Date: Sat, 04 Jan 1997 20:06:06 -0500 From: Paul Burkhardt Subject: COZY: Fuel line sealant I'm routing the fuel lines and I'm wonering what type of sealant to use on the AN fittings. I'm talking about the Pipe thread type of course. Can I use teflon tape or is a gasket type sealant the best? Paul Burkhardt Date: Sun, 5 Jan 1997 07:15:35 -0500 From: Wschertz@aol.com Subject: COZY: Re: Fuel Line Sealant Paul Burkhardt writes: >..... Can I use teflon tape or is a gasket type sealant the best? Paul Burkhardt In "Firewall Forward" and "Engines" Tony Bingelis cautions AGAINST using the Teflon Tape sealant. Bill Schertz Date: Mon, 6 Jan 1997 05:23:35 -0500 From: INFINITY Aerospace <72124.347@compuserve.com> Subject: Re: COZY: Fuel line sealant Hi Paul, >I'm routing the fuel lines and I'm wonering what type of sealant to use on the AN fittings. I'm talking about the Pipe thread type of course. Can I use teflon tape or is a gasket type sealant the best?< If you are EXTREMELY careful, tape is fine - your doing the work. It's not like hiring someone and you don't really know how careful they were and what materials they used. By doing it yourself, you know how careful you will be. But Murphy is always around. I use liquid type in a squeeze tube for really important things, like keeping the engine running. It's probably more peace of mind. That doesn't mean a glob of this stuff won't stop an engine. The probable thinking is one is less likely to get it into the system than a piece of teflon tape. Check out books like Firewall Forward, A & P books, etc. HTH. Infinity's Forever, JD From: Epplin_John_A@hpmail1.90.deere.com Date: Mon, 6 Jan 97 07:53:47 -0600 Subject: COZY: Fuel line sealant > I'm routing the fuel lines and I'm wonering what type of sealant to use > on the AN fittings. I'm talking about the Pipe thread type of course. > Can I use teflon tape or is a gasket type sealant the best? Paul > Burkhardt > Teflon tape has the chance of flaking off small pieces, not good. Wicks and others sell a product call FUELUBE for this purpose. I think this is based on beeswax, at least it used to be. The down side is you need a drop or two and the stuff is $15+ per pound. See if your local EAA chapter has a supply. John Epplin Mk4 #467 A&P Date: Mon, 06 Jan 1997 18:16:31 -0500 From: Paul Burkhardt Subject: COZY: Fuel pump fittings Working further along on the fuel line installation, I ran into a problem with the fuel pump fittings. It seems that a regular AN thread is what is used, However it requires the use of a nut and washer, O-ring(supplied with pump)I called the company concerning the fitting and they only had 90 deg. fittings. I need straight fitting. Nat listed the fittings as an AC # 6470069. in the plans. I cant find this in the Wicks cat. Any help from you A/P's out there. Paul Burkhardt From: "Krasa, Paul" Subject: COZY: Wing to strake contouring Date: Fri, 10 Jan 1997 13:42:09 -0500 I'm currently filling in the area between the strake and the wing. There is a slight miss match between the two. To say the least this job is a pain in the A-- when contouring the bottom, so I have a suggestion. If possible before the winglets are installed the contouring between these two surfaces should be completed. This will allow the fuselage to be flipped over and the wing matted easily thus facilitating sanding without being under the airplane. If anybody has done it this way or if for some reason this is not viable let me know. Oh well, back to sucking micro dust. Paul Krasa Long EZ 214LP !---*---! From: "Krasa, Paul" Subject: RE: COZY: Wing to strake contouring Date: Fri, 10 Jan 1997 14:46:59 -0500 Westlande@aol.com[SMTP:Westlande@aol.com] writes Any suggestions for getting a clean/straight line between the wing and strakes? Dust everywhere, Eric For the aft portion which runs perpindicular to the fuselage, I drew long lines with a Sharpie marker inline with the wing attach fittings such that when a ruler was layed aligned with the markers, the cut line would be through the same plane as the fittings. Then I glassed the wing to the strake top and bottom with a 3" two ply bid strip and a layer of peel ply. The top was wieghted in place and for the bottom my friend who has a beutiful Cozy III showed me how to hold the layup in place using a thick piece of flat AL and yard sticks. Once the layup has setup, peel off the peel ply, sand the surface and slather on micro. For the sides of the strakes: For the sides of the strakes take a carpenters square and draw a line perpendicular to the other line to facilitate anouther cut line. For the sides I mixed up some very dry micro and filled the gap. ( A note of caution: If using WEST SYSTEMS epoxy when your micro gets thick it will exotherm. I literally had smokin micro on my plane. Scared the S--T out of me. ) Once the gap is filled with dry micro go to slightly wetter micro to build up because it spreads easier. Contour the wing to the strake. Once all the contouring is complete take a steel yard stick and hot glue it or bondo it inline with the marks in the rear. CAREFULLY run a hacksaw from one end to the other. Use long strokes. DO NOT cut through and then saw, this causes a ragged edge. Again, use LONG STROKES, and be careful. Once the aft line is cut. Take remove the ruler with heat if hot glued in place or by sanding off the bondo. So far so good. I have gotten to this point on the airplane and all looks well. Moving onto the side of the strake. Attach a ruler to the cut line for the side of the strake on both the top and the bottom. The ruler should stick out beyond the end of the strake. If your lines a parallel and start from the same point top and bottom a plumb bob will line up with the bottom ruler. IF not adjust the rulers until they line up. Use the plumb bob on a string to place marks on the top joint were the ruler is not touching the surface. Play connect the dots and draw your cut line. Use same procedure as above to cut the side. This method works although it takes time. I've seen the results. It comes out beautiful. Paul Krasa Long EZ 214LP !---*---! From: "Krasa, Paul" Subject: COZY: Strake to wing contouring Date: Mon, 27 Jan 1997 07:58:12 -0500 I've completed the strake to wing contouring this weekend. It turned out nice. I'd like to thank our friends from Berkut with the suggestion of using a piece of AL for the strake to wing joint. After cutting the joint which runs along the longitudinal axis and haveing it be less than perfect, I sanded the micro out and used the AL. Worked great! I used car wax as a release agent, and to remove the AL, I had to tap on it with a hammer. The line is straight, and looks great. Thanks Paul Krasa Long EZ 214LP !---*---! Date: Wed, 26 Mar 1997 18:56:24 -0500 (EST) From: SWrightFLY@aol.com Subject: COZY: Re: Fuel tank leaks After pressure testing my tank at (decrease the altimeter to 1000') All the pressure leaks out over a 15 hour period. Using the soap bubble search method did not yield any leaks. Any suggestions of a better method for finding tiny leaks? by SERV05.SLAC.STANFORD.EDU (PMDF V5.1-8 #16063) with SMTP id <01IGYQO5JQ5S005I3P@SERV05.SLAC.STANFORD.EDU> for cozy_builders@hpwarhw.an.hp.com; Wed, 26 Mar 1997 16:25:06 PST Date: Wed, 26 Mar 1997 16:27:34 -0800 From: hrogers@SLAC.Stanford.EDU (Howard Rogers) Subject: Re: COZY: Re: Fuel tank leaks >After pressure testing my tank at (decrease the altimeter to 1000') All the >pressure leaks out over a 15 hour period. Using the soap bubble search method >did not yield any leaks. >Any suggestions of a better method for finding tiny leaks? Perhaps I can help, here, though (not to brag) my tanks had NO leaks. I have had a lot of experience hunting some very tiny leaks in a variety of systems, here at work (physics lab). First of all, you mention DECREASING the altimeter to 1000'. I hope this meant a POSITIVE pressure in the tanks in order to search for leaks with soap bubbles. The reason for using the altimeter is so you can read very small pressures accurately. If you use more than 2 or 3 psi, you are at risk of rupturing the tanks. It is extremely easy to do (an EZ building friend of mine did it, and had a lot of work to do, as a result). I reccomend not even using a pressure source like an air compressor, as a little slip of the wrist can ruin your whole week! It takes a while, but a bicycle pump or rubber-raft foot-pump is amuch more controllable way to increase the pressure while monitoring carefully. I borrowed some long, gently-tapered soft rubber stoppers from work to plug my fuel vent lines. If this method doesn't yield results with soap bubbles, there are other ways. A halogen leak detector is very sensitive, and only requires a little freon in the tank before pressurization. Better quality air conditioning service shops may have them, in lieu of the coarser "flame type" of freon detector. Of course freon is getting as scarce as frog hair, these days, so that may not do it for you. Another surprisingly effective and sensitive method uses just about any hydrocarbon. Propane works fine. We have some little detectors that are no bigger than a pack of cigarettes, and can sniff a very tiny leak. Disadvantage: explosive mixture in the tank. Of course this is true of gasoline, too. Use extreme caution. There are other types of detectors that work on thermal conductivity, and simply sample the test probe, and compare it to air. Argon or CO2 are different enough to show up well, and they aren't flammable. I wish I could tell you where to find these beasties. Do you know anyone nearby in the research business? Write me, if you have any specific questions. --Howard Rogers, 415-926-4052 hrogers@slac.stanford.edu Date: Mon, 31 Mar 1997 22:25:48 -0500 From: INFINITY Aerospace Subject: Re: COZY: Re: Fuel tank leaks Hi Rego and All, It's a good idea to leak check your tanks again after 40, certainly by 100, flight hours to see if anything has changed. Infinity's Forever, JD Date: Mon, 31 Mar 1997 20:12:26 -0800 From: Rego and Noleen Burger Organization: R.N.B. Enterprises Subject: Re: COZY: Re: Fuel tank leaks Hi S. Wright I guess, ?? Wrote! My 2c worth, Have not got much for you other than encouragement,... I feel soap al-la, diswash liquid works well. Lots of patience. Test the obvious like fittings first , then after lots of pain started to find my leaks. Places where I found tiny I mean tiny bubbles: 1.) The homemade sumps I manufactured myself ( Too! lean on resin ) 2.) The inboard ribs on the fuselarge side ( Too! lean on resin ) 3.) The cut lines along the leading edges ( not enough micro ) Some tips of areas to concentrate on - good luck! Rego Burger Cozy Mk4 #139 Port Elizabeth RSA Date: Thu, 24 Apr 1997 12:00:02 -0400 (EDT) From: astrong@dvsdghse.com Subject: COZY: Re;cozy n86lm accident... Cozy III plans.CHap.21,page-1 Wings,Strakes and Fuel Tanks:"NOTE,Safe-t-poxy should be used on all fuel tank layup,even if using RAE epoxy on the rest of your layups" N306AN four years flying almost 400 hrs using 80 octane and 100 LL with addative.No problem. A.Strong Cozy III N306AN astrong@dvsdghse.com STRONG ELECTRIC PITCH TRIM Date: Thu, 24 Apr 1997 10:01:09 -0600 (MDT) From: Ron Lee Subject: Re: COZY: N86LM accident (fwd) -Reply At 16:28 97/4/24 +0200, you wrote: SNIPPPPPPP > >I'm even thinking of cutting the strakes open to line it with some other >system, will someone flying with a 2427 strake system please tell me >it's not neccessary. > > >Rego Burger I am not certain that an incident like this I recently read about is in fact the one you are discussing. However, in one case, I believe that Rutan types examined the wreckage and concluded the stoppage was due to construction debris. Before you cut open your strakes, get a bit more info on this epoxy. I used Safety Poxy in my strakes and Rutan et al studied av gas effects on it and felt it was fine. Whether 2427 has the same av gas characteristics I do not know. Of course, auto fuel may alter the equation even more. Personally, I will avoid it just in case! Ron Lee Date: Thu, 24 Apr 1997 11:49:48 -0600 (MDT) From: Ron Lee Subject: COZY: Re: Avgas vs. Safe-T-Poxy (note: Fred's original informative comments cut to save space) Fred, Thanks for that posting. As a still in construction Long-EZ owner, it is great to have folks with mucho real life experience around to correct those like me who are currently Internet fliers. Your posting raises two discussion items: 1) What is it about 100LL that caused the sticking valves due to lead build-up and is there any way to correct it other than changing to an unleaded autogas? I am aware that 100LL has a "large" amount of lead ("large" being unquantified). 2) How would you continue to get specks of foam and fiberglass for about a year? I assume that even a good vacuuming will leave some so is that amount something that is to be expected (and corrected by frequent screen cleaning)? Is there a better way to get those few small specks out prior to first flight? Ron Lee Date: Thu, 24 Apr 1997 12:50:06 -0700 From: Mahan Subject: Avgas vs. Safe-T-Poxy (was Re: COZY: N86LM accident (fwd) -Reply) Ron Lee wrote: > Before you cut open your strakes, get a bit more info on this epoxy. I used > Safety Poxy in my strakes and Rutan et al studied av gas effects on it and > felt it was fine. Whether 2427 has the same av gas characteristics I do not > know. > > Of course, auto fuel may alter the equation even more. Personally, I will > avoid it just in case! > > Ron Lee Ron, I've been flying my Long-EZ almost 10 years. I used Avgas exclusively in it for about the first year, but before long I had occasional bouts of "morning sickness" (sticking valves because of lead deposit buildups). I was acutely aware of it because, at the time, I was hand-propping the engine (O-235L2C). The problem gradually got worse -- the engine would run very rough on startup, smoothing out over 15-20 seconds. TCP helped, but occasionally I still had a little "morning sicknss." I switched over -- cautiously, one tank at a time -- to Amoco 93 octane unleaded mogas after hearing about the good results a friend had with an even higher-compression, larger engine, an IO-360C1C (8.7 to 1 and much bigger bores than my 8.5 to 1 engine). I've never had any trouble whatsoever with the Amoco 93 octane unleaded, and the "morning sickness" symptoms have never returned. I check my carb needle valve every annual, and have never found any deposits on it. There were fiberglass and blue foam bits in the screens the first year or two, but no signs of anything coming out of the Safe-T-Poxy-lined fuel tanks. I've occasionally used other brands of 93 octane mogas, but prefer the Amoco because it's distinctive (lack of) color assures me that I'm getting the "real thing" from my Amoco mogas vendor, not some inferior stuff (possibly with alcohol added) from XYZ refinery. Of course, on cross-country flying, I'm back to 100 LL. Fred in Florida Long-EZ N86LE Defiant project Date: Thu, 24 Apr 1997 16:47:40 -0400 (EDT) From: Nigel Field Subject: Re: COZY: Re: Avgas vs. Safe-T-Poxy At 11:49 AM 4/24/97 -0600, Ron Lee : > >2) How would you continue to get specks of foam and fiberglass for >about a year? I assume that even a good vacuuming will leave some >so is that amount something that is to be expected (and corrected by >frequent screen cleaning)? Is there a better way to get those few small >specks out prior to first flight? > >Ron Lee Ron and all, Here is another war story on fuel contamination. Last winter I had my Vari-eze tanks open doing structural work replacing the main spar. This involved a lot of grinding and coated the tank insides with some debris. Being fully aware of the consequences of dirty tanks, I vacuumed them out and used a rag to wipe dowm all the insides that I could reach. When I had them completely clean I installed the new spar and closed up the tanks. Later I flushed them with 5 gals soapy water TWICE, then 5 gals gasoline. The airplane was flown for most of the summer including a trip to Osh over the lake without any problem. Then one fine day in Oct on my way home from another airfield at 7k ft 6 miles to go, my engine sagged and then quit making power altogether. I had the field made so wasn't overly concerned but found that after a few minutes with the throttle at idle I could get power for 10-15 seconds then it would sag again. After landing and taxing to my spot, I pulled the fuel filter and could not even blow through it, it was plugged solid. I cut it open and was amazed at how much debri was logged in there, about 4 tablespoons full of epoxy flakes and grinding tailings. I opened my carb and found about 1/8 inch of fine talc like sediment in the bottom of the float bowl. I replaced the filter with the new one I HAD IN MY TOOL BOX and meant to change a month before, and cleaned the carb. It ran fine after that. I have just finished doing my annual for this season and again found some debris in both the filter and float bowl, only far less. You can bet I will be changing that $3.00 filter regularly this season. I guess the moral here is change and open up your filter often on a new airplane/tank as there is probably some junk in there that you didn't get and it takes a long while to work its way out. This should also identify any epoxy breakdown and flaking should it occur. Nigel Field Subaru Vari-eze Date: Thu, 24 Apr 1997 17:23:43 -0400 (EDT) From: AlWick@aol.com Subject: Re: COZY: N86LM accident (fwd) -Reply In a message dated 