Date: Sat, 1 Jan 2000 08:42:59 +0000 Subject: COZY: Fuel flow problems From: mark w beduhn I have been having some engine problems and would like some advice from the group: I am flying a Cozy MK IV with a 180hp IO-360 (Bendix fuel injection system). About a week ago I flew when it was about 15 degrees F outside. I was flying at full throttle @5500 feet. Everything was fine for the first 15 minutes. I then noted a very subtle roughness in the engine and my rpm started to slowly drop. I immediately checked the following: Switched tanks - no change Checked ignition sytems - normal Mixture full rich - no change Switched on boost pump - rpm increased to normal. The fuel pressure without the pump was 22-23psi, with the pump on it was 26-28psi (This is the same as it has been for the last 250 hours of operation). Since things were not right, I turned the plane back toward my home base (OSH) and kept the fuel pump on. After 5 minutes or so the engine rpm again started to drop and the engine started to run a little rough. When I turned off the fuel pump, the engine lost 100 rmp and was noticably rougher. The fuel pump was switched back on and the rpm slowly started to drop. I then landed the plane (uneventfully). Back at the hanger I did a run-up and was able to achieve full power without the boost pump. I shut down the engine and checked the following: Confirmed that the fuel tank vent lines were clear. Removed the primary fuel filter (screen was clean). Checked the gas collator (screen was clean, no water/ice present) Checked the inlet filter to the Bendix fuel servo (screen was clean) Put everything back together and checked for leaks (everything normal) The next day I flew again and had similar problems, only this time I monitored the fuel flow to the engine. I decided to keep the mixture full rich and watch the fuel flow. Everthing was normal for the first 10 minutes and then the flow started to slowly drop. (Full rich was 13gph). The engine started to run rough when the flow approached 10gph. When I turned on the boost pump the flow jumped back to 13gph, but slowly dropped. Again when the flow got to around 10gph the engine started to run rough. There was a consistant flow difference of 2-3 gph depending upon whether the pump was on or off. Since I was near the airport and at high alititude I decided to turn off the boost pump for an extended period of time to see what would happen. The fuel flow continued to drop and the engine continued to run rougher, so I reduced the throttle to smooth out the engine (the rpm is now around 2200). I decided to land the plane so I throttled back to idle (to slow the plane down and loose altitude). However after about 10 seconds or so I changed my mind and went back to full throttle. Surprise surprise...the plane surged forward as the engine developed full power. Fuel flows were again normal! I continued to run full throttle, and after 15 minutes or so the fuel flow again started to drop. When the flow got to 9gph I pulled the throttle back to Idle, held it there for 5 seconds, then went back to full power. Again the fuel flow returned to normal. The following day it was warmer and I did the same test again with similar results. It seems to be very repeatable. So what is it? My best guess is the Bendix servo. Any advice would be appreciated. Thanks, Mark Beduhn Cozy N494CZ From: "david vollrath" Subject: Re: COZY: Fuel flow problems Date: Sat, 01 Jan 2000 11:19:23 PST >So what is it? My best guess is the Bendix servo. Any advice would be >appreciated. Hello Mark: My opinion is the same as yours, that you have a fuel servo problem. Also check for for fuel hose inner lining interfering with flow. Sometimes when hose ends are installed, the insert will tear a flap of rubber from the inner lining that will restrict flow. Good luck, and tell us what you find. David Vollrath Cozy III N22AZ ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com From: cdenk@ix.netcom.com Date: Sat, 1 Jan 2000 15:57:27 -0500 (EST) Subject: Re: COZY: Fuel flow problems This is a case for having individual EXT/CHT for each cylinder. I have to assume with the reduced fuel flow and roughness, the mixture was lean. The temperature was below freezing, and I assume the airframe was in a warm (above freezing) hangar till shortly before takeoff. Makes me suspect ice somewhere, did you check the the gascolator, is it a conventional aircraft type?, and aircleaner installation? The bendix is near bullet proof, the only 2 issues I have had with mine is twice a clogged cylinder jet, and once the leaning was not smooth reacting, I had the servo overhauled by D & G Supply. The unit was back within the week and price very good. Give them a call 1-800-446-8160, and http://www.dgsupply.com. A phone call would be very helpful. I wouldn't fly it until I find and correct a reasonable reason for the problem. Ask D & G what could cause fuel flow to drop, like induction air starvation, but that would cause to run rich I would think. What is the exhaust and spark plug color?? Sooty black is rich, toward white, light gray is lean. The ground running may have changed that. Incidently we have flown numerous times at temperatures to below zero F. with no issues. Don't have carb heat. Do you have an alternate air source, need one of those! From: cdenk@ix.netcom.com Date: Sun, 2 Jan 2000 13:13:35 -0500 (EST) Subject: Re: COZY: Fuel flow sender On 01/02/00 07:03:23 you wrote: > >Hi Group, >Where is best place to mount the "fuel flow sender"? > >A. Between the flow divider and the servo. >B. In the back seat area. >C. Somewhere else. >Thanks, Don >Cozy Mark IV #580 > > > You don't say what your fuel/air mixer is - Bendix, Airflow but the idea is mount at a location, where it is not part of a loop of tubing, but all fuel going through the sender is burnt and not returned to a point before the sender where it can get measured again. Mine with a bendix isn't in the backseat, and if I remember right is inlet to the flow divider. Date: Mon, 03 Jan 2000 14:29:23 -0600 From: David Domeier Subject: COZY: Re: [c-a] Fuel flow sender Steve, re " The sender doesn't have to be hard mounted. It can be located unsupported in the middle of two flexible hoses if necessary... Am I correct in assuming this is true with the Ellison TB as well?" I have mine mounted down stream from the engine pump in the flex fuel line....so far so good. No problems to date. There is an "up" side to the sender that needs to be reasonably up. dd From: cdenk@ix.netcom.com Date: Mon, 3 Jan 2000 18:54:16 -0500 (EST) Subject: Re: COZY: Re: [c-a] Fuel flow sender Was said I don't think I would leave it unsupported. For one, that would create unnecessary fatigue on the connected wires. From: Epplin John A Subject: COZY: Engine, electrical Date: Mon, 10 Jan 2000 12:32:15 -0600 Need some advice here. I am using the Rose Electroair ignition system. I set the system up on the bench and checked the current drain with an oscilloscope and related stuff. Seems the average is around 1.25 amp at 2800 rpm, which is well and good. The problem is the peak current is about 11 amps, this occurs at each firing or twice per revolution. There is a pretty steep decay of this peak, about 5 microseconds from 10 amps to near 0. The spark appears to occur at about the midpoint of the decay, I am not sure if the scope is showing me a big spike because of coupling from the spark gap or there is a transient on the power lead, I am going to assume that spike is coupling from the spark gap and my bench setup. The unit was delivered with #18 shielded wire for the power lead. My concern is introducing noise in the radio equipment. Does anyone out there with these rear engine plastic airplanes with comm antennas on the wing tip have any experience with the Electroair system. Did you use shielded wire to the instrument panel area? Any other precautions I should consider? There will be about a 1 volt drop in 15 feet of #18 wire at the peak current. In my opinion that will be acceptable. I believe these units are made from GM automotive parts, these things are just about bullet proof in cars with AM / FM radios working fine. However there usually is not AM VHF equipment in cars. Just want to avoid making a goofy mistake in the installation. TIA for any sharing of experience! John Epplin Mk4 #467 Date: Mon, 10 Jan 2000 13:43:32 -0600 From: Michael Pollock Subject: RE: COZY: Engine, electrical John Epplin wrote: >Does anyone out there with these >rear engine plastic airplanes with comm antennas on the wing tip have any >experience with the Electroair system. Did you use shielded wire to the >instrument panel area? Any other precautions I should consider? John, We use the Rose Electroair direct ignition system (DIS) and one Slick mag on our Velocity and love the system. We did use shielded wire for the power lead and we do not have any noise from the DIS system. If you setup the DIS system per Jeff Rose's installation manual, you will not be disappointed. David Domeier also uses the Rose DIS system on his Lycoming. Michael.Pollock@wcom.com Flying Velocity N173DT Building Cozy MKIV #643 From: mister@neesnet.com Date: Thu, 13 Jan 2000 13:21:46 -0500 Subject: Re[2]: [c-a] Re: COZY: Cozy Cold Wx Ops RE: the crankcase breather: I built a simple oil separator from fiberglass and mounted it on my firewall. (as I recall this was described in one of the CSA newsletters.) The breather is piped to the inlet, the outlet goes through a flexible hose to an aluminum tube that runs out along the exhaust. There is a third port to the separator that I leave plugged with a cover I made with RTV and a 1" piece of plastic tubing. I let the gunk accumulate until oil change time and then drain it. This setup has worked fine for me in the 150 or so hours I've had it. I don't get any oil on the prop. Bob Misterka COZY III N342RM LYC. 0320-E3D ********************************************************************** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. This footnote also confirms that this email message has been swept by MIMEsweeper for the presence of computer viruses. New England Electric System Companies ********************************************************************** Date: Mon, 17 Jan 2000 04:36:37 +0000 Subject: COZY: Re: [c-a] Fuel flow problems From: mark w beduhn On Mon, 17 Jan 2000 02:00:49 EST Reallymeg@aol.com writes: > Were you able to find out the problem? > > Meg Most of the responses I got indicated that a plugged vent was the most likely cause of the problem. The only change I made before flying again was to I adjust the mixture on the fuel servo so that I could run a little richer. The day I went flying it was above freezing (if ice had plugged the vent, it would have melted). I confirmed that the vents were clear and went flying...no problems at all. What I want to do now. is go flying when the temp is below freezing and see if I still have no problems. So far, a plugged vent line appears to have been the problem. I will keep the group posted if I learn anything new. Mark Beduhn Cozy N494CZ Date: Fri, 21 Jan 2000 22:34:27 -0500 From: kent ashton Subject: COZY: lord mount part numbers Anybody got a good part number for the heavy duty Lord mounts suggested in the Mark IV plans? I tried ordering by the P.N. in the plans but ACS didn't seem to recognize it. This is the rubber mount for the Brock engine mount and O-360 combination. Thanks. --Kent Ashton Date: Fri, 21 Jan 2000 20:22:11 -0800 From: Eric Westland Subject: Re: COZY: lord mount part numbers I don't have the plans in front of me, but I think they just call for the ACS "generic" mounts. I used the special heavy duty mounts, PN 08-036000 although the standard ones may work just as well. Eric Westland N325PD kent ashton wrote: > > Anybody got a good part number for the heavy duty Lord mounts suggested in the > Mark IV plans? I tried ordering by the P.N. in the plans but ACS didn't seem > to recognize it. This is the rubber mount for the Brock engine mount and > O-360 combination. Thanks. > > --Kent Ashton From: cdenk@ix.netcom.com Date: Sat, 22 Jan 2000 00:07:36 -0500 (EST) Subject: Re: COZY: lord mount part numbers In the world of certified aircraft, the lord mounts are an airframe item. Each manufacturer for each application selects the lord mount material (slight differences in dimensions and durometer (neophrene stiffness)) to absorb the vibrations they feel best suits their airframe/engine. I haven't heard of anyone trying to sort this out, to what might give the smoothest installation for an EZ, but my feeling is anyone will be adequate. Just make sure that they match the engine/mount geometry, i.e. Lycoming dynafocal will fit Lycoming Dynafocal. Note: Some lycomings, the IO-320-B1A from a Piper twin Commanche is a type 2 dynafocal and requires a different geometry mount than most others, but the lord mount is the same. From: "Nat Puffer" Subject: Re: COZY: oil cooler Date: Fri, 28 Jan 2000 08:19:22 -0600 Tim, I prefer to mount the oil cooler on the airframe, for less vibration. I try to minimize the number of things fastened directly to the engine. Regards, Nat ---------- From: Tim To: cozy_builders@canard.com Subject: COZY: oil cooler Date: Thursday, January 27, 2000 10:02 PM I am ready to mount the oil cooler. Has anyone tried mounting the cooler near the flywheel using exit air to cool. Does anyone have a recent database for the garmin gps 90. Tim Kilgore cozy mark IV 372 Date: Fri, 28 Jan 2000 07:04:26 -0500 From: Jeff Russell Subject: Re: COZY: oil cooler > Tim wrote: > > I am ready to mount the oil cooler. Has anyone tried mounting the > cooler near the flywheel using exit air to cool. Tim, I did this on a Berkut I built. Works fine and I would do it again. W&B moves back a little with the oil cooler back that far. -- Jeff Russell/AeroCad Inc. 2954 Curtis King Blvd. Ft. Pierce, FL. 34946 Shop# 561-460-8020 7:00am to 3:30pm Home# 561-344-6200 Website: http://www.Aerocad.com From: "Gary Dwinal" Subject: COZY: Starter Problems All Cured - As Usual It Only Takes Money Date: Thu, 27 Jan 2000 20:28:22 -0500 Well, I got my new B&C starter and installed it and used the same gell cell battery and it turned the engine over much better than did the SkyTec starter. I then installed the new B&C gas recombinant battery and it along with the new B&C starter spun my big ol' 360 over like the "spark plugs were removed". What a difference! I am a strong advocate for Bill Bainbridge's B&C ) products as I now have his starter, 60 amp alternator, LR-3 