Date: Wed, 21 Feb 1996 21:57:33 -0700 From: Eric Westland Subject: [Fwd: SV: Strakes] I received this nice reply today and thought I would pass it on for feedback. I don't recall anything in the newsletters about it (wouldn't be the first time). Any thoughts? From: jan-erik.synnerman@lf.se To: Eric Westland Subject: SV: Strakes Eric, Nice to get a aircraft related letter on e-mail! Its the first time for me. I am building a Cozy III. Slowly, because I have a demanding job, three kid s (now grown up) etc. But I love building, and I think I will have a straight , good looking and fairly light aircraft in the end. I_m now in the finishing stage sanding micro. The project started 1986 (puh!). Four of the ten years have ment complete idleness. During such a long time lots of things happen. The rights for the Cozy III where bought by Uli Wolter, Cozy Europe, Ahornstr. 10, 865 10 Ried , GERMANY. Newsletter $ 15. He has done a great job promoting the type in Europe, and it is popular especialy i France. So I have been reading three newsletter regulary for quite a time - Puffer_s, Uli_s and Rutan_s. I have tried to pic up only those modification s that make sens to me, relying also on my own flying experiense and on experience we have here in Sweden (EAA Chapter 222 - Yes, the largest chapter in the world is the singel one covering Sweden I believe. Not some chapter in Texas...) flying Vari Eze and Long EZ. I want to ad safety and utility, not complexity and weight. To use the larger fork and nosewheel for the Cozy IV, and a heavy duty spring, is an example of an easy decision. Nose heavy, nose down, big engin e acceleration is no fun with this type of aircraft. When I flew with Uli we couldn_t rotate until we reached 85 knots! This mod will correct part of th e problem, I think. The extra ply (uni) on the stakes (three instead of two) is quite another story! It_s a mod invented by Uli and authorities in Germany. Calculations and experience from static load testing (necessary in some countries but no t here in Sweden) indicated that the wing needed to bee more twist resistant (torsionaly stiffer). To prevent the leading edge of the wing from moving u p or down, they recomended sturdy extra ribs in the wing root and on the strake forward of the main spar. And a heavy bolt through both near the leading edge to lock them together. Finaly, to carry the twisting load to the fuselage, they recomended adding an extra ply to the strakes, top and bottom. I was saying ugly things loud in my workshop when this newsletter arrived. This hadn_t been necessary with hundreds of canards already flying. It was not Rutan or Puffer making the recommendations. To the best of my knowledge , no accident trigged the mod. It was lots of extra work. And it added WEIGHT ! What, then, made me make the decission incorporate this mod? First, like yo u I was just getting started on the strakes at the time. I had to make a decission promtly. Second, experience from EZ flying here in Stockholm showed signs of delamination and softness in the strakes, especially in where people sit etc. when climbing in and out of the back seat. Third, i t was a mandatory change. My license is with Puffer, but I want to fly and perhaps sell i Germany. It might be stratgically right to comply after all. Fourth, static loading showed no contact or binding betwen wing and strake when under load, in contrast to unmodified aircraft. Fifth, at such it couldn_t hurt to make the aircraft stronger and the tanks more leakproof. So I made the decission and built the mod, cursing all the time. Puffer indicated in his newsletter that Rutan was mad when he heard of it. There i s a missconseption, however, that shimming a wing with washers to correct minor building errors is not possible with this mod. It is. You dont put th e bolts in place permanently until you have made the test flying. Well, Eric, this was a rather long answer to a short question. But I think it is important that You have an understanding of the pro_s and con_s. Please spread the information if You like to prevent rumors. Best regards Jan Erik Synnerman ---------- FrE5n: MIME:Eric Westland Till: JES AngE5ende: Strakes Datum: den 19 februari 1996 17.52 <> Jan Erik, I am a Mark IV builder in Mukilteo, Washington, USA. I am just getting started on the strakes and read your post on the Canard Aviators page where you stated to placed extra bid in the strakes. Where did you do this and for what reason? Thanks, Eric Date: Wed, 21 Feb 1996 22:00:19 -0700 From: Eric Westland Subject: Fuel Vents The plans show the fuel vents exiting at the top of the turtle back, but I m not sure I have ever seen that in a Cozy - they seem to exit under the spar next to the fuselage sides. How have some of you routed yours? Eric Date: Thu, 22 Feb 1996 19:05:33 -0500 From: PBurkha238@aol.com Subject: Re: Fuel Vents I routed my vent lines up through the rear, inside area of the strake(corner) through the cosmetic plywood piece. then up to the top of the turtle back area and then back down the opposite side and out through the cowling flange under the strake. I believe this is how Nat has his installed. Paul Burkhardt Date: Thu, 22 Feb 1996 23:04:51 -0500 From: KSPREUER@aol.com Subject: Re: [Fwd: SV: Strakes] In a message dated 96-02-22 00:59:42 EST, you write: >Subj: [Fwd: SV: Strakes] >Date: 96-02-22 00:59:42 EST >From: westland@premier1.net (Eric Westland) >. Second, experience from EZ flying here in Stockholm >showed signs of delamination and softness in the strakes, especially in > where people sit etc. when climbing in and out of the back seat. Eric's comment reminded me of the softness I noted in my 3 place as stated above. I put an extra layer of bid both inside and outside between the fuselage and the first bulkhead from the L.E. back to the diagonal bulkhead that separates the fuel tank from the baggage area. I reccomend this to all. Date: Thu, 22 Feb 1996 23:05:10 -0500 From: KSPREUER@aol.com Subject: Re: Fuel Vents In a message dated 96-02-22 01:03:00 EST, you write: >Subj: Fuel Vents >Date: 96-02-22 01:03:00 EST (Eric Westland)) > >The plans show the fuel vents exiting at the top of the turtle back, but >I m not sure I have ever seen that in a Cozy - they seem to exit under >the spar next to the fuselage sides. How have some of you routed yours? > >Eric > Most people tie the two vents together at the top of the firewall and then run one line down to the arm pit area. This is supposed to avoid syphoning when parked. It doesn't always work, however. If the vent in the tank is in the reccomended position (near the center) and the tanks are full and the plane is parked nose down, the