97-04-24 11:11:05 EDT, burgerr@telkom.co.za (Rego Burger) writes: << I'm even thinking of cutting the strakes open to line it with some other system, will someone flying with a 2427 strake system please tell me it's not neccessary. >> I've been soaking 2427 materials in various gasolines for many months. I've very very confident that it is not affected. Peel strength, however, is another issue. But doesn't come into play with fuel tank. Incidently, I'm planning on increasing the amount of surface area where the top skin of tank mates with strake ribs. I'll do this by glueing a narrow strip of foam to top side of ribs. This should greatly reduce chance of fuel leak, and have near zero weight penalty. FWIW -al building canopy, will close strakes next week. 57% done, 1.7 years to go. Date: Thu, 24 Apr 1997 16:38:16 -0700 From: berkut@loop.com Subject: Re: COZY: Pre-made BID Tapes INFINITY Aerospace wrote: > One can then take these pre-made cured BID tapes and flox them into >place, say the fuel baffles in the top side of the tank, to increase the >amount of surface area for the top strake tank skins to mate to, like Al >wants to do. Only straight sections can be used. Around the leading edge, >short straight sections can be used, or one side of the pre-made cured BID >tapes could be scarfed many times to have a continuous curve. If someone >was real rambunctious, a mold of the inside curvature of the strake fuel >tank could be made to make one continuous curve of pre-made cured BID >tapes. In fact, someone could sell these (Jeff ?). Make sure that your ribs are trimmed to closely match the inside of your strake skin. Then... 1: Mark on the inside of the upper strake skin with a sharpie marker where the ribs contact the upper skin. 2: apply 2 pieces of 2" wide duct tape along each mark on the inside skin, one piece to one side of the mark, the other just overlapping it and extending towards the second side of the mark ___________________________ | |Tape ___|__________________________|______ Mark | | |__________________________|Tape 3: lay up a quantity of 2 ply bid on the bias on aluminum foil (total area TBD by measurement, you'll figure it out). Cut into 2" wide strips with an Olfa cutter. Use West 105/206 4: apply the bid tapes to the duct tape, centered on previous marked line, now visible as the butline in the duct tape. 5: Apply West Micro to the top of each rib 6: put the upper strake skin in place, weight it down, let it cure 7: Pop the skin off 8: remove the excess micro from under the "T" tape at the top of the rib. Radius the micro, sand the underside of the tape and the top of the rib sides. 9: apply 1 ply of bid tape 2" wide (again, with WEST) from the bottom of the "T" to the sides of the rib. Let cure. 10: Sand the top of the "T", sand the inside of the upper skin. Apply 1 very wet sealing ply of 7725 to the inside of the upper skin. When it reaches "B" stage... 11: Apply wet flox to the top of the "T" tapes, (mix wet flox, put it in a Ziplock bag, cut off the corner and use it like a Pastery tube) 12: Put the upper skin in place, weight it down __HEAVILY__ (at least a couple of hundred pounds) Clamp an electric motor to the airframe with an eccentric weight on it's shaft, vibrate the airframe, watch the flox ooze. -- Richard Riley Renaissance Composites, Inc. 3025 Airport Ave Santa Monica CA 90405 310.391.1943 "Who the hell wants to hear actors talk?" Jack Warner, 1928 See the Berkut at http://www.berkut.com From: Marc J. Zeitlin Subject: Re: COZY: Pre-made BID Tapes Date: Fri, 25 Apr 97 9:33:33 EDT Sorry for the previous message - apparently the mailer doesn't like single "."'s on a line :-). Richard Riley wrote; >Use West 105/206 > >5: Apply West Micro ...... > >9: apply 1 ply of bid tape 2" wide (again, with WEST) ..... Why West? Why not whatever epoxy we're using for everything else? -- Marc J. Zeitlin Email: marcz@an.hp.com Date: Fri, 25 Apr 1997 18:27:23 -0400 (EDT) From: AlWick@aol.com Subject: COZY: Re: adding surface area to strake close. Wow. Thanks for the excellent suggestions regarding how to improve strake seal. Obviously well thought out and very well explained. I'll abandon my more simple approach and adopt the duct tape approach. It should greatly reduce odds of both initial and eventual fuel leak. Thanks! -al by InfoAve.Net (PMDF V5.1-5 #17060) with SMTP id <01II8WV4OS2W937RG3@InfoAve.Net> for cozy_builders@hpwarhw.an.hp.com; Mon, 28 Apr 1997 17:38:56 EST Date: Mon, 28 Apr 1997 17:38:09 -0400 From: Jeff S Russell Subject: Re: COZY: Pre-made BID Tapes on molded tanks Organization: AEROCAD INC. berkut@loop.com wrote: > > wrote: Snip...... In fact, someone could sell these (Jeff ?)>. Your own mold would fit better then one I could come up with. > Make sure that your ribs are trimmed to closely match the inside of your > strake skin. Then....... Snip > 3: lay up a quantity of 2 ply bid on the bias on aluminum foil (total area > TBD by measurement, you'll figure it out). Cut into 2" wide strips with an > Olfa cutter. > Use West 105/206 We just layup one ply of BID on marked plastic on the bias, then cut out the BID to size and then plastic tranfer the BID TAPE on the duct tape that is on the MOLDED top strake. Some don't have this if building by MKIV or 3 place per plans. We also ONLY use EZ poxy in fuel tanks (same as Safe-t-poxy) for the T-strips We then let the strips almost jell, then add dry-micro to the ribs. Same process of weighing the top strake down over the ribs until cured. > 5: Apply West Micro to the top of each rib > > 6: put the upper strake skin in place, weight it down, let it cure > > 7: Pop the skin off > > 8: remove the excess micro from under the "T" tape at the top of the rib. > Radius the micro, sand the underside of the tape and the top of the rib sides. ditto that. > 9: apply 1 ply of bid tape 2" wide (again, with WEST) from the bottom of the > "T" to the sides of the rib. Let cure. Same but with EZ-poxy > 10: Sand the top of the "T", sand the inside of the upper skin. Apply 1 > very wet sealing ply of 7725 to the inside of the upper skin. When it > reaches "B" stage... Sand the "T" and trim to 1" wide total. Sand all the inside of tank and molded top. We just wet the top tank and inside the tank with wet with EZ-poxy and as it's jelling and do it again until there is no fish-eyes (sometimes 3 times). > 11: Apply wet flox to the top of the "T" tapes, (mix wet flox, put it in a > Ziplock bag, cut off the corner and use it like a Pastery tube) Ditto again > 12: Put the upper skin in place, weight it down __HEAVILY__. I was told by Dave Ronenberg how to do this and have done this every time with great success. No leaks! What are friends for? Tell us their tricks that they have found to work. I do not know how EZ this will be without molded tanks? -- AeroCad Inc. Jeff Russell (Check out our web site for Cozy compatible parts and the AeroCanard) phone/ call first for fax 910-961-2238 E-mail: Jeff@aerocad.com web site with NEW pictures under heavy construction: http://www.aerocad.com Composite workshop info: http://www.Sportair.com Date: Tue, 29 Apr 1997 19:59:59 -0700 From: rfisher@spacetech.com Subject: Re: COZY: Pre-made BID Tapes on molded tanks On Mon, 28 Apr 1997, Jeff S Russell wrote: >We also ONLY use EZ poxy in fuel tanks (same as Safe-t-poxy) for the T-strips >We then let the strips almost jell, then add dry-micro to the ribs. Same >process of weighing the top strake down over the ribs until cured. Jeff, Why do you insist on using ONLY EZ poxy? Scott at PTM&W assured me that Aeropoxy was completely fuel proof. I plan on soaking some samples anyway before I get to the strakes, but I was wondering about your reasoning. See ya, Russ Fisher Date: Tue, 29 Apr 1997 20:13:45 -0700 From: berkut@loop.com Subject: Re: COZY: Pre-made BID Tapes on molded tanks >On Mon, 28 Apr 1997, Jeff S Russell wrote: > >>We also ONLY use EZ poxy in fuel tanks (same as Safe-t-poxy) for the T-strips >>We then let the strips almost jell, then add dry-micro to the ribs. Same >>process of weighing the top strake down over the ribs until cured. > Gougeon has a LOT more test work on WEST than we have on Epolite/EZ/Safe-T poxy, including auto fuel tests - they've been making boat fuel tanks out of it for about 25 years. It's just about inert, though (strangely) 205 shows slightly better fuel resistance than 206, no one knows exactly why. by InfoAve.Net (PMDF V5.1-5 #17060) with SMTP id <01IIB4BNFI868ZIMU7@InfoAve.Net> for cozy_builders@hpwarhw.an.hp.com; Wed, 30 Apr 1997 07:33:52 EST Date: Wed, 30 Apr 1997 07:32:36 -0400 From: Jeff S Russell Subject: Re: COZY: Pre-made BID Tapes on molded tanks Organization: AEROCAD INC. rfisher@spacetech.com wrote: > Why do you insist on using ONLY EZ poxy? Scott at PTM&W assured me that > Aeropoxy was completely fuel proof. I plan on soaking some samples anyway > before I get to the strakes, but I was wondering about your reasoning. Russ, It is the only resin system that I have not had problems with water and peel strength. The new PTM&W system was tested by us and 2427 with bad peel strength in the wet winter time and the only kind that worked for us EVERY time was SAFE-T-POXY. This could be to water in the glass and foam and resin. -- AeroCad Inc. Jeff Russell Date: Tue, 20 May 1997 22:14:50 -0400 (EDT) From: DevoCoach@aol.com Subject: COZY: Fuel Boost Pumps I am installing my engine on a cozy lll project and had two questions regarding the plumbing between the electric fuel boost and engine driven pumps. The plans show fuel going from the gascolator thru the fuel boost pump directly to the engine driven pump. It seems that if either of these pumps fail, it could block fuel from getting to the carb. Has anyone plumbed this differently? Perhaps a "T" from the gascolator to each individual pump, and from the fuel boost to a "T" tee on the outlet side of the engine driven pump. This would allow each pump to move gas individually to the carb. Any thoughts? Also, is the electric fuel boost pump always on during flight? Thanks, Jeff Mallia Date: Wed, 21 May 1997 08:31:04 -0400 From: wilhelmson@scra.org Subject: Re: COZY: Fuel Boost Pumps Aircraft engine driven fuel pumps are designed with double diaphragms and valves that allow higher pressure fuel to open the valves and flow through. This is evident by the fact that if you turn on the boost pumps with the engine stopped the pressure at the carb inlet shows 5-7 psi. Bypassing the engine pump will introduce a whole new set of failure modes that you should examine very carefully. Date: Wed, 21 May 97 07:40:57 EST From: MISTER@neesnet.com Subject: Re: COZY: Fuel Boost Pumps Jeff Mallia asked: "I am installing my engine on a cozy lll project and had two questions regarding the plumbing between the electric fuel boost and engine driven pumps. The plans show fuel going from the gascolator thru the fuel boost pump directly to the engine driven pump. It seems that if either of these pumps fail, it could block fuel from getting to the carb. Has anyone plumbed this differently? Perhaps a "T" from the gascolator to each individual pump, and from the fuel boost to a "T" tee on the outlet side of the engine driven pump. This would allow each pump to move gas individually to the carb. Any thoughts? Also, is the electric fuel boost pump always on during flight? " I have the same concern on my 3 place. I think you are on the right track. My initial impression is that you will need to install some check valves to prevent fuel from flowing backwards through one of the pumps. The electric fuel boost pump is ususally only on during takeoff and landing. Bob Misterka N342RM Date: Wed, 21 May 1997 17:55:43 -0400 (EDT) From: DevoCoach@aol.com Subject: Re: COZY: Fuel Boost Pumps Thanks for the reply. What set of problems are you talking about? I will admit that the cozy plans are pretty well thought out. But the O-320-E3D I got from a piper plumbed the boost pump to a T on the outlet side of the engine driven pump. I assume they had a reason for doing that. I will also say that I've never taken an engine driven pump apart, so I don't know exactly how it is engineered, or what could happen if it failed. I'd appreciate your thoughts! Thanks, Jeff Mallia Date: Wed, 21 May 1997 21:07:21 -0400 From: David Domeier Subject: Re: COZY: Fuel Boost Pumps Bob, The fuel system in the Cozy III and MKIV is the same as with the original Long EZ. I wouldn't mess with the design. If you use the specified fuel pumps, either will flow through if the other fails. It is not a problem. dd Date: Wed, 21 May 1997 19:39:54 -0700 From: Berkut@loop.com Subject: Re: COZY: Fuel Boost Pumps We lost a Berkut to a failed, brand new mechanical fuel pump - the diaphram burst, and with the fuel venting through the diaphram the electric pump couldn't deliver enough pressure for the fuel injector. It resulted in an AD against that batch of pumps. Even given that, my Long EZ has a conventional, pass-through setup. At 09:07 PM 5/21/97 -0400, you wrote: >Bob, > > The fuel system in the Cozy III and MKIV is the same as with the >original Long EZ. I wouldn't mess with the design. If you use the >specified fuel pumps, either will flow through if the other fails. It >is not a problem. > >dd > > Subject: Re: COZY: Fuel Boost Pumps From: resiebert@juno.com (Reid E. Siebert) Date: Thu, 22 May 1997 08:39:14 EDT >I am installing my engine on a cozy lll project and had two questions >regarding the plumbing between the electric fuel boost and engine >driven pumps. The way you are suggesting is the way Piper does it on their Cherokees. I plan to do this parallel plumbing method, too. >Also, is the electric fuel boost pump always on during flight? It is only on when switching fuel tanks, and during takeoff and landing. But, you are free to do as you please. Date: Tue, 27 May 1997 21:51:51 -0400 From: David Domeier Subject: Re: COZY: Fuel Boost Pumps re " Since I have had one engine failure do to problems with fuel systems, I am always looking for a more fail safe setup. I am presently running a Ellison TBI but I have a port injection system that is used as a fixed power backup and primer. If there is sufficient interest I will share the details with anyone who asks?" I am. I just completed an untested primer system that I "think" will keep the engine running if necessary. What have you come up with? Thanks. dd Date: Wed, 28 May 1997 07:29:30 -0400 (EDT) From: Pmsunset@aol.com Subject: COZY: RE: Fuel system Mr. Wilhelmson writes: >REID: > With reference to the fuel pump plumbing subject, I was not > aware that the Piper Cherokee bypassed the engine pump with > the boost pump. I learned something and I thank you for the > info. I have a few questions, because I am considering > replumbing my airplane this way. >snip Failure modes of things always interest me, and I asked an IA friend of mine about the the boost pump plumbed in series with the engine-driven pump and he said he had not encountered any instances where the diaphram failing in the engine-driven pump caused engine stoppage (is that a word?) :>) This was with the boost pump "on", of course. He said more times than not your real problem in that situation was gas mixing with the oil in your engine...........I ask some more questions about the parallel-plumbed Cherokee system....... Eddie ....."and miles to go before we sleep"....(poem snip) Pmsunset@aol.com Date: Wed, 28 May 1997 09:33:47 -0400 From: wilhelmson@scra.org Subject: Re: COZY: RE: Fuel system The fuel system backup I use is actually a fixed flow port fuel injection system. It is different from a standard primer system in that the flow is controlled to make sure that it falls within 50 to 90 % of the full power flow of the engine with boost pump pressure on and the distribution to the cylinders is controlled to make it relatively equal. It consists of the following: Steel tee at the central carb. inlet with armored flex line running to a 12v solenoid (WICKS b2dx62x12v). Outlet of solenoid plumbed with soft copper to a aluminum fuel distributor (made from a 2.5"d aluminum bar stock drilled and tapped with one 1\8" npt inlet and four 1/8" npt outlets.) This part is symmetrical to insure even distribution. The four outlets are plumbed with soft copper to the primer ports which have standard copper fittings with the hole size reduced by brazing them closed and drilling out to .016 (O320 the size can be verified by the full power flow rate at 5-7 psi for whatever engine is used). The solenoid and distributor can be mounted on a .125 aluminum bracket and mounted under the front of the engine on a case bolt. The solenoid control switch should be mounted and protected with a cover so that it cannot accidentally be turned on in flight. Operation: Emergency fuel test: 1. full throttle. 2. mixture full lean to cutoff. 