voltage regular, and now his gas recombinant battery. The only thing that upsets me now is that I should have gone this way to begin with and I wouldn't have an extra brand new starter and battery to try to get rid of. I would also have an extra $440 in my pocket! I think I am going to take them over to the little field where I learned to fly and donate them to the owner as he is always struggling financially to keep his airplanes maintained properly. Maybe it will help some young kid to get his / her pilots license. I am telling you all about this embarrassing situation only to, maybe, keep someone else from making the same mistake. If you have an 0-360 buy the B&C starter FIRST!!!!! Gary Dwinal From: Epplin John A Subject: COZY: RE: [c-a] Code union fittings Date: Mon, 7 Feb 2000 10:18:57 -0600 I have the same thing facing me. I believe lead-tin solder would be too low melting temperature for this application. Normally would probably work but it is certainly marginal. I was planning on silver solder such as the air-conditioning people use. This requires the appropriate flux and also an acetylene torch. The problem is that the melting temp of the silver solder is not far below the brass fittings. Care must be taken to not melt the thin walls of the fitting. Very small tip as acetylene torches go. Will let you know when I get some experience which will be in a few days. I mounted the engine for what I hope is the last time this weekend. As an aside, has anyone tried to use this arrangement as an emergency fuel delivery system? Will it provide enough fuel flow to make usable power? Just a wild thought. John Epplin Mk4 #467; > -----Original Message----- > From: SWrightFLY@aol.com [SMTP:SWrightFLY@aol.com] > > I have received the code union fittings (AN800-2) from Wix ...see page > 177 of the current catalog ....and need to solder them to the 1/8" > copper primer lines so I can attach to the primer fittings...on my > XP-0360..... > > Have never done this so any suggestions as to the solder technique or > type of solder to use would be appreciated. > > From: cdenk@ix.netcom.com Date: Sun, 6 Feb 2000 18:53:12 -0500 (EST) Subject: Re: COZY: Code union fittings If the stainless will allow solder to stick to it: same materials and techniques as copper water pipes in your house I would think: 1: Clean all mating surfaces shiny clean. 2: Coat surfaces with solder flux, I prefer the "Nocorrode" brand., and assemble 3: Heat with propane (Benzamatic) torch until solder touching parts melts and flows into the joint. 4: Air cool. But, I'm not sure this is approved aircraft procedure, check the approved practices book. The injector lines on my IO-320 are stainless, and are silver soldered. Same procedure as above except special flux and solder wire. Could try a jeweler or home or industrial air conditioning repair. Date: Mon, 07 Feb 2000 18:52:47 -0600 From: Michael Link Subject: Re: COZY: RE: [c-a] Code union fittings Epplin John A wrote: > I have the same thing facing me. I believe lead-tin solder would be too low > melting temperature for this application. Normally would probably work but > it is certainly marginal. I was planning on silver solder such as the > air-conditioning people use. This requires the appropriate flux and also an > acetylene torch. The problem is that the melting temp of the silver solder > is not far below the brass fittings. Care must be taken to not melt the > thin walls of the fitting. Very small tip as acetylene torches go. Will > let you know when I get some experience which will be in a few days. I > mounted the engine for what I hope is the last time this weekend...... John, I have a fair amount of experience braising stainless steel using silver solder. First, good silver solder ( more than 25% silver ) melts at a high temp. but a propane torch will do the job on small parts like the fittings in question. Mapp gas with it's hotter flame works better, and it won't melt brass. I always use Boric Acid paste flux. There is some technique to braising that is difficult to express in text. One tip that I can pass on is to brush on the flux where you want the solder to flow but do not put the flame tip directly on the flux as it will turn black and become inneffective. Properly heated , the flux will liquify and glow red. At that point you are ready to touch the silver solder to the area. Hope this helps. Regards, Michael Link COZY MK-IV N-171-ML Date: Mon, 7 Feb 2000 21:11:10 -0500 From: Bill Theeringer Subject: COZY: Code union fittings Don't use lead solder to secure this fitting. Use silver solder as recomended by other posts. Ordinary 60/40 electronic solder melts at 190c or 374F. I'm sure the fitting gets much hoter than this in normal use, and lead is certainly not physically strong enough to withstand the vibrations or the temperature. Bill T. N29EZ Date: Fri, 11 Feb 2000 21:53:56 -0500 From: "Marc J. Zeitlin" Subject: COZY: Chapter 15: Fiberfrax Glue People; So I've started the firewall, and I pull out my two year old roll of fiberfrax to start cutting it to shape, to find out that Wicks shorted me 2 ft. on a 5 ft. length and I don't have enough. OK, I've got to place an order for some other stuff anyway - I'll get some more. In the meantime, I get out the can of QF-180 glue (also two years old) and open it up. Wierd stuff - it's totally seperated, with some hardened stalagtites hanging off the can top. Anyway, after about 15 minutes of mixing, it seems to be a smooth, white, thick liquid - no lumps or discolorations. The plans are a bit thin on the usage of this stuff - what the heck am I supposed to do with it? 1) Is it a contact adhesive? 2) Do I apply it to one side or both? 3) Do I let it dry before applying the Fiberfrax to the firewall (on one side or both)? 4) Do I have to put pressure on it while it dries? 5) How long does it take to dry? 6) Is it temperature sensitive - i.e. what happens in a cold garage? 7) Once I'm ready to apply the aluminum to the fiberfrax, the same questions apply..... Thanks for any insight into this stuff. -- Marc J. Zeitlin mailto:marc_zeitlin@alum.mit.edu http://www.ultranet.com/~marcz/ From: alwick@juno.com Date: Fri, 11 Feb 2000 21:23:00 -0800 Subject: Re: COZY: Chapter 15: Fiberfrax Glue On Fri, 11 Feb 2000 21:53:56 -0500 "Marc J. Zeitlin" writes: > what the heck am I > supposed to do with it? Toss it. If you think about it, that red silicon silastic is ideal. It's high temp, doesn't penetrate the fiberfax. Anything will work, as long as it doesn't destroy the thermal properties of fiberfax. The adhesive does nothing until your firewall burns thru. at that point it just holds the fiberfax in place to protect the wood for a while. -al wick Canopy Latch System guy. Artificial intelligence in cockpit, powered by Subaru. Now mounting engine. Aug 2000 first flight scheduled ________________________________________________________________ YOU'RE PAYING TOO MUCH FOR THE INTERNET! Juno now offers FREE Internet Access! Try it today - there's no risk! For your FREE software, visit: http://dl.www.juno.com/get/tagj. From: "Paul Stowitts" Subject: RE: COZY: Chapter 15: Fiberfrax Glue Date: Fri, 11 Feb 2000 22:24:13 -0800 > The plans are a bit thin on the usage of this stuff - what the heck am I > supposed to do with it? > > 1) Is it a contact adhesive? No. > 2) Do I apply it to one side or both? One side is enough. > 3) Do I let it dry before applying the Fiberfrax to the firewall (on one side or both)? No. > 4) Do I have to put pressure on it while it dries? Yes. > 5) How long does it take to dry? Depends on temperature. Faster when warmer. > 6) Is it temperature sensitive - i.e. what happens in a cold garage? Don't know. Probably still works. > 7) Once I'm ready to apply the aluminum to the fiberfrax, the > same questions > apply..... > Marc, The stuff is like white glue that dries to a powdery consistency. You need to apply the Fiberfrax while the glue is wet and it dries quickly in warm weather. I agree with Al - use the silicon. Paul Stowitts Cozy Markl IV #200 From: cdenk@ix.netcom.com Date: Sat, 12 Feb 2000 08:35:26 -0500 (EST) Subject: Re: COZY: Chapter 15: Fiberfrax Glue I use any silicone RTV I have handy. My firewall protection is fiberax covered with .012" or .016" stainless steel over it. The perimeter of the stainless is sealed (caulked) with a bead of one part urethane caulking (Vulkem brand or equal is available) bought at (Home Depot for Ron Wilson we found) commercial construction chemical house. The urethane is impervious to fuel and oil. I use 100LL to clean off RTV, it makes it curdle. Other areas like cowling near exhaust pipes I use fiberax with a 2" grid of RTV for the fiberax and heavy duty kitchen aluminum foil with a bead of RTV to seal edges. RTV color either clear or aluminum to match, heat doesn't seem to be an issue. Date: Sat, 12 Feb 2000 07:51:50 -0600 From: Michael Link Subject: Re: COZY: Chapter 15: Fiberfrax Glue alwick@juno.com wrote: > On Fri, 11 Feb 2000 21:53:56 -0500 "Marc J. Zeitlin" > writes: > > what the heck am I > > supposed to do with it? > > Toss it. If you think about it, that red silicon silastic is ideal....... I AGREE ! I found the stuff to have lousy bonding propreties. The high temp silicone is rated at 600 degrees F. and should work fine. Michael Link COZY MK-IV N-171-ML From: Epplin John A Subject: RE: COZY: Chapter 15: Fiberfrax Glue Date: Sat, 12 Feb 2000 09:17:11 -0600 Marc: I would do as someone else suggested, throw it out. It does not adhere to metal at all, not very well to the epoxy even after it is roughed up. I used a product from 3M called Fire Barrier CP25WB+ Caulk. It is available from electrical supply houses. Used in building construction to seal electrical boxes etc in severe environments. Goes on like latex caulk, dries but stays pliable like silicon. It also expands when heated, providing a good seal. John epplin Mk4 #467 > -----Original Message----- > From: Marc J. Zeitlin [SMTP:marc_zeitlin@alum.mit.edu] > > The plans are a bit thin on the usage of this stuff - what the heck am I > supposed to do with it? > > Date: Sat, 12 Feb 2000 10:30:16 -0500 From: "Marc J. Zeitlin" Subject: COZY: Chapter 15: Fiberfrax People; Thanks for all the input on the fiberfrax - I'll use the silicone to install it and the metal shield. I wrote that Wicks had shorted me on the fiberfrax - this is not strictly true. While the plans call for 10 sq. ft. of FF, the Wicks Chapter 15 Kit only calls for 6 sq. ft. I didn't catch this discrepancy when I purchased it, so I did in fact get what I paid for; I just didn't get as much as I need. Make sure you check this when you order yours. -- Marc J. Zeitlin mailto:marc_zeitlin@alum.mit.edu http://www.ultranet.com/~marcz/ Date: Sun, 13 Feb 2000 23:15:50 -0500 From: "Marc J. Zeitlin" Subject: COZY: Chapter 15: Firewall Mat'l. - was "Fiberfrax Glue" Gregg Perry wrote: > Another issue that I never got a really good answer on was the aluminum >piece from Wicks that came with the chapter order. The plans do say (at >least at one point) stainless steel - but that's not what comes from Wicks. Yes, I remember a number of discussions we've had that stated that the L.E. plans had long ago switched to Stainless Steel for the firewall from the original aluminum. The material list in the plans, and the plans themselves (at least those before S/N 500) say aluminum. As far as I can tell, there was no correction from the newsletters saying to switch to SS. However, the one place that DOES say SS is the drawing of the firewall, showing the plywood, glass, fiberfrax, and then the SS. I also remember some tests that Steve Wright did on fire resistance, and IIRC, there wasn't a whole lot of difference in protection between the SS and the Aluminum..... Anyway, the Wicks chapter kit calls out Aluminum, not SS, so if you want the stainless, you need to correct that. Wicks only sells .018" SS, so I'll be purchasing a .016" piece from ACS. -- Marc J. Zeitlin mailto:marc_zeitlin@alum.mit.edu http://www.ultranet.com/~marcz/ From: SWrightFLY@aol.com Date: Mon, 14 Feb 2000 08:46:36 EST Subject: Re: COZY: Chapter 15: Firewall Mat'l. - was "Fiberfrax Glue" In a message dated 2/14/00 5:44:12 AM Central Standard Time, marc_zeitlin@alum.mit.edu writes: << I also remember some tests that Steve Wright did on fire resistance, and IIRC, there wasn't a whole lot of difference in protection between the SS and the Aluminum..... >> After the testing I became confident enough with the 477 epoxy (contact Hi-Grade at 800-783-2449) that I have used it on my Stagger EZ firewall. The only unknown is how it behaves as high velocity air is whipping around the firewall. As the material heats up - it expands creating a fire barrier good for 5 minuets on cardboard before the cardboard would smoke. This thick expanding material can be blown off the surface but more material expands to take its place. I will try a simulated cowl/firewall this spring to see how it works in more of a real world environment. I am also coating all aluminum pushrods and parts in the engine compartment with 477. Until alot more testing is done with this material I suggest y'all follow the plans exactly. Steve Wright Stagger EZ N700EZ AirBike...Ultralight EAA Technical Advisor Wright Aircraft Works LLC http://www.canard.com/noselift/ Wright Aircraft Works LLC: Electric Nose-Lift for EZEs Sponsor- Canard Aviators www.canard.com canard Aviators page Date: Mon, 21 Feb 2000 23:19:32 -0500 From: "Marc J. Zeitlin" Subject: COZY: Engine baffling So I'm working on the engine (O-360-A2A) baffling - I feel like I'm cutting origami that cuts back. I get a few of the pieces cut and decide to start bolting them on temporarily to see how things line up. What do the plans say...... bolts. Don't mention what size... must be AN3's..... nope - too small. Must be AN4's.... hey, they don't fit either. What's up? What does the parts list say.... nothing useful regarding baffle bolts. Threads look different... HEY, those are 1/4-20 screws, not 1/4-28 's (AN4's). What they heck??? Lycoming uses UNC, not AN (UNF) hardware? Well, let's try the left front top baffle bolt... Dang, that's a 10-24, not a 10-32 (AN3). Stumped again by this airplane stuff. I'd have thought that aircraft engines would use aircraft hardware, but that's what I get for making assumptions. And heaven forbid that they use the same size consistantly. There, the steam's blown off now..... Also, get a good pair of shears/snips for the 0.016" SS firewall. You'll need it. John Epplin mentioned "Fire