I've got a TAS core ( for overhaul ) for my airplane-to-be and this is interesting to me.also. It's easier to move things pre-build... Thanks, James > >dd Date: Tue, 26 Oct 1999 06:43:12 -0400 From: bil kleb Subject: Re: COZY: Static pressure David Domeier wrote: > > Also, a small fence is located in front of the port to > slow down the relative speed for a more accurate indication. the "fence" typically creates a lower pressure behind it, and a higher pressure in front of it; so it would seem that you would want to try a "fence" behind the port. you can vary either its position w.r.t. the inlet (fore and aft) and/or its thickness (height) to adjust its effect. just remember that this is just a "point" correction, i.e., it may make indications at other speeds more inaccurate. as always, it is a compromise: do you want accurate "stall" speeds or accurate cruise speeds? think of the front of the step bringing all the moving air to rest, hence dumping all its "moving" energy into a higher measured "static" pressure. (this is the same principle behind the pitot part of the system except we're not measuring completely stagnate flow, but the flow some distance ahead of the stagnation area.) behind a step, there is an expansion of the air as it tries to fill a larger space, thus lowering the pressure. some production ga static ports have a step molded into them for just this type of correction while other, less ethical companies, put their static port in the highest vacuum area they can find (typically some slightly aft-facing surface or just downstream of some big wake producing thing like the wing, etc.) just so they can advertise faster cruise speeds.* -- bil *with a footnote about how this speed is ias (with no mention of cas). Date: Tue, 26 Oct 1999 07:50:21 -0500 From: David Domeier Subject: Re: COZY: Static pressure bil, re "the "fence" typically creates a lower pressure behind it," I wonder. Certainly, dynamic pressure will be less but we are concerned about static pressure which we know increases as speed decreases. It seems to me if air flow is slowed down, static pressure should increase at the port. dd From: "Capps Family" Subject: Re: COZY: Static pressure Date: Tue, 26 Oct 1999 09:46:46 -0500 SNIP" > It seems to me if air flow is slowed down, static pressure should increase at the port. > > dd SNIP" The pitot tube measures the total pressure (Pt) in the tube. This pressure is comprised of the velocity pressure (Pv - pressure due to the momentum of the drive wind) and the static pressure. Pv+Ps=Pt If we isolate Pv, we can then calculate the velocity of the airflow using the following equation: Pv=Pt-Ps v = 1096 * (Pv / D)^1/2 D = density of the fluid (i.e. air) Larry Date: Tue, 26 Oct 1999 15:33:38 -0400 From: bil kleb Subject: Re: COZY: Static pressure David Domeier wrote: > > I've decided a static pressure test of the altimeter and airspeed > indicator on the ground is not an indication of what the instruments > will indicate in flight. the test i outlined earlier was a dynamic pressure test of the airspeed indicator, i.e., it will tell you if you have a leak in the pitot system and if you're airspeed indicator is giving the correct speed. > static pressure which we know increases as speed decreases. this is only true for a flow with no losses. with a fence/object of this nature there would be a total pressure loss downstream of it, and coupled with entrainment from the boundary layer, the static pressure would decrease since the dynamic pressure would remain fairly constant (at least after a bit downstream of the disturbance). > It seems to me if air flow is slowed down, static pressure should increase > at the port. only if the air is slowed down "nicely" (isentropically). think of the suction wake behind a semi-truck that you use to catapult yourself past the high pressure wave of the semi-truck's cab. basically, for a non-streamline shape bernoulli falls flat. actually, don't bother with all this theory, just go experiment! -- bil Date: Sat, 30 Oct 1999 17:39:56 -0500 From: David Domeier Subject: Re: COZY: Static pressure bil, re "the "fence" typically creates a lower pressure behind it, and a higher pressure in front of it; so it would seem that you would want to try a "fence" behind the port. you can vary either its position w.r.t. the inlet (fore and aft) and/or its thickness (height) to adjust its effect." bil kleb is absolutely correct. I thought slowing the air with a fence in front of the port would increase static pressure across the port but it doesn't. I tried it and the pressure decreased significantly - IAS was up some 10 knots. When I put the fence behind the port, the pressure increased resulting in a decrease in IAS of about 40 knots. In fact I couldn't get the IAS about 100 no matter how fast I went. I think the fence created a pitot effect in the static port. Cessna uses a small metal fence shaped like a half moon on some models. It is mounted in front of the port. It could be there is much engineering in that little device to achieve whatever it is they wanted. My little device was not at all scientific, but a small piece of plywood 3/16" thick shaped somewhat like a half moon. For the time being I am back to dual static ports with a known error factor of about 7-8 knots at cruise speed and not much error at traffic pattern speed. That really is no big deal. Maybe later I'll play around with some sort of a device to get IAS a little closer to CAS at cruise speed. dd Date: Sat, 30 Oct 1999 17:58:05 -0500 From: David Domeier Subject: Re: COZY: Static pressure Larry, re "Pv+Ps=Pt" and "Pv=Pt-Ps" True. That's how the ASI works. But if Ps on the back side of the ASI is not the same as the Ps at the pitot port, the result is not accurate. Our problem is getting an accurate Ps to the back side of the ASI. dd From: Epplin John A Subject: RE: COZY: Static pressure Date: Sun, 31 Oct 1999 09:10:57 -0600 Dave and all Thought that struck me. Any error in the static sense would be reflected on the altimeter. The only place that you can easily check the altimeter is on the ground at known conditions. What would a few passes just off the runway at different airspeeds while observing the altimeter tell us? Seems to me that one could hold altitude within 20 feet of target in this condition and you could have airspeeds from the lowest point of interest to near Vne. If the altimeter was within accepted tolerance in these conditions one would be led to believe the static port was working properly. Just a crazy idea. John Epplin Mk4 #467, still sanding. From: cdenk@ix.netcom.com Date: Sun, 31 Oct 1999 12:02:36 -0500 (EST) Subject: RE: COZY: Static pressure Not crazy, other opportunities to verify altitude include tall towers, mountains, and many other landmarks labeled on sectional charts. Also traffic from radar point outs, that should be at same altitude. Date: Sat, 30 Oct 1999 16:21:09 -0700 From: "LCDR James D. Newman" Subject: COZY: Re: Static pressure Hi Dave and All, > Dave Domeier wrote: > For the time being I am back to dual static ports with a known error factor of about 7-8 knots at cruise speed and not much error at traffic pattern speed. That really is no big deal. Maybe later I'll play around with some sort of a device to get IAS a little closer to CAS at cruise speed. I'd be interested to know what you come up with - maybe a chip or something (like the big boys and military do) to have an accurate ASI at all density altitudes.. In the interim, if you have the panel space, calibrate one ASI for landing and install it in the " T " in front of you, and install another ASI mounted off to the side calibrated for your typical cruising altitude. May end up costing the same having 2 ASI's as figuring out a chip. Infinity's Forever, JD From: cdenk@ix.netcom.com Date: Sun, 31 Oct 1999 12:19:08 -0500 (EST) Subject: Re: COZY: Re: Static pressure Was said install 2 airspeed indicators: For landing, takeoff, and low speed operations - Each plane's performance in this range should be based on the indicated airspeed, as long as one uses as system, the planes performance and the particular instrument, and fly the numbers related to that system. For higher speeds somewhat the same exists, the red line was determined with a particular system, including the static port installation. Thats the bottom line for redline speed. Lets say that after checking the redline speed as safe, the indicator is found to be reading high, corrected, then the redline should be rechecked! All this assumes that the indicator is reasonably accurate, and 5% at 200 MPH = 10 MPH. Probably the higher end of the range is more important, since a controller may ask you to maintain a speed for traffic spacing. Date: Sun, 31 Oct 1999 16:32:22 -0600 From: David Domeier Subject: Re: COZY: Static pressure John, re " Any error in the static sense would be reflected on the altimeter." It is. I flew next to a buddy in a RV4 several weeks ago and when we increased speed from 100 knots to 140, my altimeter increased about 80'. (decreased static pressure due to speed?) When we started I was indicating some 180' feet higher than he, but all that is not indicative of what's going on 'cause there's no way of knowing how accurate the RV4 system is. dd From: "Todd Carrico" Subject: RE: COZY: Static pressure Date: Tue, 02 Nov 1999 04:07:10 PST This may be too obvious, Why not port the back of the instrument to the same static source? i.e. enclose the back of the instrument and port it right next to the static port on the airframe. tc ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com From: cdenk@ix.netcom.com Date: Tue, 2 Nov 1999 15:03:57 -0500 (EST) Subject: RE: COZY: Static pressure 2 items: 1: I have a static port on both sides, the "T" between them is equal length tubing from each to minimize side/side effects. 