vent covered with fuel. Then when the solar heating generates some vapor pressure it drive fuel up to the top of the firewall. Once it gets that high it goes over the top and starts a syphon action and will drain the tank until the vent is uncovered. This can also happen in flight in a high angle of attack climb. In this condition the inboard L.E. of the fuel tank is also higher than the firewall. You won't loose much fuel that way because as soon as you stop climbing it breaks the syphon. To solve this, I located the vent in the tank at the rear inboard end near the spar. I ran the vents together at the top of the firewall and then ran forward to a spot just behind the split between the front part of the canopy and the rear. This location is always higher than the L.E. in a climb. In the parking position the vent is in the vapor portion of the tank and it can vent normally. In climb the airplane won't get significant solar heating. In a climb it could experience expansion of the vapor due to gain in altitude and I may loose some fuel in the tank not in use. The other disadvantage is the in the rare event of a roll over the fuel could flow out the vent. I don't believe there is any single solution that is always best. Date: Fri, 23 Feb 1996 08:52:10 -0500 From: CheckPilot@aol.com Subject: Fwd: Fuel Vents Keith is right. There is no best system. I fly an Aerostar for a living (and a Baron) and it has a complex, multiple outlet venting system with vents on the upper fuselage, lower fuselage, and wingtips. The wingtip vents have valves that are supposed to open at 1.5 psi to prevent the wing tanks from pressurizing. Guess what, it doesn't work. When ever we park the aircraft it is company policy to "pop" the wing fuel caps so that the tanks vent, otherwise the pressure builds so high it pushes fuel out through the seams in the wet wing. The moral is, if it works don't fix it and the simple way may be good enough (and light enough too). Jim Cozy #455 StarCheck 432 (MKE) Date: Sat, 24 Feb 1996 13:50:46 -0800 From: brimmer@ix.netcom.com (Kenneth Brimmer ) Subject: Vents - 2nd Try was cut off. (I have got to away from netcom). Last summer I went on an accident investigation of a Cozy 3 place. You could write a book about the many errors the builder made but the one that killed him was the leaving off of the standard fuel vents. These vents are suppose to go from the gas tanks aft to the highest point of the plane which is the top of the firewall and then back down to exit just aft and under the main spar. The reason for this is that if the plane turns turtle the fuel will not run out the vent. In this case, the pilot on attempting to land on a narrow dirt field (with only 4 hrs. experience on his Cozy), flipped the plane over (over the nose) and the fuel drained out of the vents and caught fire; the pilot burned to death. Had he not left off the vents I am almost sure he would have lived with possibly no injury at all. Of course he had to have had vents of some kind but I could not locate them and he definitely did not have the recomemded vents. Don't forget to bend the vents 10 degrees into the slipstream. Too much bend and you will over pressurize the tank and possibly pop the fuel cap. Too little and you can lose fuel on climb-out. Date: Tue, 12 Mar 1996 02:10:38 -0500 From: JHocut@aol.com Subject: Fuel System? If anyone has succesfully made use of alternative fuel system designs I'd like to hear the details. I'm considering copying the Velocity fuel system because a) I'd like to avoid fuel lines in the passenger compartment if possible b) as a CFI I'm learning more and more that pilots (including me) are stupid and any little chore like switching tanks we can avoid is a plus. However, I'm VERY reluctant to mess with a proven fuel system design. It was stressed at the flight advisor forum at OSH that the # 1 cause if incidents in homebuilts is fuel system problems, and right up there in that category is builder mods that don't work. Anyway, I'm thinking about copying the Velocity fuel system as closely as possible, including vent lines etc. Any input???? Thanks, Jim Date: Tue, 12 Mar 1996 08:44:01 From: JRaerocad@gnn.com (Jeff Russell) Subject: Re: Fuel System? >From: JHocut@aol.com >If anyone has succesfully made use of alternative fuel system >designs I'd like to hear the details. I'm considering copying >the Velocity fuel system because a) I'd like to avoid fuel lines >in the passenger compartment if possible b) as a CFI I'm >learning more and more that pilots (including me) are stupid >and any little chore like switching tanks we can avoid is a plus. >Anyway, I'm thinking about copying the Velocity fuel system as >closely as possible, including vent lines etc. Any input???? I built a Velocity RG. The Velocity never parks down on its nose. There for its vents are not even close to what is in the Long-Ez or Cozy. I have install a fuel system like the Velocity in our AeroCanard becouse I also did not want to switch tanks. I installed a burp valve in the sump tank to get the air out when first filling the mains. The vents in the mains are like the Cozy design. Both of my tank fill caps seal very tight (no leaks). The only thing that I had to adjust were the vents being at the same angle under the strakes (about 20 deg down to the slip stream) to get equal useage from both mains into the sump. The fear of one fill cap coming open in flight would mean loss of fuel on one side? I use double locking caps $110.00 each to keep this from happening. The other bad thing we heard could happen would be getting bad fuel or water on one side and it would not give you the chance to keep the other side uncontaminated. There are no side sumps in the AeroCanard. The center sump sits on the main gear box with 1/2" lines from the mains feeding it. From there to the gascolator on the firewall and then to the fuel pumps. There are nose down drains on the mains, one in the sump low spot, and the gascolator. Four total drains. hope this helps AeroCad Inc. Jeff Russell 1445 Crater Lane Yadkinville, NC. 27055 910-961-2238 E-mail: JRaerocad@gnn.com From: Lee Devlin Subject: Fuel lines in the passenger compartment Date: Tue, 12 Mar 96 17:12:49 MST So far, I've seen several builders on this mailing list express concern about fuel lines plumbed through the passenger compartment. However, I have noticed that just about every GA plane I've ever flown has had this arrangement. If it were truly a safety hazard, would it not have become apparent by now? One alternative is to have the fuel valve mounted remotely and controlled by a cable or torque rod. I think it is better to to have the fuel valve close at hand rather than have an additional actuating component which can break. In addition to making it easier to feel the detents on the valve, I believe there's another advantage to being able to reach the valve. I once read a story about a pilot who switched tanks and had the fuel valve handle come off in his hand. It happened as the valve was in between tanks and essentially turned the fuel flow off. I began carrying vice grips just in case this ever happens to me. Another option is to connect the tanks together. I prefer the separate tanks for the following reasons: 1. If you loose a fuel cap, it can only siphon fuel from one tank. 2. If the fuel is contaminated with water, jet A, or dirt, it may be isolated to a single tank which is only helpful if you can switch tanks. 