Barrier CP25WB+ Caulk" as the stuff to use for sealing the firewall. The 3M web page sure makes this sound like the stuff to use. If anyone knows a convenient chain store that carries it, please let us know. Home Depot doesn't have it, and the closest place to me that 3M lists as a distributor is 25 miles away and doesn't mail order. -- Marc J. Zeitlin mailto:marc_zeitlin@alum.mit.edu http://www.ultranet.com/~marcz/ Date: Tue, 22 Feb 2000 10:03:10 -0500 From: Paul Krasa Subject: Re: COZY: Engine baffling At 23:19 2/21/00 -0500, Marc J. Zeitlin wrote: >So I'm working on the engine (O-360-A2A) baffling - I feel like I'm cutting >origami that cuts back. I get a few of the pieces cut and decide to start >bolting them on temporarily to see how things line up. > yep, been there. I made the baffling out of heavy poster board which can be purchased at your local hobby/art supply store. It is much easier to cut thick paper and tape it together than to cut AL. I only had to make one piece of baffling twice. I made the baffling around the cylinders out of red RTV, and BID. >Threads look different... HEY, those are 1/4-20 screws, not 1/4-28 's >(AN4's). What they heck??? Lycoming uses UNC, not AN (UNF) hardware? >Well, let's try the left front top baffle bolt... Dang, that's a 10-24, not >a 10-32 (AN3). I used Stainless Steel 1/4-20 7/16" head bolts to connect the baffling. Use a stainless lock washer and flat washer under each bolt head. The standard screws will corrode in the holes and breakoff. Carbon steel and AL love each other. Stumped again by this airplane stuff. I'd have thought >that aircraft engines would use aircraft hardware, but that's what I get >for making assumptions. And heaven forbid that they use the same size >consistantly. Don't ya just love this education process of building an airplane? ! ;') Paul Long EZ 214LP From: "Brian & Susan DeFord" Subject: COZY: Re: Instruments, Fuel flow. Date: Tue, 4 Apr 2000 18:01:17 -0700 > John Epplin wrote: > > > ....... It has 1/4 in pipe threads for the inlet and outlet. > Marc Z replied: > Doubt it - I'll bet they're 1/8" NPT - 1/4" NPT is huge. Are they really > that large? Yes, they are that large! I just mounted my VM1000 fuel flow transducer yesterday and had to go to the local FBO for a couple of AN816-4-4D fittings (1/4" NPT - 1/4" hose nipple). Marc continues: > While I have not mounted this (or anything else) in this manner, I would > caution against hanging long skinny transducers off of the engine in a > cantilevered fashion. I would be very concerned with vibration causing > failure not only of the electronics in the transducer but also of a > mechanical failure that would lead to a fuel leak. > > I would mount this thing on ADEL clamps to the engine mount and run fuel > hoses to it instead. IIRC, the plans state NOT to mount fuel, oil, or other > transducers directly to the engine. > I'd do as Marc suggests and not mount it to the engine in any way. It may require additional length of hose, but the vibration will surely cause problems eventually. I have a fuel injection unit and have to run #4 hose from the fuel controller to the fuel flow meter, then another #4 hose from the meter to the fuel distribution block. I mounted my meter on the engine mount. Brian DeFord N309BD - http://www.deford.com/cozy From: "Ed Richards" Subject: COZY: Re: Instruments, Fuel flow. Date: Tue, 4 Apr 2000 21:17:47 -0400 In a message from John Epplin Mk4 #467 >>Just received a Flow Scan transducer, to be used with the AV-10................... Has anyone mounted it in this manner? If so, are there any problems with vibration from the engine? Any problems with the overhanging moment of the transducer?<< John, I have a similar transducer with the RMI unit. I mounted it to the firewall then flex hose to the engine pump then the TBI. So far seems to be working OK. My $.02. Ed Richards Cozy Mark IV N826ER Date: Tue, 04 Apr 2000 21:18:19 -0400 From: Nick Ugolini Subject: Re: COZY: Instruments, Fuel flow. I have my transducer, primer solenoid and 4 point injector (primer) distribution block hanging off a tee on the carb and it has worked flawlessly for well for over 1000 hrs. Nick > > > Has anyone mounted it in this manner? If so, are there any problems with > > vibration from the engine? Any problems with the overhanging moment of > the > > transducer? > > While I have not mounted this (or anything else) in this manner, I would > caution against hanging long skinny transducers off of the engine in a > cantilevered fashion. I would be very concerned with vibration causing > failure not only of the electronics in the transducer but also of a > mechanical failure that would lead to a fuel leak. Date: Tue, 11 Apr 2000 23:03:37 -0400 From: "Marc J. Zeitlin" Subject: COZY: Chap. 23 - Primer Line fittings/soldering So I'm working on the primer lines last Saturday, bending and fitting the 1/8" tubing, mounting a manifold on the crankcase, and flaring the tubing for the standard fittings to the manifold, when I get to the primer end. First, I find that I don't have a 3/16" allen wrench to remove the primer hole plugs in the top of the cylinders - no big deal - I'm sure the hardware store has one. So I decide to try to silver solder the strange code union thingy onto the copper tubing (why they can't just use a flared fitting, I don't know). Get out the MAPP gas, use the small nozzle, get out the stuff in my plumbing supply kit that looks like the silver solder that I've got some vague recollection of using 17 years ago when soldering the primer lines for the Q2, and give it a shot. No dice - all I get is soot on the copper, and the solder won't even melt. By this time, a friend has come over to kibbitz, and says I've got to use MORE HEAT. !!!DANGER WILL ROBINSON!!! DANGER!!!! DANGER!!!! The robot's talking to me, but do I listen? Nope - don't see it coming. So, I put the larger nozzle on the MAPP gas can, and proceed to rough up (320 grit) and flux up the fitting and tubing. We smack that little teeny thing with the full force of the flame, and just as the solder stuff starts to melt, I see a big blob of something drip down onto the workbench. Hmmm. Solder barely melted - what was..... DANG, we just melted the brass fitting. That was pretty cool. Head upstairs, look up silver solder and the melting point of brass on the web (lots of info out there.....) and find that we had gotten it up to over 1340 deg. F. Anyway, $3.50 down the drain. Work on something else for a while, and then head over to the hardware store and pick up the last spool of real live silver solder (no clue what that other stuff I had was). Back to the small nozzle, try again with the new stuff, and bingo - nice solder joint that's good up to 700 deg. F. Anyway, the lesson for the day is "don't melt your fittings" :-). -- Marc J. Zeitlin mailto:marc_zeitlin@alum.mit.edu http://www.ultranet.com/~marcz/ From: "Doug Shepherd" Subject: Re: COZY: Chap. 23 - Primer Line fittings/soldering Date: Wed, 12 Apr 2000 07:46:34 -0700 Marc said: > find that we had gotten it up to over 1340 deg. F. If it hadn't melted at that temperature, it must have been brazing rod, my guess would be a silver/nickel alloy. Brazing is the same operation as soldering (forming a joint by fusing a filler material with NO fusing of the base materials), but using a filler with a melting point over 700 degrees rather than a lower melting-point filler like silver solder. A brazed joint is far stronger than a soldered one, but as you've discovered, some materials like aluminum, brass and copper require special techniques and brazing alloys to be successfully brazed. > Anyway, $3.50 down the drain. Too bad all of life's lessons aren't so cheap! Doug Shepherd Date: Sun, 16 Apr 2000 08:10:30 -0500 From: David Domeier Subject: COZY: Pipe time in service.... There have been a number of requests concerning the time in service of the failed #4 exhaust pipe. It was 167 hours. Carl Denk feels very strongly that we should stop using a heat muff system welded to the exhaust pipe. I agree. Anyone using a welded system should inspect it frequently and if possible, replace it. We do not have an AD procedure but we sure can help ourselves by learning from our experiences and not ignoring what we know. dd From: SWrightFLY@aol.com Date: Sun, 16 Apr 2000 10:45:19 EDT Subject: Re: COZY: Pipe time in service.... In a message dated 4/16/00 8:19:10 AM Central Daylight Time, david010@earthlink.net writes: << Carl Denk feels very strongly that we should stop using a heat muff system welded to the exhaust pipe. I agree. Good idea.........so can any of you heat-transfer-experts out there give us a design recommendaton. I would like to make one out of thin stainless and about 4" long for my Stagger EZe. I built one for my Varieze out of 2024-T3 Al. that came apart after about 850 hours and the spring wrapped around the pipe as a heat sink began to come apart. The stainless replacement is still on and as installed after 1800 hours total time now. Steve Wright Stagger EZ N700EZ AirBike...Ultralight (kinda) EAA Technical Advisor Wright Aircraft Works LLC http://www.canard.com/noselift/ Wright Aircraft Works LLC: Electric Nose-Lift for EZEs Sponsor- Canard Aviators www.canard.com canard Aviators page From: "Eric Westland" Subject: Re: COZY: Pipe time in service.... Date: Sun, 16 Apr 2000 08:05:25 -0700 David, I agree completely. Having the same pipe with a welded heat muff, can anyone tell me what my options are? That is, can I cut the welded muff off and still use the pipe or will the fact that it has been welded at all cause weak spots that may later lead to cracks? How is the clamped muff different from the original and can it be used again somehow? I have no problem just ordering a new pipe and muff when safety is the issue, but at the same time I don't want to throw away good parts if I don't need to. Thanks, Eric Westland Mukilteo, WA N325PD ----- Original Message ----- From: David Domeier To: ; Canard mail list Sent: Sunday, April 16, 2000 6:10 AM Subject: COZY: Pipe time in service.... > > There have been a number of requests concerning the time in service > of the failed #4 exhaust pipe. It was 167 hours. > > Carl Denk feels very strongly that we should stop using a heat muff > system welded to the exhaust pipe. I agree. > > Anyone using a welded system should inspect it frequently and if > possible, replace it. We do not have an AD procedure but we sure can > help ourselves by learning from our experiences and not ignoring what we > know. > > dd > > > > From: alwick@juno.com Date: Sun, 16 Apr 2000 15:45:31 -0700 Subject: Re: COZY: exhaust pipe failure On Sun, 16 Apr 2000 08:10:30 -0500 David Domeier writes: > Anyone using a welded system should inspect it frequently and if > possible, replace it. We do not have an AD procedure but we sure can > help ourselves by learning from our experiences and not ignoring what we > know. > Thanks alot Dave for sharing your experience. I just finished building my exhaust sys 2 weeks ago. At the time I went thru a Failure Modes and Effects Analysis. I arrived at the conclusion that the risk of pipe into prop was extremely small. (Keeping in mind that I don't have a stock exhaust design). I have since revisited the problem to make sure I didn't make any bad assumptions. I end up with a lot of questions. Would appreciate peoples thoughts. 1) I assume you have a 4 pipe system? 2) The failed pipe was the upper pipe? 3) The failed section was around 5" long? I suspect all of the above were factors that contributed to the failure. Of course, I'm ignoring the other likely cause related to welded heat muff. The reason I ask this, is if the design was 2 pipe sys, it would dramatically reduce odds of pipe into prop. I also understand that 2 into 1 pipe systems are consistantly more efficient. When weld fails on 2 into 1 sys, their is a huge moment on pipe which would cause it to fall to bottom of cowl instead of moving to rear of aircraft. I assume then that only the upper pipes can cause a prop failure. The lower pipe would always fall to bottom of cowl. May want to place heat muff on lower pipes only, no weld. Would appreciate feedback, particularly if I'm making some bad assumptions. -al wick Canopy Latch System guy. Artificial intelligence in cockpit, powered by Subaru. Now sanding the last components. Aug 2000 first flight scheduled ________________________________________________________________ YOU'RE PAYING TOO MUCH FOR THE INTERNET! Juno now offers FREE Internet Access! Try it today - there's no risk! For your FREE software, visit: http://dl.www.juno.com/get/tagj. From: "allan aaron" Subject: COZY: Engine Gaskets Date: Sun, 16 Apr 2000 23:30:38 +1000 A question for the engine guys .... I've just had the prop governor o/hauled and am replacing the (engine) fuel pump and oil filter mounting assy on my IO320. Should I just install these parts with new gaskets or should I also use some sort of gasket sealer as well. Thanks in advance Allan Aaron From: "Nat Puffer" Subject: Re: COZY: Pipe time in service.... Date: Mon, 17 Apr 2000 07:48:22 -0500 ---------- > From: Eric Westland > To: cozy_builders@canard.com; Canard mail list > Subject: Re: COZY: Pipe time in service.... > Date: Sunday, April 16, 2000 10:05 AM > That is, can I cut the welded muff off and still use the pipe Yes or will the fact that it has been welded at all cause weak spots that may later lead to cracks? No How is the clamped muff different from the original and can it be used again somehow? It is the same. Just clamped, not welded > > > Eric Westland > Mukilteo, WA > N325PD > > From: "Nat Puffer" Subject: COZY: Exhaust failures Date: Mon, 17 Apr 2000 08:26:38 -0500 Builders, We have had 3 known failures of the 4 pipe exhaust system since it was first designed probably 10 years ago. The first was Mike Pinnock. His number 4 pipe broke at the elbow and the pipe fell down into the cowling and the exhaust exited into the cowling. He was flying over the Gulf and the exhaust gasses were traveling along the center section spar. This intense heat cause the hardpoints for the wing to soften and change the wing incidence after he landed and parked. The reason for the failure was believed to be that he didn't have #4 fastened to #2 with the shroud shown in the plans. The second failure was Carl Denks after about 500 or so hours. The pipe cracked but did not separate. Carl was the one who identified the problem. The pipe gets much hotter than the muff welded to it. The differential expansion