2: When set to current altimeter setting (which can be had from ATIS, AWOS, tower, and some FBO's) the altimeter should read within say 30 feet of your elevation. If it doesn't then one should consider the instrument being adjusted or overhauled. Its likely if not done, won't pass next required inspection and delay/come back to get the sign off. Might have some difficulty in determining the correct elevation to use. 30' over a 1000' distance is difficult for even a trained eye to recognize. Probably check with airport management, they should have an accurate topographic survey of the airport, and know where the published elevation occurs. Date: Fri, 05 Nov 1999 07:45:57 -0600 From: David Domeier Subject: Re: COZY: Static pressure John, re "I will try to rough figure the consequences here..." last week. I think you are in the ball park. One issue I addressed this week is a leak in the static air system. FAR part 23.1325 (i) says with regard to pressure checking it, "Unpressurized airplanes. Evacuate the static pressure system to a pressure differential of approximately 1 inch of mercury or to a reading on the altimeter, 1,000 feet above the aircraft elevation at the time of the test. Without additional pumping for a period of 1 minute, the loss of indicated altitude must not exceed 100 feet on the altimeter." When I had my airplane certified, it just passed that check. This week I completely rebuilt the system and it leaks no more at all. Some of the fittings were used and the plastic line was of a local hardware store source....that stuff gets brittle quick and it has been replaced with tygon and quality fittings from Wicks. Anyway, I thought fixing that leak would make a difference but a flight check yesterday proved otherwise. The difference from CAS to IAS is the same - 9 knots at 8500, full throttle. The issue remains unsettled- how does one tap an accurate source of static pressure in flight? I think it is not possible. That's why high performance airplanes use Air Data Computers and airplanes in our category live with the error. That's why flight plan forms and performance charts are in calibrated airspeed or true airspeed. Indicated airspeed is whatever it is and we need be aware it may not always be accurate. dd From: "D. Rothrock" Subject: COZY: UMA ASI Date: Tue, 9 Nov 1999 19:47:02 -0500 Hi Group, I just received my ASI and the calibration data back from UMA, Inc. I had purchased it from Wicks and after reading about DD's problems I sent it to UMA. I asked them to test it and send me a copy of the calibration data. I must say, they were all very helpful and seemed anxious to make me happy. They did! Date: Thu, 18 Nov 1999 17:12:44 -0600 From: David Domeier Subject: COZY: Static pressure stuff.... For those of you interested in the subject.... After a few more flight checks, I've determined that adding a fence in front of the static port lowers pressure (increases IAS) and adding a fence aft of the port increases pressure (decreases IAS). I have tried 2 aft fences, one .25" and one .0625". I know that's quite a jump down in size but it was warranted since the .25 fence increased the pressure so much, max IAS was just 100 knots no matter how fast the airplane flew. The .0625 fence left me with an IAS at 10 knots below CAS. Without any fence I'm running about 9 knots fast. I think I'm closing in on the problem, but have decided not to mess around with fences. Today I mapped an area of 3" around both static ports and filled the it with Super Fill. I'm going to sand the area tomorrow leaving a slight rise aft of the port, go fly it and see what gives. I think I can adjust the slope fore and aft of the port to get it just right, then prime and paint it. I'll probably burn 50 gallons of gas solving this problem, but what the heck, I could end up with the most accurate ASI flyin'. That's worth something. dd Date: Thu, 18 Nov 1999 22:31:44 -0600 From: David Domeier Subject: Re: COZY: Static pressure stuff..part 2... Nat is wondering why I am having so much trouble getting an accurate airspeed indication while no one else is. (other than the fiasco with the ASI labeled in knots and calibrated in mph) This could be a self induced problem and I admit it. The plan position for the static port did not work on my airplane because I installed a heated pitot tube forward and exactly in line with the static port. Not on purpose. Without looking aft to see where the static port was located (after all, it is a very small hole) it ended up in perfect alignment as if I had planned it. That was mistake number one. It caused, in my opinion, turbulence in the slip stream to make for erratic static pressure. The ASI, altimeter, and vv were never steady. So, I moved the static port aft about 20 inches. I also installed one on the right side. I bought 2 static port fitting from ACS for this purpose. These fittings are about 2" in diameter and have a circle of holes in the center and are surface mounted. That may have been mistake number 2. The surface mount units are not flush with the fuselage skin and could be causing the low pressure. At least that is what I concluded today after looking at the airplane for a long time trying to imagine what is going on. (I would like very much to not have this problem) Anyway, I decided to dump the dumb looking fences and use fill in to make the ports blend in with the fuselage skin. I have a feeling, maybe wishful thinking, that this will make the problem go away. If not, I may scrap the airplane and start all over. dd From: "Nat Puffer" Subject: COZY: Static ports Date: Fri, 19 Nov 1999 10:03:19 -0600 Builders, David Domeier commented that he installed a heated pitot tub ahead of and in line with his static port. I don't know if this disturbed the air ahead of the static port (it probably did), but it reminded me to suggest drilling 3 static ports in a vertical alignment with about 1/2 inch spacing. This is easy to do because the tubing for the static line is inserted vertically against the outside skin. This will avoid problems with one port putting your system out of business. Regards, Nat Date: Fri, 19 Nov 1999 14:54:24 -0500 From: Jeff Russell Subject: Re: COZY: Static ports Nat Puffer wrote: > > Builders, > David Domeier commented that he installed a heated pitot tub ahead of and > in line with his static port. I don't know if this disturbed the air ahead > of the static port (it probably did), but it reminded me to suggest > drilling 3 static ports in a vertical alignment with about 1/2 inch > spacing. This is easy to do because the tubing for the static line is > inserted vertically against the outside skin. This will avoid problems with > one port putting your system out of business. I have one set of static ports on the pilot side. Both this airplane and the Cozy 3 put in a right slip with rain would give me weird jumping readings until I came out of the slip. Installing 2 sets on each side with balanced lines will stop this problem in a slip with rain. Talking to Scott at Velocity aircraft, they have tried the same but the longer less blunt nose has a different problem with pressure and they went with a .062 thick strip in front of the ports changing the pressure like David is doing. Slips also gave a single sided static port weird readings so they went to the duel ports. -- Jeff Russell/AeroCad Inc. Website: http://www.Aerocad.com From: extensionsystems@mindspring.com Subject: Fw: COZY: panel instruments Date: Mon, 15 Nov 1999 08:22:59 -0000 Check out Wicks page 125 bottom left. These are the nuts used for years on instruments. The ones with the bent lock end seem to work best as they will not push out when inserting the screw, however the straight ones work if you let the threads on the screw pull its self in. Thanks & Regards Brian Dempster brian@CheapAirParts.com -----Original Message----- From: alwick@juno.com To: cozy_builders@canard.com Date: Monday, November 15, 1999 4:46 AM Subject: COZY: panel instruments >I'm getting ready to install instruments to panel. I've elected to use an >aluminum panel on the face of the fiberglass bulkhead. What's the best >way to secure instrument? Is it ok to tap the holes in the instrument? Or >do nylock nuts work best? >Appreciate the suggestions. > >-al wick >Canopy Latch System guy. >Artificial intelligence in Cockpit >Cozy sn 389 driven by stock Subaru 2.5 ltr 106% complete, Aug 00 first >flight sched.. > >___________________________________________________________________ >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. From: alwick@juno.com Date: Mon, 15 Nov 1999 08:22:08 -0800 Subject: Re: Fw: COZY: panel instruments Thanks Brian, Dave, John and others. I never expected they would have special nuts for these things. I went ahead and tapped them all to 10-32. The resulting percent of full thread isn't that good on some of the holes. However, the thread engagement distance is huge (1/2" or so). Thus the thread quality should be insignificant. Now next year at the flyin, if you guys notice my instruments tilting down or wobbling about, you can say I told you so.... Maybe I have discovered a new g-meter. When you hit turbulence, if your instruments fall out, SLOW DOWN. Hmmm, maybe I'll spring for the nuts next spruce order. Thanks -al On Mon, 15 Nov 1999 08:22:59 -0000 extensionsystems@mindspring.com writes: > These are the nuts used for years on instruments. The ones with the bent > lock end seem to work best as they will not push out when inserting the > screw, however the straight ones work if you let the threads on the screw > pull its self in. > ___________________________________________________________________ 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. From: extensionsystems@mindspring.com Subject: Fw: Fw: COZY: panel instruments Date: Mon, 15 Nov 1999 18:27:53 -0000 One thing to keep in mind about doing to much to your instruments, you may be voiding any warranty and these may not be able to be used for cores when it comes time to replace them. If the damage is already done, I would not worry about it. I would however not be drilling and installing heli coils into instruments where you may be breaking an important seal. We need to remember that we sometimes rely on these to get us home in one piece. Thanks & Regards Brian Dempster -----Original Message----- From: norm doty To: alwick@juno.com Cc: cozy_builderscanardcom Date: Monday, November 15, 1999 9:15 PM Subject: Re: Fw: COZY: panel instruments >well if youve already tapped them and its not strong enough, go to a tool >supply house, or some auto parts stores(napa) for example and get a heli >coil kit for 10-32, it will have a special tap(slightly larger than 10-32) >then tap it with the also special tap, then insert the heli coil, now your >10-32 screws will have the correct grip and they will be screwed into the >new stainless steel threads youve just put in. >norm & monda >cozy IV #202 >ford v6 powered > > Date: Tue, 16 Nov 1999 11:14:21 -0600 From: David Domeier Subject: COZY: Cruisin' the Cozy The GPS , Navaid, and S-Tec altitude hold were all working at the same time so I decided to launch on a 100 mile sortie yesterday to check it out. The weather has been fantastic in the mid west for 2 weeks so this was a fun, leisurely trip. The GPS coupled to the Navaid very nicely. It didn't a week ago 'cause I had failed to ground the shield wire on the NMEA cable as instructed in the GPS manual. There are 5 or 6 wires in that cable but only one is used to send data to Navaid. But the shield must be grounded or it won't work all the time. Also, the unused VOR inputs to the Navaid must be jumpered. Navaid says to do that in their manual but I over looked it first time through. Tacking is satisfactory but it probably needs fine tuning. The system stays in the 1.25 course width but seems to ricochet from one side of the corridor to the other. It does not lock on to the course. Maybe that's the way it works. It does get the airplane to destination but criss crosses the course within the 1.25 corridor getting there. I will ask Porcine about this. S-Tech worked for 2 flights and on the 3rd flight it pitched up rather abruptly when engaged. I couldn't get it to work at all after that so sent it to Texas for evaluation. The company put it on the bench for 3 days and could not duplicate the problem but to make me happy they sent me another pressure transducer and data processor. It has worked just dandy since. I recommend these items for cross country flight if you can afford 'em. It is neat to sit back, fine tune the engine mixture, watch for traffic, fold and unfold charts, monitor position and simply relax. It sure beats driving down a freeway where you can't relax for a second. I set the power at about 52.9% (using my theory of fuel flow to determine hp) and here are the numbers recorded. At 5500', manifold