3. A leak at a low point in the fuel system will not automatically drain both tanks. 4. As much as I hate to admit it, inadvertently running a tank dry in a low fuel situation adds a sense of urgency to land and thus adds an extra measure of safety. (I've heard of pilots who intentionally run a tank dry before switching but can imagine why.) Lee Devlin Date: Tue, 12 Mar 1996 23:11:49 -0500 From: Nigel Field Subject: Re: Fuel System? At 02:10 AM 3/12/96 -0500, Jim wrote: Wow 02:10 AM and your on your computer to the list, thats dedication or is your PC clock off a bit? >If anyone has succesfully made use of alternative fuel system >designs I'd like to hear the details. > Jim you asked so here is what I have succesfully proved on my VE and am doing to my Cozy III. The VE design connects the two strake tanks together as one which feeds the fuel selector valve. It also has an aux tank behind the rear head rest which I now use to collect excess fuel flowed up to the carb but not used, and which flows by gravity back to the mains at the input side of the fuel valve. The valve feeds a 1 quart plenum (sump) located under the rear seat which contains two automotive centrifugal submersible electric pumps and is vented (important). My carb is on top of the engine with no mechanical pump thus 2 electric pumps for redundancy. My fuel valve is two position ON and OFF and located on the firewall activated by a torque rod. It is only operated on the ground so if it jambs, which they sometimes do, its just a pain, NOT an emergency. Its a circulatory system, like modern autos, which has the advantage of emulsifying any modest amount of water so you wont get a big slug of it in your float bowl in case it didnt show up on the pre flight. Yes it happens often. The engine can handle a small proportion of water without stopping dead but might get a little rough if the percentage is high. I have ground tested this by deliberately adding 1 cup of water and running the engine at full power. It takes 3 minutes or so and the water is all gone with no noticeable change in engine performance at full rich. If you loose a cap you may loose your prop and vent fuel so I use tight fitting fuel caps that wont come off. They are fibre filled nylon boat fuel fittings sold by Great Plains at an excellent price, have an O ring and mount totally flush so no drag. The cap screws in and has a slot for a large coin to turn them. They positively dont leak and are firm to unscrew for the first half rotation. After six years they are still good as day one, I highly recommend them. The under wing vents allow siphoning which happened to me several times and upset a few FBOs when I vented a couple of gallons on the ramp. I could not find a way to get it stopped, just had to hold my finger over the vent and look stupid while someone tried to find a pail. I moved the vents to the top of the turtle deck and that cured it. There is a danger to this as pointed out by another member in that if you if you flip it over on landing the fuel will run out the vents. To prevent this on my Cozy I am installing the vents in the tanks as upside down stand pipes so that when inverted they are in the air. We did this on RC models for sustained inverted flight and it worked fine. Will test it first to make certain it will vent the tanks OK. Facing your vents into the airstream will help at 200 KTS you get about 2" mercury or 1 PSI which wont bother your tanks. Advantages are a simple, light, system that wont jamb inflight, no fuel in cockpit. It provides an added measure of tolerance to water and no asymetric fuel load as you burn both together. Disadvantages is if you get bad gas or jet fuel both tanks are contaminated but surely this would become obvious during taxi or run up. I will probably get some flak for this but I think this is a good system or I wouldnt be repeating it in my Cozy. Regards, Nigel Field Date: Wed, 13 Mar 1996 08:57:16 -0500 From: wilhelmson@scra.org Subject: Re[2]: Fuel System? How are the electric fuel pumps backed up in case of electrical system failure? Date: Wed, 13 Mar 1996 09:51:27 -0500 From: CheckPilot@aol.com Subject: Re: Fuel lines in the passenger compartment Hey folks, one more item to stir the pot. Anyone ever have a Cessna single spout fuel out of one tank on preflight 'cause the airplane is leaning, i.e. ramp/parking area not level, bent landing gear (don't laugh I have seen this). When two tanks are interconnected the will level themselves even if the airplane is not level. The C-182Q checklist tells you to leave the aircraft parked with the fuel selector on one wing tank to prevent cross flow. My $ 0.02 (0.000005 when adjuste for inflation) Jim Date: Wed, 13 Mar 1996 11:05:00 -0500 From: Dick.Finn@FNB.sprint.com Subject: Re: Fuel lines in the passenger compartment I seem to remember, perhaps from one of Nat's newsletters, that Lee's suggestion was the original design that Burt Rutan came up with. Apparently the fuel selector valve was controlled via a torque tube from the front cockpit on the Vari-eze and Long-eze. The design was changed, as I remember it, because there were problems with being unable to feel the valve clicking into the detent when actuated. It also sticks in my mind that there were issues with the torque tube having enough flex in it so as to simply twist and not actually switch the valve. I guess this would be due to the tube not being rigid enough. Anyway, I think some one has been there and done that already. Dick Finn Cozy Mark IV #46 ______________________________ Reply Separator _________________________________ Subject: Fuel lines in the passenger compartment Author: leed@hpgrla.gr.hp.com at INTERNET Date: 3/12/96 7:29 PM So far, I've seen several builders on this mailing list express concern about fuel lines plumbed through the passenger compartment. One alternative is to