eventually causes something to break--usually the pipe. Following Carl's experience, we redesigned the #4 pipe so that the same identical heat muff was clamped in place, rather than welded. We made this a mandatory change. I changed my #4 pipe immediately, even though it had over 300 hours on it with no evidence of potential failure. The 3rd failure was David's, where the #4 pipe separated and went through the prop. Some of the e-mails on this subject bring up an additional potential problem, and that is some builders have the mistaken idea that there should be a lot of clearance around the pipes where they exit the baffle. This is WRONG! It was intended that there be no clearance around the pipes where they exit. It is a fallacy that there should be a lot of clearance and then have some sort of flexible material to seal, or no seal at all. The pipes are supposed to be supported at the rear baffle by the baffle. The plans (M-33) say to reinforce the baffle with .032 aluminum to provide the support. I found that .032 aluminum wears too fast so I used .125 in. aluminum (1/8") plates around the pipes, bolted to the baffle, to provide this support. The baffle is attached to the engine, and so are the pipes, so you don't need to provide for any relative movement. I have replaced these 1/8 inch plates after 300 to 400 hours when they have worn so they are no longer tight. If you reinforce the baffle and the pipes are held tightly in this way, it is unlikely that the pipe could go through even if it breaks. The second intent of the design was to wrap a shroud around pipes #2 and #4 to complete the heat muff and to provide additional support for the long #4 pipe. Removing the welded muff and clamping it in place should greatly reduce the stress on #4 pipe and prevent it from breaking. Having no space around the pipes where they pass through the rear baffle should practically eliminate any chance that the pipe going through the prop, should it ever break. I will be investigating possibly fastening something to each pipe to make sure it couldn't go through the baffle. Will say more in the next newsletter. You should remember that exhaust pipes are subject to more abuse than any other part of the airplane. They are repeatedly heated to cherry red (1500 deg F) and cooled down again. They will not last forever. They must be checked repeatedly and replaced at any evidence of cracking. We deeply regret David's accident, but very grateful he was able to put his Cozy down on the runway with no injury to himself or further injury to the airplane. Best regards, Nat From: "Nat Puffer" Subject: COZY: Re: Exhaust failures Date: Mon, 17 Apr 2000 12:54:33 -0500 ---------- David Domeier says:> > > Just read your post on this subject. > > Would you consider changing "We made this a mandatory change." to > read "We are making it a mandatory change". > > Newsletter #61, where you reported the problem, does not include the > term "mandatory change" but says "Exhaust Systems - Important". > Builders, I stand corrected. Changing #4 pipe from welded to clamped heat muff will become a MANDATORY change. Best regards, Nat> From: "Ron Larock" Subject: COZY: pipes Date: Mon, 17 Apr 2000 16:31:54 -0400 The two that must be selected are the two that are completely anti-phase, not the two on the same side of the engine When I used to be in drag racing, we used headers off the engine. We would run the engine and find the spot where the pipes turned blue. That is where we cut the pipe and the pipe was tuned to the cylinder. Most headers had weird curves to them to make the pipes the same length at the tuned point. If you connect the pipes across the engine, I would say the pipes would be different lengths and not tuned. Based on my old race experience, I would say that 4 pipes tuned properly would be the easiest and best way to accomplish the best power. Ron Date: Tue, 18 Apr 2000 09:06:57 -0400 From: "Johnson, Phillip" Subject: RE: COZY: pipes >Ron Larock writes> Based on my old race experience, I would say that 4 pipes >tuned properly would be the easiest and best way to accomplish the best >power.< > >You are absolutely correct but with an engine revving at 2700 rpm the pipe >would be about 10 to 15 ft in length to get the fundamental resonance. >Coupling the other three pipes brings the resonant length down by a factor of >four. (In this configuration the resonance is less strong.) This is still too >long for a tuned Lycoming pipe system but, because of the bandwidth of the >tuning, (multi-pipe systems have a wider bandwidth), some of the benefits are >still attainable. > >To summarize: > >1) Four pipes into a single pipe: Most power, difficult to install, and >heavy at the wrong end of the engine, >2) Four pipes into two pipes with crossover pipe, easier to install but heavy >as above, >3) Two pipes into two pipes on same side of engine, worst case condition but >lightest configuration. >4) Two pipes into two pipes crossed over, good performance but not as good as >1) & 2) above and heavy, and; >5) Four single pipes, looses performance compared with 1), 2) &4) above but >better than 3). This probably provides the best weight/performance >compromise. > >Remember 100 rpm increase is an increase in power of a little over 10%. > >Phillip Johnson >Cozy MKIV RG #0030 (getting close to finishing) >Subaru EG33 Powered > From: "Reid Siebert" Subject: COZY: Power pipes Date: Wed, 19 Apr 2000 07:25:23 -0500 Check out this website for tuned exhaust systems: www.powerflowsystems.com Drop them an email, letting them know of your interest in a system for a Cozy, and maybe if enough of us do this, it will catch their attention. Reid Siebert From: alwick@juno.com Date: Wed, 19 Apr 2000 10:00:50 -0700 Subject: Re: COZY: exhaust pipe failure On Mon, 17 Apr 2000 14:13:00 -0400 DL Davis writes: > > My hangar mate had a similar #4pipe fracture that separated from the > cylinder head completely. Did a little calculating. 1.5" x .065 exhaust pipe weighs .996 lbs per foot. Guess we could round to 1 # per foot. Apples to apples pipe length comparison: 4 pipe into two, with balancer tube would use 80" of tubing. (Stock auto method...pipes joined at header, then cross near oil pan at rear). 4 individual exhaust pipes would use 98" of tubing. So 4 individual exhaust pipes require you to lug around an extra lb of metal. It wastes energy (less efficient). It includes the failure mode of pipe falling into prop. If we all focused on optimizing our exhaust systems and minimizing risk, we'd go the route of 4 pipes into 1. Instead of extending the exhaust outlet past the cowl, we'd exhaust inside cowl near prop spinner so that we get the benefit of accelerating the cooling air. This also would entirely eliminate the pipe into prop failure mode. This method would use only 40" of tubing, total weight savings around 4 to 5 lbs. Wow. I didn't have a clue about this till we started hashing this subject. No wonder Nigel Fields used this method on his VE. Downside: it's different...change = unknown risk. You lose the esthetics of 4 pipe outlet. -al wick Canopy Latch System guy. Artificial intelligence in cockpit, Cozy IV powered by Subaru. Now sanding/painting last parts. Aug 2000 first flight scheduled ________________________________________________________________ YOU'RE PAYING TOO MUCH FOR THE INTERNET! Juno now offers FREE Internet Access! Try it today - there's no risk! For your FREE software, visit: http://dl.www.juno.com/get/tagj. From: alwick@juno.com Date: Thu, 20 Apr 2000 11:38:20 -0700 Subject: Re: COZY: exhaust pipe failure On Thu, 20 Apr 2000 12:09:19 -0500 David Domeier writes: > re "3) The failed section was around 5" long?" > > I've had a chance to measure the failed section that went through > the prop....it was 17". > > dd > >From my business experience, I know that many people have tough time entertaining the "multiple cause" scenario. But let me throw this out there anyway. Another way to view the failure is to look at the situation AFTER the pipe broke. If you think about it, a broken pipe that is held rigid in all axis except the horizontal.......has to move into prop. The broken end can't move up, down. It can't move forward because the other half of the pipe is still there. It's pretty tough to stay in place due to the multiple vibration frequencies, exhaust force. So we eliminate the weld because we strongly suspect it caused the failure. But if we change the failure MODE, to eliminate movement into prop.....we end up with the realization that we no longer care if the pipe breaks anywhere in the system. You then have a robust design. This is the logic that a lot of the automotive engineers use now. You assume that the component will fail, and then you make sure you have a desirable failure mode. Years ago, when your auto brake pads finally gave out, you noticed it when your vehicle refused to stop. Now they design the pads to squeel like hell when you still have 15% material left. There's lot's of simple ways to alter the failure mode. FWIW -al wick Canopy Latch System guy. Artificial intelligence in cockpit, Cozy IV powered by Subaru. Now sanding/painting last parts. Aug 2000 first flight scheduled ________________________________________________________________ YOU'RE PAYING TOO MUCH FOR THE INTERNET! Juno now offers FREE Internet Access! Try it today - there's no risk! For your FREE software, visit: http://dl.www.juno.com/get/tagj. From: "Wilhelmson, Jack" Subject: RE: COZY: Power pipes Date: Fri, 21 Apr 2000 09:25:38 -0400 Cozy builders flyers: My exhaust system is a original two into one system with slip joints and stainless springs made by sport flight 14 years ago. When it was discovered that a four pipe system increased performance I cut my large pipe length wise and welded in a flat separater plate to isolate the exhaust pressure pulses. My rpm at cruise increased 100 RPM. This system has been working fine for 500 hrs and has welded on heat muffs. It has the advantage of a round pipe throught the baffles and cowling. It has the added advantage of mutiple point support. My experience as a engineer tells me that the failures with the 4 pipe system is cause by resonate vibration in a pipe that is supported rigidly at one end. If this is the cause, not welding the heat muff on will change the resonate frequency and may fix the problem. However; it would apperar that a mutiple point support system that also eliminates the chance that a broken pipe could exit the airplane is needed. Jack Wilhelmson N711cz From: "Nat Puffer" Subject: COZY: Exhaust failure Date: Fri, 21 Apr 2000 15:18:46 -0500 Dear builders, I just received pictures from David Domeier showing where his #4 pipe failed. The pipe cracked on both sides horizontally along the aft welds of the heat muff. It then cracked vertically above the forward end of the welds and then vertically below the aft end of the welds. Clearly, the welds were involved and probably the cause of failure. We had the supplier stop welding the muff on some time ago, and clamp it instead. We will make it MANDATORY that anyone with a welded heat muff GROUND their airplane until they replace pipe #4 with a clamped heat muff. In addition, we suggest that you make the shroud around the two pipes at the heat muff tight, so the pipes cannot move relative to each other and they support each other, and make the holes through the aft engine baffle tight so the pipes cannot move relative to the engine. You will need to reinforce the baffle with an 1/8" plate to reduce wear of the baffle by the pipes. You should first cut two 1.75" holes in an 1/8" aluminum plate with a hole saw (be sure you clamp it to the table when cutting). Then bolt this plate to the baffle either as one piece, or you can cut it in half and bolt each half to the baffle. As an added precaution, it is suggested that you clamp the two pipes together just forward of the aft engine baffle, so that if either or both of the pipes break, they can't go through the 1.75" holes in the baffle. Inspecting your exhaust pipes should be done every time you remove the cowlings, which should be more often than your annual inspections. David said that when one blade (out of 3) broke off near the hub, the shaking was intense, and he shut down the engine automatically immediately. We are fortunate that Dave is an excellent pilot and was able to dead-stick his Cozy onto a runway without injury to himself or damage to his airplane, and thank him for alerting everyone else so they can avoid having a similar emergency. Best regards, Nat Date: Wed, 26 Apr 2000 21:36:49 -0500 From: David Domeier Subject: COZY: Broken exhaust pipe wrap up... I returned to Auburn, Alabama, on Monday of this week hoping to retrieve my Cozy which had been sitting there since April 12 after the #4 exhaust pipe went through the prop. The first thing on the list was to check the engine flange for run out. I borrowed a micro dial gauge from a friend and checked it twice - max run out I could detect was .001. The new limit for this engine is .002 and the service limit is .005. The flange is not bent. The next thing checked was the engine mount and firewall hard points- no cracks anywhere. Then a die penetration check of the prop extension - no cracks on it. On the engine itself I found 2 of the 4 primer lines broken at the #2 and #4 cylinder intake ports. I capped the lines, removed the nozzles and installed plugs. Also found about 5 rivets in the baffle system broken and replaced them. Everything else in the engine compartment appeared secure. Up front the canard was checked. It looks normal. Attach fittings are without visible cracks. That 10 or 15 seconds of flutter really got my attention. A metal surface probably would have disintegrated. There was about a gallon of water in the nose down section. Removed it. Next I installed the new exhaust stacks at #2 and #4. I also closed the exit through the baffle system from 2 inches to 1.75. Also installed a steel hose clamp just forward of the baffle on each pipe. The pipes now are very tight and will not leave the airplane ever again. All this work took about 10 hours on Monday evening and Tuesday. Finally at about 4 pm Tuesday it was time to flight test the beast. The wind was rather gusty but I wanted to get this over with so I cranked it up and did it. The engine came to life immediately and all system were working. I flew for 30 minutes, became weary of the turbulence and called it quits. Before returning to my motel and a couple beers, I pulled the cowling