pressure 19.4, rpm 2230, fuel flow 6.9, IAS 141 knots, GS 148 knots, OAT 11.5°C. Using the GPS E6B computer I entered a calibrated airspeed of 134 (the 141 IAS is about 7 high) and it came up with a TAS of 146.6 knots. Not too shabby for a 4 place airplane. That works out to 24.34 mpg while zipping along at 168 mph TAS. All in all, I'd say Nat has come up with a fairly decent airplane. I sure enjoy flyin' it. dd Date: Tue, 16 Nov 1999 12:21:57 -0600 From: Curt Smith Subject: Re: COZY: Cruisin' the Cozy At 11:14 AM 11/16/99 -0600, David Domeier wrote: > > Tacking is satisfactory but it probably needs fine tuning. The >system stays in the 1.25 course width but seems to ricochet from one >side of the corridor to the other. It does not lock on to the course. >Maybe that's the way it works. It does get the airplane to destination >but criss crosses the course within the 1.25 corridor getting there. I >will ask Porcine about this. > Dave, Check the manual for the track width adjustment. I've had to adjust mine once. Set it to the min width and it will track like it's on rails. Curt LE N86CS Date: Thu, 18 Nov 1999 16:50:00 -0500 From: Paul Krasa Subject: Re: COZY: elt required by faa I was told by my DAR that an ELT was mandatory equipment in the airplane. I bought the one which uses standard D cell batteries. Easy and cheap to change out. It is installed in the strake on the bulk head which runs along the seat back. Paul Long EZ 214LP The Future is virtual VFR on a flat panel display using a 3D terrain database. At 12:56 11/18/99 -0800, alwick@juno.com wrote: >Is an elt mandated for experimental aircraft? >What type is needed? voice capable? > > >-al wick >Canopy Latch System guy. >Artificial intelligence in Cockpit, bozo in pilot seat. >Cozy sn 389 driven by stock Subaru 2.5 ltr 106% complete, Aug 00 first >flight sched.. > >___________________________________________________________________ >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: Thu, 18 Nov 1999 16:48:58 -0600 From: David Domeier Subject: Re: COZY: elt required by faa Al, re "Is an elt mandated for experimental aircraft? What type is needed? voice capable?" Yep. Check out FAR 91.207 Emergency locator transmitters. If you remove all the seats except yours, you don't need one. dd From: cdenk@ix.netcom.com Date: Thu, 18 Nov 1999 22:09:34 -0500 (EST) Subject: Re: COZY: elt required by faa Was said It OK to use brand names on this list, but if you have an (money) interest in an issue, then it would be ethical to state there is an possiblity to benefit. Wherever mounted, it should be readily available. I have an ACK ELT that uses D batteries. It is mounted next to the front seat brace on the floor aft of the front seat. Rear seat passengers have not complained of its location. Several times it went off while the plane was parked, required changing batteries while away from home. Also its portable if one were to leave the crash site. Should instruct frequent passengers of its portable operation. From: alwick@juno.com Date: Sun, 14 Nov 1999 20:36:02 -0800 Subject: COZY: panel instruments I'm getting ready to install instruments to panel. I've elected to use an aluminum panel on the face of the fiberglass bulkhead. What's the best way to secure instrument? Is it ok to tap the holes in the instrument? Or do nylock nuts work best? Appreciate the suggestions. -al wick Canopy Latch System guy. Artificial intelligence in Cockpit Cozy sn 389 driven by stock Subaru 2.5 ltr 106% complete, Aug 00 first flight sched.. ___________________________________________________________________ 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: Mon, 15 Nov 1999 00:13:38 -0800 From: Nick Subject: RE: COZY: panel instruments The best way I found of securing your instruments to the panel is to take a thick piece of aluminum (you could use scrap from the panel), cut into little rectangular pieces with a radius on one side to the dia of the inst. Flox these directly onto the inst. Drill and tap the Al to make the "nut". Works great. BTW with your turn bank and the artificial horizon, file the mounting holes in the inst panel into a slight oval slot. This will allow you to slightly adjust the inst (rotating it around the axis) in case the bank of the plane or the inst does not agree with each other. I tried the push in nuts from ACS and Wicks. There are various sized depending on the length of the mounting "ears" What size and how many will you need? Sometimes the screws will push the nuts out of the inst, They sometime fall off in the back of the panel, or the little ears that hold them onto the inst break. They are more of a pain then they are worth. Nick I'm getting ready to install instruments to panel. I've elected to use an aluminum panel on the face of the fiberglass bulkhead. What's the best way to secure instrument? Is it ok to tap the holes in the instrument? Or do nylock nuts work best? Appreciate the suggestions. From: Fritzx2@aol.com Date: Mon, 15 Nov 1999 09:20:54 EST Subject: Re: COZY: panel instruments Al, >I'm getting ready to install instruments to panel. >I've elected to use an aluminum panel on the face of >the fiberglass bulkhead. What's the best way to secure >instrument? Is it ok to tap the holes in the >instrument? Or do nylock nuts work best? >al wick For fastening instruments to thin sheet aluminum, I would use a PEM nut on the back of the aluminum panel. PEM nuts clintch into the back side of the sheet metal and stay put. They are steel so you then have a nut that can't spin, won't fall off, and won't be prone to the treads stripping out like thin aluminum would. Check out their web site at http://www.pemnet.com/ You could press the PEM nuts onto the back of the aluminum instrument panel (as they are designed to do) and then you wouldn't have to fumble with nuts. I'm nut sure if they have locking features on any of their products but once you have the instruments in for the last time you could always put a little of the not to agressive thead locking compound, Loctite, on the screw so the instrument doesn't fall out on your lap. John Fritz fritzx2@aol.com From: cdenk@ix.netcom.com Date: Mon, 15 Nov 1999 17:02:43 -0500 (EST) Subject: Re: COZY: panel instruments Several methods 1: For those instruments that have tapped holes, the machine screw has a head on the aft side of the panel, goes through a clearance hole in the panel, and then threads into the instrument. 2: Most flight instruments have clearance holes. On these usually one can use instrument nuts - Wicks page 195, P/n A89?4- 632-493. The parallel pieces slip from the forward face of the instrument flange, and then the machine screws as above. 3: For round instruments with no holes, I have mad a ring out of 0.032" alum. with ears for 4 screws, then used machine screws with regular nuts. Date: Mon, 15 Nov 1999 12:54:03 -0500 From: bil kleb Subject: COZY: Summary of methods to determine true air speed (to calibrate ASI) a nice summary to compliment our recent discussion of asi errors: [from Peter Chapman via news:rec.aviation.homebuilt] FLIGHT TESTING TO DETERMINE TRUE AIR SPEED -- AS PART OF THE PROCESS TO CALIBRATE THE AIR SPEED INDICATOR Pilots of homebuilt aircraft may be interested in determining the errors in their indicated air speeds. Speed over the ground can be determined with the aid of map & stopwatch, or a GPS. Compensating for wind converts ground speed to true air speed, which in turn is converted using density altitude to determine what the IAS should be. A major difficulty is trying to compensate for wind, as perfect no-wind conditions are hard to find, especially if one isn't lifting off at the crack of dawn. Over the years I heard of various wind-compensation methods, not all of which sounded like they would be mathematically accurate. This write-up is the result of compiling and comparing the various methods that I've heard of, to help decide how to calibrate the airspeed indicator on the homebuilt I co-own. This document is not exhaustive, but should give the reader a useful overview of some of the methods that have been tried. I have no insight into the world of professional test flying, as my own qualifications or lack of same are: Private pilot (200hrs), skydiver, paraglider pilot, co-owner of a Zenair Zodiac homebuilt, degree in aeronautical engineering (but haven't been working in the field for years). GENERAL TECHNIQUES Results can naturally be more accurate when more data points can be taken, and the more accurately the tests can be flown -- maintaining constant airspeed, heading (or ground track, depending on the test), altitude, and engine power. The job becomes more difficult if there's turbulence or rising and falling air. Holding all values constant becomes mathematically impossible. If there is thermal activity, it may be better to focus on holding a constant airspeed, as chasing altitude in a thermal would require putting the nose down and increasing speed. Some test methods require tracks to be flown, while others require headings. The aircraft's equipment affects which is more convenient. A directional gyro helps to fly accurate headings, although it may precess in the time it takes to fly a few test legs. A GPS will provide accurate track information. Whether it is more difficult to maintain, on average, a steady ground track or a heading when there is turbulence and varying winds is another issue, which my personal experience cannot answer, as my new GPS hasn't yet been used in an aircraft. A test run is flown for each indicated air speed for which a correction is desired. Indicated air speed errors result from errors in measuring pitot and static pressure, and internal instrument errors. The methods described here will account for the combined errors from all these sources. The instrument errors can also be determined separately by ground tests: A manometer of clear plastic tubing is made, with a difference in water (or other fluid) level corresponding to a particular pressure, which corresponds to an air speed that should be shown. (One source on manometer testing of ASI's: Kitplanes July '89, "How to Calibrate Your ASI" by Jim Weir. Also found on his web site at: http://www.rst-engr.com/ A more detailed source of calibration info is at an RV aircraft builders' site: http://members.xoom.com/_XMCM/kevinhorton/ssec.html ) FIVE METHODS OF COMPENSATING FOR WINDS #1) 'OPPOSITE HEADING RUNS' (OR 'OPPOSITE TRACK RUNS') This is an old and often mentioned method. True air speed is calculated by averaging the ground speed from runs along ground tracks or headings 180 degrees apart. Sources have suggested using a 3 to 5 mile course, measured accurately on a topographic map. Nowadays two GPS waypoints could be used. Ground speed is calculated by time over the course divided by distance. A fair bit of detail on this method follows, so it may be worth skipping to method #2 if attempting to quickly review the different methods available. Typically flight along opposite headings -- not ground tracks -- is called for, which means that the flight is actually between two parallel lines a specified distance apart, rather than between two points that same distance apart. The airplane is allowed to drift with any crosswind component. The FAA's Amateur-Built Aircraft Flight Testing Handbook (AC 90-89) may favour flying a heading rather than a ground course, but does not make the distinction clear. Sources often don't distinguish between three ways to carry out this method of runs on opposite headings: 1a) Fly the track (between the start and finish points). Use GPS ground speed. Or use time divided by course distance. 