have the fuel valve mounted remotely and controlled by a cable or torque rod. Date: Wed, 13 Mar 1996 14:21:48 -0500 From: Phillip.Johnson@Lockheed.on.ca (Phillip Johnson) Subject: Re: Fuel lines in the passenger compartment At Oshkosh last year Nat spoke of the original Rutan design using the torque tube and a rear mounted fuel valve. Nat said that Rutan was asked by the FAA to amend the design because of the difficulty in feeling the detent and the risk of torque tube breakage. I understand that the Long-eze was an LEFT-OFF-RIGHT valve like the Cozy but rear mounted. If you combine the two tanks, as Nigel Field has already discussed, then the need for in flight tampering with the fuel valve goes away. Nat's concern with a common feed, given at OSHKOSH, was twofold: 1) Risk of loosing fuel from both tanks if one of the fuel caps came off in flight: 2) Reduction in pressure to the fuel system, if one of the fuel caps came off in flight, resulting in fuel starvation. These may be real problems however the FAA statistics say that, for all general aviation aircraft, the accidents relating to seized fuel valves are up in the top three. A good pre-flight check will detect a poorly secured fuel cap. Adequate taxi and power check time will also detect contaminated fuel in all but the most unusual cases so statistically the safest system is the coupled left and right tanks with a simple on off valve. With this valve you can mount it at the rear and use a torque tube without risk of an inflight failure. My Cozy is equipped with retractable gear so I have built a sump tank that is fitted between the two landing gear attach bulkheads used in the fixed gear configuration. The two tanks then feed fuel to this sump tank through 1/2" pipes. The sump tank is also vented although the final design of the vents is not complete. The vent design will connect all of the vents together near the top of the firewall so that there is a common vent pipe. Just below the top of the firewall I will install a Tee. One of the outlet of the Tee then goes to the bottom of the engine cowl and the other outlet goes to the top of the cowl through a simple ball valve. The ball valve is arranged with the flow arrow downwards. In normal operation the ball valve is wide open providing air flow in both directions so the tank may vent through either the top and/or the bottom vent. In the unfortunate condition of an overturned aircraft the ball moves to the other end of the valve and seals the hole thereby preventing fuel discharge through the vent at the top of the cowl. The benefit of this technique is that siphoning is not possible when the aircraft is in the normal orientation simply because the normally open ball valve breaks the siphon yet the overturned aircraft will not discharge fuel. A note to other retract builders: If you plan to install a sump tank similar to the one described above, you must exercise caution in the area of the bottom of the sump tank and its drain. If at any time you are forced to do a gear up landing there must be sufficient material between the bottom of the aircraft and the bottom of the sump tank and its drain to prevent puncture. If it does puncture, well you all know the consequences. Phillip Johnson Date: Wed, 13 Mar 1996 19:45:27 -0500 From: Nigel Field Subject: Re: Re[2]: Fuel System? Jack wants to know: > How are the electric fuel pumps backed up in case of > electrical system failure? Short answer: same as the wing, canard, landing gear and a hundred other parts. Long answer: There are two pumps in case one quits. Each is on its own electrical circuit,ie wiring + &-, cockpit accessible blade fuses, panel switches, extra ground path to engine compartment. There are two sources of DC, the alternator and the battery. There is no contactor relay, a high failure component and single point of failure (spf). The DC master is a 4 pole double throw mil spec switch and IS a spf, but you have to stop somewhere. Question for Jack. How is your Ellison TBI backed up in case of a failure? Short answer is OK. Nigel Date: Thu, 14 Mar 1996 08:36:33 -0500 From: wilhelmson@scra.org Subject: Re[4]: Fuel System? With ref to Ellison TBI. backup. I have a experimental primer\port injection system that backs up the TBI. I learned the hard way that it may be needed. Date: Mon, 18 Mar 96 15:10:05 -0800 From: Eric_Westland@msvl.wednet.edu (Eric Westland) Organization: Marysville School Dist. Subject: Strake Woes in Mukilteo, WA I have placed the top foam piece on top of the first strake - did it per plans and all seemed to be going great. But after I removed the wooden frame pieces, I noticed that the foam did not bend completely between R33 and R57 - essentially leaving a flattened "dent" (0.2" at the deepest point) in the curvature. I guess this must be the bending problem that people have written about in past newsletters. What I am wondering is the best way to repair it. There is no way to pull it out, but I was thinking of microing on some additional PVC foam and then spline sanding it down so I won't have as much filling to do. Have some of you run into this and if so, what was your solution? How also can one prevent this to begin with? I still have the other side to do. Thanks in advance for the help, Eric -- -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Marysville School District, Marysville, WA, 98270, USA -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Date: Tue, 19 Mar 1996 08:41:41 -0500 From: wilhelmson@scra.org Subject: Re: Strake Woes in Mukilteo, WA All FIRST TIME BUILDERS HAVE THIS PROBLEM. Your solution is the way everyone fixes it. Second time builders use premolded strakes. Date: Fri, 22 Mar 1996 19:50:05 -0500 From: KSPREUER@aol.com Subject: Re: Strake Woes in Mukilteo, WA Eric writes: " I noticed that the foam did not bend completely between R33 and R57 - essentially leaving a flattened "dent" (0.2" at the deepest point) in the curvature." I don't understand why this would happen unless perhaps the foam slits were not deep enough. You should also bend each one of them to make sure the foam is not attached across the bend all the way to the inside glass surface. Make sure no weights are placed between the ribs. What I did was glue a board along the L.E. and place weights on the board so that the weights don't try to side off and so the weight is only on the very front of the L.E. of the foam. This also prevents any weight from forcing the foam below contour between the ribs. On the repair of the first side, you may get into a mess trying to put foam back into the depression due to the difficulty in sanding the adhesive surface beween the 2 foam surfaces. It