3. boost pump on and primer \ emergency fuel switch on. 4. adjust mixture with throttle for smooth engine if required. Primer operation is normal. This system is very simple and easy to construct. The only special part is the distributor and this can be made with a drill press and normal shop tools. Date: Sun, 1 Jun 1997 20:39:32 -0400 (EDT) From: DFinn7971@aol.com Subject: COZY: Gas Tanks Hello Everyone, I guess I'm resurrecting a discussion from a few months back about coating the inside of the tanks. I have an old Honda cycle with a rusty gas tank. After cleaning it as best I could I went over to Pep Boys (Auto parts store) and bought a bottle of a rust inhibiting coating. They had a number of different products and the fellow I talked to told me about something he bought in Florida that sounds vaguely like an epoxy coating. At least it came in two parts and had to be mixed. All of them coat the inside of the tank and dry to a rubbery like consistancy. Has anyone tried one of these products on the inside of an eze tank? If so, what was the result? Dick Finn Date: Mon, 2 Jun 1997 08:51:22 -0400 (EDT) From: SWrightFLY@aol.com Subject: Re: COZY: Gas Tanks In a message dated 6/2/97 12:43:19 AM, DFinn7971@aol.com wrote: <> Anything in the tank which can (over time) possibly let go and block the fuel filter can have potentially dangerous conquesenses. My Varieze safety poxy tanks are 15 years old and (based on scratch test) are as good today as when they were built. by SERV05.SLAC.STANFORD.EDU (PMDF V5.1-7 #16063) with SMTP id <01IJMZ2TD5IK000O64@SERV05.SLAC.STANFORD.EDU> for cozy_builders@hpwarhw.an.hp.com; Tue, 3 Jun 1997 13:42:03 PDT Date: Tue, 03 Jun 1997 13:44:59 -0800 From: hrogers@SLAC.Stanford.edu (Howard Rogers) Subject: Re: COZY: Gas Tanks >Hello Everyone, > >I guess I'm resurrecting a discussion from a few months back about coating >the inside of the tanks. > >I have an old Honda cycle with a rusty gas tank. After cleaning it as best I >could I went over to Pep Boys (Auto parts store) and bought a bottle of a >rust inhibiting coating. They had a number of different products and the >fellow I talked to told me about something he bought in Florida that sounds >vaguely like an epoxy coating. At least it came in two parts and had to be >mixed. > >All of them coat the inside of the tank and dry to a rubbery like >consistancy. Has anyone tried one of these products on the inside of an eze >tank? If so, what was the result? > >Dick Finn Dick, we used to use similar products, in the "old days" to try to get Cherokee tanks to stop leaking. Without exception, they eventually failed and created mucho problems. Don't do it! (at least not to your airplane). --Howard Rogers A&P 2005148 id <01IKAOABF9HS9855CM@pmdf.cinops.xerox.com> for cozy_builders@hpwarhw.an.hp.com; Fri, 20 Jun 1997 12:51:54 EST id <01IKAO3Z33SG96XENN@pmdf.cinops.xerox.com> for cozy_builders@hpwarhw.an.hp.com; Fri, 20 Jun 1997 12:51:38 -0400 (EDT) Date: Fri, 20 Jun 1997 08:47:51 PDT From: "Hamilton,Thom" Subject: COZY: Aluminum Fuel Tanks?? Posting-Date: Fri, 20 Jun 1997 11:57:52 -0600 Hop-Count: 3 Way out of Left Field question here. Has anyone considered ( or already has done this) : Putting aluminum liners in the stock fuel tanks during construction to guard against future fuel requirements?? My reasoning for even considering this MAJOR pain of an improvement(?) would be to guarantee that I would not have to tear open the strakes and redo the fuel tanks in 5 or 6 years to accommodate a change to Mogas or (God forbid) Ethanol or Methanol. I know, the FAA is supposed to insure that we have appropriate fuel supplies that will work well in our planes forever, but the growing power of the Clean Air lobby and the current rumblings that Gore might try and promote a ban on Leaded fuels by 2002 have me worried that Mogas might be the wave of the future. (Plus I love the idea of gas for $1.10 a gallon after the Road Tax Refund!!) Any thoughts on just how difficult or impossible this might be? I am still pre-construction so I don't have to make this decision for a while. BTW: Anyone else who has not already started construction or is still on Chpt 4,, do yourself a big favor and READ THE PLANS!!! I mean the WHOLE SET!! I couldn't believe the number of times that you make something and 3 chapters later you cut it out of the plane!! Thanks in advance, Thom Hamilton thom_hamilton@so.xerox.com Cozy MK-IV #620 Date: Sun, 22 Jun 1997 21:21:09 -0700 From: marcna Subject: COZY: Weak Strakes I'm in the middle of installing the strakes and I am a little puzzled. The plans call for one bid tape to attach the bulkheads to the bottom skin, which seems a little weak for the load they need to carry. A friend of mine who is building an Eracer said this plans call for 3 plies of bin tape. Did I miss something? Is one ply OK? Or will I dump fuel one day? Marc Parmelee N425CZ id <01IKG613SEDS985CGV@pmdf.cinops.xerox.com> for cozy_builders@hpwarhw.an.hp.com; Tue, 24 Jun 1997 11:13:47 EDT id <01IKG5YM4ONK985DCE@pmdf.cinops.xerox.com> for cozy_builders@hpwarhw.an.hp.com; Tue, 24 Jun 1997 11:13:36 -0400 (EDT) Date: Tue, 24 Jun 1997 07:09:58 PDT From: "Hamilton,Thom" Subject: RE: COZY: Aluminum Fuel Tanks?? -Reply Posting-Date: Tue, 24 Jun 1997 10:20:38 -0600 Hop-Count: 3 OK, now I feel really dumb. I had read about VinylEster Resins being fuel resistant a couple of years ago and somehow the knowledge just leapt from my mind while I was thinking about future fuels. Thanks to Rego Burger for pointing out the OBVIOUS solution to the possibility of some noxious, non-100LL future fuel situation. So now, a question. I see VinylEster Resin listed in AS&S and need to know if there are any special precautions that make it difficult to use on the fuel tanks/strakes of a plane that is otherwise built from regular epoxy resins. I would guess that you just start using it in place of regular resin (allowing for the unusual promoter, etc. stuff) when you get to the parts of the strakes that will be in actual contact with any fuel in the future. What about the fuselage side? Can you just paint a thick coat of Vinyl Ester over the cured epoxy on the side next to the fuel gauge? I would guess the above to be correct, but just to be safe I thought I would ask. Thanks in advance, Thom Hamilton thom_hamilton@so.xerox.com Cozy MK-IV #620 ---------- <*>From: Rego Burger <*>To: Thom_Hamilton@so.xerox.com <*>Subject: COZY: Aluminum Fuel Tanks?? -Reply <*>Date: Sunday, June 22, 1997 11:59PM <*> <*>Build your tank out of Polyvinylester Resin it's Chemical resistance is <*>able to handle onols ... <*>It also sticks to PVC foam without chewing it up! <*> <*>Rego Burger <*>Port Elizabeth <*>RSA ( Rep. South Africa ) <*>cozy Mk 4 # 139 <*>http://www.home.intekom.com/glen/rnb.htm <*>041-386113 (work) <*> <*>Date: Fri, 20 Jun 1997 17:47:51 +0200 <*>From: "Hamilton,Thom" <*>To: cozy_builders@hpwarhw.an.hp.com <*>Subject: COZY: Aluminum Fuel Tanks?? <*> <*>Way out of Left Field question here. <*> <*>Has anyone considered ( or already has done this) : Putting aluminum <*> liners in the <*>stock fuel tanks during construction to guard against future fuel <*> requirements?? <*> <*>My reasoning for even considering this MAJOR pain of an improvement(?) <*>would <*>be to guarantee that I would not have to tear open the strakes and redo <*> the fuel tanks <*>in 5 or 6 years to accommodate a change to Mogas or (God forbid) <*> Ethanol or Methanol. <*> <*>I know, the FAA is supposed to insure that we have appropriate fuel <*> supplies that <*>will work well in our planes forever, but the growing power of the <*> Clean Air lobby and <*>the current rumblings that Gore might try and promote a ban on Leaded <*> fuels by 2002 <*>have me worried that Mogas might be the wave of the future. (Plus I <*> love the idea of <*>gas for $1.10 a gallon after the Road Tax Refund!!) <*> <*>Any thoughts on just how difficult or impossible this might be? I am <*> still pre-construction <*>so I don't have to make this decision for a while. <*> <*>BTW: Anyone else who has not already started construction or is still <*> on Chpt 4,, <*>do yourself a big favor and READ THE PLANS!!! I mean the WHOLE SET!! <*>I couldn't believe the number of times that you make something and 3 <*>chapters <*>later you cut it out of the plane!! <*> <*> <*>Thanks in advance, <*>Thom Hamilton <*>thom_hamilton@so.xerox.com <*>Cozy MK-IV #620 <*> <*> Date: Tue, 24 Jun 1997 12:31:22 -0500 From: tpierce@ghg.net (Terence J. Pierce) Subject: Re: COZY: Aluminum Fuel Tanks?? -Reply When I took Jeff Russells composite workshop class we talked about VinylEster Resins. And from memory, the reason we don't use the stuff is #1 it is not compatible with some of the foams we use(I can't remember the name of the foam right now, but I believe it is the stuff the wings and canard are made from). And #2 it expands and contracts a lot with heat changes. I think Jeff said if you take a plane that has a perfect finish on it, and let it sit out on a hot sunny day that you can see the weave of the glass print through. Once it cools back down you can't see it any more. Other than this I hear it is some great stuff. It is cheap, it fuel proof, it is easy to work with because you can adjust the cure time by how much promoter you use, and I guess hardly anyone gets an alergic reaction to it. Correct me if I didn't remeber this correctly Jeff. -- Terry Pierce e-mail: tpierce@ghgcorp.com Cozy Mark IV #600 Hamilton,Thom wrote: > > OK, now I feel really dumb. I had read about VinylEster Resins being > fuel resistant > a couple of years ago and somehow the knowledge just leapt from my mind while > I was thinking about future fuels. Thanks to Rego Burger for pointing > out the OBVIOUS > solution to the possibility of some noxious, non-100LL future fuel situation. > > So now, a question. I see VinylEster Resin listed in AS&S and need to > know if there > are any special precautions that make it difficult to use on the fuel > tanks/strakes of > a plane that is otherwise built from regular epoxy resins. I would > guess that you just > start using it in place of regular resin (allowing for the unusual > promoter, etc. stuff) > when you get to the parts of the strakes that will be in actual contact > with any > fuel in the future. What about the fuselage side? Can you just paint > a thick coat > of Vinyl Ester over the cured epoxy on the side next to the fuel gauge? > > I would guess the above to be correct, but just to be safe I thought I > would ask. > > Thanks in advance, > Thom Hamilton > thom_hamilton@so.xerox.com > Cozy MK-IV #620 Date: Tue, 24 Jun 97 12:41:39 EST From: "KEN SARGENT" Subject: Re[2]: COZY: Aluminum Fuel Tanks?? -Reply I believe you will get Derakane 410 form AS&S. Dow does not recommend using anything but Derakane 470 with >10% Alcohol Gasahol. 410 is listed in their techmanual as ok for aviation and automobile fuels with service temperature under 180. But, be warned, if you use unleaded gas or gasohol (under 10%) the service temperature goes to 120. You can look at Dow's web page and get this literature sent to you. You may find it hard to keep the Derakane from curing quicker than you want. It is very temperature sensitive. Also remember vinyl ester resins are air-inhibited, so you actually do not want to peel ply (keep air away) for secondary bonding. Keep surface sticky for next lay-up. Dissolved styrene in the resin will dissolve, guess what, stryofoam. Also, it can get tricky to get a vinyl ester to stick to an epoxy. The epoxy must be completely cured. And a final thing, the cobalt used as an initiator is free on the cured surface, it can react with moisture to form black spots. This lead to 101 Dalmation looking white icebergs I saw made once. I would recommend doing a solvent wipe or peel ply, on the cured surface to remove the initiator, so this would deposit in your engine. I have though alot about vinyl esters though, because they are tough and have good HDT. Ken Sargent Cozy#555 Chp 6-8 ken_sargent@wda.disney.com ______________________________ Reply Separator _________________________________ Subject: RE: COZY: Aluminum Fuel Tanks?? -Reply Author: "Hamilton,Thom" at DISNEY-WDW-INTERNET Date: 6/24/97 11:55 AM >OK, now I feel really dumb. I had read about VinylEster Resins being fuel resistant a couple of years ago and somehow the knowledge just leapt from my mind while I was thinking about future fuels. Thanks to Rego Burger for pointing out the OBVIOUS solution to the possibility of some noxious, non-100LL future fuel situation. So now, a question. I see VinylEster Resin listed in AS&S and need to know if there are any special precautions that make it difficult to use on the fuel tanks/strakes of a plane that is otherwise built from regular epoxy resins. I would guess that you just start using it in place of regular resin (allowing for the unusual promoter, etc. stuff) when you get to the parts of the strakes that will be in actual contact with any fuel in the future. What about the fuselage side? Can you just paint a thick coat of Vinyl Ester over the cured epoxy on the side next to the fuel gauge? I would guess the above to be correct, but just to be safe I thought I would ask. Thanks in advance, Thom Hamilton thom_hamilton@so.xerox.com Cozy MK-IV #620 ----- From: AlWick@aol.com Date: Thu, 31 Jul 1997 14:32:06 -0400 (EDT) Subject: COZY: Strake closure Just closed my last strake. Strongly recommend method posted by the gentleman from Renaisance Composites (adding 2" wide flanges to top of strake ribs). I haven't gotten the courage to test strakes for leaks yet, but feel his method will reduce chance of leaks. Follow his instructions to the letter. Sure is nice to be at the point in building process where you are running out of materials, and know you don't really need any additional. Now, anyone want to donate to my engine, instruments fund? Fully tax deductible of course :-). $1000 minimum accepted. * Poof --- Oh, sorry. Must have been daydreaming again. -al wick Date: Thu, 31 Jul 1997 15:26:18 -0400 (EDT) From: "George A. Graham" Subject: Re: COZY: Strake closure On Thu, 31 Jul 1997 AlWick@aol.com wrote: I > haven't gotten the courage to test strakes for leaks yet, but feel his method > will reduce chance of leaks. Congrats Al, when you test them with the altimeter, first test something that you know doesn't leak. I had terrible nightmares when I tested mine, then I discovered that the plastic fittings were leaking, not the strakes ! Now, anyone want > to donate to my engine, instruments fund? Fully tax deductible of course :-). > $1000 minimum accepted. Checks in the mail Al. Did you see the heat exchangers Micheal Mims suggested ? They look good. George Graham Modified Eracer #206 (716) 874-3277 ca266@freenet.buffalo.edu From: AlWick@aol.com Date: Wed, 6 Aug 1997 14:41:38 -0400 (EDT) Subject: COZY: Alignment of strake to wing After closing my strakes, I rolled the plane outside and mounted the wings to verify that the strake surfaces mate up to the wing surfaces (still haven't glassed outside surfaces of strakes). Place my straight edge on top side of strake and compared to wing top. Looks great! I was suprised at the close match considering how easy one could mess up strake. Checked bottom side of each, once again right on. BUT, when I laid straight edge at leading edge, there is about a 1 inch gap at the wing leading edge. As if the strakes are too long. Am I the only one to encounter this? Both sides are identical. Best solution I can come up with is to just add a blob of material at wing leading edge adjacent to strake. I s'pose that would look ok, but still bugs me. Also, how do you handle covering the top of the spar? Here you got this beautiful curve to strake, which flows into a smooth strake top, then you got this bumpy spar top. Would prefer not blobbing micro to fill all the irregularities. Anyone try gluing foam to spar top, then sand till paper thin? What about the huge gap between the spar rear and the wing front where the two mate? You know, near the wing mounting holes? Would look ugly trying to use gap sealing tape to fill 3/8" gap. Doesn't help that instructions had us put large radius on spar corner and wing corner. Puzzles me that I haven't heard others with these issues. Been careful at all steps and these are my first real problems. Fortunately they aren't very significant. Would appreciate your advice on best approaches to these three problems. Hanging in thar. -al wick Date: Thu, 07 Aug 1997 08:25:53 -0400 From: David Domeier Subject: Re: COZY: Alignment of strake to wing Al, re "What about the huge gap between the spar rear and the wing front where the two mate? You know, near the wing mounting holes? Would look ugly trying to use gap sealing tape to fill 3/8" gap. Doesn't help that instructions had us put large radius on spar corner and wing corner." I bridged the gape between the wing and spar with a 2 ply lay up and very carefully cut it down the middle of the gap. Making the cut centered over the gap is the tricky part since it's been covered. I used a long straight edge and it worked OK. I tried the same trick where the wing and strake meet with less success. I did not keep it centered as the wing curved and making that cut line was difficult. I then removed the wing and did a single ply lay up on the inside corner. The miss match at the leading edge of the wing and strake is common. I fared a piece on the wing and tried to meet the strake as gracefully as possible. I'm sure there are other ways to beat this beast, Jeff Russell probably has some good ideas. dd From: MISTER@neesnet.com Date: Thu, 07 Aug 97 10:08:47 EST Subject: Re: COZY: Alignment of strake to wing Al Wick was asking about filling the wing, strake, spar gaps. Triple check your wing incidence before you do the finishing in this area!! I used foam and fiberglass to fill any large gaps and/or misalignments. Then I took strips of posterboard paper and covered it with duct tape (for release) and strategically placed this to provide a small gap between the pieces to be joined. I filled the gaps with micro, let it cure then removed the