1b) Fly the heading (perpendicular to parallel start and finish lines). Use GPS ground speed. 1c) Fly the heading (perpendicular to parallel start and finish lines). Use time divided by distance between start and finish line on the chosen heading. Or determine the component of GPS ground speed along the heading direction. For a pilot, flying a ground track (#1a) may be intuitively wrong when attempting to determine true air speed. The plane is clearly losing out on some speed towards the target point by having to correct for drift. But flying a constant heading is no better if the pilot simply uses GPS ground speed for calculations (#1b). By flying a heading where there is a crosswind, the ground speed will increase by a similar percentage as the ground speed would have decreased if flying a constant track. Even when averaging runs in opposite directions, one method will slightly over-estimate true air speed from ground speed, and the other will slightly under-estimate it. For a 100 mph aircraft in a 10 mph crosswind, the errors are about 1/2 %. The most accurate version is #1c: The key is to measure the ground speed perpendicular to the start and finish lines, that is along the chosen flight heading. This component of the ground speed is unaffected by any crosswind component. Only in this way does flying headings become superior to flying a ground track. If the wind is a pure crosswind, then its effect is entirely removed by method #1c. If there is a pure head or tailwind, its effect is entirely removed by averaging the speeds from runs in opposite directions. If, however, there is a combination of crosswind and head or tailwind, the method provides a very close approximation to the true air speed. For the 100 mph aircraft in a combined 10 mph crosswind and 10 mph tail or headwind (i.e., 14.1 mph on a heading 45 degrees from the course direction), the error in estimating true air speed is a negligible 0.05 %. If doing method #1c the old fashioned way, the stopwatch is clicked when the start and finish lines are crossed. With a GPS, some geometry work would be necessary after the flight, to determine what component of the speed along the track actually flown is in the direction of the chosen heading. Airspeed and track information for each leg can be gathered at different levels of detail. A pilot could simply jot down the track direction and ground speed from time to time when flying the leg, averaging them later. Or data could come from the entire leg flown. The test run would be determined by flying a heading, marking a start and a finish waypoint with the GPS some minutes apart, while recording times for these events by stopwatch. If the GPS has a moving map then it likely has a track log feature that records a steady stream of time and position data. If downloaded to a computer, mapping software can be used to determine an average track and speed. Sources that describe using time over a measured course don't always note how easily errors can occur. Even over a 5 mile course, a 1 second error in timing becomes 1/2 mph error at 100 mph, or 2.2 mph at 200 mph. It becomes important to mark the time accurately, which is more an issue of determining when the start and finishing line have actually been crossed, than just how quickly one can punch the button on the stopwatch. Without careful attention, it may look as if a point or line on the ground is being passed, when it is still only 85 degrees below and not 90 degrees. The greater the height, the more difficult it is to be accurate. No matter which version of the opposite heading runs method is used, accuracy is improved if the runs can be flown into and out of the wind, with as little crosswind as possible. By using the version of the method that uses the component of ground speed along the chosen course heading (#1c), the calculations are nearly mathematically correct for determining true air speed. Other versions of the method are less accurate for most wind conditions, but may be sufficient. #2) 'AVERAGED HEADING TRIANGLE' EAA's Experimenter magazine, Dec. '97, reprinted a method that had been printed in the Rans company's newsletter. The pilot flies three legs with headings 120 degrees apart. The true air speed is the average of GPS speeds from the three legs. The method is only an approximation, which the article does not state. For a couple sample calculations with different wind directions and a 100 mph aircraft in a 10 mph wind, the error was about 1/4 %. It is as if the method average out the errors the simpler versions of method #1, which were seen to vary between zero and 1/2 % for the same aircraft and wind, depending on the wind direction. (The article's correction factors for density altitude are wrong, by the way, since they say to multiply by values which are the air density ratios rather than the square root of the air density ratios.) #3) 'THREE GROUND SPEEDS AND TRACKS' (OR 'THE CIRCLE OF VECTORS') By flying three legs in different directions, and recording both ground speeds and tracks, wind velocity (speed and direction) and true air speed can be determined without approximation. Some trigonometry is necessary, but the equations are available on a spreadsheet. While headings need to be maintained accurately, it does not matter what the chosen headings are, so an accurate compass swing is not necessary. Best results are found for headings 90 to 120 degrees from each other. I have also called the method 'the circle of vectors' because of a helpful diagram in the article proposing the method. Doug Gray wrote the PDF document found at: http://www.hlos.com.au/~doug.gray/home.html #4) 'THREE TRACKS AT 90 DEGREES AND PYTHAGORAS-LIKE FORMULA' This method uses one leg in one direction, a second leg at 90 degrees to the first, and a third leg in the opposite direction to the first. Tracks are flown, and only ground speeds are recorded. A formula that has parts resembling the Pythagorean theorem determines a mathematically correct true air speed. I haven't done the derivation myself but the method is apparently correct. The formula is: true air speed = (square root(A^2 + B^2 + C^2 + A^2 * C^2 / B^2) )/ 2 where A, B, and C are the ground speeds for the three legs in the order described above. This formula was presented by David Fox in the Feb. 1995 issue of Kitplanes (which I haven't seen), and is referred to in notes associated with the web sites for method #3 and #5. If headings were flown instead of tracks, the formula would only be an approximation. (For a 100 mph aircraft with a 10 mph wind perpendicular to the two runs that are in opposite directions, the error is 0.91%. When the same wind is parallel to the two runs, the error was a miniscule 0.005%. But method #1 produces better approximations if one can correctly guess the wind direction relative to its two runs.) #5) 'THREE HEADINGS AT 90 DEGREES AND ITERATIVE CALCULATION' Only ground speeds need to be recorded in this method, but three headings at 90 degrees to each other must be flown. Data is entered into a Java applet from Craig Cox at: http://www.reacomp.com/TrueAirspeed/index.html It iteratively calculates the true airspeed and wind velocity. The program shows results to whole number values only, but more accuracy can be attained by multiplying all inputs by 100 (and dividing the output speeds by the same amount). Both Doug Gray's and the iterative method are recommended at the following site, which has a number of useful flight testing resources and links: http://members.xoom.com/kevinhorton/rvlinks.html OTHER ERROR SOURCES While some of the simpler methods are only approximations, their errors may be acceptable when considering other errors in the measurements. Error sources include: 1) Selective Availability (SA) Selective Availability causes a GPS's reported position to slowly wander in a pseudo-random manner. The speed error with SA turned off is small, about 0.1 mph. While I don't have confirmed numbers available, one web site said that the SA-induced errors are 'typically 0 to 3 mph when at rest (but can be more), and typically plus or minus 1 mph when travelling over 60 mph'. The motion added by SA is actually independent of the GPS user's speed, but when the user is moving fast enough only the error motion parallel to the user's path with have much of an effect on the displayed speed. (An SA "crosswind" has less effect on reported speed than an SA "headwind" or "tailwind".) So while flying the error introduced may usually be less than 1 mph. From time to time the wandering motion will happen to be both rapid and in line with the aircraft's track, so GPS speed errors could occasionally be at least as high at 3 mph, assuming the above information on position wandering is correct. Repeating airspeed calibration tests at different times, at least 15 minutes apart, can improve test accuracy. Just taking multiple data points during a 5 minute run may not be sufficient, as the speed and direction of the position wandering may be similar throughout. While more detail is available on GPS related web sites, the period of the most significant SA wandering is very roughly on the order of 10 or 15 minutes. 2) Display Error Some GPS's only show speed to whole mph (or kts or km/h) when above a value of 100, resulting in another plus or minus 1/2 unit inaccuracy. 3) Variations in wind velocity, and inability to fly a perfect flight path. All the flight test theory in the world may feel rather academic when one is bouncing around in a small, low wing loading homebuilt. One may want to climb somewhat to get above low level mechanical turbulence, wind shear, and thermals. 