and checked things one more time. All looked well. This morning at 8:30 I took off bound for St. Louis. It wasn't the most relaxing flight I've ever made but the trusty Lycoming purred like a kitten for 3:20 minutes and got me home. The take off out off Auburn was a little tense as there was a line of trees off the runway and just beyond that a shopping center which I turned away from. But once at10,500, the flight was within gliding distance of a hard surface runway most of the trip and I kept track of where these airports were constantly. (probably would be a good idea to do that all the time....) Because I will not be able to fly this airplane again without wondering about the accessory section, I've already started to jerk the engine so as to comply with AD91-14-22. The purpose of this AD is "To prevent loosening or failure of the crankshaft gear retaining bolt, which may cause sudden engine failure". While this AD is not mandatory on experimental airplanes, it would seem prudent to comply with it. Lycoming also has a "mandatory service bulletin" advising an engine tear down, which the FAA has not yet deemed appropriate as an AD. Like 5 or 6 guys who responded saying the engine probably is OK, I agree. But I will feel better after going through the hassle of checking that little bolt. I will hire a qualified mechanic for the inspection, installation and security of the bolt, the dowel, and its gear. This event was preventable. If the baffle exit holes had been at 1.75 instead of 2 inches, the broken pipe probably would have jammed there. Also, if my inspection procedure had included removing the aluminum heat shield at each oil change, certainly the cracks would have been apparent before the pipe broke. That pipe went from no cracks to compete failure in a little over 100 hours. With regard to a theory that the pipe exit hole through the baffle has some affect on cooling, I submit this for contemplation. Some time just before the pipe broke and interrupted my serene flight, I wrote down some CHT numbers at 10,500. (I was somewhat bored) The average CHT with the 2 inch holes and the 1.75 inch pipe was 352°. Today, with the same power setting at the same altitude, the average CHT was 315°. (1.75 hole with a 1.75 pipe in it.) The only difference today was a OAT at 8°C cooler. That would account for some of the difference, but not all of it. The hole in the baffle larger than the pipe probably does not make for cooler running. Hope to be flying again in several weeks.... dd From: cdenk@ix.netcom.com Date: Thu, 27 Apr 2000 17:04:36 -0400 (EDT) Subject: Re: COZY: Broken exhaust pipe wrap up... That Lycoming service bulliten talks about connecting rod bolts, they are accessible without splitting the case, just pull the cylinders if you want. From: "Eric Westland" Subject: COZY: Fw: Cozy Exhaust Date: Thu, 27 Apr 2000 14:36:20 -0700 I received this today from the Custom Aircraft Parts folks (I inquired as to what my options may be) and thought others may want to know. -ew ********************************************* Dear Eric, We have some options for you, #1 purchase a complete new #4 pipe with the clamp on style heat muff for $205.00, or #2 send in your #4 pipe and we will inspect it and if it is ok we will remove the welded on heat shroud and install the clamp on version cost is $150.00, or #3 inspect the pipe yourself for cracks and if none are present carefully remove the heat shroud and install the new clamp on version at a cost of $75.00 This should be accomplished before further flight Sincerely Clinton Anderson From: cdenk@ix.netcom.com Date: Thu, 27 Apr 2000 22:36:33 -0400 (EDT) Subject: Re: COZY: Fw: Cozy Exhaust I would NOT go for the option of removing the heat shroud if welded on for 4 reasons: 1: The weld causes a stress riser in itself. 2: There may be the start of a crack, like crystalization, but still invisible to all but expensive laboratory equipment. 3: Most people, and I'm assuming that you are fairly artful with the hands, could not do an acceptable job of removing the existing muff, and therefore this is not an option. 4: For a $55 savings, its certainly isn't worth the risk. On a tractor prop installation I might have a different view. And Dave's experience has shown that in addition to the risk, it is expensive, considering the new prop, rental car, time off work, etc. On 04/27/00 14:36:20 you wrote: > >I received this today from the Custom Aircraft Parts folks (I inquired as to >what my options may be) and thought others may want to know. > >-ew > >********************************************* > > >Dear Eric, > >We have some options for you, #1 purchase a complete new #4 pipe with the >clamp on style heat muff for $205.00, or #2 send in your #4 pipe and we >will inspect it and if it is ok we will remove the welded on heat shroud and >install the clamp on version cost is $150.00, or #3 inspect the pipe >yourself for cracks and if none are present carefully remove the heat shroud >and install the new clamp on version at a cost of $75.00 > >This should be accomplished before further flight > >Sincerely >Clinton Anderson > > > > From: alwick@juno.com Date: Fri, 28 Apr 2000 12:27:06 -0700 Subject: Re: COZY: Fw: Cozy Exhaust On Fri, 28 Apr 2000 07:06:18 -0700 "Eric Westland" writes: > Thanks Carl. I'll probably spend the money, but I still have a basic > question that I hope someone in the group can clear up for me. That is, if > one was to remove the heat muff carefully, why would those "stress risers" > from the welds be any worse than the ones created farther down the pipe > where 1" long pieces of 1/8" welding rod are tacked on? > When we see a broken component, we tend to focus on that as the cause. The weld zone on any product is always a weaker area. But not necessarily the primary cause. I think there was a lot of substance to Jacks post on the subject. Anytime you have a rigidly mounted tube attached to an engine, with no supports near the rear of the tube, it will oscillate and flex. If you double the wall thickness and add additional weight due to muff, you force a stress concentration at that point. On top of that, you have reduced the fatigue resistance due to welding the same location. If you add a support to the tube, you are reducing the total flex seen at the joint and all other locations. This lack of support explains failures at other locations of exhaust (see Jack's post). I've seen finite element studies of tubing. We tend to think of it as a straight piece of pipe, but it actually takes the shape of an ocsillating sine wave during flight. Adding supports to the tube reduces the loads and controls the frequency response. I suspect..... No exhaust with supports past the muff will fail. ...................... occasionally an exhaust w/o supports will fail. .......................more frequently exhaust with welded muffs will fail. Keep in mind, you will never find any auto with exhaust just left hanging off of vehicle. -al wick Canopy Latch System guy. Artificial intelligence in cockpit, Cozy IV powered by Subaru. Now sanding/painting last parts. Aug 2000 first flight scheduled ________________________________________________________________ YOU'RE PAYING TOO MUCH FOR THE INTERNET! Juno now offers FREE Internet Access! Try it today - there's no risk! For your FREE software, visit: http://dl.www.juno.com/get/tagj. From: "Nat Puffer" Subject: COZY: Tuned pipes Date: Fri, 28 Apr 2000 16:01:21 -0500 Dear Builders, This is a pretty erudite (how do you like that word?) group, so I hope you can help me. Because of all the attention on exhaust systems lately, and Eric Westland's question on mixture leaning, I have become reinterested in the design of our exhaust system, and how it might affect engine operation. I am interested in how the length of an exhaust pipe determines the efficiency of a cylinder, and how our design stacks up. I can remember reading in Sport Aviation or Kitplanes magazine, several years ago, how to calculate the optimum pipe length, based on engine rpm. Do any of you remember where or when this article was published, or know of other references I might study? I have been talking to Lycoming, and apparently they leave exhaust pipe design up to the airframe manufacturer, even though it obviously can affect engine performance. Regards, Nat Puffer From: ezaviator@earthlink.net Date: Fri, 28 Apr 2000 22:53:48 -0400 Subject: Re: COZY: Tuned pipes The study of high performance exhaust systems is a discipline in and of itself. I did a considerable amount of sutdy while racing enduro go-karts. A difference in this endeavor is the fact that we were using two cycle engines as opposed to our 4-cycle aircraft powerplants. On a 2-cycle engine, proper exhaust scavenging = power. Try squeezing 25 horse power out of 100cc 2-cycle engine! It is not uncommon for these engines to turn 18,000 RPM and propel my kart to 115 MPH. The same theory is applicable to our engines. We can't take into account just the exhaust pipe length. This is just component of a larger equation. The entire exhaust system takes into account combustion chamber volume, piston speed, intake and exhaust valve overlap, cylinder bore, stroke, whether or not a silencer is used, exhaust valve diameter, gas speed, volumetric efficiency, pipe diameter, desired peek performance engine RPM... A thorough study even includes the propogration of sound wave, wave length, and velocity. There are several quality books written on this subject. Practical Gas Flow by John Dalton The Design and Tuning of Competition Engines by Philip H. Smith Scientific Design of Exhaust & Intake Systems (3rd edition) by Philip H. Smith and John C. Morrison For anyone who wishes to know more than they ever wanted to about induction and exhuast systems, I can highly recommend these readings. Dave At 04:01 PM 4/28/00 -0500, Nat Puffer wrote: >Dear Builders, >This is a pretty erudite (how do you like that word?) group, so I hope you >can help me. Because of all the attention on exhaust systems lately, and >Eric Westland's question on mixture leaning, I have become reinterested in >the design of our exhaust system, and how it might affect engine operation. > I am interested in how the length of an exhaust pipe determines the >efficiency of a cylinder, and how our design stacks up. I can remember >reading in Sport Aviation or Kitplanes magazine, several years ago, how to >calculate the optimum pipe length, based on engine rpm. Do any of you >remember where or when this article was published, or know of other >references I might study? >I have been talking to Lycoming, and apparently they leave exhaust pipe >design up to the airframe manufacturer, even though it obviously can affect >engine performance. >Regards, >Nat Puffer > > Dave "Things should be made as simple as possible, but not any simpler." Albert Einstein Date: Fri, 28 Apr 2000 22:50:17 -0500 From: David Domeier Subject: Re: COZY: Tuned pipes Nat, I wonder if Clinton Anderson has improved the pipes he is making for the Cozy by increasing the length. The #2 and #4 units I just received are about 2.4 inches longer than the old ones. I guess I best call Custom Aircraft next week to see if it is OK to cut them the same size as they were. At present they are noticably longer than #1 and #3, and 2.4 inches closer to the prop. dd From: cdenk@ix.netcom.com Date: Sat, 29 Apr 2000 08:50:53 -0400 (EDT) Subject: Re: COZY: Tuned pipes I just cut mine to a comfortable clearance to the prop, and this dimension depends on your extension length to start with. My thought was they were made to more than long enough. Everyone seems to be talking about pipe length for tuning the pipe length. Haven't heard the other issue, when talking total performance, the drag caused/minimized by pipe placement. From: alwick@juno.com Date: Sat, 29 Apr 2000 11:01:18 -0700 Subject: Re: COZY: Tuned pipes On Fri, 28 Apr 2000 16:01:21 -0500 "Nat Puffer" writes: > I am interested in how the length of an exhaust pipe determines the > efficiency of a cylinder, and how our design stacks up. Excellent idea Nat. Rather than getting too hung up on the theoretical, I'd suggest making cheap proto exhausts and testing the concepts. For example, if the best length is 26", make up sys at 20" and then just slip on a 6" and 10" extension. Safety wire. You can then test all 3 lengths. Design considerations I can think of: Can't fall into prop. Total weight. Noise level (personal hangup, I made muffler for mine. Soooo quiet.) Efficiency. tube diam. burned prop induced airflow vacuum source (save 10 lbs or so) If you guys come up with new design, I have all the tools to convert your cartesian coordinates into format suitable for any tubing company. They could build your sys with no development time at all. Save you guys some $ -al wick Canopy Latch System guy. Artificial intelligence in cockpit, Cozy IV powered by Subaru. Now sanding/painting last parts. Aug 2000 first flight scheduled ________________________________________________________________ YOU'RE PAYING TOO MUCH FOR THE INTERNET! Juno now offers FREE Internet Access! Try it today - there's no risk! For your FREE software, visit: http://dl.www.juno.com/get/tagj. Date: Sat, 29 Apr 2000 19:40:14 -0500 From: Ken Brimmer Subject: Re: COZY: Tuned pipes Carl, If I remember right it was Klaus S. who came up with the 3" gap between the prop and the end of the exhaust. At 08:50 AM 4/29/00 -0400, you wrote: >I just cut mine to a comfortable clearance to the prop, and this dimension depends on your extension length to start with. My >thought was they were made to more than long enough. Everyone seems to be talking about pipe length for tuning the pipe >length. Haven't heard the other issue, when talking total performance, the drag caused/minimized by pipe placement. > > Ken Brimmer Cozy III (ESN) Maryland "There is a time in the life of every problem when it is big enough to see, yet small enough to solve" -MIKE LEAVITT Date: Sat, 29 Apr 2000 20:30:12 -0500 From: Michael Link Subject: Re: COZY: Tuned pipes cdenk@ix.netcom.com wrote: > I just cut mine to a comfortable clearance to the prop, and this dimension depends on your extension length to start with. My > thought was they were made to more than long enough. Everyone seems to be talking about pipe length for tuning the pipe > length. Haven't heard the other issue, when talking total performance, the drag caused/minimized by pipe placement. I originally left mine the length as shipped to me. I have an O-360 with a 6" extension. I noticed