posterboard strips and sanded the surfaces even. It actually gives you a nice even gap at the mating surfaces. Micro rules! Bob Misterka N342RM From: "Krasa-1, Paul" Subject: RE: COZY: Alignment of strake to wing Date: Fri, 8 Aug 1997 07:38:55 -0400 If you look back in the archieves, we discussed this late last year. How I did mine was I made two marks with a marker to act as a cut line, placed a two layer bid tape accross the junction between the aft part of the strake and the wing, then once cured hot glued a ruler in place using the marks, and cut it with a hacksaw blade. For the sides, held a piece of 1/8" AL covered with mold release in place with bondo, and then filled the gap with micro. Once cured gently tap on the AL until it comes free and then work from side to side until you get it out. This works great, and looks good to just remember to use a straight piece of AL Paul Krasa Long EZ 214LP >---------- >From: Jeff S Russell[SMTP:JRAEROCAD@yadtel.net] >Sent: Friday, August 08, 1997 4:10 PM >To: cozybuilders >Subject: Re: COZY: Alignment of strake to wing > >David Domeier wrote: > >> I'm sure there are other ways to beat this beast, Jeff Russell probably >> has some good ideas. > >Building the Velocity RG, the molded strakes had tails of solid glass that >covered the main spar and wing spar about 1". After the parts were bonded >with flox, the gap seal was made by cutting the wings off at the solid glass >cover in between the spars. Then 1 ply BID on the inside finished the >wing fairings. Matching the wings to the molded part was done by sanding >the strakes to fit the wings. Piece of cake! This is what we do on our >kits. > >-- >Jeff Russell/AeroCad Inc. E-mail: Jeff@aerocad.com > > Phone/ fax (call first): 910-961-2238 > > AeroCad: http://www.aerocad.com >Composite workshop info: http://www.Sportair.com > by InfoAve.Net (PMDF V5.1-8 #23426) with SMTP id <01IM5XCVR5AU8ZN726@InfoAve.Net> for cozy_builders@hpwarhw.an.hp.com; Thu, 7 Aug 1997 16:14:56 EST Date: Fri, 08 Aug 1997 16:10:32 -0400 From: Jeff S Russell Subject: Re: COZY: Alignment of strake to wing Organization: AEROCAD INC. <33E9BED0.BE3@earthlink.net> David Domeier wrote: > I'm sure there are other ways to beat this beast, Jeff Russell probably > has some good ideas. Building the Velocity RG, the molded strakes had tails of solid glass that covered the main spar and wing spar about 1". After the parts were bonded with flox, the gap seal was made by cutting the wings off at the solid glass cover in between the spars. Then 1 ply BID on the inside finished the wing fairings. Matching the wings to the molded part was done by sanding the strakes to fit the wings. Piece of cake! This is what we do on our kits. -- Jeff Russell/AeroCad Inc. E-mail: Jeff@aerocad.com Phone/ fax (call first): 910-961-2238 AeroCad: http://www.aerocad.com Composite workshop info: http://www.Sportair.com by m5.boston.juno.com (queuemail) id HPO27957; Tue, 12 Aug 1997 07:30:25 EDT Subject: Re: COZY: Alignment of strake to wing From: mbeduhn@juno.com (Mark W Beduhn) Date: Tue, 12 Aug 1997 07:30:25 EDT On Wed, 6 Aug 1997 14:41:38 -0400 (EDT) AlWick@aol.com writes: >. . . BUT, when I laid straight edge at leading edge, there is about a 1 inch gap >at the wing leading edge. As if the strakes are too long. Am I the only one to >encounter this? Both sides are identical. Best solution I can come up with is to >just add a blob of material at wing leading edge adjacent to strake. I s'pose that >would look ok, but still bugs me. I had the exact same problem. At first I panicked, but after thinking about it for awhile I did what you are going to do. I mounted the wing and used a straight edge to determing how much filler to put on the leading edge of the wing. After several iterations of filling, sanding, straight edge, filling sanding... I glassed the filler on the wing, primed and painted. Actually it came out very nice! When Vance Atkinson came out a few weeks ago to view my work, he noticed what I had done, and said that it was a common problem (that made me feel better). Anyway, don't worry about it, just fare it in so it looks good. >Also, how do you handle covering the top of the spar? Here you got this >beautiful curve to strake, which flows into a smooth strake top, then you got >this bumpy spar top. Would prefer not blobbing micro to fill all the irregularities. >Anyone try gluing foam to spar top, then sand till paper thin? I used micro with a layer of 3/4 oz glass on top. I wouldn't bother with foam because it won't get thicker than 1/8". >What about the huge gap between the spar rear and the wing front where >the two mate? You know, near the wing mounting holes? Would look ugly >trying to use gap sealing tape to fill 3/8" gap. Doesn't help that instructions >had us put large radius on spar corner and wing corner. I assembled the wing on the spar, put box sealing tape across the gap and put down 2 layers of glass (attached to the spar, but made to release from the wing). I trimmed the glass so that it lapped about 1/4" on to the wing. Then I used micro on top of the wing to make a smooth transition from the glass to the wing (use tape to keep the micro from sticking to the glass lip). Then I removed the wing and glassed 2 more layers under the 2 layers of BID - except I was careful NOT TO GLASS THE TRAILING 1/4" where the glass touches the wing. This ended up looking great and didn't need any silicone sealant in the gap (as shown in the plans). The one drawback is that I will have to sand the glass if I need to change the incidence of the wing (Vance said that it is likely that I will have to do this). I won't know until my first flight (which is scheduled for September). >Puzzles me that I haven't heard others with these issues. Been careful >at all steps and these are my first real problems. Fortunately they aren't >very significant. Would appreciate your advice on best approaches to these >three problems. > Puzzled me too. If I hadn't been so busy building, I would have mentioned it to the group earlier...sorry. Mark Beduhn Cozy IV N494CZ - 6 weeks and counting until 1st flight! Date: Thu, 14 Aug 1997 07:17:48 -0400 From: "David R. Kuechenmeister" Subject: Re: COZY: Checking Fuel Tanks Should be 13.6 inches of water for every inch of mercury -- or for every thousand feet of altitude. Regards, Dave At 9:21 PM -0400 8/13/97, gperry@usit.com wrote: > I'm about to try checking my fuel tanks for leaks again. It didn't go >so well the first time but I've done some filling of the leaks so I'll give >it a try again. This time, I'm using a water level rigged out of 1/4" ID >tubing to prevent any possible leakage from an instrument. My question is: >does anyone know how many inches the water needs to climb to equal 1000' of >altimeter change? > > Gregg Perry -- David R. Kuechenmeister Georgia Tech Research Institute Atlanta,GA 30332-0853 mailto:David.Kuechenmeister@gtri.gatech.edu Voice: (770)528-7738 Date: Thu, 21 Aug 1997 09:32:16 -0400 From: Phillip.Johnson@lmco.com (Phillip Johnson) Subject: Re: COZY: Checking Fuel Tanks When I was checking my sump tank for leaks (I have RG so I use the gear attach bulkheads as the basis of my sump. I recover most of the fuel loss from the wing tanks.) I use a positive pressure of about 3 ft of water. I did this in the evening, the next day when I checked the pressure the level had dropped about two inches. I decided to monitor the pressure over the course of the day and noticed that the pressure increased again back to the original value. The ambient temperature had been changing resulting in expansion of the air in the tank. On average the pressure was a constant. My advice is to let the pressure settle then monitor the pressure over the course of at least one temperature cycle i.e. at least a day. This method is applicable to both positive and negative pressure testing. I used the positive pressure method because the tank was small and there were a number of pipe fittings entering the tank. The positive pressure method allowed me to check for leaks around the fittings using the soapy water method. THIS POSITIVE PRESSURE METHOD IS NOT RECOMMENDED FOR THE WING TANKS because the tanks are constructed with large areas of unsupported surface. Even a small positive pressure in the wing tanks could separate some of the joints and weaken the tank. My two cents worth. Phillip Johnson From: gperry@usit.com Date: Fri, 29 Aug 1997 22:43:42 -0400 (EDT) Subject: COZY: Fuel Tank Leaks Hey everyone, I need some help! I CANNOT get my fuel tanks to pass the leak test. I have the Jeff Russell fuel strakes and have been working on getting rid of the leaks for months. I have sealed every possible connection I can find with teflon tape or hot glue. I even covered the fuel cap with a square of plexiglass sealed with hot glued to the top of the strake (Steve Sharp's idea - my caps leaked a small amount). I've been using a water level to prevent air from escaping from an altimeter. I disconnected the fuel line from the fuel selector and have plugged that. I have put enough soap suds on every possible joint and seam to run a car wash. And STILL, the water level decreases by about 3" every 24 hours. It is getting very frustrating. Steve Wright was kind enough to travel from Nashville to check it out and suggested cutting a "window" into the tanks from the rear seats and trying to glass the joints from the inside that I could reach. I did this with the fuselage upside down but no luck. In fact, I ended up having to do the "window plugs" twice to fix the leaks that ensued after the fix. I have talked and written to Jeff Russell who's last advice was to consider putting something like propane gas inside the tank and see if I can smell any leaks. Is he kidding? And, to make things worse...this is only the first tank. The other one leaks even WORSE in preliminary checks! This is getting masochistic! Does anyone have any advice - even if it is to scrap the strakes and start over? Gregg Perry Date: Fri, 29 Aug 1997 23:28:35 -0700 From: Mahan Subject: Re: COZY: Fuel Tank Leaks gperry@usit.com wrote: > > Hey everyone, > > I need some help! I CANNOT get my fuel tanks to pass the leak test. Gregg, this worked for me and several friends who built Long-EZ's. Cultivate a friend in the air conditioning or refrigeration business. Auto air conditioning, house air conditioning, refrigeration, it doesn't matter. Perhaps you have one in your EAA chapter? Have him squirt some Freon gas (or whatever Freon substitute they're currently using) into the tank, then tape it back up. Blow around the outside tank with a fan to chase all of the Freon gas away. Then, have your friend look for leaks with his electronic halogen leak detector. They are sensitive enough to detect the evaporation of 1 oz. of refrigerant per year. When he finds the leaks for you, mark the spots, attach an altimeter to the tank, pull 1500' of vacuum on the tank, and put daubs of pure epoxy on the spots identified as leakers. You can actually see the epoxy get sucked into the crack. When you've treated all of the leakers, let the tank go to ambient pressure, perhaps put another dab at the leaker spots, let the epoxy cure, then check again for leaks. Repeat as necessary! It's frustrating, but we all have leaks and have to treat them. Good luck! Fred in Florida Long-EZ N86LE Defiant project From: "Steve Campbell" Subject: Re: COZY: Fuel Tank Leaks Date: Sat, 30 Aug 1997 12:33:27 Fred gave some excellent advice, as did Phillip. Many auto mechanics have what you need and should be able to help you, once you explain what you are trying to do. If you have access to a nearby university or any place that makes vacuum systems, you could also find a He leak detector with a "sniffer" attachment. Same principle, just a different (smaller molecule) gas. Regards Steve On Fri, 29 Aug 1997 23:28:35 -0700, mahan@digital.net wrote... >gperry@usit.com wrote: >> >> Hey everyone, >> >> I need some help! I CANNOT get my fuel tanks to pass the leak test. > > >Gregg, this worked for me and several friends who built Long-EZ's. >Cultivate a friend in the air conditioning or refrigeration business. ************************************************ Stephen A. Campbell, Associate Professor, ECE University of Minnesota 200 Union Street Minneapolis 55455 (612) 625-5876 phone / (612) 625-4583 fax Campbell@ee.umn.edu ************************************************* by InfoAve.Net (PMDF V5.1-8 #23426) with SMTP id <01IN1M4SBHQ0905I29@InfoAve.Net> for cozy_builders@hpwarhw.an.hp.com; Sat, 30 Aug 1997 08:38:24 EDT Date: Sat, 30 Aug 1997 08:36:56 -0400 From: Jeff S Russell Subject: Re: COZY: Fuel Tank Leaks Organization: AEROCAD INC. Mahan wrote: > then check again for leaks. Repeat as necessary! It's frustrating, > but we all have leaks and have to treat them. When installing fuel tanks you MUST not do what we learn on the rest of our airplane parts and try to have just the right amount of epoxy to fill the weave. I use a extra gal. kit of epoxy to make all of the inside look like a mirror before I close the top. As Gregg said, leaks are a major pain to find sometime and fix because of where there at. I knew I heard about a gas that someone used on this group and Fred came through on this one. Thanks group. -- Jeff From: "Johnson, Phillip" Subject: RE: COZY: Fuel Tank Leaks Date: Sat, 30 Aug 1997 08:50:01 -0400 Greg, I can't be an awful lot of help here but your leak may be in two places. For example, the leak may be in the inner skin at the fuel cap with a small path through the PVC foam then to the atmosphere at some other location. These can be difficult to locate. One method of homing in on the location for the leak is to partially fill the tank with water. Only a small amount at first, just enough to cover the bottom skin and all of its seams. Then go and do the pressure test. The water has a much greater Viscosity than the air so a small leak will completely close up. If you do get an improvement, tilt the tank so that only half of the bottom is covered by the water and then test again. Continue doing this halving the area each time to localize the leak. I work in the underwater defense business and one thing is for sure, there is no such thing as a small leak. A leak is a leak. Phillip Johnson >---------- >From: gperry@usit.com[SMTP:gperry@usit.com] >Sent: Friday, 29 August, 1997 10:43 PM >To: cozy_builders@hpwarhw.an.hp.com >Subject: COZY: Fuel Tank Leaks > >Hey everyone, > > I need some help! I CANNOT get my fuel tanks to pass the leak test. I >have the Jeff Russell fuel strakes and have been working on getting rid of >the leaks for months. I have sealed every possible connection I can find >with teflon tape or hot glue. I even covered the fuel cap with a square of >plexiglass sealed with hot glued to the top of the strake (Steve Sharp's >idea - my caps leaked a small amount). I've been using a water level to >prevent air from escaping from an altimeter. I disconnected the fuel line >from the fuel selector and have plugged that. I have put enough soap suds >on every possible joint and seam to run a car wash. And STILL, the water >level decreases by about 3" every 24 hours. It is getting very frustrating. >Steve Wright was kind enough to travel from Nashville to check it out and >suggested cutting a "window" into the tanks from the rear seats and trying >to glass the joints from the inside that I could reach. I did this with the >fuselage upside down but no luck. In fact, I ended up having to do the >"window plugs" twice to fix the leaks that ensued after the fix. I have >talked and written to Jeff Russell who's last advice was to consider putting >something like propane gas inside the tank and see if I can smell any leaks. >Is he kidding? And, to make things worse...this is only the first tank. >The other one leaks even WORSE in preliminary checks! >This is getting masochistic! Does anyone have any advice - even if it is to >scrap the strakes and start over? > Gregg Perry > > From: gperry@usit.com Date: Sun, 31 Aug 1997 21:41:25 -0400 (EDT) Subject: COZY: Fuel Tank Leaks Thanks to all who replied to my question about the leaking tanks. A special thanks to Steve Sharp who got in his car the same day he read the question and drove to Morristown from Knoxville to check it out in person. It turns out that one of the nurses I work with has a husband who works in the heating and air conditioning field and I am going to contact him about the freon idea first. I'll keep you all updated. Gregg Perry From: lschuler@cellular.uscc.com Date: Sun, 31 Aug 97 12:27:32 -0600 Subject: COZY: Fuel Tank Leaks --simple boundary Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Gregg Perry wrote: >I need some help! >snip Just a thought(I havn't gotten that far, so not speaking from experience). Might consider filling tank(s) with some heavily died water and "SEE" where the leaks are coming from. Also, maybe a high quality sloshing compound will provide the seal you need. Sounds like just a small leak like a pin hole or something. If so, maybe apply the compound and then pressurize the tank(s) to force the compound into the leak. Larry Schuler --simple boundary Content-Type: text/plain; charset=US-ASCII; name="RFC822.TXT" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="RFC822.TXT" Received: from gatekeep.uscc.com by cellular.uscc.com (ccMail Link to SMTP R8.00.01) ; Fri, 29 Aug 97 21:50:33 -0600 Return-Path: Received: from www.uscc.com (ns.uscc.com [204.179.101.2]) by gatekeep.uscc.com with ESMTP id WAA01916 for ; Fri, 29 Aug 1997 22:47:33 -0400 (EDT) Received: from palrel1.hp.com (palrel1.hp.com [156.153.255.235]) by www.uscc.com with ESMTP id VAA07378 for ; Fri, 29 Aug 1997 21:47:17 -0500 (CDT) Received: from hpwarhw.an.hp.com (hpwarhw.an.hp.com [15.57.193.122]) by palrel1.hp.com (8.8.6/8.8.5) with SMTP id TAA28944 for ; Fri, 29 Aug 1997 19:49:11 -0700 (PDT) Received: by hpwarhw.an.hp.com (1.37.109.8/15.5+IOS 3.22) id AA09954; Fri, 29 Aug 1997 22:45:47 -0400 Received: from relay.hp.com by hpwarhw.an.hp.com with SMTP (1.37.109.8/15.5+IOS 3.22) id AA09399; Fri, 29 Aug 1997 22:45:46 -0400 Received: from smtp.usit.net (smtp.usit.net [199.1.48.16]) by relay.hp.com (8.8.6/8.8.5) with ESMTP id TAA25567 for ; Fri, 29 Aug 1997 19:46:14 -0700 (PDT) From: gperry@usit.com Received: from LOCALNAME (BULL-MAX120.DYNAMIC.USIT.NET [199.1.58.151]) by smtp.usit.net (8.8.6/8.8.5) with SMTP id WAA06213 for ; Fri, 29 Aug 1997 22:43:42 -0400 (EDT) Date: Fri, 29 Aug 1997 22:43:42 -0400 (EDT) Message-Id: <199708300243.WAA06213@smtp.usit.net> X-Sender: gperry@pop.usit.net X-Mailer: Windows Eudora Light Version 1.5.2 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" To: cozy_builders@hpwarhw.an.hp.com Subject: COZY: Fuel Tank Leaks Sender: owner-cozy_builders@hpwarhw.an.hp.com Precedence: bulk Reply-To: gperry@usit.com --simple boundary-- Date: Sun, 31 Aug 1997 14:42:57 -0400 From: David Domeier Subject: Re: COZY: Fuel Tank Leaks This is to Gregg, Double check the plumbing to your altimeter. I had the same frustration and finally redid all the plumbing to the altimeter and was delighted to find the leak there. It is amazing how secure a vacuum line can look and still leak. You may have an interal leak in the altimeter also. dd Date: Mon, 01 Sep 1997 13:29:07 +0200 From: Rego Burger Subject: Re: COZY: Fuel Tank Leaks -Reply >Double check the plumbing to your altimeter.