4) Compressibility Compressibility effects are usually ignored, but one might want to look into the issue when dealing with a high speed homebuilt. The difference between compressible and non-compressible calculations of speed from pitot pressure differ by less than 1% if under 200 mph and in the lower atmosphere. TRAILING BOMB or CONE One method of calibrating airspeed without using ground speed (and therefore having to compensate for wind) is the 'trailing bomb' or 'trailing cone' method. Instead of measuring static pressure on the aircraft, where it is so easily influenced by local pressure changes in the airflow, static ports are placed on an object trailed behind and below the airplane. Normally this is regarded as a method for professional flight testing only, but it can be done at home with 50' of soft tubing, a plastic funnel, and other simple parts. A description can be found in Sport Aviation, March 1977. ("A study of Cruise Performance of the T-18" by Howard Henderson and Peter Roemer.) Comments and additions welcome! Peter Chapman Toronto, Canada November 1999 p.chapman@utoronto.ca -- bil From: jhocut@mindspring.com Date: Tue, 16 Nov 1999 12:16:49 -0500 Subject: Re: Re: COZY: Summary of methods to determine true air speed (to calibrate ASI) >I am reasonably certain the cause is a lower than real static >pressure to the ASI. One then has to wonder what the effect on the atlimeter reading is. It's for sure going to read high, maybe someone with either a super memory or an AE textbook at hand can look up the correlation. From: mister@neesnet.com Date: Tue, 16 Nov 1999 14:45:55 -0500 Subject: Re[2]: COZY: Summary of methods to determine true air speed As another point of reference, I did a couple of runs a few months ago on my 3 place COZY to check my airspeed calibration. I used the method shown in http://www.reacomp.com/TrueAirspeed/index.html#instructions. This method calls for flying the same indicated airspeed on three cardinal headings and taking groundspeed readings from the GPS. This is a very simple and (I assume ) accurate method of determining the actual airspeed. I don't have the numerical results handy but my recollection is that my airspeed was accurate within about 1 knot. I have the per plans static and pitot setup. The pitot is an AN-910 coupling epoxied into the nose and I screw in an AN-840 Hose nipple for a pitot tube. Bob Misterka COZY III N342RM ********************************************************************** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. This footnote also confirms that this email message has been swept by MIMEsweeper for the presence of computer viruses. New England Electric System Companies ********************************************************************** Date: Tue, 16 Nov 1999 21:03:53 -0500 From: Jim Sower Subject: Re: COZY: Summary of methods to determine true air speed (to calibrate Dave et al, My guess is that if you have a known well calibrated A/S indicator indicating fast, you've got an altimeter hooked to the same port that's indicating high. I would bet money that an accurate static probe could be made by sticking a 2" long .25 Al tube out the nose right alongside the pitot probe. Put a bullet-plug in the end and drill some holes in the side(s). Replicates your '20-mm' store bought and weighs zilch. Holes in both sides (& top and bottom?) cancel out yaw (& pitch?) effects. Arguably easier to install and maintain than plans port. Just a theory, Jim S. David Domeier wrote: > bil, > > Your post from Peter Chapman is very informative regarding a > determination of TAS but does not address dealing with the pressure > drop on the side of the Cozy where static pressure is measured. > > When one stands forward of the Cozy and looks aft, the fuselage > curves out constantly to about the strake area and then curves in. The > speed of air across the surface of the fuselage side has to be > increasing as the fuselage widens which, in my opinion, is causing a > pressure drop greater than if it were a perfectly flat surface. > > It is relatively easy to get at an accurate true airspeed with GPS, > 29.92 for pressure altitude, measure OAT and come up with calibrated > airspeed. My airspeed indicator is very accurate on the bench - they > sent me the numbers and it is with 1 or 2 knots of where it should be at > all speeds up to 200 knots. Yet, in flight, it is reading a consistent > 9 knots fast on the top end of the speed envelope. I've performed a > half dozen full throttle runs at 8500' pressure altitude the results are > always the same - 8 or 9 knots fast. And I am reasonably certain the > cause is a lower than real static pressure to the ASI. > > I had a chat with a former Navy and McDonnell Douglas test pilot > who is building a Lancair in a nearby hangar. He looked at my airplane > and suggested extending a probe forward of the fuselage to get a more > accurate static pressure reading. I have an old WWII pitot/static probe > that is about 12" long, weighs a pound or 2, and would look like a 20mm > cannon in the nose. I just haven't decided if I want to mess up the > nose of the airplane to get a better static pressure reading. I know > what the error is so it really is no big deal but it would be satisfying > to have a more accurate IAS if possible. I will think about mounting > that cannon forward temporarily just to see if it makes a difference. > > dd Date: Wed, 17 Nov 1999 16:54:46 -0500 From: bil kleb Subject: Re: COZY: Summary of methods to determine true air speed (to David Domeier wrote: > > Your post from Peter Chapman is very informative regarding a > determination of TAS but does not address dealing with the pressure > drop on the side of the Cozy where static pressure is measured. you're correct. it does what manufacturers do: it provides some means of measuring the total combined errors of the system so you can make up a nice calibrated airspeed table for the pilot's operating handbook. (of course you'd have to work tas back to cias to get there.) -- bil Date: Sun, 21 Nov 1999 10:19:33 -0600 From: David Domeier Subject: COZY: Static pressure - problem resolved... Once again, to those interested.... Yesterday I flew 2 flights for a total of 24 GPS legs, logged all the information on a form I made and finally got to the bottom of the static pressure problem on my airplane. I faired the static ports to contour with the fuselage sides thinking this might be a solution. Below are the results. Pressure altitude 3000' OAT 8°C IAS TAS CAS Error ias/cas 160 157 150 +10 140 138 133 +7 120 119 114 +6 100 100 96 +4 As the numbers indicate, there is a direct relationship between speed and ASI error. I think the theory that slip stream air speed is causing a pressure drop at the static ports on my airplane is correct. Ironically, the error is such that I could relabel my ASI to read True Airspeed Indicator, the numbers are so close. After lunch, I installed a .032 fence about .10" aft of the static ports. (I was going use fill for this purpose but didn't want to wait a day for cure) Previously I have tried .25 and .062 fences but the error was still there only in the negative column. Here are the results after installing the .032 fence. Pressure altitude 4000' OAT 12.7°C IAS TAS CAS Error ias/cas 150 160 150 0 140 149 140 0 120 129 121 -1 100 108 101 -1 I am amazed that a .032 strip of aluminum can make such a difference but it has. I think these numbers are quite accurate since all the legs were flown in very still air, on auto pilot with alt hold. I was able to tweak the indicated airspeed very precisely which is necessary to get accurate GPS ground speed. The applet TAS calculator on the RV forum appears to be very accurate as the wind direction and speed was about the same on all speed runs. The wind had switched to the Southwest from North during the afternoon runs which is why the temp was warmer at 4000'. I have also determined that if your ASI is reading incorrectly due to static pressure error, the altimeter will read about 12' in error for each knot of IAS error. 10 knots fast equals about 120' high on altitude. This is an estimate based on flying next to another airplane on several occasions. This fix for my airplane may not work on your's. I think every airplane has it's own set of static pressure challenges, but if you are interested in really knowing what's going on, it is possible to find out and do something about it. I am convinced there are many airplanes flying around with less than accurate ASI information, but it is no big deal at the speeds we fly unless you are bent on having it be accurate like me. In bigger, faster airplanes it is a big deal and the air data computers are a reliable fix for it. dd Date: Sun, 21 Nov 1999 13:21:12 -0500 From: Jeff Russell Subject: COZY: Re: pressure resolved... David Domeier wrote: > After lunch, I installed a .032 fence about .10" aft of the static > ports. It's interesting that Velocity aircraft does this in reverse. .062 in the front of the ports. The more squared off nose of the MKIV might make this difference. -- Jeff Date: Thu, 25 Nov 1999 08:47:16 -0600 From: David Domeier Subject: COZY: Electronic Ignition Stuff 'been curin' little problems lately..... The Electroair ignition system has been working fine, but the optional Advance Meter has not so I got into that one this past week. The Advance Meter is a micro digital DC volt meter. There is an ADV output on the ignition module and it puts out .01 volts for each degree of ignition advance. The numbers on my gauge have been very unstable and meaningless. So I did a little exploring with it. The first thing I noticed was that with all electric systems off, in worked. But as I turned on radios, lights, etc., the numbers jumped all over the place and meant nothing. I called Jeff Rose. He said sometimes the meter does that and he suggested I power it as close to the battery as possible. That was easy. I hooked it up to the DIS on-off switch which is hot off the battery instead of the electric panel. Still no good. I then ran a ground wire from the DIS module base to the Advance Meter and bingo, it worked. Evidently, it did not like the ground or power from the electric panel. I called Jeff and told him what I thought he already knew and he said it was news to him and glad to hear it. I flew the airplane today with everything turned on and for the first time I had DIS ignition advance info in-flight. Jeff gave me some numbers on what one should see. After start the system advances from zero to 37°. It stays at 37° but gradually backs off to 25° at take off power. It stays at 25° until manifold pressure decreases to 24 inches and then advances 2° for each one inch drop in MP. I saw numbers in that ball park today. I like the system but have retained a mag as back up. The DIS puts out so much voltage at the plug (about 85000 volts, I believe, vrs 14-15000 for the mag), it could do the job just fine by itself, but you never know, the Slick mag may come in handy someday if all electric power fails. dd From: Epplin John A Subject: COZY: Engine instruments. Date: Mon, 6 Dec 1999 09:40:21 -0600 I saw a complete engine monitor system at OSH that had a box at the firewall to gather all the thermocouple leads and make the conversion at that point rather than run all that wire forward. If I remember correctly it was set up for 4 EGT as well as 4 CHT probes and some undedicated inputs also. I believe the connection to the display was through a serial link, only a few wires from firewall to panel. Sounds like a good deal if one wants a complete diagnostic monitor. Cannot remember who it was or where to contact them. Anyone else see this and remember the contact? Any help would be appreciated John Epplin Mk4 #467 N100EP Date: Mon, 06 Dec 1999 11:18:44 -0600 From: David Domeier Subject: Re: COZY: Engine instruments. John, re "I agonized over the cost of the lights (and lots of other things) for a long time before I broke down and bought the Whelen's. I believe it was the right choice for the sake of reliability." Sounds like Vision Microsystems to me. I have it and it is great. dd Date: Mon, 06 Dec 1999 12:27:16 -0500 From: "Johnson, Phillip" Subject: RE: COZY: Engine instruments. I think that this is the one to which you were referring. http://www.afavionics.com/ Phillip Johnson >-----Original Message----- >From: Epplin John A [SMTP:EpplinJohnA@jdcorp.deere.com] >Sent: Monday, December 06, 1999 10:40 AM >To: cozy_builders@canard.com >Subject: COZY: Engine instruments. > >I saw a complete engine monitor system at OSH that had a box at the firewall >to gather all the thermocouple leads and make the conversion at that point >rather than run all that wire forward. If I remember correctly