may come out better to put some micro on the depression smooth it out roughly, then cover with peel ply and smooth to contour. After cure remove the peel ply and if necessary spline sand to contour. The cured micro/peel ply surface will make a good glass bonding surface. Yes this is a slight weight penalty but in these situations you usually have to accept that. Date: Thu, 18 Apr 1996 13:35:06 -0700 From: Eric Westland Subject: Pressure Testing Fuel Tanks In the plans, an altimeter is called for for checking the strakes. Another method was suggested by a Mike Davis in a newsletter, that is using a column of water (manometer). He attached some tubing to the vent line, put some water in it and blew pressure into the tank until he had about a 12" differential in heights. Now for my bonehead question : Is that enough pressure? If not, what height would be required to duplicate the 1500' elevation change Nat calls for in the plans? Thanks, Eric From: Gary_S._Tiebens@ccmail.northgrum.com Date: Thu, 18 Apr 1996 13:38:37 -0700 Subject: Re: Pressure Testing Fuel Tanks In response to pressure testing fuel tanks Eric, I don't have the plans yet, but I can help you out with some numbers. 1" of water is equal to 0.03609 psi. Therefore, 12" differential of water would be equal to 0.433 psig or 15.133 psia (14.7 + 0.433). Since the lapse rate of pressure with altitude is ~ 1 psi per 2000 ft Alt, a 1500' elevation change is equal to 0.779 psi and that is equal to 21.59" of water! Hope that helps you out some !! Gary ______________________________ Reply Separator _________________________________ Subject: Pressure Testing Fuel Tanks Author: Eric Westland at INTERNET Date: 4/18/96 1:35 PM In the plans, an altimeter is called for for checking the strakes. Another method was suggested by a Mike Davis in a newsletter, that is using a column of water (manometer). He attached some tubing to the vent line, put some water in it and blew pressure into the tank until he had about a 12" differential in heights. Now for my bonehead question : Is that enough pressure? If not, what height would be required to duplicate the 1500' elevation change Nat calls for in the plans? Thanks, Eric From: Marc J. Zeitlin Subject: Pressure Testing Fuel Tanks (fwd) Date: Thu, 18 Apr 96 17:32:01 EDT Eric Westland writes: >.......... He attached some tubing to the >vent line, put some water in it and blew pressure into the tank until he >had about a 12" differential in heights. > >Now for my bonehead question : Is that enough pressure? If not, what >height would be required to duplicate the 1500' elevation change Nat >calls for in the plans? Well, if we recall that the atmospheric pressure at 18,000 ft (7.35 psi) is about 1/2 of sea level (14.7 psi), then we can get a rough estimate of the decrease in pressure with altitude: 18,000 ft ft ---------- ~= 2500 --- 7.35 psi psi Since 1 psi is ~ equal to 27.7 inches of water, we get: 2500 ft/psi ft ------------------------- ~= 90 -------------- 27.7 inches of water/psi inch of water So, 12" of water is equal to an altitude of ~1080 ft. Go with ~18" of water for the 1500 ft. This is ~0.65 psi. Thinking about this, if we say that the maximum depth of the tank is about 9", and that gasoline has about the same density as water (yeah, I know it's less), then this means that the bottom of the tank will have been tested to a pressure that is twice what it would see in a one gee environment. I'm not at all convinced that this is an adequate test. In a 3 gee turn, the bottom of the tank will see pressures higher than it has been tested to, and this is not an unreasonable phenomena by any means. Now, it may be the case that if the tank doesn't leak at 0.65 psi, it won't leak ever (well, without a structural failure, anyway) and that if you pressurize the tank more than that, the structure will fail (since the pressure is everywhere). I certainly hope that these are the reasons for the 0.65 psi test pressure. -- Marc J. Zeitlin Email: marcz@an.hp.com Date: Thu, 18 Apr 1996 19:23:14 -0400 From: Phillip.Johnson@Lockheed.on.ca (Phillip Johnson) Subject: Re: Pressure Testing Fuel Tanks I have retracts on my cozy so I used the landing gear box as a sump tank. The bottom of the tank is approximately 18" below the top of the fuel tanks in the strake. Now I wanted to allow for a 4G landing without bursting my sump tank. This equates to 6 feet of fuel head or 4 feet of water head. I made the simple manometer and pumped the water to 4 feet difference. I held this pressure for three days after an initial panic where I had not sealed one of the AN fittings correctly. There are a couple of points to note using this method. 1) when you initially set up the pressure test, you are compressing the air, this causes adiabatic heating. After about half an hour the temperature stabilises but the volume is less. The manometer pressure falls to accommodate the change in volume. After stabilisation has occurred the pressure should remain constant if all is well. 2) A small change in room temperature will also cause a change in reading. Yes I had another panic when I looked at the reading the next day in the morning when the temperature was lower. I made a point of raising my room temperature to the value the day before and sure enough the level reverted to the original value. Just a couple of tips. I hope they are of use to someone. Phillip Johnson Date: 17 May 96 22:17:48 EDT From: "Edmond A. Richards" <103235.1336@compuserve.com> Subject: COZY: Fuel Cap Installation Gentlemen, If anyone has already installed their fuel caps in the strakes I would like to know how you did it or would suggest doing it. I purchased the FC100-002 cap assemblies as called for in the plans and I am installing them in AeroCad molded strake skins. The plans call for simply cutting a hole in the strake top AFTER PAINTING and floxing them in place. My problem with this is first once the airplane is painted I don't plan on cutting any holes or floxing anything and second I think it would look awful with the aluminum flange showing above the strake. I thought I might scrap the stamped aluminum inserts that come with the caps and machine new ones with a boss on the top surface that would stick through the top glass skin. These could then installed from the inside of the strake top by removing the foam in that area, letting the insert stick through the top glass skin and then glassing them in place from the inside before I attach the top skin to the aircraft. The problem, of coarse, is this is a lot of extra work. Another alternative I considered is to just buy better (more expensive) caps, as Jeff Russell suggests, which