some damage to the surface finish of the prop. I have since cut the pipes almost flush with the cowling and have experienced no further problems. Regards, Michael Link Date: Wed, 3 May 2000 00:00:42 +0000 From: James Russell Subject: COZY: 4 Pipe Exhaust Pipe problems Hi all: This thread has certainly been interesting to me because ( in racing ) we used to talk about exhausts alot... To avoid failure at the flange, we would TIG weld the pipe to the flange on the inside of the pipe, then braze around the outside of the pipe, making a collar to "spread the load" and support the pipe well. A sheet metal saddle ( w/ a spring stretched over the secondary pipe ) supported the free end of the tailpipe. The collector was a slip-fit to the 4 primary pipes to allow for growth... We used much thinner tubing so that once cracks started showing up, welding them just created more stress-risers for more cracks, etc. When the metal got fatigued, we just changed the part. I worked for a very smart engineer who was designing and building drone prototypes for McDonald-Douglas. He wanted to build the exhaust from short sections of tubing welded together. I built the first one (not for flight) after convincing him it would fail pretty fast ( the engine was a 2-stroke @ 7000 RPM! ). He wanted to cantilever the muffler off the end of the exhaust pipe also... Racing really was a great materials education because we inspected so much so we could catch stuff before it failed... >For fatigue to take place, there must be stress reversal (alternating tension and >compression), and the below some low value of stresses (pounds per square inch) >there will not be failure. At higher values, the higher value, the less cycles of >stress reversal will be tolerated before failure. This is certainly true for ferrous metal, but non-ferrous metals ( like aluminum) don't have such well defined fatigue limits. If you ever want to get a bit of practical education in materials, get the great book Engineer to Win by Carroll Smith ( ISBN 0-87938-186-8 ). It has in the first 9 chapters a super introduction to applied metallurgy. >at the aft end of the elbow. There vibration of the edge (smooth >burrs removed) of >the stainless sheet was weating a groove or 1" >long notch in the pipe. It didn't look >that deep, until I took a >dremel with a You can use the "header wrap" insulating fabric tape to shim between sheet metal parts and tubing to avoid this wear. We used it on the exhaust support saddle for this. The stainless braid on AeroQuip hose makes a great unintentional low-speed file! I certainly enjoy this mail list because I usually learn something from someone every night. And I like Cozys, too. Regards, James From: "Ed Richards" Subject: COZY: Fuel Pressure Date: Sun, 7 May 2000 16:57:02 -0400 Greetings All, With only a few hours left before I reach the 40 hour mark I discovered an interesting phenomenon today. At higher altitudes, say above 6,000 ft., the fuel pressure drops to near zero. The engine continues to run OK, although I'm not sure for how long since I haven't left the pressure at zero for more than a few seconds. Switching on the boost pump brings the pressure immediately back the normal 4 to 5 psi however if you switch off the electric boost the pressure will again slowly drop to nothing. Once I descend below about 6000 ft. the fuel pressure, with just the engine driven pump, comes back to normal. I have checked the fuel filters several times during the testing process and have found them to be absolutely clean each time. I also tried switching tanks to see if this would have any effect; and it did not. The airplane has the standard Lycoming O-360 with the Ellison TBI and the engine driven pump is vented with a 1/4" tube through the bottom cowling flange. I should also mention that the OAT at 8,500 ft. here in FL this morning indicated 5 deg C (41 deg F) so I don't think anything was freezing. Any thoughts would be most appreciated. Ed Richards Cozy IV N826ER From: cdenk@ix.netcom.com Date: Mon, 8 May 2000 05:33:17 -0400 (EDT) Subject: Re: COZY: Fuel Pressure Was written Subject: COZY: Trace of Alloy Steel Cozy pipe through the prop..... After 12 days of down time to remove and reinstall the engine in order to check the crankshaft gear retaining bolt, I flew 10CZ for about 30 minutes yesterday. All went well. Every engine indication was normal. Today I received a written report from Aviation Laboratories on the oil sample and filter I sent in after the flight from Alabama. Total time on the oil and filter was 10 hours with 4 hours since the pipe dinged the prop. The oil analysis is normal and consistent with 2 previous samples. The filter analysis revealed a trace of alloy steel, closest match being AMS#6270. Their definition of trace is 0-10 % of total filter content and represented10 to 15 flakes. AMS#6270 is cam material. I pulled the suction screen in the oil sump after the phone call on this subject last Wednesday. It had not been pulled since overhaul (new cam installed at that time - just over 100 hours ago). It was almost clean. I rinsed it in av gas in a glass pie plate and ran a magnet through the fluid. It pulled in a minute amount of metal and carbon. Maybe 8 or 10 very small particles almost invisible. I've decided to run the engine hard for 15-20 hours to see what follows. There seems to be a prevailing view that if the cam is failing, the metal will increase dramatically. It's a no brainer what to do about that. The question I pose to the collective wit and intelligence of this forum is this - what if the metal show is a trace again? How much metal if any, is normal in the filter? Have any of you been cutting your filter and what are you finding? Thanks. dd From: "Todd Carrico" Subject: COZY: Re: Trace of Alloy Steel Date: Mon, 8 May 2000 18:54:52 -0700 > > The filter analysis revealed a trace of alloy steel, closest match > being AMS#6270. > > > The question I pose to the collective wit and intelligence of this > forum is this - what if the metal show is a trace again? How much metal > if any, is normal in the filter? Have any of you been cutting your > filter and what are you finding? > > Thanks. Something to keep in mind is that this cam is gear driven. Some of this material could be coming from the gear end of the cam as well. Never heard of a cam going bad that way, but the thought occurred that with a prop strike, and the nature of geared things... I have had a couple of cams go bad (automotive), and they go bad real rest. Shouldn't take long if its the cam. Superior tried to make lifters a couple of times. Seems their is some real magic in making lifters. To hard, or too soft and bad things happen. The tests did not last long at all. tc From: cdenk@ix.netcom.com Date: Mon, 8 May 2000 22:02:54 -0400 (EDT) Subject: Re: COZY: Trace of Alloy Steel First: Lycoming Service instruction #1492B which if I am reading correctly says, every 50 hours, to inspect the filters, screens for foreign debris and that a specrographic analysis (is encouraged) does not take the place of screen and filter inspection, compression check, and boroscope examination. I respect "Engine Oil Analysis" quite highly, and Howard is probably more knowledgeable than anybody. He should be able to say where possible and likely sources are. It's common when an engine is opened up for work for dirt (small quantities of dust will do) that then upset the oil analysis. Usually silicon (from sand and earth dirt) is the culprit. If it is the cam going, then I wouldn't think thats the fault of the prop failure. I think access to the gears could be through the magneto holes, where one could look for worn teeth. It might not be the cam gear, or gears in immediate contact with the cam gear, but one of the other numerous sliding surfaces in the accessory case, including the fuel pump cam. If it is a cam lobe going, it won't take long, doesn't generally (next to never)cause sudden stoppage, and should be able to limp home. Should be able to measure the cam lift with a dial indicator just by removing rocker covers. Then pulling a cylinder (I have pulled and replaced in a long evening) will give access to visually inspect if necessary, but if worn, you are looking a a major overhaul since the case must be split, and usually that means new bearings, rings, gaskets, etc. and inspection of cases, crank, etc. Also there is an A.D. at 500 hours (or around there) to inspect the Bendix Magneto impulse coupling. If you have certified equipment on board the F.A.A. will expect the A.D.'s to be complied with. From: ReitzCozy@aol.com Date: Tue, 9 May 2000 00:30:56 EDT Subject: Re: COZY: Trace of Alloy Steel In a message dated 5/8/00 5:38:23 PM, david010@earthlink.net writes: << How much metal if any, is normal in the filter? Have any of you been cutting your filter and what are you finding? >> David, I have a screen instead of an oil filter on my O-320 with 750 hours. When changing oil every 25 hours I clean the screen in solvent and pour the fluid through a white coffee filter. I usually have a few, very small, bright metal particles that are visible in the sunlight. Also find a few black carbon pieces. Local A&P says it is not a concern and Howard Fenton's oil analysis says all is normal. Best Regards, Richard Reitz Cozy N23CZ From: "Eric Westland" Subject: Re: COZY: Trace of Alloy Steel Date: Tue, 9 May 2000 06:52:13 -0700 Here's an article from the TBO Advisor on how much metal is too much. Mainly geared for determining overhaul time, but good info. http://www.tboadvisor.com/Samp.htm Eric Westland From: "Ed Richards" Subject: COZY: Re:Fuel Pressure Date: Mon, 8 May 2000 22:11:19 -0400 Thanks for all the great input gentlemen. I ordered a new engine driven pump from Spruce today and plan to install it next weekend. I'm not brave enough to keep flying with a suspect pump on the engine, but I will try to inspect things carefully as I replace the pump. I will be sure to report back on whatever I find. BTW just for sake of completeness, the fuel pressure sensor was supplied with the RMI engine monitor. And, with the exception of the carb temp sensor (which doesn't work with the Ellison) the unit seems to work quite well. Ed Richards Cozy IV N826ER From: "Ed Richards" Subject: COZY: Re: Fuel Pressure Date: Tue, 9 May 2000 22:04:07 -0400 Marc Zeitlin wrote: > What I'm getting at here is that if the engine kept running, then maybe the > problem is in the sensor/gauge, and not in the pump....... Obviously if > the engine stopped, then the pressure really _was_ zero, and you need a new > pump :-). > > Can you elaborate on the symptoms? Thanks. > > -- > Marc J. Zeitlin No problem to elaborate Marc. The answer is no the engine did not quit, in fact power seemed normal for that altitude. However I was watching the fuel pressure and when I saw it hit "zero" I turned on the boost pump. I guess if I was really brave I would have waited to see if I got a "flame out" figuring that once the boost pump was turned on the engine would restart. I wasn't that sure. The other thing to consider is there may be enough fuel pressure from the vent ram air to push fuel into the Ellison; the sensor only reads in 1 psi increments. I believe the sensor is OK however, I will recalibrate it when I change the pump. At this point I feel the pump is suspect and would rather be safe and change it then take the chance. I'll let you know what I find next week. Ed Richards From: "Ed Richards" Subject: COZY: Fuel Pressure Update Date: Mon, 15 May 2000 22:22:50 -0400 Greetings All, As promised here is the update on saga of the vanishing fuel pressure. I replaced the engine driven fuel pump this past weekend with the help of fellow Cozy builder Jerry Schneider. Guess what.....the indicated fuel pressure is worse. Now the fuel pressure vanishes at any altitude.....are beginning to suspect the sensor yet? Well you should. Checked the sensor Sunday afternoon and sure enough it's flaky at the very low end (0 to 3 psi) after that (higher pressures) it seems to work OK. I called Rocky Mountain Instruments today and spoke with Ron about the problem. He asked if before replacing the sensor I would try exercising the unit through its full range 20 or 30 times and see if this would stabilize the reading at the low end of the range. He says the sensor is a diaphragm with a wire wound resistor and wiper (potentiometer) to vary the resistance with pressure. The full range cycles are an attempt to "work" and set everything. I'll give it a try and see what happens. The problem was easy to diagnose with an ohm meter and pressure gauge once I allowed myself to think that the sensor might be bad. I sure feel stupid replacing a perfectly good pump. So now I have a spare fuel pump. I'll let you know how the pressure cycles work. Ed Richards Cozy IV N826ER From: Militch@aol.com Date: Tue, 16 May 2000 09:32:40 EDT Subject: Re: COZY: Fuel Pressure Update I am surprised that the sensor design you described is used for this application. Admittedly, fuel pressure probably tends to be very stable, so the sensor won't see a lot of motion if it is highly damped, but potentiometers are prone to wear if used like this. i.e. to measure a parameter that tends to sit around a very small range of values. BMWs use a pot to provide position feedback for the air bypass valve in the fuel injection idle circuit. As soon as the car starts hunting around at idle, and stalling for no apparent reason, it's time to replace the valve. I'll be quite surprised if the fix you have been asked to try actually works. Regards, Peter Militch Cozy Mk IV #740 - Landing gear. From: "Paul Stowitts" Subject: COZY: Ordering spinner Date: Wed, 24 May 2000 09:08:23 -0700 I wanted to pass along another tidbit of information regarding spinners. I ordered the AC-1 spinner from ACS. They ask for a lot of information such as bolt size, hub thickness, etc. I gave them my prop thickness but I did not take into account the crush plate thickness (nor did they ask). Turns out the inside bulkhead was off by the thickness of the crush plate. I was able to mount the bulkhead between the crush plate and the prop after machining down the crush plate edge to fit the inside radius of the bulkhead. (This may be hard to picture without having the bulkhead in front of you.) Needless to say, when you order a spinner, make sure they know about the crush plate as well. Paul Stowitts Cozy Mark IV #200 Date: Tue, 11 Jul 2000 20:04:56 -0400 From: "Marc J. Zeitlin" Subject: COZY: Engine Mount Checking See: http://cozy.canard.com/chapters/chap09_oaf.html http://cozy.canard.com/chapters/chap18_oaf.html http://cozy.canard.com/chapters/chap21_oaf.html For the previous three installments of our Oaf's (mis)-adventures..... Fourth (and hopefully last) in our Oaf's Saga: So our Oafish hero has worked on Chapter 23 (Engine Installation) on and off since February, 1999. He had previously purchased an engine (O-360-A2A) from AeroSport Power, and an engine mount from one of the mount vendors. He had worked his way through the engine mounting, the firewall installation, most of the cowling installation, the airbox/heat ducts and most of the miscellaneous cables and tubes that venture through the firewall and attach to the engine somewhere. As far as our Oaf's dim bulb of a brain could tell, things had gone basically OK, but there had been a few nagging issues....... 