it was set >up for 4 EGT as well as 4 CHT probes and some undedicated inputs also. I >believe the connection to the display was through a serial link, only a few >wires from firewall to panel. Sounds like a good deal if one wants a >complete diagnostic monitor. > >Cannot remember who it was or where to contact them. Anyone else see this >and remember the contact? Any help would be appreciated > >John Epplin Mk4 #467 N100EP From: Epplin John A Subject: RE: COZY: Engine instruments. Date: Mon, 6 Dec 1999 13:43:22 -0600 Thanks Eric, Phillip and all, afavionics is the one I looked at. They have a nice web site, I will call them and start some discussion. John e... > -----Original Message----- > From: Johnson, Phillip [SMTP:phillip.johnson@lmco.com] > I think that this is the one to which you were referring. > > http://www.afavionics.com/ > > Phillip Johnson > > Date: Mon, 06 Dec 1999 08:34:25 +0000 From: Eric Westland Subject: Re: COZY: Engine instruments. John, It may have been the Audio Flight Avionic AV-10, http://www.afavionics.com/. This is the unit I have and so far I think it's great. Unfortunately, I can't recommend it to you as the customer service is poor. I have also read of others complaints of long delivery times, or worse yet, units paid for and then never delivered. This was last summer, possibly it has all been resolved somehow, but if you decide to head that way, I'd recommend caution. It's too bad as the unit itself is very well done. Eric Epplin John A wrote: > > I saw a complete engine monitor system at OSH that had a box at the firewall > to gather all the thermocouple leads and make the conversion at that point > rather than run all that wire forward. If I remember correctly it was set > up for 4 EGT as well as 4 CHT probes and some undedicated inputs also. I > believe the connection to the display was through a serial link, only a few > wires from firewall to panel. Sounds like a good deal if one wants a > complete diagnostic monitor. > > Cannot remember who it was or where to contact them. Anyone else see this > and remember the contact? Any help would be appreciated > > John Epplin Mk4 #467 N100EP From: alwick@juno.com Date: Mon, 6 Dec 1999 17:55:10 -0800 Subject: COZY: fuel cap, vent, ice failures I'm in the process of wiring my plane to prevent the more common failures. Have agonized for a few years about how to prevent failures related to fuel cap loss, clogged fuel vent (due to mud daubers), and iced up fuel vents. As you recall a Velocity just bit it due to cap loss, I just read of crash locally due to two fuel vents clogged with local insects(deep inside vent). I was pretty confident that the concept we brainstormed (sorta) a few months ago would work. That was replacing the fuel cap retention device with one(a cone shaped piece) that will reduce or stop fuel loss when cap dislodges. I was never able to find aluminum that was thin enough to conform to shape necessary upon cap loss. I got close. In concept, this method is fantastic, because it makes the aircraft insensitive to the failure cause. This type of solution is the best of all approaches, but just didn't pan out. I think someone else could solve it though. Anyway, I finally arrived at my best solution. I've used an extra pressure sensor I had lying around to measure the fuel vent pressure. If cap comes off, pressure in tank drops dramatically, and I can head back to airport. I'm pretty sure I can accurately detect the failure before departure, but I have to handle that correctly. Don't want to distract a pilot on takeoff. Just wanted you guys to know in case someone else was also concerned. Don't worry, I still intend to DETECT the problems using checklist. I've added sensors also that tell me which tank is selected, whether selector is positioned properly,how long I've been running on that tank, etc,etc. So it knows that I'm using left tank and that is the one with missing cap. P.S. It's a bit ironic that I have to disable fuel cap detection circuit that's part of all new auto engines, and add it for my own system. -al wick Canopy Latch System guy. Artificial intelligence in cockpit, powered by Subaru. Now wiring. Aug 2000 first flight scheduled ___________________________________________________________________ Why pay more to get Web access? Try Juno for FREE -- then it's just $9.95/month if you act NOW! Get your free software today: http://dl.www.juno.com/dynoget/tagj. Date: Tue, 07 Dec 1999 10:16:49 -0600 From: David Domeier Subject: Re: COZY: fuel cap, vent, ice failures Al, re "I've added sensors also that tell me which tank is selected, whether selector is positioned properly,how long I've been running on that tank, etc,etc. So it knows that I'm using left tank and that is the one with missing cap." What ever happened to the old Pietenpol theory - Keep It Simple, Stupid? I believe, Al, your airplane will be so complex, you'll need to come out at least a day early to preflight to make sure all the safety systems are working. Certainly, you won't want to fly if the selector sensing system is defective. I say this, of course, with tongue in cheek. You are to be commended for your concern for safe flight. But like the eternal bureaucrat who has never been able to write a rule or policy that incorporated a bit of common sense, you can not guarantee life eternal with 999 bells and whistles in an airplane. Granted, there have been accidents caused by just about every reason conceivable . I heard one the other night at an EAA meeting where a guy took off, lost all power and crashed. A mouse had eaten a hole in the scat tube to the carb air box, moved in and built a nest in the engine intake. Should a mouse detector now be installed in every airplane? I think not. It is one of the risks we live with just like being hit by a falling star or developing cancer. I am of the opinion that flight is risky. But the risk can be managed and we each have our own ideas on how to do it. I believe in a well written check list. There is a feeling of security in flight knowing the "check list" was complied with. It does not have to be long and complicated, but it does need to cover fuel, air, and ignition to the engine, and the flight control system. A check list can be carried to the extreme that does require coming out a day early just to perform it. But does it really reduce the risk of flight? Again, I think not. We have to have some faith in our ability to perform a simple well written task or flight becomes a fearsome event always. And that is no fun. And if it is no fun, what's the point in doing it? dd From: alwick@juno.com Date: Tue, 7 Dec 1999 10:57:13 -0800 Subject: Re: COZY: fuel cap, vent, ice failures On Tue, 07 Dec 1999 10:16:49 -0600 David Domeier writes: > What ever happened to the old Pietenpol theory - Keep It Simple, Stupid? > I believe, Al, your airplane will be so complex, you'll need to come > out at least a day early to preflight to make sure all the safety > systems are working. Appreciate your honesty David. I would expect a lot of people read my posts, and think "That idiot must have a maze of wires", or "kiss", or "$$". My entire work career involved finding solutions to failures. I was fortunate to be able to implement solutions and then measure how effective the solution was. This allowed me an excellent perspective of what works, what doesn't. Try this, the failure rate drops from 1 in 100 to 1in 1000, not good enough. Try something else, remeasure, etc. Last company I worked for we reduced external failure rate by 8 times the previous average. You'd be hard pressed to find another US company with that record. The nature of failures in business are identical to those in aircraft. All sorts of interesting patterns to the root causes. Your statement about needing to do preflight a day early is ironic. Actually, preflight will be very fast and more important, meaningful. As we do a normal checklist preflight, it's very common for our brains to read item and totally skip it. My computer will do the pre-flight and actually tell me what to do. It then checks to see that the appropriate sensors function. There really aren't that many. It'll say "full throttle", "idle", "landing brake deploy", etc etc. Don't forget also, my systems are supplements to the normal method. Nothing is flight critical. > Should a mouse detector now be installed in every airplane? The auto engines have one. It's called Mass Airflow Sensor. Adjusts air volume to compensate, if too severe "check engine" activates. Familiar with the 80/20 rule? 80% of all failures are the result of 20% of the potential causes. I focus on that 20%. Example: I just heard that 34% of all engine outs are caused by carb ice. I have EFI that doesn't ice up. No carb heat. > I am of the opinion that flight is risky. But the risk can be > managed and we each have our own ideas on how to do it. I believe in a > well written check list. I measured how effective checklists are, and use method that measures more effective. I've been trained in how to make checklists effective. Very interesting the difference you can make by just re-designing your checklist. We should discuss. > And that is no fun. And if it is no fun, what's the point in doing it? I have fun, I fly every week. I enjoy challenge of creative activities. Enjoyed the exchange. I mentioned the solution I found to help those with similar concerns. Not for everyone. -al ___________________________________________________________________ Why pay more to get Web access? Try Juno for FREE -- then it's just $9.95/month if you act NOW! Get your free software today: http://dl.www.juno.com/dynoget/tagj. Date: Tue, 07 Dec 1999 15:20:34 -0600 From: "Tom Brusehaver" Subject: [Fwd: COZY: fuel cap, vent, ice failures] X-Mozilla-Status2: 00000000 Message-ID: <384D64D1.3D133DE6@uswest.com> Date: Tue, 07 Dec 1999 13:49:37 -0600 From: Tom Brusehaver X-Mailer: Mozilla 4.61 [en] (WinNT; I) X-Accept-Language: en MIME-Version: 1.0 To: David Domeier Subject: Re: COZY: fuel cap, vent, ice failures References: <19991206.175511.