< mmm.......... As this is a sensitive instrument, maybe we should get a simple LOW PRESSURE gauge instead....The question is..What is the max pressure in psi or bar we should pressure the tanks too to get an equal 1500ft altitude????? I've seen bicycle pressure gauges that are sensitive, and you can make homemade tube gauges to have the same effect. This will at least eliminate one leak possibility! Rego Burger Port Elizabeth, RSA ( Rep. South Africa ) Cozy Mk 4 # 139 EAA 778 President mailto:rnb@intekom.co.za http://home.intekom.com/glen/rnb.htm Date: Mon, 01 Sep 1997 07:39:46 -0700 From: Rick and Adele Roberts Subject: Re: COZY: Fuel Tank Leaks -Reply Rego Burger wrote: > > >Double check the plumbing to your altimeter.< > > mmm.......... > > As this is a sensitive instrument, maybe we should get a simple LOW > PRESSURE gauge instead....The question is..What is the max pressure in > psi or bar we should pressure the tanks too to get an equal 1500ft > altitude????? > > I've seen bicycle pressure gauges that are sensitive, and you can make > homemade tube gauges to have the same effect. This will at least > eliminate one leak possibility! > > Rego Burger Port Elizabeth, RSA ( Rep. South Africa ) > Cozy Mk 4 # 139 EAA 778 President > mailto:rnb@intekom.co.za http://home.intekom.com/glen/rnb.htm Hi Rego, 1500 ft = 1.5 inches of mercury or 38.1 mm of mercury (I think that is Bar) mercury is 13.565 times more dense than water so multiply either one by this number to get the column of water. I think this is right, it's early here on a holiday. Rick From: Pmsunset@aol.com Date: Wed, 3 Sep 1997 17:13:17 -0400 (EDT) Subject: Re: COZY: Fuel Tank Leaks In a message dated 97-09-03 15:17:09 EDT, lschuler@cellular.uscc.com writes: << Gregg Perry wrote: >I need some help! >snip >> Got me to wondering, also. I never hear much about leaks developing in flying a/c after some time period . Has anyone ever checked their tanks at "annual time" (plastic/canard a/c) to see if minute leaks have developed......maybe not just poor fuel consumption....? Maybe this is addressed in the plans somewhere I haven't reached yet.. Discussion would tend to make one think once all the dastardly leaks are repaired, future leaks are a non-occurrenc. Is this true? Eddie Pmsunset@aol.com MkIV610 advanced to Bathroom remodeling chapters Date: Wed, 3 Sep 1997 18:20:41 -0400 (EDT) From: Nigel Field Subject: Re: COZY: Fuel Tank Leaks At 05:13 PM 9/3/97 -0400, you wrote: >I >Got me to wondering, also. I never hear much about leaks developing in >flying a/c after some time period . Has anyone ever checked their tanks at >"annual time" (plastic/canard a/c) to see if minute leaks have >developed......maybe not just poor fuel consumption....? Maybe this is >addressed in the plans somewhere I haven't reached yet.. Discussion would >tend to make one think once all the dastardly leaks are repaired, future >leaks are a non-occurrenc. Is this true? > > If you get a leak after you get it flying you will smell fuel even from a very small leak. Then you just have to track it down. Nigel From: SWrightFLY@aol.com Date: Fri, 5 Sep 1997 14:15:35 -0400 (EDT) Subject: Re: Re: COZY: Fuel Tank Leaks -Reply In a message dated 9/5/97 1:09:07 PM, you wrote: <> No - I was careful to mix the epoxy with the perfect ratio ( the CP newsletter mentioned that was important). We all used the balance beam to measure epoxy back in the "old days". Steve Wright Wright Aircraft Works From: Marc J. Zeitlin Subject: Re: Re: COZY: Fuel Tank Leaks -Reply (fwd) Date: Fri, 5 Sep 97 15:59:51 EDT Steve Wright wrote: ><finished building it? >This could be a clue to the success of a long lasting fuel tank.>> > >No - I was careful to mix the epoxy with the perfect ratio ( the CP >newsletter mentioned that was important). We all used the balance beam to >measure epoxy back in the "old days". Steve, I think the question was not "what was the resin/hardener ratio", but "what was the epoxy/glass ratio". I think the point of the question was to see if there was a lot more epoxy to fill the interstices of the glass than you would use for an optimum strength/weight ratio. Personally, I'm planning on using the AeroCad pre-fab strakes, but I'll be sanding the interior surface and putting a layer of epoxy on it with a full peel-ply covering. I find that I can ensure COMPLETE epoxy coverage with no holes this way, and it's very easy to visualize where air bubbles or other problems are through the wetted out peel-ply. I'll also be using the "flange" technique (described multiple times in the archives over the years) for mounting the strake tops to ensure maximal surface area for flox sealing and strength. -- Marc J. Zeitlin Email: marcz@an.hp.com From: SWrightFLY@aol.com Date: Sat, 6 Sep 1997 10:26:33 -0400 (EDT) Subject: Re: Re: COZY: Fuel Tank Leaks -Reply (fwd) In a message dated 9/6/97 1:23:27 PM, marcz@hpwarhw.an.hp.com (Marc J. Zeitlin) wrote: <<"what was the epoxy/glass ratio". I think the point of the question was to see if there was a lot more epoxy to fill the interstices of the glass than you would use for an optimum strength/weight ratio.>> My EZ along with all the other EZs with no fuel tank problems that were built in the late 70s and early 80s would glass the inside of the tanks as follows- Using safety-poxy, wet out the glass inside the tank with a very heavy wet coat of epoxy. We would then wait until the surface cured to a "tacky" state (about 4 to 6 hours) then brush on another thick coat of expoxy then a third heavy coat until the surface was slick -(covering all the weave). About 2 hours after the last coat the tank was closed with lots of wet flox to seal the edges. The exterior of the tank was given a "bit" more expoxy as it was wet out than the rest of the structure. Steve Wright Wright Aircraft Works LLC From: gperry@usit.com Date: Sat, 6 Sep 1997 21:33:59 -0400 (EDT) Subject: COZY: Fuel Tank Leaks Greetings all, Here's the latest on my leaking fuel tank saga. I had a nice gentleman named Gene Lynch come over this morning. He owns a heating and air conditioning company here in Morristown and was quite intrigued by the idea of checking a homebuilt's fuel tanks. He brought a tank of freon, a halogen detector and a tech to run the whole show. Raising the water level 13" (1000' of altitude) only took about 2 lbs of pressure by his gauges. At this pressure, there were NO LEAKS found - despite my tests showing the water level dropping about 3" every 24 hours. After some discussion, we disconnected the water level and he pressurized the tank up to 5 lbs. by his gauge. I had some concern about pressurizing the tank at this level but it was done slowly. The only discernable change was the plexiglass pieces which I had hot glued over the fuel caps (I already know they leak air) were bulging quite a bit. At this pressure, the detector picked up a leak around the fuel sump area. Put on some soap suds and guess what - NO BUBBLES! This leak must be pretty small. I'll sand and epoxy the whole area in the next day or so. One question the tech had was: in using a water level to check pressure, does any of the pressurized air "diffuse" through the water over 24 hours? I have no idea. Any thoughts? Gregg Perry (there's GOT to be an easier way!) by InfoAve.Net (PMDF V5.1-8 #23426) with SMTP id <01INKKLWM3F490R4D2@InfoAve.Net> for cozy_builders@hpwarhw.an.hp.com; Fri, 12 Sep 1997 22:20:00 EDT Date: Fri, 12 Sep 1997 22:18:11 -0400 From: Jeff S Russell Subject: Re: COZY: Fuel Tank Leaks Organization: AEROCAD INC. Jeff Russell wrote: >Was this on both tanks? Glad to hear this news. I talked to Gregg last night, he had a heating and air conditioning man who came out with a tank of freon, a sensitive halogen leak detector and a tech to run things. The front water drain was opened and the tank was purged with freon until we could detect it coming out the drain. The drain was then closed and the tank was pressurized to 13" of water (1000 feet of altitude change) with freon. On the right tank, a detector was picking up something on the bottom skin near the sump - but this was equivocal...it didn't pick it up every pass. NO OTHER LEAKS WERE DETECTED! On the left tank, a leak was detected in that impossibly tight corner of the triangle on the upper skin. AGAIN, NO OTHER LEAKS WERE DETECTED EVEN THOUGH THE TANKS WERE ULTIMATELY PRESSURIZED TO 2 1/2 THE PRESSURE NAT RECOMMENDS (2500' altitude change). He went back and heavily coated the area of the leak on the right side TWICE using negative pressure to draw the epoxy in. The left side wasn't so easy...He had to cut the top skin out of the triangle shaped area to get at the leak. Once he did, it was repaired using negative pressure inside the tank to draw the flox and epoxy into the leaking area. This was allowed to partially cure and a second coat of epoxy was added to all areas. So...again, he tested both tanks again. The soap bubble test was negative - as it has been for some time now. BUT...THEY BOTH STILL LEAK ACCORDING TO THE WATER LEVEL. I spoke to him on the phone and found out that both ends of the strakes still had open foam between the skins. A leak from the inner-skin can get to the core and then move to another point of the end that has open foam. He might never find the pin hole that's giving him grief. The freon sniffer did not check at the ends that might be leaking. Gregg said that he will seal the ends with flox and test again. Anyone have any better things to try, we would both love to hear them. The one thing that we use that can cause a problem in fuel tanks IF the inside skin it NOT sealed is the scored PVC foam. Air or fuel can travel all over in it and come out somewhere else. Gregg's tanks will hold pressure on the water level about 3", so the leak must be small enought to seal at low pressure :-) Is there any better way to sniff for a leak. Color fuel, water or something as long as it can be cleaned out of the tank? -- Jeff by InfoAve.Net (PMDF V5.1-8 #23426) with SMTP id <01INLZPL53OA8ZTRWL@InfoAve.Net> for cozy_builders@hpwarhw.an.hp.com; Sat, 13 Sep 1997 22:43:38 EDT Date: Sat, 13 Sep 1997 22:41:36 -0400 From: Jeff S Russell Subject: Re: COZY: Fuel Tank Leaks Organization: AEROCAD INC. cdenk@ix.netcom.com wrote: > why is there scored foam there? Another case of not following the > tried and true. We use this type PVC on all our foamed parts for vacuum bagging. The bond in peel in far better then without the scores. This gives skin to skin bonding! The tanks MUST be sealed in the inner skin so NOT to leak somewhere in the foam. The Velocity's all use this type tanks and we have for years. Hope that helps on why. -- Jeff Russell/AeroCad Inc. E-mail: Jeff@aerocad.com Phone/ fax (call first): 910-961-2238 AeroCad: http://www.aerocad.com Composite workshop info: http://www.Sportair.com Subject: Re: COZY: Fuel Tank Leaks Date: Mon, 15 Sep 97 08:12:08 -0400 From: "David R. Kuechenmeister" What physical setup are you using to set the pressure in inches of water? I have been testing my tanks with the setup that Rutan recommended in the Long-EZ plans -- an altimeter on a tee fitting so that you can blow air into the tank and raise the pressure by 1000 feet. I have trouble setting and holding the pressure with this setup and I'm interested in the alternatives From: gperry@usit.com Date: Mon, 15 Sep 1997 19:52:40 -0400 (EDT) Subject: Re: COZY: Fuel Tank Leaks At 08:12 AM 9/15/97 -0400, you wrote: >What physical setup are you using to set the pressure in inches of water? >I have been testing my tanks with the setup that Rutan recommended in the >Long-EZ plans -- an altimeter on a tee fitting so that you can blow air >into the tank and raise the pressure by 1000 feet. I have trouble setting >and holding the pressure with this setup and I'm interested in the >alternatives > I don't know about others but I can tell you the setup I have been using (and using, and using). I'll give credit to Steve Wright for helping me with this. First, seal all exits from the tank (fuel line into selector valve, fuel drain) except the vent line and fuel cap. Take a short piece of flexible tubing (ID same as OD of vent line) and connect one end to the vent line and the other to a "T" connector. Now, take another short piece of tubing and connect one end to one of the remaining openings of the "T" and the other to a tire valve (I bought mine at a local auto store). Seal with hot glue if necessary. Then, take a LONG piece of flexible tubing (about 12' or more) and connect one end to the last opening of the "T." From there, I looped the tubing over a rafter, back down to the floor and then back up to the top of a step ladder where it terminates - creating a large "U" shape. I then took the fuel cap off the tank and filled the bottom of the "U" with water so that it came about two feet up each side. When both sides were at the same level, I marked one with masking tape. Place another mark approximately 13 inches above the first mark on the side of the "U" with the open end of the tubing. Replace the fuel cap. In my case, I further sealed the fuel cap by hot gluing a small piece of plexiglas over it. Then, SLOWLY introduce air via the tire valve. If you go too quickly, it will shoot the water out of the top of the open end of the tubing - (Been there, done that!) By adding air a bit at a time or releasing slowly from the tire vavle, you can get pretty accurately hit the 13" mark. I would go ahead and check all the connections with soap bubbles at this point and seal with hot glue if necessary (but seal with the tanks depressurized). Fill one more time to the correct height, then wait 24 hours... Gregg Perry Date: Mon, 29 Sep 97 08:24:00 PDT From: Brian DeFord Subject: COZY: One way fuel flow valve? >From Jim's "Scorecard from Newsletter #59" >13) Do not hook your fuel tanks together. >We didn't and didn't want to, because of the fuel syphoning problem >that is mentioned in the newsletter. Still, I wish there was a way to >hook the tanks together, eliminate the selector valve and fuel lines in >the cockpit, and still avoid the syphoning problems. I'll assume (probably incorrectly) that this is the only reason not to hook the lines together. What about installing a valve in each fuel line feeding a sump that limits the flow of fuel in one direction? That way syphoning won't occur. Any thoughts? I don't currently have plans to do this, but would like to avoid having a valve and fule lines running into the cockpit. Brian Date: Mon, 29 Sep 97 13:54:00 PDT From: Brian DeFord Subject: Re[2]: COZY: One way fuel flow valve? Text item: Rego replies: >It's the obvious way to go but life has a way of making these things >fail. It is this reason alone that folks don't try them. You can have 3 >million oneway valves that work fine and the one I buy will pack up! >Just the same if I took all the women in the world and through them up >into the sky and catch one, I'll catch the same mother in law! >Jokes aside...if there are oneway valves used in fuel tanks in >aeroplanes why have we none? >Here is my over simple reason, you go into a prolonged left turn and >what happens? The fuel fills the left tank...how does it get to the >right tank to level again? There was a crsh report some years ago of a >system like this, just couldn't find it. The best Idea is to have a fuel >valve that has a BOTH feed possition, No inter tank feed.This type of >valve HAS the one way facility in it to stop the fuel syphoning into the >other tank. >:-) Ok, so I went home at lunch, looked in my ACS and Wicks catalogs and they both have a free flow one way check valve intended for fuel lines. The ACS application shows it used as a bypass in case of emergency fuel pump loss. This is exactly the type of valve I was thinking of. (by the way, they are priced as follows: ACS P/N 10630 - $19.90, Wicks P/N CV-3/8 - $15.75) ___________ ____________ | L TANK | | R TANK | |___________|_______[-->]___ __[<--]_________|____________| valve _|_______|_ valve | | | SUMP | |___________| | | outlet to engine Minus the vent lines, this is my simple schematic of the fuel system with the check valves in line prior to the sump. In response to your scenario, I think after leveling out from a prolonged turn the tank that is fullest will exert a greater pressure to refill the sump. Since the sump remains relatively full, the full tank will be the primary provider of fuel until equilibrium is achieved (Plus, that would have to be one AWFUL LONG prolonged turn to make much difference). I agree that if a cap comes off or is left off AND the valve for that tank fails, you will still syphon fuel. All I am suggesting is that this can be a simple safety system to counteract the syphoning should the condition occur. Two failures occuring at the same time in the same system is less likely than one failure. Brian Text item: External Message Header The following mail header is for administrative use and may be ignored unless there are problems. ***IF THERE ARE PROBLEMS SAVE THESE HEADERS***. Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=us-ascii References: Subject: Re: COZY: One way fuel flow valve? To: Brian DeFord MIME-Version: 1.0 X-Mailer: Mozilla 3.0 (Win16; I) Organization: R.N.B. Enterprises Reply-To: rnb@intekom.co.za From: Rego and Noleen Burger Date: Mon, 29 Sep 1997 21:20:36 -0700 Message-ID: <34307E14.1EAD@intekom.co.za> Received: from psw25-01-p10.ec.saix.net ([196.25.6.30]) by cheetah.intekom.co.za (Post.Office MTA v3.1 release PO203a ID# 0-42644U7500L2900S0) with SMTP id AAA15522 for ; Mon, 29 Sep 1997 21:24:44 +0200 Received: from cheetah.intekom.co.za (cheetah.intekom.co.za [196.25.69.2]) by pan.ch.intel.com (8.8.6/8.8.5) with ESMTP id MAA14014 for ; Mon, 29 Sep 1997 12:28:02 -0700 (PDT) Received: from pan.ch.intel.com (pan.ch.intel.com [143.182.246.24]) by chmail.ch .intel.com (8.8.5/8.7.3) with ESMTP id MAA26426 for ; Mon, 29 Sep 1997 12:19:56 -0700 (PDT) Return-Path: rnb@intekom.co.za From: "mel" Subject: Re: COZY: One way fuel flow valve? Date: Mon, 29 Sep 1997 18:01:50 -0400 hi folks. one way valves are around and they do a good job except sometimes they stick closed. if used after the fuel pump the pressure helps to avoid this but our fuel pumps dont develop much pressure. i dont opt for "check valves" but i hate the fuel lines in the cockpit also. so it looks like were taking our lives in our hands a different way, were going to use a motorized valve (not a solonoid) which stays in the last position ordered without any power applied. it also switches the return line back to the correct tank also. norm ---------- > From: Brian DeFord > To: cozy_builders@hpwarhw.an.hp.com > Subject: COZY: One way fuel flow valve? > Date: Monday, September 29, 1997 11:24 AM > > From Jim's "Scorecard from Newsletter #59" > > >13) Do not hook your fuel tanks together. > >We didn't and didn't want to, because of the fuel syphoning problem > >that is mentioned in the newsletter. Still, I wish there was a way to > >hook the tanks together, eliminate the selector valve and fuel lines in > >the cockpit, and still avoid the syphoning problems. > > I'll assume (probably incorrectly) that this is the only reason not to > hook the lines together. What about installing a valve in each fuel line > feeding a sump that limits the flow of fuel in one direction? That way > syphoning won't occur. Any thoughts? > > I don't currently have plans to do this, but would like to avoid having > a valve and fule lines running into the cockpit. > > Brian From: cdenk@ix.netcom.com Date: Mon, 29 Sep 1997 19:46:46 -0500 (CDT) Subject: Re: Re[2]: COZY: One way fuel flow valve? How do you shut off the tank, that accidently got the wrong fuel or water in it? Check valves are notorious for leaking. Stick with the tried and true. I prefer the Allen valve. with 500 hours on it, it is smooth and has nice detents. Carl Denk: "cdenk@ix.netcom.com" Date: Mon, 29 Sep 1997 23:31:29 -0400 (EDT) From: Nigel Field Subject: COZY: Cozy fuel System At 01:54 PM 9/29/97 PDT, Brian wrote: > > > ___________ ____________ >| L TANK | | R TANK | >|___________|_______[-->]___ __[<--]_________|____________| > valve _|_______|_ valve > | | > | SUMP | > |___________| > | > | outlet to engine > >Minus the vent lines, this is my simple schematic of the fuel system >with the check valves in line prior to the sump. In response to your >scenario, I think after leveling out from a prolonged turn the tank that >is fullest will exert a greater pressure to refill the sump. Since the >sump remains relatively full, the full tank will be the primary provider >of fuel until equilibrium is achieved (Plus, that would have to be one >AWFUL LONG prolonged turn to make much difference). I agree that if a >cap comes off or is left off AND the valve for that tank fails, you will >still syphon fuel. All I am suggesting is that this can be a simple >safety system to counteract the syphoning should the condition occur. >Two failures occuring at the same time in the same system is less likely >than one failure. > >Brian > Hi Brian, All, At the risk of stiring up the muck, I have never seen a logical explanation of why NOT to connect your tanks together as your diagram suggest only _minus_ the check valves, you don't need them. My Varieze is that way with a sump tank which also contains 2 (redundant) submersible electric automotive fuel pumps to feed my carb. My fuel valve is remote 2 positions on and off, on in the morning off when done for the day, never in flight. It all works great. My Cozy will be the same. If you make a turn sufficient to transfer fuel across to the other tank you will hear the skid ball banging on the canopy trying to get back into the airplane, you may need some more flying lessons. If you get bad fuel in one tank you will pick it up on start, taxi and run-up especially if feeding from both tanks which ensures the bad fuel gets to the engine (just in case you only filled one tank and took off on the other one then switched to the jet fuel over the middle of no-where). If you got water you blew it on you pre-flight since the drains are at the leading edge where the water goes after anything more than 2 minutes. Put a drain in your sump also just to be sure. One of the leading causes of forced landings is fuel starvation caused by siezed fuel valves. If you normally only fill one tank as I do, no problem it will balance out within a few minutes and, as you state will feed off the fullest tank until balanced. How do you keep it balanced with independant tanks anyway? You eliminate a lot of plumbing and fuel in the cockpit, save on the valve cost, don't bang your elbow on it, crack the bracket 3 times before making out of glass and it will never seize in flight. If you loose a fuel cap you will probably eat you prop also but if not you may vent some fuel if full but not much, this is proven. Oh yes just be sure to but a vent line in the sump or it will vapour lock. I just can't see any reason why not to do it, I think it far better, but if someone actually has a good reason I would love to hear it. Nigel Field From: Epplin John A Subject: RE: Re[2]: COZY: One way fuel flow valve? Date: Tue, 30 Sep 1997 07:25:38 -0500 > >Here is my over simple reason, you go into a prolonged left turn and > >what happens? The fuel fills the left tank...how does it get to the > >right tank to level again? > > [Epplin John A] What ever happened to a coordinated turn? For my money the simple system as in the plans is the most fool-proof. I would like a remote valve but the problems associated with the linkage etc far outweigh the benefits. Gasoline has one good characteristic - It stinks. You will smell it long before you have a dangerous mixture present. John Epplin Mk4 #467 From: "mel" Subject: Re: Re[2]: COZY: One way fuel flow valve? Date: Tue, 30 Sep 1997 08:59:34 -0400 i totally agree (here we go) except that my engine is fuel injected and REQUIRES a return line to the same tank it was drawn from, and i havent been able to find a manual valve with 6 ports, but did find electric ones. so the scenario is. we check valve by switching it before takeoff much like a mag check. it has position switches to indicate which set of ports its currently connected to. we fly for a while then switch to the next tank then fly some more, then switch tanks again. if the valve fails to switch were still ok in as much as we havent used any 1 tank below the 1/4 way mark so we meet the faa rules for backup and for enough gas for a 2 hr reserve. but you are correct in case of electric failure were going to land straight ahead because the engine requires electricity to run. norm & monda cozy IV #202 ---------- > From: Epplin John A > To: cozy_builders@hpwarhw.an.hp.com > Subject: RE: Re[2]: COZY: One way fuel flow valve? > Date: Tuesday, September 30, 1997 8:25 AM > > > > > > >Here is my over simple reason, you go into a prolonged left turn and > > >what happens? The fuel fills the left tank...how does it get to the > > >right tank to level again? > > > > > [Epplin John A] > What ever happened to a coordinated turn? > > For my money the simple system as in the plans is the most > fool-proof. I would like a remote valve but the problems associated > with the linkage etc far outweigh the benefits. Gasoline has one good > characteristic - It stinks. You will smell it long before you have a > dangerous mixture present. > > John Epplin Mk4 #467 From: "astrong" Subject: Fw: Re[2]: COZY: One way fuel flow valve? Date: Tue, 30 Sep 1997 06:26:08 -0700 ---------- > From: EpplinJohnA@JDCORP.deere.com > To: Alex > Subject: RE: Re[2]: COZY: One way fuel flow valve? > Date: Tuesday, September 30, 1997 3:55 AM > > > > > > > >Here is my over simple reason, you go into a prolonged left turn and > > >what happens? The fuel fills the left tank...how does it get to the > > >right tank to level again? > > > > > [Epplin John A] > What ever happened to a coordinated turn? > > For my money the simple system as in the plans is the most > fool-proof. I would like a remote valve but the problems associated > with the linkage etc far outweigh the benefits. Gasoline has one good > characteristic - It stinks. You will smell it long before you have a > dangerous mixture present. > > John Epplin Mk4 #467 John, I agree with you on the plans system. however a change I made should be of interest (safety wise) make a detent to prevent you from accidentally putting the valve on "off" ala Cessna. Alex A.R.Strong Homepage "http://www.canard.com/trim" From: AlWick@aol.com Date: Tue, 30 Sep 1997 14:12:04 -0400 (EDT) Subject: Re:COZY: One way fuel flow valve? In a message dated 97-09-30 09:05:07 EDT, norm.doty@worldnet.att.net writes: << i totally agree (here we go) except that my engine is fuel injected and REQUIRES a return line to the same tank it was drawn from, and i havent been able to find a manual valve with 6 ports, but did find electric ones. so the scenario is. we check valve by switching it before takeoff much like a mag check. it has position switches to indicate which set of ports its currently connected to. we fly for a while then switch to the next tank then fly some more, then switch tanks again. if the valve fails to switch were still ok in as much as we havent used any 1 tank below the 1/4 way mark so we meet the faa rules for backup and for enough gas for a 2 hr reserve. but you are correct in case of electric failure were going to land straight ahead because the engine requires electricity to run. norm & monda cozy IV #202 >> You don't mention your other option, which is common fuel sump. Your FI return line then goes to one place, doesn't need to be switched. This is the method I will use. See Nigels post on this subject. -al Date: Tue, 30 Sep 1997 17:06:26 -0400 (EDT) From: Nigel Field Subject: Re: Re[2]: COZY: One way fuel flow valve? At 08:59 AM 9/30/97 -0400, norm & monda wrote: >i totally agree (here we go) except that my engine is fuel injected and >REQUIRES a return line to the same tank it was drawn from, and i havent >been able to find a manual valve with 6 ports, but did find electric ones. Easy Norm, return the excess fuel to the sump, that _is_ the tank it came from. Thats what I do even though I use a carb mine is a circulatory system as is fuel injection. Nigel Field From: lschuler@cellular.uscc.com Date: Wed, 01 Oct 97 12:57:36 -0600 Subject: COZY: Cozy fuel System --simple boundary Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Nigel Field wrote: >At the risk of stiring up the muck, I have never seen a logical >explanation of why NOT to connect your tanks together as your diagram >suggest only _minus_ the check valves, you don't need them. My Varieze is >that way with a sump tank which also contains 2 (redundant) submersible >electric automotive fuel pumps to feed my carb. My fuel valve is remote 2 >positions on and off, on in the morning off when done for the day, never >in flight. It all works great. My Cozy will be the same. Will be doing very similar with SVX pump in sump (gotta be a pun in there somewhere...) Just like it is in the car. Pump turns on and off with a switch; no tank valve. Are your pumps in parallel or series? If parallel, how do you keep back-feed through a faild pump from reducing pressure? I realize you have a carb so only low pressure is needed; SVX pressure is considerably higher. If series, what kind of pressure you looking for and why this way? >If you make a turn sufficient to transfer fuel across to the other tank you >will hear the skid ball banging on the canopy trying to get back into the >airplane, you may need some more flying lessons. Darn! Wish you hadn't reminded me of that...... Had plumb (that "Is" a pun) forgot about it. >If you get bad fuel in one tank you will pick it up on start, taxi and >run-up especially if feeding from both tanks which ensures the bad fuel >gets to the engine (just in case you only filled one tank and took off on >the other one then switched to the jet fuel over the middle of no-where). I agree totally... >If you got water you blew it on you pre-flight since the drains are at the >leading edge where the water goes after anything more than 2 minutes. Put a >drain in your sump also just to be sure. Hmmmm. Was thinking just drains in sump; are strake drains also going to be needed? Seems to make some sense....especially if preflight is all done with nose down... >One of the leading causes of forced landings is fuel starvation caused by >siezed fuel valves. >If you normally only fill one tank as I do, no problem it will balance out >within a few minutes and, as you state will feed off the fullest tank until >balanced. How do you keep it balanced with independant tanks anyway? What size tubing are you using in LE and Cozy from mains to sump? Where is best place to make the hole between strake and sump? How did you reinforce this spot? >You eliminate a lot of plumbing and fuel in the cockpit, save on the valve >cost, don't bang your elbow on it, crack the bracket 3 times before making >out of glass and it will never seize in flight. Agree. I have a bracket already mounted (was following the plans) and bought a valve. Might be for sale (but I ain't gonna rip the bracket out for anyone). >If you loose a fuel cap you will probably eat you prop also but if not you >may vent some fuel if full but not much, this is proven. Has this happened in LE/Cozy? I'm a bit new to glass, so missed a lot of Central States reports. >Oh yes just be sure to but a vent line in the sump or it will vapour lock. Really? If mains are both vented and only source for the sump, is this really necessary? Guess I can understand the possibility of the pump cavitating if there is a return to mains (re fuel injected) and the lines between mains and sump are too small to supply the volume. But that would also mean the sump can be drained by the pump with fuel not comming into the sump fast enough! I'd like to hear more on the vapor lock/sump vent. >snip Good stuff Nigal. Thanks. Larry Schuler #500 ch-10 lschuler@cellular.uscc.com --simple boundary Content-Type: text/plain; charset=US-ASCII; name="RFC822.TXT" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="RFC822.TXT" Received: from gatekeep.uscc.com by cellular.uscc.com (ccMail Link to SMTP R8.00.01) ; Mon, 29 Sep 97 22:37:53 -0600 Return-Path: Received: from www.uscc.com (www.uscc.com [204.179.101.2]) by gatekeep.uscc.com with ESMTP id XAA19368 for ; Mon, 29 Sep 1997 23:34:07 -0400 (EDT) Received: from palrel1.hp.com (palrel1.hp.com [156.153.255.235]) by www.uscc.com with ESMTP id WAA12350 for ; Mon, 29 Sep 1997 22:34:51 -0500 (CDT) Received: from hpwarhw.an.hp.com (hpwarhw.an.hp.com [15.57.193.122]) by palrel1.hp.com (8.8.6/8.8.5tis) with SMTP id UAA13033 for ; Mon, 29 Sep 1997 20:36:53 -0700 (PDT) Received: by hpwarhw.an.hp.com (1.37.109.8/15.5+IOS 3.22) id AA24656; Mon, 29 Sep 1997 23:35:56 -0400 Received: from hp.com by hpwarhw.an.hp.com with SMTP (1.37.109.8/15.5+IOS 3.22) id AA24650; Mon, 29 Sep 1997 23:35:53 -0400 Received: from cyberus.ca (mail.cyberus.ca [207.216.2.6]) by