1) When first rigging up the cowling around the engine and trying to achieve the correct distance between the cowl and the ring gear on the engine, the Oaf had a heck of a time trying to get the 1.5" distance - when the cowl lined up with the fuselage/spar/wings, the distance was more like 2.5" - 2.75". "Hmmm", says the Oaf's tiny cerebral cortex, "that's interesting". 2) After fitting the aluminum baffling to the engine and reinstalling the cowls, our Oaf noticed that even though he had left 1" extra material on the top of all the baffles (to be trimmed to height later [cleverly, he had thought to himself]) the top cowl was STILL more than 1.5" away from the top of the baffles, and it seemed pretty consistant from front to back. "Hmmm", says the Oaf's tiny cerebral cortex, "that's interesting - I'll have to add a 1" riser to the top of the baffles". So he did. 3) After fabricating the airbox for the recommended air filter, our Oaf test attaches the airbox to the Ellison throttle body, climbs under the aircraft to look at clearances for the lower cowling, and notices that there is no dang way on earth that the airbox is NOT going to interfere with the lower cowl - there's no possible way to fit it. "Hmmm", says the Oaf's tiny cerebral cortex, "that's interesting - guess I'll have to modify the lower cowl somewhat". 4) While the cowls had fit reasonably well around the engine before the Oaf had mounted the exhaust pipes, as soon as he mounted them he could no longer get the lower cowling to come close to fitting (not to mention that he had to cut 1" off the bottom of the rear baffle just to get the cowling close enough to the pipes to notice that they were interfering). "Hmmm", says the Oaf's tiny cerebral cortex, "that's interesting - I'll have to hack away a substantial portion of the lower cowling (which he hadn't done yet)". 5) Other, smaller issues with positioning of components......... "Hmmm", says the Oaf's tiny cerebral cortex, "that's interesting". Now the Oaf, being the dufus that we've all come to know (if not love) was having a terrible time integrating all this information into a coherent picture. Since these issues had cropped up intermittently over a long span of time, he didn't have the brain power to associate them with one another - to him they seemed this fog of disconnected bits (sort of like what the World Wide Web seems to the Oaf's father). He hypothesized about each one, guessing that some sort of tolerance stackup had reached out and bit him in each instance (not the Oaf's instance, because the Oaf doesn't even know where he might _find_ his instance, but the problem instances) and that maybe he just needed to be more careful (given his previous experiences, this was not an altogether idiotic hypothesis). One day, while once more trying to get the lower cowling to fit (and while staring at an incipient interference issue with the engine mount and the oil cooler mount on the firewall), it struck our Oaf like a bolt from the blue - "Hey" (he thought to himself; no, wait - he said it out loud, to no one in particular, since there was no one else in his enchanted garage) "Hey - maybe the engine mount is wrong. Can such a thing be?". He rummaged around in his pile of old drawings, found the engine mount specification drawing, and began to take measurements. He found this a difficult task, as the drawings did not have all defining dimensions on them, but with a bit of hard work, he was able to determine the relationship between the dynafocal donut mount points and the firewall bolt mount points. "GOOD GRAVY, MAN!" (or words to that general effect) our Oaf thought to himself, as he determined that the dynafocal mount points were approximately 1.25" to 1.5" TOO LOW. This explained EVERY LAST ONE OF THE POSITIONAL ISSUES MENTIONED ABOVE! It _wasn't_ our beloved Oaf's fault (this time) - there's actually some other Oaf out there screwing up too! And our Oaf pays for it! At any rate, our Oaf contacted the mount manufacturer, who quickly accepted responsibility and promised to replace the mount with a better one (gratis, of course). The manufacturer also said that they now sub-contract the jigging and welding of the mount to a vendor that has made substantially more engine mounts than the previous one did, and that this problem should not occur again. So, _THIS_ Oaf's story (the story, not the Oaf) actually has a recognizable moral to it (unlike those other stories, which seem less than optimally useful without one). Do a dimensional check on _ALL_ of your purchased parts - verify that they do, in fact, meet the dimensional specifications on the drawings. In the words of our illustrious ex-president, "Trust, but verify". -- Marc J. Zeitlin mailto:marc_zeitlin@alum.mit.edu http://www.ultranet.com/~marcz/ Date: Wed, 12 Jul 2000 00:01:02 -0400 From: "Marc J. Zeitlin" Subject: COZY: Engine Mount Checking Gregg Perry asks: > Nice post...good to see you writing again! BUT...for us >"oafs-in-waiting" out in the hinterlands - what vendor did you use? I purchased the engine mount from AeroCad. They had subcontracted the welding out to RANS (airplanes and bicycles), who apparently got confused - this was the first COZY MKIV mount they had made. Jeff and I BOTH screwed up in not checking the dimensions upon receipt. Jeff tells me that he has switched to having Velocity weld his engine mounts for him now. I was VERY upset, and Jeff handled the situation professionally and courteously, accepted full responsibility and is in the process of obtaining a replacement ASAP. I'm not upset anymore. -- Marc J. Zeitlin mailto:marc_zeitlin@alum.mit.edu http://www.ultranet.com/~marcz/ From: marc_zeitlin@agilent.com Subject: COZY: Engine Mount Checking Date: Wed, 12 Jul 2000 09:50:28 -0600 Bill Kastenholz wrote: > I understood that Jeff Russell's mount was designed to be one inch lower > for a lower thrust line. Yes, but that's the engine mount for the AEROCANARD. He also sells a mount for the COZY MKIV, and that should have had the higher thrust line. It's possible that RANS built some sort of combination..... > ... Great story but I'm awaiting that first flight report from you :) Thanks - you and me both..... -- Marc J. Zeitlin marc_zeitlin@alum.mit.edu http://cozy.canard.com Non Impediti Ratione Cogitantonis (C&C) Date: Wed, 12 Jul 2000 18:22:13 -0400 From: Jeff Russell Subject: Re: COZY: Engine Mount Checking marc_zeitlin@agilent.com wrote: > > Bill Kastenholz wrote: > > > I understood that Jeff Russell's mount was designed to be one inch > lower > > for a lower thrust line. > > Yes, but that's the engine mount for the AEROCANARD. He also sells a mount > for the COZY MKIV, and that should have had the higher thrust line. It's > possible that RANS built some sort of combination..... Let me add to this a little. The Long-EZ, Cozy-3, AeroCanard, Berkut, Eraser, Velocity all use thrust line 20 (water line 20) were the prop extension comes out of the cowling. There is a one inch difference in cowlings on the MKIV. Nat wrote in one of his old newsletters that he had Ken Brock make the first 5 mount for his MKIV. When he got one of those mounts and check it by mounting it to his airplane that the engine was too low in his new cowling. All 5 mounts were changed to water line 21 to fit the new cowling that was fitted to the MKIV prototype. It is a large undertaking to make the plugs for a cowling and the master mold to make final cowling parts. I can fully understand why he chose to change the engine mount then make new plugs for the molds. Weldtech started making engine mounts for the AeroCanard and then he retired the business. We then went to Rans Aircraft to make our rudder pedals and engine mounts. When we placed the order with them for one that had waterline 20 and they must have mixed up the mount specs on the water line 20 instead of 21. When we received the mount back from Marc, I checked the spacing and found that it was a 0-360 AeroCanard mount. We had permanent tooling made by Velocity so they could make both the mounts to fit waterline 20 and 21 and to fit both the 0-360 and I0-360 engines. This change made the (X) part of the mount go to a (H) style so the fuel servo would not hit the mount in that area. I have a pictures of this that I will soon add to the website. Setting companies up to make new parts can have teething problems sometimes. I wish this could have been us instead of Marc. This is usually not the case. We stand by what we sell and resale. Note: Any Cozy builders using an AeroCanard top should use the thrust line 20 mount. Any Cozy builders using the standard MKIV cowlings need to use the thrust line 21 mount. These mount are not made by us and are not listed as AeroCad's approved Cozy parts or non approved Cozy parts. If you purchase them from us, we do not need to advise you that if you purchase and use them, you shouldn't register your airplane as a Cozy. That is up to you to wonder if this is a major change. The plans for building the mount are in the plans and few have made their own. Wonder what happen to us on the approved list of manufactured parts in the newsletter? Guess I am on the *h*t list again (-: I am glad I had mine made to fit and for less money by Weldtech. Hope that helps clear up the difference. -- Jeff Russell/AeroCad Inc. Website: http://www.Aerocad.com Sponsor- Canard Aviators www.canard.com canard Aviators page Date: Sat, 08 Jul 2000 12:40:02 -0500 From: Curt Smith Subject: COZY: CHT Cooling Group, One of the problems we all seem to share is that CHT's are never too cool (like having "too much money"!). I have experimented over the years with baffling mods (including using BID/silicone), ramps in the bottom of the cowl, etc. Some made no difference, some gave marginal improvements. I recently tried something, however, that has yeilded the best improvement yet. I have a stock cowl on an 0-235 Long. The oil cooler is in the stock location, not in the rear baffle. The prevailing theory is that high pressure air piles up in the rear of the lower cowl, where it does no good. Some of it finds its way out past the cyl's and some finds other ways out. Since that area of the cowl, behind the carb/sump is basically empty, I decided to build a dam across the bottom of the cowl making the top of it the same height as the horizontal sections that attach to the wings. I used pour foam, gave it a slight slope to the rear (to ramp the air up) and trial fitted several times to assure clearance with the air filter box (I have a Hal Hunt box) and other engine parts. Once I got the shape I wanted I glassed it with one ply of bid and went flying. So far, my CHT's have dropped approximately 50 degrees all around, so I've gone from "marginal" (high 300's-low 400's) to "comfortable" (mid 300's). Try as a might, I can't get ole' #4 (the hottest cyl) above 400, even with high power settings and leaning. Before, I was CHT-limited when it came to power settings, particularly at low alt's and hot days. I could easily get #4 up to 450 or so - too hot! This dam simply forces the air up to the vicinity of the bottom of the cylinders - the top is about even - fore and aft - with the rear (#1&2) cyl's. This is my best mod yet for better CHT's and I intend to use it when I do the cowls on my Cozy III. It's simple, no one but you will ever see it, so it doesn't have to be pretty, and only takes a few hours. Cool flying. Curt Smith LEZ N86CS Date: Thu, 13 Jul 2000 18:42:29 -0400 From: "Marc J. Zeitlin" Subject: COZY: Engine Mount Checking I wrote: >Both the drag vector and the thrust vector (both are forces) act around the >CG, both horizontal and vertical......... One thing I forgot to mention in the last two messages was that the thrust line is _NOT_ parallel to the longerons, but tilted down a degree or two (don't remember the exact #). This will move the thrust line closer to the CG, and will also more closely align with the drag vector when in cruising flight (since there's a small positive angle of attack in cruise). This makes Dennis' original calculation of the effect of the offset smaller than he estimated. -- Marc J. Zeitlin mailto:marc_zeitlin@alum.mit.edu http://www.ultranet.com/~marcz/ From: marc_zeitlin@agilent.com Subject: COZY: Engine Mount Checking Date: Mon, 17 Jul 2000 14:24:59 -0600 David Domeier writes: > ... I can't tell any change in pitch moment with power off or on ..... > Once again, I've missed something in this thread. Why would changing > the thrust line result in a better flying MKIV? It seems quite good as is. You haven't missed anything, Dave. There was a hypothesis put forward that the aircraft might be slightly more efficient with a slightly lower thrust line, due to decreased induced drag during cruise. This was instigated by the revelation that there are two different thrust lines (1" apart) for two canard aircraft variations. As some of us have responded, even the theoretical improvement would be tiny (and probably not measurable) with a 1" to 6" thrust line lowering (ignoring the prop ground clearance issue). Your response indicates what would be expected, that with the drag vector and thrust vector reasonably close already to the vertical C.G., there's almost no change in pitching moment with or without thrust. Now, in something like a Lake Buccaneer or a Seawind, with the engine far above the C.G. and drag vector, there's a HUGE pitching moment change with thrust change. In a case like that, moving the thrust line down could make a large difference in the pitch change with thrust, and make the airplane more efficient in cruise as well. In COZY's, the opportunity for improvement in this particular area doesn't