-349555.0.Alwick@juno.com> <384D32EB.4C1B9A45@earthlink.net> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit David Domeier wrote: > What ever happened to the old Pietenpol theory - Keep It Simple, > Stupid? I keep thinking of that airplane when people start talking about auto engines in airplanes. Bernard did his homework, and there are a buncha peit's flying today with Model A (and T, and Corvair) engines, with all the benefits and drawbacks. (I almost built one, but then winter came, and I ordered the cozy plans). > I say this, of course, with tongue in cheek. You are to be commended > for your concern for safe flight. But like the eternal bureaucrat who > has never been able to write a rule or policy that incorporated a bit of > common sense, you can not guarantee life eternal with 999 bells and > whistles in an airplane. At this point, I think it is good Al is experimenting. I think it is taking longer to build that airplane (I remember when Al's .sig said Apr99 first flight). I'd be more inclined to get flying, then begin experimenting, but that I have said before. Al is in a unique situation, he knows his systems (hopefully), and can make judgements when an indicator says something is unusual. If an alarm tells him the canopy is open, and he can visually check, the canopy is closed, it is likely that he will continue flying and check the system at the next convenient stop. If this airplane were sold, or systems like this were sold to others who wouldn't understand all the systems, a faulty indicator is as likely to cause a crash as what it was indicating. Some of the crashes would be caused by users trying to diagnose trouble, while others may panic, and still others would feel the system unreliable and continue to fly with real indicated trouble. The more systems a system has the more someone has to understand, to make things useful. From: alwick@juno.com Date: Tue, 7 Dec 1999 15:05:55 -0800 Subject: Re: [Fwd: COZY: fuel cap, vent, ice failures] On Tue, 07 Dec 1999 15:20:34 -0600 "Tom Brusehaver" writes: > >At this point, I think it is good Al is experimenting. I think it is taking longer >to build that airplane (I remember when Al's .sig said Apr99 first flight). Tom, How DARE you bring up such sore points :-) lol. My date was a prediction based upon 2 assumptions. A) that it would take me 2500 hours to build. B) that I could make predictions based on AVG of my past hours. I didn't expect the build hours to decline so. It's taken me 2640 hours so far, and that includes my making most of my own Brock parts, painting. Probably only 100 hours spent on unique items like auto engine, computer sys. So actually, I'm pretty much on target with most people. Just a bad predictor. >Al is in a unique situation, he knows his systems (hopefully), and can make >judgements when an indicator says something is unusual. If an alarm tells him >the canopy is open, and he can visually check, the canopy is closed, it is >likely that he will continue flying and check the system at the next convenient >stop. Actually,one of the most important characteristics of a sys like mine is to have the system diagnose any sensor failure. There aren't too many sensors it can't self diagnose. >If this airplane were sold, or systems like this were sold to others who wouldn't >understand all the systems, a faulty indicator is as likely to cause a crash as what >it was indicating. Some of the crashes would be caused by users trying to diagnose >trouble, while others may panic, and still others would feel the system unreliable >and continue to fly with real indicated trouble. You make a good point Tom. I've seen such problems with similar business applications. But it doesn't have to be that way. There are always solutions. I can think of many examples to support your statement. I can just see somebody crashing on takeoff cause he was distracted by "your seatbelt is not secure" or some other poorly timed or incorrect indicator. Any takeoff or landing flagging must be handled very very carefully. What do they say? "The cure is worse than the desease?" Actually, my big first flight delay will be when I do extensive taxi testing. But I love that stuff. Probably more than flying. ps. Finally bought my laptop today. Been waiting YEARS for them to improve screens. Another prediction gone wrong. I thought 5 years ago they would be producing high nit screens for laptops. Oh well, tft will have to do. Can't wait to test moving map in my cessna. -al wick Canopy Latch System guy. Artificial intelligence in cockpit, powered by Subaru. Now wiring. Aug 2000 first flight scheduled ___________________________________________________________________ Why pay more to get Web access? Try Juno for FREE -- then it's just $9.95/month if you act NOW! Get your free software today: http://dl.www.juno.com/dynoget/tagj. Date: Tue, 07 Dec 1999 10:59:25 -0500 From: Chuck Charles Subject: Re: COZY: Engine instruments. Hi John, I think the instrument you are talking about is ESI Engine Information System, from Grand Rapids Tech, Phone (616) 531-4893 I saw it at Sun & Fun and it is the one I will be putting in my Cozy hopefully this Spring . Hope this helps Fly Safe & Cozy Chuck Epplin John A wrote: > I saw a complete engine monitor system at OSH that had a box at the firewall > to gather all the thermocouple leads and make the conversion at that point > rather than run all that wire forward. If I remember correctly it was set > up for 4 EGT as well as 4 CHT probes and some undedicated inputs also. I > believe the connection to the display was through a serial link, only a few > wires from firewall to panel. Sounds like a good deal if one wants a > complete diagnostic monitor. > > Cannot remember who it was or where to contact them. Anyone else see this > and remember the contact? Any help would be appreciated > > John Epplin Mk4 #467 N100EP From: Militch@aol.com Date: Wed, 8 Dec 1999 23:01:55 EST Subject: Re: Re: COZY: fuel cap, vent, ice failures In a message dated 12/7/99 11:27:34 AM, david010@earthlink.net wrote: > What ever happened to the old Pietenpol theory - Keep It Simple, >Stupid? > > I believe, Al, your airplane will be so complex, you'll need to come Simple is nice, but I believe from reading Al's signature on his e-mails that he plans to run all this sensor data into some kind of rule based expert system that boils it all down to - yes, you are ok or no, there is an issue. If that works, it allows management by exception, and you get monitoring of a lot of critical parameters all the time, rather than just once on the ground by a human observer, who will eventually make an error. Since these are "experimental" aircraft, it sounds like a worthwhile venture. Of course, it is likely that he will spend 10 hours programming for every hour flying, but that can be fun too. Regards, Peter Militch #740 Chapter 10 From: "John Slade" Subject: Re: Re: COZY: fuel cap, vent, ice failures Date: Thu, 9 Dec 1999 09:22:33 -0500 Was said: >he plans to run all this sensor data into some kind of rule based expert >system that boils it all down to - yes, you are ok or no, there is an issue. Is this true, Al? I've been working with AI and expert systems for the last dozen years. On an academic level, I'd be interested to know how you're going about this. John Slade, Cozy MKIV #757, progress: http://kgarden.com/cozy West Palm Beach, FL From: alwick@juno.com Date: Thu, 9 Dec 1999 10:39:27 -0800 Subject: Re:COZY: fuel cap, vent, ice failures On Thu, 9 Dec 1999 09:22:33 -0500 "John Slade" writes: > >he plans to run all this sensor data into some kind of rule based expert > >system that boils it all down to - yes, you are ok or no, there is an issue. > > Is this true, Al? Sort yes, sorta no. There's nothing available to automatically check (to the degree I want). It's just a function of the code. I place a lot of value on determining whether sensor info is accurate. I really haven't encountered another sys that does so. Can't readily be accomplished with all sensors, but many. Fuel gage is good example. You hear people say how inaccurate they are. Totally untrue. Modern auto gages are very repeatable. I have my sys verify that the reading when tank is full, agrees with the historical reading. If I want to recalibrate fully, I will have to open fuel cap and force float to bottom with a stick. As long as both values agree with my initial calibration, I'm in great shape. Sometimes they lose it in the middle, but that too can be easily measured, automatically. I haven't done it, but I could certainly also relate fuel tank levels to rpm, manifold pressure info already available to computer. If total fuel from gages don't match engine use history, something is wrong. I doubt I'll pursue that one. Too much a pain to control fuel input to tanks. I don't remember the details, but didn't some big jet go down last year because the pilot, co-pilot, and flight engineer were all trying to debug a burned out bulb? Equally important is controlling WHEN it tells you there is a problem. I learned (from others on this list) to tell my passengers to close mouth on takeoff and landing. I have my sys do the same whenever possible. -al wick Canopy Latch System guy. Artificial intelligence in cockpit, powered by Subaru. Now completing firewall. Remounting engine soon. VRROOOM! Aug 2000 first flight scheduled ___________________________________________________________________ Why pay more to get Web access? Try Juno for FREE -- then it's just $9.95/month if you act NOW! Get your free software today: http://dl.www.juno.com/dynoget/tagj. From: "Larry & Jenny Schuler" Subject: Re: COZY: Re: Automated monitor and control (was fuel cap, ice, ventfailures) Date: Tue, 14 Dec 1999 21:18:05 -0600 > > The best thought out user interface I have ever seen is on your tv most > nights, and that is the systems shown on the newer Star Trek series. If you > pay attention... And one of my favorite Star Trek movie lines is when Scottie sits down to impart a formula for plastic steel and says: "Computer"; and.... gets no response to his wake up call. Funny thing about computers is that they do "exactly" as told to do; no more and no less. And when we tell 'em to make a mistake, they do it with blinding speed..... Repeatedly! The Microsoft blue screen of death is an excellent example. Nice diversion. Larry From: Militch@aol.com Date: Mon, 13 Dec 1999 21:31:06 EST Subject: COZY: Re: Automated monitor and control (was fuel cap, ice, vent In a message dated 12/9/99 2:02:37 PM, alwick@juno.com wrote: >Equally important is controlling WHEN it tells you there is a problem. I >learned (from others on this list) to tell my passengers to close mouth >on takeoff and landing. I have my sys do the same whenever possible. The best thought out user interface I have ever seen is on your tv most nights, and that is the systems shown on the newer Star Trek series. If you pay attention, you will note some important things: 1. The system never, ever speaks unless it is spoken to, except in the case of a warning or emergency 2. All answers are to the point, very terse in fact. Once the specific question that was asked has been answered, the system shuts up. I have often thought about how truly clever a real monitor and control system would need to be to boil all available data down, and present exactly the most useful information when it was needed. No more, no less. The rule base quickly becomes enormous. I remember reading about the cause of an Airbus crash some years ago. It was poor human interface design. The displays in the cockpit were modal. i.e. a specific indicator meant something quite different if the pilot placed the system in one mode, than if it was placed in another mode. Very, very dumb since the pilot will eventually forget which mode he is in. If you want to read a great book on human interface design, get "Tog on Human Interface Design" (or something like that. The author, Bruce Tognazini (sp?) was Apple Computer's chief designer of human interfaces. He gives marvellous examples of what to do, and what not to do. Peter Militch #740 From: Militch@aol.com Date: Wed, 15 Dec 1999 20:17:00 EST Subject: COZY: Engine power monitoring There was a thread here recently about implementing a reliable engine-out monitor. A method I have thought about for a long time would be to use a wire wound sensor (same as the crankshaft rotation sensor on a lot of cars) and implement circuitry that was smart enough to look at the acceleration and deceleration of the crank-shaft as each cylinder fired. I have never done the calculations (or measurements) to tell if