hp.com (8.8.5/8.8.5tis) with ESMTP id UAA13409 for ; Mon, 29 Sep 1997 20:33:53 -0700 (PDT) Received: from ip97.max3.dialup.ottawa.cyberus.ca (ip97.max3.dialup.ottawa.cyberus.ca [207.134.177.97]) by cyberus.ca (8.8.5/Cyberus Online Inc) with SMTP id XAA11904 for ; Mon, 29 Sep 1997 23:31:29 -0400 (EDT) Date: Mon, 29 Sep 1997 23:31:29 -0400 (EDT) Message-Id: <199709300331.XAA11904@cyberus.ca> X-Sender: nfield@cyberus.ca X-Mailer: Windows Eudora Light Version 1.5.2 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" To: cozy_builders@hpwarhw.an.hp.com From: Nigel Field Subject: COZY: Cozy fuel System Sender: owner-cozy_builders@hpwarhw.an.hp.com Precedence: bulk Reply-To: Nigel Field --simple boundary-- From: lschuler@cellular.uscc.com Date: Wed, 01 Oct 97 12:57:27 -0600 Subject: Re[2]: COZY: One way fuel flow valve? --simple boundary Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Brian DeFord wrote: >snip >Ok, so I went home at lunch, looked in my ACS and Wicks catalogs and >they both have a free flow one way check valve intended for fuel >lines. The ACS application shows it used as a bypass in case of >emergency fuel pump loss. This is exactly the type of valve I was >thinking of. (by the way, they are priced as follows: ACS P/N 10630 - >$19.90, Wicks P/N CV-3/8 - $15.75) ___________ ____________ | L TANK | | R TANK | |___________|_______[-->]___ __[<--]_________|____________| valve _|_______|_ valve | | | SUMP | |___________| | | outlet to engine >snip Same basic plan I have. Single sump in landing gear area. The only concern is "generalized" reports of stuck one-way valves; but I have never identified anyone who experienced one themselves. I think it would be very helpfull to those of us considering such an arangement with one-way valves to report any problems they have experienced or witnessed 1st hand. Should they be replaced at annual time or fuel filter time???? In any case, with two valves, the chances of both sticking simultaneously are considerably lower than the chance of one sticking. (same idea as redundant Mags). The sump supply (about 6 Gal) should allow for an expedient landing with power if two caps are lost somehow. As long as the mains are fed to the "top" of the sump and sump is independantly vented, lost caps should not siphon the sump dry even with both valves stuck-open and both caps blown off. If my plans are full of holes I'd rather have the leaks now..... fire away. All ideas welcome. Great discussion item! Larry Schuler #500 lschuler@cellular.uscc.com --simple boundary Content-Type: text/plain; charset=US-ASCII; name="RFC822.TXT" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="RFC822.TXT" Received: from gatekeep.uscc.com by cellular.uscc.com (ccMail Link to SMTP R8.00.01) ; Mon, 29 Sep 97 19:03:03 -0600 Return-Path: Received: from www.uscc.com (www.uscc.com [204.179.101.2]) by gatekeep.uscc.com with ESMTP id TAA18945 for ; Mon, 29 Sep 1997 19:59:27 -0400 (EDT) Received: from palrel1.hp.com (palrel1.hp.com [156.153.255.235]) by www.uscc.com with ESMTP id TAA11936 for ; Mon, 29 Sep 1997 19:00:12 -0500 (CDT) Received: from hpwarhw.an.hp.com (hpwarhw.an.hp.com [15.57.193.122]) by palrel1.hp.com (8.8.6/8.8.5tis) with SMTP id RAA05975 for ; Mon, 29 Sep 1997 17:02:15 -0700 (PDT) Received: by hpwarhw.an.hp.com (1.37.109.8/15.5+IOS 3.22) id AA21590; Mon, 29 Sep 1997 20:01:55 -0400 Received: from relay.hp.com by hpwarhw.an.hp.com with SMTP (1.37.109.8/15.5+IOS 3.22) id AA21585; Mon, 29 Sep 1997 20:01:52 -0400 Received: from ganymede.or.intel.com (ganymede.or.intel.com [134.134.248.3]) by relay.hp.com (8.8.6/8.8.5tis) with ESMTP id QAA24357 for ; Mon, 29 Sep 1997 16:59:49 -0700 (PDT) Received: from relay.jf.intel.com (relay.jf.intel.com [134.134.131.6]) by ganymede.or.intel.com (8.8.6/8.8.5) with ESMTP id RAA29446 for ; Mon, 29 Sep 1997 17:02:15 -0700 (PDT) Received: (from ccmgate@localhost) by relay.jf.intel.com (8.7.6/8.7.3) id QAA28101 for cozy_builders@hpwarhw.an.hp.com; Mon, 29 Sep 1997 16:57:18 -0700 (PDT) Received: by ccm.hf.intel.com (ccmgate 3.2 #8) Mon, 29 Sep 97 16:57:17 PDT Date: Mon, 29 Sep 97 13:54:00 PDT From: Brian DeFord Message-Id: To: cozy_builders@hpwarhw.an.hp.com Subject: Re[2]: COZY: One way fuel flow valve? Sender: owner-cozy_builders@hpwarhw.an.hp.com Precedence: bulk Reply-To: Brian DeFord --simple boundary-- Date: Thu, 02 Oct 1997 13:35:03 -0500 From: Paul Comte Subject: Re: COZY: One way fuel flow valve? lschuler@cellular.uscc.com wrote: > > > Brian DeFord wrote: > >snip > snip > >thinking of. (by the way, they are priced as follows: ACS P/N 10630 - > >$19.90, Wicks P/N CV-3/8 - $15.75) > > ___________ ____________ > | L TANK | | R TANK | > |___________|_______[-->]___ __[<--]_________|____________| > valve _|_______|_ valve > | | > | SUMP | > |___________| > | > | outlet to engine > Where are the valves mounted? If at the sump, could one build "pockets" into the tank at this point? The purpose would be to mount the valves and the vent lines so that if the first two bad things, a lost fuel cap (or alternate leak source) AND stuck valve occur, the siphoning tank would be more likely to draw air from the vent than pull fuel uphill. I do believe the vent at the sump could in fact speed the process of exhausting the open tank but would it also help prevent the draining of the other tank? All wet and stinking of gas or what??? Lovely thread. -- Best Regards, Paul Comte A Plus Computer Service, LLC. 5100 West Blue Mound Road Milwaukee, WI 53208-3654 (414) 456-9700 Voice (414) 456-9701 Fax Date: Thu, 2 Oct 1997 19:25:26 -0400 (EDT) From: Nigel Field Subject: Re: COZY: Cozy fuel System At 12:57 PM 10/1/97 -0600, lschuler@cellular.uscc.com wrote: > >Will be doing very similar with SVX pump in sump (gotta be a pun in there >somewhere...) Just like it is in the car. Pump turns on and off with a >switch; no tank valve. Larry you should install a valve, it is mandatory up here in Canada to ensure you can shut off the fuel in the event of engine bay fire. You can mount it on the firewall and use a torque rod to actuate it from the cockpit, thats how mine is. It can be a simple 2 port one though, on and off. > >Are your pumps in parallel or series? If parallel, how do you keep >back-feed through a faild pump from reducing pressure? I realize you have >a carb so only low pressure is needed; SVX pressure is considerably higher. > If series, what kind of pressure you looking for and why this way? My pumps are plumbed in parallel with indepedant electrical connections, wires, fuses, and switches. The glass/epoxy sump has 2 chambers, a large low pressure chamber fed by gravity from the tank feed lines and engine return line plus a vent line, and a small second chamber in the top made in a step shape with a square cross section 2/3 the depth of the sump enclosure. The pump outlets are press fit into holes into this HP chamber with "O" rings to give a reasonable seal, pumps are secure mounted in low pressure chamber with inlets on the bottom. The pumps pressurize the HP chamber which feeds the fuel through an AN fitting. Each pump has a check valve in the output port to prevent one pump feeding back through the other. Either pump or both will supply sufficient fuel well beyond the max flow required. > > >Hmmmm. Was thinking just drains in sump; are strake drains also going to be >needed? Seems to make some sense....especially if preflight is all done >with nose down... The plans location is fine for the water drains and yes put them in. Put one in the sump also its the lowest point in the system and will collect water if there is any in the mains. Haven't had any water since I changed my caps long ago, but the old Brock caps were horrible and leaked in lots of rain. I once drained out a full quart of water from each tank before I wised up and changed to screw in positive sealing caps with O rings. > >What size tubing are you using in LE and Cozy from mains to sump? Where is >best place to make the hole between strake and sump? How did you reinforce >this spot? As per plans for size, the pick up and vent line locations. 1/2 inch would be OK also. Re-inforce with flox dob and 2 ply BID where they exit, rough up the AL line first as the plans call out. > >Has this happened in LE/Cozy? I'm a bit new to glass, so missed a lot of >Central States reports. Unfortunately there are many documented cases of fuel caps coming off in flight, usually on take-off. Many resulted in fatalities, check NTSB files. Some got away with it and report that fuel will vent out the cap recepticle if the tank is nearly full. If your tanks are connected together, the low pressure on the top of the lifting stake will cause fuel to transfere across to the open tank and you will vent fuel probably until the good tank is empty. But that still leaves you more than 1/3 fuel to get somewhere. No matter how you look at it loosing a cap in flight is a major emergency so you need to get it down safely as soon as possible. You will have enough capacity to do that. > >>Oh yes just be sure to but a vent line in the sump or it will vapour lock. > >Really? If mains are both vented and only source for the sump, is this really >necessary? Guess I can understand the possibility of the pump cavitating if >there is a return to mains (re fuel injected) and the lines between mains and >sump are too small to supply the volume. But that would also mean the sump >can be drained by the pump with fuel not comming into the sump fast enough! >I'd like to hear more on the vapor lock/sump vent. This is the secret to making a sump tank work properly that I learned from experience. My first one had no vent and vapour locked on test flight number 2 right over the airfield at 8K ft. (pays to stay close when your experimenting) The engine would not run at all so I dead sticked it in. Gasoline especially auto fuel really wants to vaporize. The pumps add energy and pressure up to the engine where it is quickly relieved to zero by the regulator in the return line, plus it picks up heat from the engine bay. The result is lots of bubbles in the return fuel back to your sump which will eventually displace all of the fuel with vapour. I put in a vent line and that cured it completely. Lots of guys have problems with the Bendix and Airlow Performance injection systems cause they plumb the return fuel directly back to the pump input with no sump tank. It quickly turns the fuel to froth going round and round till the engine quits from fuel starvation. A vented sump will separate the vapour bubbles and give pure fuel up the feed. Parallel the sump vent with one of the tank vents so it will go into the tank and condense back to fuel. Works great that way. BTW Larry I get an attachment with all your Posts, is that normal?? > > >Attachment Converted: D:\MAIL\RFC82218.TXT > Nigel Field Date: Fri, 03 Oct 1997 08:02:41 +0200 From: Rego Burger Subject: Re[2]: COZY: One way fuel flow valve? -Reply I just don't like a single sump with two tanks, it's a bottle neck. Any dirt can accumulate in the single sump, however proper preflight / drains should reduce that risk. Also with the basic sketch if one valve stuck closed you would get no fuel leading into the sump. This renders you with a short range and you will be forced to land quick? I still feel the best would be a direct feed of both tanks to a left, right and both fuel selector tap. ??? However there is nothing wrong with the present design. The fears of fuel in the cabin are amplified by the fact that most folks are building the thing and see it. Most aeroplanes have fuel pipes in the cabin, unless you pull up the carpets and remove the side panels you just don't know it's there! By all means add on a roof carrier for extra luggage but think 100 x before changing the fuel system! :-) Rego Burger cz4#139 RSA ( 2 weeks leave in 4 hrs ) Date: Fri, 03 Oct 1997 10:30:06 +0200 From: Rego Burger Subject: Re: COZY: One way fuel flow valve? -Reply Question: Just to help with this Thread. >thinking of. (by the way, they are priced as follows: ACS P/N 10630 - > >$19.90, Wicks P/N CV-3/8 - $15.75)<<< Is this a spring loaded valve? If so, what logic? Some are spring loaded closed others are spring loaded open! You need to give the application some thought. Will gravity feed open it enough, the ones that are spring loaded closed rely on fuel pump pressure to keep them open. Run with it, test it think safe. Rego Burger RSA Date: Fri, 03 Oct 1997 15:09:30 -0700 From: "LCDR James D. Newman" Organization: INFINITY Aerospace - http://www.flash.net/~infaero Subject: COZY: Re: One way fuel flow valve? Hi Rego and All, >I still feel the best would be a direct feed of both tanks to a left, right and both fuel selector tap.???< I have a remotely mounted 5 way fuel valve with detents (Off/Left/Right/Both/Reserve) planned feeding a large removable fuel sump tank under the rear seat that has a window in it to see into from the back seat. The sump bottom will be the aircraft bottom between the longerons, and will have a low point to easily drain the sump. The window will be removable in case the inside needs cleaning/maintenance. The tanks are filled through a single fuel cap covered with a door on the right side of the turtle back that can only be opened from the cockpit (just like modern cars). The door can not be closed unless the fuel cap is on. The door will be wired to warn the pilot (visibly and audible) that it is not closed when the Master is on. The single point re-fueling fills a header tank behind the passengers head that fills both tanks. If you want to fill each tank individually through the single fuel cap, you can do so by putting a splitter in the header tank. If you want to level the tanks, put a line between the tanks with an On/Off valve between them. HTH. Infinity's Forever, JD From: lschuler@cellular.uscc.com Date: Mon, 06 Oct 97 12:18:11 -0600 Subject: Re: COZY: Cozy fuel System Nigel Field wrote: >Larry you should install a valve, it is mandatory up here in Canada to >ensure you can shut off the fuel in the event of engine bay fire. You can >mount it on the firewall and use a torque rod to actuate it from the >cockpit, thats how mine is. It can be a simple 2 port one though, on and off. SVX with fuel injection runs about 60 to 80 psi or so. If I install a valve between the pump(s) and the rail it would need to be one that is capable of handling that kind of pressure plus margin. Any ideas on a good sourse? Also, even after closing such a valve and shutting down the engine, the pressure in the line would remain until relieved by a hole, crack, or similar. >My pumps are plumbed in parallel with indepedant electrical connections, >wires, fuses, and switches. The glass/epoxy sump has 2 chambers, a large low >pressure chamber fed by gravity from the tank feed lines and engine return >line plus a vent line, and a small second chamber in the top made in a step >shape with a square cross section 2/3 the depth of the sump enclosure. The >pump outlets are press fit into holes into this HP chamber with "O" rings to >give a reasonable seal, pumps are secure mounted in low pressure chamber >with inlets on the bottom. The pumps pressurize the HP chamber which feeds >the fuel through an AN fitting. Each pump has a check valve in the output >port to prevent one pump feeding back through the other. Either pump or >both will supply sufficient fuel well beyond the max flow required. Interesting concept... still sounds like you have twice as much pressure (or flow) than is necessary. May not be a good idea with the SVX???? Gotta think about that one. What are you doing on this Phillip? >The plans location is fine for the water drains and yes put them in. Put >one in the sump also its the lowest point in the system and will collect >water if there is any in the mains. Haven't had any water since I changed >my caps long ago, but the old Brock caps were horrible and leaked in lots >of rain. I once drained out a full quart of water from each tank before I >wised up and changed to screw in positive sealing caps with O rings. Will do same. Thanks for the input. >snip >This is the secret to making a sump tank work properly that I learned from >experience. My first one had no vent and vapour locked on test flight >number 2 right over the airfield at 8K ft. (pays to stay close when your >experimenting) The engine would not run at all so I dead sticked it in. >Gasoline especially auto fuel really wants to vaporize. The pumps add >energy and pressure up to the engine where it is quickly relieved to zero >by the regulator in the return line, plus it picks up heat from the engine >bay. The result is lots of bubbles in the return fuel back to your sump >which will eventually displace all of the fuel with vapour. I put in a >vent line and that cured it completely. Lots of guys have problems with >the Bendix and Airlow Performance injection systems cause they plumb the >return fuel directly back to the pump input with no sump tank. It quickly >turns the fuel to froth going round and round till the engine quits from >fuel starvation. A vented sump will separate the vapour bubbles and give >pure fuel up the feed. Parallel the sump vent with one of the tank vents >so it will go into the tank and condense back to fuel. Works great that way. My take is: 1. Vent everything. 2. Return line from regulator to sump. 3. High pressure valve? (yet to decide if necessary [practical] for SVX). 