really exist. -- Marc J. Zeitlin marc_zeitlin@alum.mit.edu http://cozy.canard.com Non Impediti Ratione Cogitantonis (C&C) From: "John Slade" Subject: COZY: Re: fuel return line Date: Sat, 5 Aug 2000 11:34:22 -0400 >This may be redundant by now, but I was on the Ellison Throttle Body >page today and I came across a page discussing do's and don'ts of fuel >return lines. They also had a link to a valve that will switch both to >and from lines (I know you only have the one hole in the tank, but...) > >http://www.ellison-fluid-systems.com/faqs/recirculating_fuel.htm > > >Steve Hagan >#780 Thanks, Steve, I've taken the liberty of copying you're note to the mail list because this paper is EXCELLENT and is relevant to all airplane builders even if they're building the fuel system per plans. I HIGHLY recommend this 9 page document to all. John Slade From: "John Slade" Subject: Re: COZY: Re: fuel return line Date: Sat, 5 Aug 2000 15:49:16 -0400 Nat and builders, My apologies. I included the wrong reference. The article I was referring to is: http://www.ellison-fluid-systems.com/article/fuelsystemsforhomebuilts/fuelsy stems.htm IMHO THIS one is a must read for anyone using gasoline. I don't think even Nat would disagree. Sorry for the confusion, John Slade, Cozy MKIV #757, progress: http://kgarden.com/cozy West Palm Beach, FL From: "Nat Puffer" Subject: Re: COZY: Hot #3 CHT Date: Mon, 4 Sep 2000 09:36:13 -0500 John, In both my plans model and my 4-place prototype the hottest cylinder has been #1, followed by #3. My #2 and #4 run the coolest. The temperatures are very much affected by fuel distribution. I have discussed this at length with Lycoming. In their test cells, they use exhaust pipes that are all the same length, but their temperatures balance or peak only at 2400 rpm. At lower and higher rpms, the cylinders do not peak at the same time. This means that the velocity of air through the intake manifold affects fuel distribution. In most 0-360 installations in Cozys with 4 pipe exhaust systems, #1 runs the hottest and peaks the soonest. An educated guess is that this is true because the exhaust pipe is the shortest, and is less efficient at evacuating the burned gases from the cylinder. I have made a slightly longer pipe for #1, but haven't installed it yet. Lycoming says they have tested various exhaust systems supplied to them which are supposed to have increased engine power, but they say they don't measure up to the claims made for them, so I don't think my longer pipe will do much. I tried both short and much longer pipes on the Franklin, and they didn't seem to make any difference. When I lean my engine, I lean past the peak on #1 until the temperature starts coming down. When it gets down to 345 deg. F (measured with probes at the bottom), #3 is rising and has risen up to 345 degrees. Both #2 and #4 are quite a bit less. I don't understand why #4 is so cool, because my oil cooler is drawing cooling air from the same part of the cowling and I would have guessed #4 would run hotter. In addition to rpm, airspeed also affects temperature distribution, as well as angle of attack. My distribution is different in a climb than level flight. It would be nice to get all cylinders to run the same at all speeds and mixtures, but that is wishful thinking. I have a thermocouple under the top plug of #1 and a probe at the bottom of #1, and the plug thermocouple runs 40 degrees hotter. This does not agree with data published by RAF, because a top thermocouple under the plug should be 80 to 100 deg. hotter, because of the difference between a probe and a plug thermocouple and also the difference across the cylinder. If both are reading correctly, the only explanation I can think of is that my baffling is so tight that there is no difference across the cylinder. Hope I have adequately confused you. Regards, \Nat ---------- > From: John Vermeylen > To: Cozy builders > Subject: COZY: Hot #3 CHT > Date: Sunday, September 03, 2000 8:57 AM > > David Domeier wrote about his uneven CHTs. I've also been trying to > balance CHT's. My #3 runs about 40° warmer than the others with #4 > running the coolest. > It seems that my engine temps runs about the same as David's. I have > about 50 hours of air flow experiments on my engine all resulting in no > change in #3 CHT. It seems that #3 cylinder runs leaner than the other > cylinders. > David's conclusion: "Out of balance CHT's may well be caused by uneven > fuel > distribution more than by air flow across individual cylinders". I was > wondering if all of us are having this same problem? > John Vermeylen > N69CZ > > > > Date: Mon, 04 Dec 2000 09:02:59 -0800 From: "Rogers, C. Howard" Subject: RE: COZY: Engine advice -Why not Ground run to break in? > -----Original Message----- > From: Carl Denk [mailto:cdenk@ix.netcom.com] > Sent: Saturday, December 02, 2000 4:41 PM > To: SWrightFLY@aol.com > Cc: Rogers, C. Howard; cozy_builders@canard.com > Subject: Re: COZY: Engine advice -Why not Ground run to break in? > > > Actually running in on the ground without a test club and other > equipment such as a substantial mount, working engine instruments, and > other temp. gauges is not the way to go. The leaf blower only is a air > source at a small area, and not very much when compared to > 120+ MPH air > hitting the NACA or armpit scoops. > > Static RPM isn't going to do it, they want around 85% power generally, > which is near full trottle. check the engine power graphs to determine > the power at your RPM. By the time usual tests and > adjustments it will > be to late, the cylinders will be glazed, of course its not > that big of > a deal to pull the cylinders, break the glaze, and put it > back together > again. Might work to reuse the rings with so little time on > them, but to > me this is unknown territory. > > Best would be to find an engine shop with a test stand setup and have > them run it in. I tend to agree with Carl, primarily on the point that this is unknown territory, so there is some risk involved. Of course, there is some risk involved in breaking in the engine on a new aircraft, too. We all know that, on any new aircraft, the cooling issues frequently require considerable tweaking to achieve optimum temps and balance between cylinders. I don't believe that a good break-in is necessarily a function of horsepower output. Ideally, there should be a fairly high cylinder pressure being developed, but not too high piston speeds. Along with this, of course, there should be LOTS of airflow. With a fixed pitch prop, the choices are limited, in flight, hence the 75% (or 85%) power numbers. This is the power setting where these ideal conditions are all likely to be achieved, in flight. As far as engine shops are concerned, my experience has been that most of them have a very minimal, basic test-stand that is primarily for the purpose of verifying that the engine runs OK after an overhaul. They fire it up, watch for leaks, adjust carb/FI, check oil pressure, and adjust, if necessary, run it for a SHORT time to check the most basic things, then crate it up with a set of detailed break-in instructions. The cooling usually consists of the extra prop blast from a test club. The test-club's primary value is to absorb the horsepower at some optimum RPM, along with some cooling effect. Now it is possible that you may find someone in your area who has a considerably more elaborate test cell setup, capable of a full break-in, with adequate cooling, etc. By all means, check around. This would be a valuable asset for many builders who are facing the same dilemma. As for the leaf-blower idea, it sounds promising to me. If I were attempting this, I would want to instrument every cylinder for close temp monitoring. Don't forget the oil cooler (a third leaf blower?). It may very well turn out that some leaf blowers are up to the velocity and volume required to do this job. I don't know the mass airflow numbers required for an 0-360's cooling, but I'm sure that information could be dug up and compared with the leaf-blower's output capabilities. -Howard Rogers From: "Epplin John A" Subject: RE: COZY: Engine advice -Why not Ground run to break in? Date: Mon, 4 Dec 2000 13:40:33 -0600 A lot of good info being presented here. I like Eric's suggestion about the balloon fan. I don't have any first hand experience with these, but I am concerned about the leaf blower. My thinking is that it will take several to do the job. It takes several horsepower to move the air that is needed here. Another thing is the connection to the cowling inlet. This could be done, would take some work. Another source of air might be a grain dryer. Some of these use Hartzell (sp) fans driven by 20 or more hp. They are also designed to work with a substantial pressure differential. Think about the cooling drag on a typical lightplane. This is the energy needed to push the cooling air through the system. My engine was run over 2 hours in the test cell, the last hour at full throttle. The head temps were recorded several times during the run and showed a marked decrease before the end of the run. This indicates ring seating is well along, if not complete. Will know more in about 6 months when the first flight is scheduled. I do intend to keep the ground running to a minimum. Am not concerned about taxi test, if a lot of power is used there will be some airspeed along with it. I would like to do a full minute full power static run. I intend to try this, watching the head temps closely, if they stay within reason good, if not abort the run. John Epplin Mk4 #467 N100EP > -----Original Message----- > From: Eric Westland [SMTP:eric.westland@verizon.net] > Sent: Monday, December 04, 2000 12:30 PM > To: Cozy Builders Mailing List > Subject: Re: COZY: Engine advice -Why not Ground run to break in? > > Here are a few loose thoughts from what I learned when looking into this: > > 1) The break-in proceedure that is listed in the Lycoming Operating > manual > is for their engines which already have been run for an hour or two in the > Lycoming test cell. If you overhaul your engine yourself or get one that > has been field overhauled, it may not have any time on it at all. > > 2) It's not just the rings you need to worry about - your cam and lifters > get their lubrication from splash oil. > > 3) There is a good article on engine break-in at > http://www.avweb.com/articles/breakin.html > > 4) If you are ground running/breaking-in and trying to limit temps by > monitoring CHT's, keep in mind the real heat is being generated between > the > ring faces and the rough honed cylinder surface. If you get it too hot > (not > enough cooling air), the cylinders will glaze and possibly the rings will > overheat causing them to loose their temper. You may not catch it in time > because you are monitoring the temp of the head, not the barrel. > > 5) I thought that if I ever did try to provide cooling air on the ground, > I > would try to borrow one of those fans that is used to pre-inflate hot air > balloons before lighting the burner. They move some serious air. > > Eric > > ________________________________ > Eric Westland > Cozy Mark IV N325PD > http://public.surfree.com/ericw/ > > > Date: Thu, 21 Dec 2000 16:27:08 -0500 From: Carl Denk Subject: COZY: Lycoming nose seals The recent CSA newsletter speaks of the nose seals, and I believe needs clarification: There are actually 4 varieties available, split and one piece, and with and without ridge to fit in a machined groove in the cylindrical surface of the counter bore, and the various combinations of those variables. Engines with the groove require a seal with a corresponding square ridge on it circumference. Generally engines without the seal retainer do not have the groove, but the only for sure way is to remove the seal and look. Those engines without the groove, must not use a seal with a ridge. The split or one piece seals are a matter of personal preference, the one piece generally requires a special tool to install, but have heard of people installing without the tool. I prefer the split seal, and my engine, which originally did not have the retainer, does have the groove. After removing the seal, I thoroughly clean the counter bore paying special attention to the groove, using dental tools, lacquer thinner, brushes to get it spotless. The cleaning alone may take an hour or more. The new seal gets its lip only lubricated with oil, keeping the counter bore and mating surface dry. The adhesive for the seal to the counter bore is either (AND ONLY) Lycoming part number, or PLiobond. With the split type I also put adhesive on the seal ends that mate. My source for seals is El Reno Aviation, and when ordering, I tell them a 320 nose seal with split and ridge, they know the correct part to ship. For what ever reason, I have had to replace leaking seals (seal gets hard from heat?) every couple of hundred hours, and the start seeping oil, a few drops per flight. I would not fly s pusher without the seal retainers. THey are easy to install. Get the Lycoming parts, including bolts (with safety wire holes) use quick glue or hot glue to temporarily hold in position. Remove one of the propeller bolt bushings. Then use a transfer punch (a center punch that fits snugly in the holes) to give the drill a starting point. Drill the tap hole size (not too deep), tap initially with a standard tap, finish with a bottoming tap. Should be an easy evenings work. Date: Fri, 22 Dec 2000 09:23:28 -0500 From: Carl Denk Subject: COZY: Re: [c-a] Lycoming nose seals Was said < I would highly encourage light wet or dry sanding of the crank bearing area with 600. and grease lube before running the engine. > I don't disagree with the thoughts of grease, except the material must be compatible with the seal material, and the easiest way to do that is use an approved lubricant. In reviewing the Lycoming overhaul manual, they do not specifically say to lubricate the seal, but I like the idea. As for sanding the area with 600, I strongly disagree, The idea of an abrasive getting into the engine is not acceptable. I think even the dental tools is on the edge of being to aggressive. This is an area requiring considerable finesse and patience. As I have said the seal lips I have removed became hard and were unable to conform to the crankshaft surface allowing very small quantities of oil to escape. I aim at zero leaks, though its very difficult to attain, as part of my practice of fix all issues A.S.A.P. I have replaced the seals several times.