the moment of inertia of the crank and flywheel is low enough to make it possible to discern the presence of each firing pulse. If it is, then you could look at the amplitude of the AC component (which should always be at a frequency equal to half the number of engine revolutions per second times the number of cylinders) and detect not just the presence of power, but also the amount of power contributed by each cylinder. That would be a useful measurement since it would provide advance warning of power delivery problems on a cylinder by cylinder basis. The sensor is passive and tolerant of heat and vibration. It wouldn't be hard to build a variable rate filter using a fast DSP in order to make these measurements. Once you have the signal digitally, you could do a lot of tricks on it to extract data of interest. Has anyone heard of such a system, and if so, did it work? Regards, Peter Militch Cozy Mark IV #740 Date: Fri, 17 Dec 1999 14:08:20 -0500 Subject: Re: COZY: Engine power monitoring From: "Paul Comte" Militch@aol.com wrote: > That would be a useful measurement since it would provide advance warning of > power delivery problems on a cylinder by cylinder basis. doesn't the resistance at spark plug go up in dead cylinder? If so would this be possible to read from passive sensor around spark plug cable??? Paul Comte Milwaukee, WI Date: Fri, 17 Dec 1999 16:10:17 -0500 From: "Johnson, Phillip" Subject: Re: COZY: Engine power monitoring Militch@aol.com wrote: > That would be a useful measurement since it would provide advance warning of > power delivery problems on a cylinder by cylinder basis. Why not use an EGT sensor on each cylinder. If the cylinder is not performing the EGT goes out of limit. BTW Grand Rapids makes an engine monitor that will do six cylinders plus a whole bunch of other monitoring, for a very reasonable price, and it is equipped with alarm outputs that can be interfaced with low cost voice warning systems. It seems that we are re-inventing the wheel here. Phillip Johnson Date: Fri, 17 Dec 1999 15:41:19 -0600 From: "Tom Brusehaver" Subject: Re: COZY: Engine power monitoring Paul Comte wrote: > Militch@aol.com wrote: > > That would be a useful measurement since it would provide advance warning of > > power delivery problems on a cylinder by cylinder basis. > > doesn't the resistance at spark plug go up in dead cylinder? If so would > this be possible to read from passive sensor around spark plug cable??? Dead in what sense? Not delivering power I assume. How did it go dead? 1. Lead fouled plug, no gap, no spark, low resistance. 2. something broke, and wedged in spark plug, no gap, low reisitance. 3. something broke, no fuel into cylinder, normal resistance 4. spark plug wire broke, lotsa fuel in cylinder, lower resistance. (how do you measure resitance across a broken wire) Not saying checking resistance isn't a good idea. I saw a video on the GEM engine monitors once, and they showed where the tempratures will give really good clues when things are going/have gone bad. Date: Tue, 21 Dec 1999 17:18:00 -0500 From: "Johnson, Phillip" Subject: COZY: Canadian Vertical Card Compasses OK or not OK Carl Denk Writes> Canada has own requirements, including whiskey glass compass, vertical cards not allowed. End< Carl, I know of a number of vertical card compasses being used up here in Canada. Chapter 549 of the Airworthiness Manual states that in section 549.13, Equipment and Instruments, only three instruments are necessary: (b) Flight & Navigation Instruments: (1) An airspeed indicator. (2) An altimeter. (3) A magnetic compass. There is no reference to Whisky compasses nor that Vertical card compasses are unacceptable. I have scanned the document but it is possible that I have missed it somewhere. I have heard, possibly through this mailing list, that only direct reading magnetic compasses are allowed, but I would read that to mean that a compass requiring an external power source to operate would not be acceptable such as those remote compasses seen on Moony's, not vertical card compasses. http://www.tc.gc.ca/aviation/regserv/carac/cars/cars/549/suba.htm#549.13 is the URL that takes you to the pertinent Canadian WEB page. Phillip Johnson From: cdenk@ix.netcom.com Date: Tue, 21 Dec 1999 20:13:53 -0500 (EST) Subject: Re: COZY: Canadian Vertical Card Compasses OK or not OK Was questioned, I had said: Canada has own requirements, including whiskey glass compass, vertical cards not allowed. Going back to my previous (before the standarized blanket authorization) for "IFR required to comply with Air Navigation Order (ANO), Series V, No. 22/CRDc.-48 (Attached) "Order respecting IFR Instrumentation & Equipment"" and in that document General, para.3.c "a direct reading magnetic compass" I interpeted that as your eyeballs read directly the compass card, and with a vertical card compass, you are not seeing the actual card, but a mechanically connected disc with markings. Several other interesting things in that document: "airspeed indicator with means of preventing malfunction due to icing." (heated pitot) altimeter with alternate static source (same a USA) acceptable navigation equipment includes (adequate to navigate in area) "two low medium frequency range receivers" para. 6 (my words) ADF required functional for all IFR. para. 7 (my words) No flight into icing unless "engines props, and airframe" suitably protected... The authorization itself says "VFR On top" is prohibited in Canada. It gets interesting here in Northern Ohio: Cleveland Center, Detroit approach, and probably Cleveland Approach control airspace North of the border. Flight plans are required for any international flights, but most locals just overfly with no flight plans. Might get interesting if making an emergency landing. Best calling customs direct if short flight. Customs is a whole different issue. Date: Wed, 22 Dec 1999 09:01:36 -0500 From: "Johnson, Phillip" Subject: RE: COZY: Canadian Vertical Card Compasses OK or not OK >Carl Denk Writes> > >Going back to my previous (before the standarized blanket authorization) for >"IFR required to comply with Air Navigation Order >(ANO), Series V, No. 22/CRDc.-48 (Attached) "Order respecting IFR >Instrumentation & Equipment"" > >and in that document General, para.3.c "a direct reading magnetic compass" > >I interpeted that as your eyeballs read directly the compass card, and with a >vertical card compass, you are not seeing the actual card, but a mechanically >connected disc with markings. > >End< > >I do not interpret this statement the same way that Carl Interprets the >statement. A direct reading pressure gauge is the classical mechanical gauge >using gears and leavers. By the same token, the vertical card compas is >direct acting, in other words it requires no external influence/power source >to operate. If one takes Carl's argument to the extream even the whisky >compas is not direct acting since there is a mechanical coupling between the >magnet and the markings. The common usage of vertical card compasses in >Canada suggests that they are acceptable and that "a direct reading magnetic >compass" is either a whisky compass or vertical card compass. There are a >number of Canadian members to this list and I suggest that if a verticle card >compas is required by the builder for whatever reason, then that individule >should contact Transport Canada, their inspector, or visit the Transport >Canada Web site at http://www.tc.gc.ca/en/menu.htm rather than listen to >gosip and rumour. > >Carl also writes> > >acceptable navigation equipment includes (adequate to navigate in area) "two >low medium frequency range receivers" > >I haven't read this part of the order for a number of years but as I recal >this refers to Sparsely Populated Areas. > >Canada has large areas of unpopulated land in which there is no VHF NAV or >COMS. In these areas it is necessary to revert to the MF and HF bands. It is >not mandatory accross the populated regions. Unless you are a bush pilot or >flying to Europe using the Greenland, Iceland route it is unlikely that you >will encounter this problem. > >Carl is correct in stating that: "VFR On top" is prohibited in Canada. > >Phillip Johnson > From: cdenk@ix.netcom.com Date: Wed, 22 Dec 1999 18:13:49 -0500 (EST) Subject: RE: COZY: Canadian Vertical Card Compasses OK or not OK Was said My webster's: gossip: ...chatters, repeats idle talk and rumors... rumor: ...talk not based on definite knowledge... I quoted accurately the regulation, then stated my interpetation, which wouldn't get anyone in trouble. Agree, that ask the Canadians is best route. AND other countries could have other requirements. The "adequate to navigate in area" with reference to range receivers is an accurate quote from the regulations. And yes this might be needed at some very sparsely populated area, I added this mre in jest, for the benefit of the younger set. I think I have seen only one range station on a chart in recent years, and 33 years ago there weren't many then. The requirement for ADF, the actual wording "an automatic direction finding radio compass" of all IFR flight is a requirement! This all comes from a fax from the Canadians dated June 11, 1996, and is Amendment no. 45, dated 20/5/74 (May 20, 1974). If it has been superceded someone tell us. This document has been part of my Canadian operating limitations since the date received. From: Ian Douglas Subject: RE: COZY: Canadian Vertical Card Compasses OK or not OK Date: Wed, 22 Dec 1999 22:12:23 -0500 > >Carl is correct in stating that: "VFR On top" is prohibited in Canada. > > Since I have a VFR OTT rating on my license (Canadian) I am permitted to fly VFR OTT (got it while working on my multi IFR). The rules are at: http://www.tc.gc.ca/aviation/regserv/carac/CARS/cars/602e.htm#602_116 From: cdenk@ix.netcom.com Date: Fri, 17 Dec 1999 17:22:28 -0500 (EST) Subject: Re: COZY: Engine power monitoring Was said This is a very common by many vendors piece of equipment, and I would not be without!!! Mine is an Electronics Internation Ultimate Scanner. It has 16 thremocouple inputs that I use for all CHT's and EGT's, OAT, cabin temp, nose mounted landing lights, cabin air coming through the firewall, top rear of engine for a fire warning, and a loose one that I move around. The instrument has programmable high and low limits and shock cooling on CHT's. THe limits display the offending sensor (cylinder number for CHT/EGT) and whether its high or low temp. The EGT's in particular react to cylinder condition, plus the trend of a EGT/CHT compared to the others helps finding a problem early. The unit comes with a many paged troubleshooting manual. I have several time quickly isolated a clogged injector jet or fouled sparkplug where I have pulled exactly one component to fix the problem. Once was on the ground less than 15 minutes with a clogged injector nozzle. 2 disadvantages, one common to all units like this - they including the cable and sensors are a little heavy and expensive, but it is so important that I consider this to be a worthwhile trade off. Second is this particular model - The LCD display is hard to read at a flat angle, but the newer model has cured this. Bottom line this instrument solves many of the problems recently discussed with an off the shelf recognized product that has other uses.