4. Drain valves in sump and strakes. I did note the Soob posts on vapor lock as well. Interesting reading. >BTW Larry I get an attachment with all your Posts, is that normal?? Unfortuantely it seems to be 'normal' for my server to add this routing garbage. Larry Schuler #500 lschuler@cellular.uscc.com From: "Johnson, Phillip" Subject: COZY: RE: Cozy Fuel System Date: Mon, 6 Oct 1997 16:47:28 -0400 Larry Schuler Wrote: > What are you doing on this Phillip? I have two external pumps connected in parallel. The fuel valve is installed ahead of the pump and two micro switches attached to the fuel valve lever disable the pump power when the valve is in the off position. The valve only sees low pressures hence a simple valve works. If the micro switches fall off the selector handle, pressure is maintained as a fail safe. The micro switches protect the pump against damage for the 'selector off' and 'pump on' scenario. Each pump is sourced from its own fuel pump switch, on the instrument panel, and its own breaker. As an alternative I am considering using the stock Subaru pumps intank pumps and an industrial valve. The valves are quite capable of operating with the 90 psi max from the pump. Normal operating pressure is about 35 psi above manifold pressure. The area of concern should be the fuel return. Consider the scenario in which the pilot has anticipated a forced landing, turned off the fuel tap believing that if the engine is torn from the airframe, no fuel will be spilled. The fuel return line will almost certainly be severed as well. A one way valve, similar to the one that has been discussed so feverishly in the last few days, should be installed, on the return line, close to the sump tank. Now when the return line is severed the contents of the fuel tanks are not expelled resulting in a fire hazard. ------------------------------------------------------------------------ --------------------------------------- Phillip Johnson Cozy MKIV RG Subaru EG33 Plans set # 30 Ottawa Ontario Canada ------------------------------------------------------------------------ --------------------------------------- From: "Kim Schallhorn" Subject: COZY: Vent Line Date: Wed, 8 Oct 1997 11:39:59 -0500 Hi all, We are currently about to put in the vent line into the right fuel tank, but we are a little confused on the size of the tube. Can anyone tell us (Daryl Lueck-builder) the size of the tube. Thanks for the help. Kim Schallhorn From: Marc J. Zeitlin Subject: COZY: Vent Line (fwd) Date: Wed, 8 Oct 97 13:21:19 EDT Kim/Daryl ask: >We are currently about to put in the vent line into the right fuel tank, >but we are a little confused on the size of the tube. Can anyone tell us >(Daryl Lueck-builder) the size of the tube. The plans call out 3/8" aluminum tubing for the fuel lines, and the material list calls out 1/4" line as well, but only 11 ft. of it. I make the assumption (although the plans don't call out the tubing size for the vent lines) that the 3/8" is for fuel line runs to the valve and the engine, while the 1/4" line is only for the venting. The lengths and sizes make sense that way (you'd want large diameter for the liquid, and small for the air). See Chapter 2, page 4 for the material list, and Chapter 21, step 4, 6, and 11 for line size info (what there is of it). -- Marc J. Zeitlin Email: marcz@an.hp.com Internet Mail Server 2.0b8); Wed, 8 Oct 1997 19:05:56 -0600 Date: Wed, 08 Oct 1997 19:05:46 -0500 From: Chris Anderson Subject: COZY: Strake windows I saw the strake window indea on the web site, and I was wondering if the issue of added windows was in the archives, (where are the mail archives anyways...) I had been planning on putting in roughly 6" tall by 8" wide plexi windows in the sides of the fusalage tub somewhere along the line so I could see down a little better. I think the strake window idea is better. Also, have folks discussed making that forward area of the strake fule tank? Thanks From: cdenk@ix.netcom.com Date: Wed, 8 Oct 1997 20:27:12 -0500 (CDT) Subject: Re: COZY: Vent Line (fwd) My drawings called for 1/4" O.D. soft aluminum tubing. I have 2 vents per tank. One in the normal location roughly center in plan view, and of course as high a possible (the high point in levle flight), and the second is located inboard aft against the spar (the high point when parked on the nose). Both run high on the forward face of the firewall. Then One from each side crosses and exits on aft (between wing and spar) side of spar several inches from fuselage side on the opposite side as the tank it serves. The other vents do a 180 degree turn, and exit on the same side as served tank. Both exit side by side with flox and bid wrapping. They project about 3/4" and are cut at 45 degree opening facing forward to slightly pressurize tanks. Several advantages: 1: In the event the aircraft ends up upside down, fuel will not drain, as would happen with the vents on top the turtleback. 2: Vents are sheltered from weather. 3: In the event a mud dabber wasp decides to build a nest, and clog one side (its unlikely that both would happen at the same time) you would still have a functioning vent for each tank. 4: When parked on the nose, the drawing vents may be under fuel liquid, and with cool fuel warming, will spill fuel over the top of the plane. Carl Denk: "cdenk@ix.netcom.com" Date: Wed, 8 Oct 1997 22:54:32 -0400 From: "Edmond A. Richards" Subject: COZY: Re: Strake windows Chris, I installed windows in in my strakes to improve downward visability. = Seemed like a good idea to me and I felt the risk of creating any structural problem was small. I have not posted any info because, as yet= , the design is untested. Once the plane is flying I will let the group kn= ow how well it worked. Ed Richards Cozy Mark IV #088 From: AlWick@aol.com Date: Thu, 9 Oct 1997 09:41:22 -0400 (EDT) Subject: Re: COZY: Vent Line In a message dated 97-10-08 12:41:41 EDT, kimschallhorn@ultracom.com writes: << We are currently about to put in the vent line into the right fuel tank, but we are a little confused on the size of the tube. Can anyone tell us (Daryl Lueck-builder) the size of the tube. >> I really don't think the size could matter. I went to a larger 5/16" ? so I could run wires from internal fuel gages through vent line. The wires exit the vent line above fuel level by drilling a small hole in side of vent line. This is later covered with fiberglass. I then end up with auto fuel gages in tanks w/o having to penetrate the tank wall with wires. I strongly recommend this because an oversight causing fuel starvation is a leading cause of crashes. Analog gages with "low fuel" warning light as used on auto's will greatly reduce odds of you being victim. FWIW -al Date: Thu, 09 Oct 1997 12:45:57 -0700 From: "LCDR James D. Newman" Organization: INFINITY Aerospace - http://www.flash.net/~infaero Subject: COZY: Re: Vent Line Hi Al and All, >I really don't think the size could matter.< Size does matter (she says). In a race at Sun 'N Fun a few years ago, the Questar Venture, with their first aircraft with a new larger engine with more HP, would quit about 10 to 15 minutes into the race. It would restart after gliding for several seconds. Then 10 to 15 minutes latter, it would quit again. The pilot figured out that at full throttle the vent line for each tank was too small of an ID not allowing the tanks to vent properly for the fuel flow of this new larger engine, causing the engine to quit. When the tank pressures normalized, it would re-start. They had never run this new larger engine with more HP at full throttle for that long of a period until that race. The vent lines that were in it was for a smaller HP engine. Needless to say, after the race they put in more vent lines. Several 1/4" ID vent lines would probably be better than just one big ID vent line. In fact, one big ID vent line per tank, which allows for the wires, and a few 1/4" vent lines strategically placed would probably be best. >I went to a larger 5/16"? so I could run wires from internal fuel gages through vent line. The wires exit the vent line above fuel level by drilling a small hole in side of vent line. This is later covered with fiberglass. I then end up with auto fuel gages in tanks w/o having to penetrate the tank wall with wires.< Excellent idea. Since the wires probably come out of the vent line well above the tank, RTV or silicon may be better than the rigid fiberglass so the wires can be protected with a softer material and be more easily removable if need be. Food for thought. >Analog gages with "low fuel" warning light as used on auto's will greatly reduce odds of you being victim.< Should be mandatory in all aircraft. Infinity's Forever, JD From: cdenk@ix.netcom.com Date: Thu, 9 Oct 1997 17:13:42 -0500 (CDT) Subject: Re: COZY: Re: Vent Line J. Newman writes < prefers larger (5/16" or larger) tubing.> agree. Don't like anything electrical near fuel vapors - smallest spark could cause explosion. Check chemical resistance of material. I use 100LL aviation fuel to clean epoxy off canard/fuselage and strake/wing joints whenever I have one off. Carl Denk: "cdenk@ix.netcom.com" From: cdenk@ix.netcom.com Date: Thu, 9 Oct 1997 17:20:04 -0500 (CDT) Subject: Re: COZY: Vent Line Agree electric gauges are mandatory in a Cosy because you will be loading luggage for trips that will hide the sight gauges. I have the skysports capacitive, also Vance Adkinson a\has a set of electronic. Carl Denk: "cdenk@ix.netcom.com" From: AlWick@aol.com Date: Sat, 11 Oct 1997 00:30:57 -0400 (EDT) Subject: Re: COZY: Re: Vent Line In a message dated 97-10-09 15:48:53 EDT, infaero@flash.net writes: << Size does matter (she says). In a race at Sun 'N Fun a few years ago, the Questar Venture, with their first aircraft with a new larger engine with more HP, would quit about 10 to 15 minutes into the race. It would restart after gliding for several seconds. Then 10 to 15 minutes latter, it would quit again. The pilot figured out that at full throttle the vent line for each tank was too small of an ID not allowing the tanks to vent properly for the fuel flow of this new larger engine, causing the engine to quit. When the tank pressures normalized, it would re-start. They had never run this new larger engine with more HP at full throttle for that long of a period until that race. The vent lines that were in it was for a smaller HP engine. Needless to say, after the race they put in more vent lines. >> Thanks for the info here. I really learned something. I just assumed that the liquid could be easily displaced by pressurized air. Gotta admit, at some point, if vent too small, fuel flow could outpace air intake. Probably even more significant for my application where I will be using auto engine which pumps large volume of fuel and dumps excess back to tank. Perhaps. Thanks for the input JD. I retract my original statement that size is not significant. -al Date: Fri, 10 Oct 1997 23:30:58 -0700 From: Pat Zeeb Organization: INFINITY Aerospace - http://www.flash.net/~infaero Subject: COZY: Re: Vent Line Hi Al and All, >Thanks for the info here. I really learned something. ... Thanks for the input JD.< Just something that stuck in my mind when I read it long ago. This is what this group is all about - sharing knowledge, ideas and lessons learned. Glad I remembered something that helped someone. >I just assumed that the liquid could be easily displaced by pressurized air. Gotta admit, at some point, if vent too small, fuel flow could outpace air intake. Probably even more significant for my application where I will be using auto engine which pumps large volume of fuel and dumps excess back to tank.< Auto engine - me too (SVX) - same concerns. Something else about these fuel vents for canards, they are/were originally mounted above the passenger in a low pressure area, particularly low pressure area at higher angles of attack at slow flight/in the pattern. Also, if the pilot filled the tanks as full as s/he could, then went in to pay for fuel and the tanks warmed up, fuel would start flowing out the vent onto the passengers head into the back seat. Anyone have this happen? Routing the tank fuel line vents to a manifold at the top of the turtle back then one or two lines back down to below the strakes out the side of the fuselage in a high pressure area and out of the passengers back seat is how some have done it. HTH. Infinity's Forever, JD From: CCady@aol.com Date: Sat, 11 Oct 1997 07:06:01 -0400 (EDT) Subject: Re: COZY: Re: Vent Line In a message dated 97-10-11 02:32:23 EDT, you write: << Something else about these fuel vents for canards, they are/were originally mounted above the passenger in a low pressure area, particularly low pressure area at higher angles of attack at slow flight/in the pattern. Also, if the pilot filled the tanks as full as s/he could, then went in to pay for fuel and the tanks warmed up, fuel would start flowing out the vent onto the passengers head into the back seat. Anyone have this happen? >> My fuel vents on my old Long-Ez would leak out fuel back over the cowling but only if the tanks were 3/4 full or more. Also had them leak forward when parked nose down. I got some paint problems as a result of this leakage. When I made my E-Racer I wanted to change the vent arrangement. I installed the vent lines at the high point of the tank near the fuselage sides and ran them out toward the end of the strake. I have them exiting into a wheel well area for the retract gear on the E-Racer. But the interesting thing it that I never get any leakage or dripping at all. I figure when you are banked the outboard vent end on the high side is up higher and on the other low side the fuel is moving away from the inside vent tube end near the fuselage. I'm not saying you should do this but it worked for me. :-) Cliff From: John B Vermeylen Subject: COZY: Cozy: fuel vent lines Date: Sat, 18 Oct 1997 23:55:47 -0400 Hello Group, I coming in late on the vent line discussion but would like to = contribute my thoughts on the matter. I haven't used my Mechanical = Engineer Degree for much lately but after thinking about the vent line = size debate I came up with a different concern. I think the quarter = inch lines, as specified in the plans, are adequate enough to even over = pressurize the fuel tanks. We should be talking about how the vent = lines are directed in the air stream instead. If you look at Nat = Puffers vent lines, they are bent forward at about a 45 degree angle. = This is probably the best angle. If you point them straight down you = chance pulling a vacuum in the tank. If angled straight to the air = stream, a weak tank can pop its top seam. Talk to Nat Puffer first if = you have a concern about the fuel tank vent line size. John B Vermeylen N69CZ From: AlWick@aol.com Date: Wed, 22 Oct 1997 09:56:17 -0400 (EDT) Subject: COZY: Before you build fuel strakes If you haven't built your fuel strakes yet, go to last chapter in book 1 and add: "BOLT wings to spar, then 5 minute glue a template matching wing shape. Template glues to end of spar and provides guide for matching front half of wing to strake." If you don't do this you run high risk of some sort of misalignment. I ended up with a perfect match top and bottom, but the leading edge of strake is one inch ahead of wing leading edge. Easily fixed, but I would have preferred to not have this problem. This suggestion courtesy of Jim White. -al Date: Wed, 22 Oct 1997 20:37:11 +0200 From: blecoq Subject: Re: COZY: Before you build fuel strakes Hi from France Another optionnal tip on this one. I built my strakes with the wing bolted on the side I was building the strake (well supported of course)This allows a much finer alignement of the strake bottom and top with the wing skins. I also had previously double checked the wing angle of attack and did it again after having both strakes done.This is justified by the fact that the torque strength of the spar is a lot lot stronger once the strakes are done.So I found that to fine tune the wing incidence it needed to be changed by a ~ tenth of a degree(1/10 of a degree) or so.It took me several days to check out precisely on that and I did both wings bolted on and before doing the very last fairings (Strake leading edge and outboard fairing to the wing). I now find it quite easy to do the finishing on this part, having that done. For this of course ,you need a two car garage which I am lucky enough to have thought about it when I builded it some years ago.(That is called planning ahead) Happy building. Beno=EEt. Date: Wed, 22 Oct 1997 17:06:52 -0500 (CDT) From: cdenk@ix.netcom.com Subject: Re: COZY: Before you build fuel strakes Bleqot writes I agree, this is the way I did it except I had the room to bolt both wings at the same time. Went around and around with templates that fit top surfaces, water level and accurate 4 foot carpenters level. Spent several evenings doing this before proceding. Note: To test a level, set on a flat surface, shim one end to make bubble between marks, switch level (not shim) end for end. Bubble will remain in same position (relative to marks) when the level IS LEVEL. If that is not where the marks are, either adjust (only a few actually are) or make new marks. Now put a penny flat under one end. notice the bubble should have noticeably moved, if not it isn't sensative enough to use in aircraft construction. From: cdenk@ix.netcom.com Date: Wed, 22 Oct 1997 17:26:41 -0500 (CDT) Subject: Re: COZY: Before you build fuel strakes AL Wick writes