can be installed from the inside. Any suggestions would be greatly appreciated. Ed Richards Cozy Mark IV #88 Date: Mon, 20 May 1996 11:58:13 +0000 From: Eric Westland Subject: Re: COZY: Fuel Cap Installation Edmond A. Richards wrote: > > Gentlemen, > > If anyone has already installed their fuel caps in the strakes I would like to > know how you did it or would suggest doing it. I purchased the FC100-002 cap > assemblies as called for in the plans and I am installing them in AeroCad molded > strake skins. The plans call for simply cutting a hole in the strake top AFTER > PAINTING and floxing them in place. My problem with this is first once the > airplane is painted I don't plan on cutting any holes or floxing anything and > second I think it would look awful with the aluminum flange showing above the > strake. > > I thought I might scrap the stamped aluminum inserts that come with the caps and > machine new ones with a boss on the top surface that would stick through the top > glass skin. These could then installed from the inside of the strake top by > removing the foam in that area, letting the insert stick through the top glass > skin and then glassing them in place from the inside before I attach the top > skin to the aircraft. The problem, of coarse, is this is a lot of extra work. > > Another alternative I considered is to just buy better (more expensive) caps, as > Jeff Russell suggests, which can be installed from the inside. > > Any suggestions would be greatly appreciated. > > Ed Richards > Cozy Mark IV #88 Ed, I purchased the Aero Fuel Caps which ACS carries. I was lucky enough to meet the factory rep last year at Arligton and he sold me the set he was showing Nat and others for $50 each. They are $116 in the ACS catalog, but superior to the standard caps which I returned. They have a flange on them that will allow me to install them flush and most important, a positve lock (in addition to the key lock) that will make it impossible for them to go through my prop. The standard caps rely on a thermos bottle type seal which can cause them to come out (one reason for the chain on the cap) if not adjusted correctly. Glasair also sells a cap they make and when I checked into that a couple of years ago, they sold for around $160 for the pair. -eric Date: Mon, 20 May 1996 19:20:52 From: JRaerocad@gnn.com (Jeff Russell) Subject: Re: COZY: Fuel Cap Installation >Edmond A. Richards wrote: > Another alternative I considered is to just buy better (more > expensive) caps, as Jeff Russell suggests, which can be installed > from the inside. >Eric Westland wrote: > I purchased the Aero Fuel Caps which ACS carries. They are $116 in the > ACS catalog, but superior to the standard caps which I returned. They > have a flange on them that will allow me to install them flush and > most important, a positve lock (in addition to the key lock) that > will make it impossible for them to go through my prop. This is the same fuel caps we used on the AeroCanard. Good Stuff cost more!!!! AeroCad Inc. Jeff Russell 1445 Crater Lane Yadkinville, NC. 27055 910-961-2238 E-mail: JRaerocad@gnn.com From: "Daryl H. Lueck" Subject: COZY: Any Strake Building Tips Date: Thu, 5 Sep 1996 18:16:06 -0000 Any tips out there concerning the strake building process? I've already got the CSA article on using the Featherlite parts, and that helps some. Since it was written for a long EZ, you need to convert the measurements. I'm using the Featherlite leading edges and it's a pain aligning the edge, the bottom skin and the bulkheads. Some people use the bonded building table attached to the spar, the CSA article did not..... Any help or suggestions would be appreciated. Thanks, Daryl Lueck Cozy IV #243 N797DL (my new reserved number! Oshkosh 97!) Date: Fri, 13 Sep 1996 14:01:42 +0200 From: Rego Burger Subject: COZY: Fuel Tank filter system: chp. 21 Hello all Cozy Builders and enthusiasts. FILTERS: I know Nat would hit the roof but, The plans show a flat screen filter over the inlet hole to the sump blister. I am thinking of placing a dome type filter over the hole. I'll tell you why! I once had the priveledge of seeing someone else have the misfortune of having a solid item land up in a fuel tank of a motor boat with a similar flat screen primary gauze. ( homemade tank )The result,... fuel cut off !!!! OK, ...radio the coast-guard for a tow. Yes I know he didn't have the choice to switch tanks. Now one may argue that this should never happen in an aeroplane. Unless you install a padlock on you fuel caps ( we have some sick people in society who would drop things in) a little extra insurance while building now will take care of that. By using a dome, round side up, you will eliminate this potential. If you mount it round side down you back to square 1, with the fear of filling it up with dirt until clogged. As this is only primary filtration a wide mesh should be used to keep the fuel flow up and "large" items out. A finger filter on the tubing in the sump can be used to keep the fine stuff out. I would like some comment from all those interested before I go ahead with my idea as: 1. It would be a change in a VITAL area! 2. Discussion is a good thing ( think tank, no pun intended ). It is always possible to miss out on another aspect of any new design, this should not deter the attempt. I wish to install the filters on Monday16th 1996, it will take Nat two weeks to get a letter response to me. If someone on the e-mail is near to him please sound it off with him on my behalf. Enjoy a good building weekend, hope to have some thoughts on Monday. $0.02 worth of info. I have just passed the R 45 000,00 mark on my balance sheet. That translates to about $10 000,00. A years salary as a Telkom ( phone company ) technician. Time to date on project 3.5 years of part time work. Rego Burger Port Elizabeth South Africa Cozy Mk- IV # 139 e-mail: burgerr@telkom32.telkom.co.za Date: Fri, 13 Sep 96 08:39:46 EDT From: wlanza@wingnut.mlb.semi.harris.com (Wayne Lanza) Subject: Re: COZY: Fuel Tank filter system: chp. 21 Rego Burger writes about changing the fuel sump strainer to a dome vs a flat screen and his concerns about this deviation from the plans. When I installed the screen in my MK3 I learned that some builders were using a dome of aluminum screen as a strainer. I like the dome idea but not the aluminum screen. My fix was to buy a couple of simple stainless steel tea strainers. I left the 'crimped' ring around the top of the screen attached but cut the handle and other protrusions off close to the ring. In gluing the upside down tea strainer to the strake floor, I used flox (wet) and a 1/2" wide strip of cloth around the outside of the base of the strainer. The installation turned out very neat and only cost a few bucks. Wayne Lanza Cozy MK3 N452WL Date: Fri, 13 Sep 1996 23:03:12 -0400 From: RonKidd@aol.com Subject: Re: COZY: Fuel Tank filter system: chp. 21 Hi Rego, I installed Ecko brand kitchen strainers over my sump holes in my 3 place 450 flight hours ago. I got the SS ones, cut off the handles and floxed them in place before closing the strakes. I can't take credit for this. I think it was in an old newsletter. Ron N417CZ Date: Tue, 17 Sep 1996 13:17:20 +0200 From: Rego Burger Subject: COZY: CHAPTER 21 FUEL TANK / VENTS Hello Cozy Builders, My task of filters has been solved thanks for the response guys, - "stainless tea strainers it is." NOW I have some questions about the vents. 1. What is the purpose for the vent below & outside of the outboard ribs? The only benefit I can see is protecting the outboard wing from foam ( polystyrene )collapse in the case of a fuel leak! The tank vent goes all the way to the top of the firewall ( as per plan ). 2. Why can't it go below tank level ? This will give added safety in the case of fuel spill should the plane flip on it's back in the case of a bad off - field landing. 3. Must the outside tube face into the airflow ? If in ice conditions the blockage would cause the fuel pump to suck a vacuum and this would lead to starvation. Love to have your response please. Rego Burger Port Elizabeth South Africa Cozy MK - IV # 139 Date: Tue, 17 Sep 1996 10:52:35 -0400 (EDT) From: "George A. Graham" Subject: Re: COZY: CHAPTER 21 FUEL TANK / VENTS On Tue, 17 Sep 1996, Rego Burger wrote: > 1. What is the purpose for the vent below & outside of the outboard > ribs? The only benefit I can see is protecting the outboard wing from > foam ( polystyrene )collapse in the case of a fuel leak! I think that you are correct in your assumption Rego, don't you think that benefit is worth the effort ? > The tank vent goes all the way to the top of the > firewall ( as per plan ). > 2. Why can't it go below tank level ? This will give added safety in the > case of fuel spill should the plane flip on it's back in the case of a > bad off - field landing. Right again ! But, it will also siphon fuel onto the ramp whenever you park nose down, full tanks, temperatures rising, which happens often, as opposed to what might happen. You pick. (The Velocity does not park nose down, vents out the bottom). > 3. Must the outside tube face into the airflow ? If in ice conditions > the blockage would cause the fuel pump to suck a vacuum and this would > lead to starvation. Right here too. a Canard Pusher says to drill a small hole in the back of the tube to prevent the ice formation. Modified E-Racer #206 Strakes and Mazda Engine next George Graham {ca266@freenet.buffalo.edu} Date: 23 Sep 96 22:09:01 EDT From: "Edmond A. Richards" <103235.1336@compuserve.com> Subject: COZY: Strake Windows Gentlemen, I am about ready to flip the fuselage over to make the last layups on the fuel tanks and finish the bottom. I am considering adding Plexiglass windows to the lower strakes in the forward baggage area. I would be interested in any opinions as to the usefulness and structural implications of such a feature. I dont believe installation would be that difficult and it seems the downward visibility would be a real benefit. Thanks Ed Richards From: "Krasa, Paul" Subject: RE: COZY: Strake Windows Date: Tue, 24 Sep 1996 03:23:10 -0400 Edmond A. Richards writes > I am considering adding Plexiglass windows to the >lower strakes in the forward baggage area. I would be interested in >any >opinions as to the usefulness and structural implications of such a >feature. I can't answer for the structural questions, but as for the usefulness, it sure improves the view from the back seat. Nice option, I wich I had done it, and maybe still will. Paul Krasa Long EZ 214LP !---*---! Date: Tue, 24 Sep 1996 06:47:56 -0400 From: HighPlane@aol.com Subject: Re: COZY: Strake Windows I have a friend who has windows in the strakes of his Long EZ. I don't know about the structural implications--I'll let somebody else address that question--but the view's terrific. He finds them really useful--he uses the plane for atmospheric research in his job with NOAA, and sometimes has instrumentation looking down through them. 'Course, he also spends a lot of hours flying 50 feet AGL over dense forests, so he may not be the best role model ... Jon Jefferson AeroCanard in slow, schizophrenic progress From: "Dewey Davis" Date: Tue, 24 Sep 1996 09:07:50 -0400 Subject: Re: COZY: Strake Windows On Sep 23, 22:09, Edmond A. Richards wrote: > Subject: COZY: Strake Windows > Gentlemen, > > I am about ready to flip the fuselage over to make the last layups on the fuel > tanks and finish the bottom. I am considering adding Plexiglass windows to the > lower strakes in the forward baggage area. I would be interested in any > opinions as to the usefulness and structural implications of such a feature. I > dont believe installation would be that difficult and it seems the downward > visibility would be a real benefit. > > Thanks > > Ed Richards > >  >  >-- End of excerpt from Edmond A. Richards Your passengers in the back will love them. I have heard nothing but gushing praise from the wives that ride in the back of Long EZs after the windows were retrofit. I don't suppose you'll have passengers in the back of a COZY nearly as often, but the windows make a world of difference for anyone in the back. The visibility is pretty bad without them. No structural problems with the installation. The biggest problem is keeping them from becoming scratched with all the stuff that gets thrown in that area. I haven't put these windows in my own COZY, but I wouldn't hesitate if I were building now. If I had a Long EZ, I would retrofit. Dewey Davis Subject: Re: COZY: Strake Windows Date: Tue, 24 Sep 1996 09:50:22 -0400 (EDT) From: "Randy Smith" > Your passengers in the back will love them. I have heard nothing but > gushing praise from the wives that ride in the back of Long EZs after > the windows were retrofit. I don't suppose you'll have passengers in > the back of a COZY nearly as often, but the windows make a world of > difference for anyone in the back. The visibility is pretty bad > without them. No structural problems with the installation. The > biggest problem is keeping them from becoming scratched with all the > stuff that gets thrown in that area. I haven't put these windows in > my own COZY, but I wouldn't hesitate if I were building now. If I > had a Long EZ, I would retrofit. > > Dewey Davis > Perhaps some clear mylar (or some other kind) tape over the plexiglass. When it gets too scratched up, remove it and add more. --* --- -* **-* *-** -*-- -* Crash Rescue Team 7 - Don't PANIC! |Cozy MkIV| NCR General Purpose Computing Randy.Smith@ColumbiaSC.NCR.COM |---( )---| Global Support Center Voice 803-939-7648, V+ 633-7648 ___o/o\o___ West Columbia, SC 29170 "I am the way, the truth, and the life..." -JC Date: Tue, 24 Sep 1996 23:24:21 +0200 (MET DST) From: bcannac@club-internet.fr (Bernard CANNAC) Subject: COZY: Strake Window Hi Edmonds, a friend named Eddie Vann who built a splendid Long-ez with a 140 hp continental has put strake windows. I flew several times on his long-ez, and I found that nice to have a look on the ground, in this angle. I am not yet sure I will not do that too when the time will come to decide it. It is not really a great advantage but it is a kind of courtesy to the rear passenger. Tell us what you decided regards Long-Ez F-PYVH Cozy MIV 552 beginning by InfoAve.Net (PMDF V5.0-6 #4800) id <01I9V8AHPU5A8WZGL1@InfoAve.Net> for cozy_builders@hpwarhw.an.hp.com; Tue, 24 Sep 1996 18:46:42 -0400 (EDT) Date: Tue, 24 Sep 1996 18:46:42 -0400 (EDT) Date-Warning: Date header was inserted by InfoAve.Net From: Nick Ugolini Subject: Re: COZY: Strake Windows At 10:09 PM 9/23/96 -0400, you wrote: >Gentlemen, > >I am about ready to flip the fuselage over to make the last layups on the fuel >tanks and finish the bottom. I am considering adding Plexiglass windows to the >lower strakes in the forward baggage area. I would be interested in any >opinions as to the usefulness and structural implications of such a feature. I >dont believe installation would be that difficult and it seems the downward >visibility would be a real benefit. > >Thanks > >Ed Richards > > I talked to a long-eze builder who has them. I would recommend placing a window in the floor of the the rear seats. He said the strakes do not provide enough visual area, and you use the strakes for stowage. He likes the floor approach (he has flown in one) and wishes he had placed his in the floor because it gives a wider range of vision over the area you are actually flying over. Nick Ugolini unick@mail.charleston.net Varieze N89RS Date: Wed, 25 Sep 1996 09:04:11 +0200 From: Rego Burger Subject: COZY: Strake Windows >Gentlemen, >I am about ready to flip the fuselage over to make the last layups on the fuel >tanks and finish the bottom. I am considering adding Plexiglass windows to the >lower strakes in the forward baggage area. I would be interested in any >opinions as to the usefulness and structural implications of such a feature. I >dont believe installation would be that difficult and it seems the downward >visibility would be a real benefit. >Thanks >Ed Richards I like the idea Ed You've just got me at chp 21. Now I'm thinking of it too!(now thanks to you) Pros. Good visibility. Cons. Scratches from luggage etc. Points: 1. Make the windows screw on ( replaceable ). ( a better option should they crack too.) Use countersunk screws from the lower surface with nuts ( plates ) inside. ( idea ) 2. Use at least a 3-4mm high-impact acrylic. I've seen them drop a brick on the stuff. You don't want to take chances here. I'm a little concerned with perm. bonding if one should need to replace them. How did the Long - EZE guys install them? Please respond folks. Rego Burger P.E. S.A. Cozy Mk-IV # 139 Date: Wed, 25 Sep 1996 11:42:12 +0200 From: Rego Burger Subject: COZY: FUEL TANK EARTH- STATIC Hello all, Brainwave? As there is so much of non conductive material in our craft I thought of running a piece of wire braid ( like microphone shield ) or copper strip from the bottom of the tank to a common point.( still planning it ) Maybe to the engine mount or so. PURPOSE: To avoid static flash when filling up at the gas pump. Some guys have little "tails" running off the main gear to discharge any static on landing. Is it worth it? Comments eg. pros. and cons. welcome. Rego Burger P.E. S.A. Cozy Mk IV # 139 From: Marc J. Zeitlin Subject: COZY: FUEL TANK EARTH- STATIC (fwd) Date: Wed, 25 Sep 96 10:10:17 EDT Rego Burger writes: >As there is so much of non conductive material in our craft I thought of >running a piece of wire braid ( like microphone shield ) or copper strip >from the bottom of the tank to a common point.( still planning it ) >Maybe to the engine mount or so. The plans address the static discharge issue while fueling - they call out a metal tail on the fuel cap which lies in the fuel. The gas truck clips to the fuel cap. Seems perfectly adequate - I've never heard of a COZY lighting up :-). -- Marc J. Zeitlin Email: marcz@an.hp.com Date: Wed, 25 Sep 1996 12:26:09 -0400 From: DFinn7971@aol.com Subject: Re: COZY: Strake Windows In a message dated 96-09-24 18:53:47 EDT, unick@charleston.net (Nick Ugolini) writes about strake windows: << I talked to a long-eze builder who has them. I would recommend placing a window in the floor of the the rear seats. >> I plan to put windows in my strakes. I saw them in a friends Long-eze and he reported positive feedback from passengers. The cost is trivial (i.e. you don't have to buy the plexiglass from Brock, AS&S or Wicks). As far as the floor mounted windows go I'm not so convinced. You would have to put them behind the front seat brace to avoid the landing brake. Further, they would have to be located on either side of the air duct. I would guess that the passenger would have to spread his/her legs to look down. With two people in the back seat you are already crowded so this could be difficult. A second thought is that the windows would quickly become scuffed with people getting in and out or with baggage being loaded on them. I also wonder how structurally sound the plexiglass would be. People do step on the floor -- could they actually dislodge the window. Anyway, the above is my opinion and worth every cent you are paying for it. Dick Finn Cozy Mark IV #46 DFINN7971@AOL.COM Date: Mon, 14 Oct 1996 14:59:11 -0400 From: AlWick@aol.com Subject: COZY: Strakes I recommend you amend instructions for strakes as follows (chapt 21-5? top of page): After checking the fit of the various baffle components to the bottom foam, flip bottom foam over and mark the six parallel lines described in instructions. Cut thru the foam only at those points where foam seam intersects parallel lines. Only then do you do your first glass layup to the inside of the bottom foam pieces. Continue as instructed. The purpose of this extra step is to avoid the divot many people get in the area of the foam seam due to not scoring full depth. It also avoids the tendency to score too deep and risk fuel leak. -al