From: cdenk@ix.netcom.com Date: Thu, 1 Jul 1999 19:14:36 -0500 (CDT) Subject: COZY: Wheel pant cracks Originally my wheel pants were prone to cracking on hard landings. The tire would bulge out and catch the aft sharp edge of fiberglass at the aft side where the turning wheel was entering the wheel pant. I made the pants slightly wider, hot glued a 1/4" O.D. plasic tube to the aft side opening area and 2 plys BID to make a rounded edge. Haven't had a cracked wheel pant since, but have seen some wear on the paint. Date: Fri, 09 Jul 1999 17:26:20 -0500 From: David Domeier Subject: COZY: Wheel pants blues.... After spending what seemed a 1000 hours installing a set of wheel pants, I did a flat out run at 8500' today to see what it meant in airspeed. On June 24, 1998, the numbers were 155 KIAS at 2680-90 RPM. OAT 15°C (no wheel pants) Today, July 9, 1999, the numbers are 155 KIAS at 2620 RPM. OAT 17.8°C (with wheel pants) A little disappointing. The result could be 'cause the new engine is running tight. I can not get the RPM above 2620 with same prop as last year. If RPM is an indication of horse power, the engine is producing about 2.7% less hp than before it was overhauled. The total RPM picture with the new engine makes no sense to me - I'm getting more on take off (2390 vrs 2340) but less (2620 vrs 2690) on the high end?? Go figure that!! The wheel pants are not optimal for sure. I decided to slow the outflow of cash and bought a set of MF-3's ($142) from Spruce rather than the Cozy set ($295) also available from Spruce. I had to modify the MF-3's greatly to get them to fit and they are not shaped like they were. If I had to do it over again, I would go with MF-5's (for a 6" wheel) or the Cozy set. I figured the MF-3's would be just fine for our 5" wheel, but that ain't the case. Our strut is too fat and comes in at too great an angle for that skinny profile. I think also, most of the other uses of the MF-3 have the brake housing outside the faring. dd From: cdenk@ix.netcom.com Date: Fri, 9 Jul 1999 21:24:16 -0500 (CDT) Subject: Re: COZY: Wheel pants blues.... Was said What happens when you carefully lean the mixture at low altitude? Moderate leaning should if the mixture is near right should result in about 20 RPM increase in RPM. At 8500' a little more leaning should find a peak RPM (max. power). When was the before pants numbers gotten? Before or after engine work. When checking performance, set the altimeter to 29.92 (standard barometer) and fly the same altitude. Eliminates one correction. If your engine has more than 5 or 10 hours since work, its, not break-in, but some other issue. Do you have EGT and CHT for all cylinders, if so, use EGT 1450F as a limit and lean to that point. Are all EGT within 100F of each other? Have you checked compression? Its possible to have wiped a cam lobe, or other problem (cam not timed, gear off a tooth)? Fly with the pants (no pun intented) on, take your pants off (the aircraft) and fly again. Select a time when weather conditions are stable. Now hopefully you have eliminated a bunch of variables. Record OAT, manifold pressure, RPM, and if you have fuel flow, and engine temps. Normally pants result in atleast 10 MPH increase. Could be you have created more drag. They MUST be parallel to air flow in cruise. Do you have someone that can fly tight formation with a camera, get some yarn tufts, and masking tape, and check the airflow around. Trying to save $$$ CSA has several sets of wheel pant molds available to members, they come with a video instruction and aren't difficult to make. Date: Sat, 10 Jul 1999 17:55:05 -0500 From: vance atkinson Subject: Re: COZY: Less blue.... David Domeier wrote: > Carl, > > Thanks for all the suggestions on the subject.....my handicap is > that I've had 2 jobs in my life - milking cows and since leaving the > farm, flying airplanes. I tend to kick the tires, light the fire, and > if everything checks out, blast off. Some of you guys have an well > tuned engineering discipline - I wish I had more of it. > > Today I followed a script, somewhat, and the results are a bit more > encouraging. Yesterday, I spent no time leaning to peak EGT. Today I > took about 4 minutes to get things settled down and here are the results > with comparisons. (all at 8500' full throttle) > > June 24, 1998, 155 KIAS at 2680-90 RPM. OAT 15°C (no wheel pants - old > engine)(casual leaning) This was a very quick take 'cause it was just > the 3rd flight and I was still waiting for pieces to come off the > airplane. > > July 9, 1999, 155 KIAS at 2620 RPM. OAT 17.8°C (with wheel pants - new > engine)(casual leaning) > > July 10, 1999, 160KIAS at 2670 RPM OAT 14°C (careful leaning to max EGT > of 1512°F AND much smoother air) JUST SO YOU HAVE A COMPARISON........ I PUT 4 NEW SUPERIOR CYLINDERS ON MY O320 LYC TODAY AND HERE ARE THE RESULTS FROM 2 HOURS AGO.............................. > > > You like numbers, Carl, here are some more. > Manifold Pressure=22.7 UNKNOWN > (DIDN'T LOOK) > RPM=2670 ONE > HOUR AT MAX 2950 > Fuel Flow=10.2 14.2 > EGT 1-4 1512° 1362° 1362° 1430° ABOUT THE SAME AS > YOURS ( WITHIN 10%) > CHT 1-4 362° 362° 380° 396° 362 380 365 > 376 (THIS IS ALL THE HOTTER IT GOT ) > Oil Temp 200° 218 > > OAT 81F INDICATED SPEED 186 KTS AT 2000' > > The #1 EGT of 1512° is out of line and all I can say is that at high > power settings, it is. On take off it is always spiked. At 65% or less > it is drops down with the other 3. I've talked to Nat about this and he > has the same phenomena on his airplane....could be caused by the short > stack.....but we don't know for sure. > > TAS comes to be 184 (or 212mph for you marketing guys). Nat said in > the last newsletter he increased his speed up to 218mph with the > Sensenich prop so I think I'm in the ball park with the guru. The GPS > showed 157K on 270° and 196K on 090° which comes out to average 176.5, > but I do not know if it is more or less accurate than the airplane > gauges in determining TAS. In my working days there were times when a > reversed course had a headwind as did the previous course....has > something to do with drift angle, track, and maybe the coriolis force. > Who knows? > > What's really neat about these airplanes is coming into the traffic > pattern with 2300 rpm, fuel flow 7.6, and indicating 150 knots....it is > very neat! Just takes a little planning to get slowed up to 75 on final > which I am finding to be a comfortable approach speed. > > dd Date: Fri, 03 Sep 1999 20:21:25 -0400 From: Gregg Perry Subject: COZY: Wheel Pants Greetings, I'm starting to work on my wheel pants have been checking out different installations. I've seen wheel pants with vents on the top, vents in the rear, and no vents at all. What are the advantages/disadvantages of these various types? Gregg Perry From: cdenk@ix.netcom.com Date: Fri, 3 Sep 1999 19:54:46 -0500 (CDT) Subject: Re: COZY: Wheel Pants I have top slots, one per pant. In plan view they are 1" wide x about 3" long, centered sideways, and forward edge about 3" aft of axle centerline. in crossesection U shaped, the bottom sloped from 1" down forward to meeting the pant at aft edge. Have numerous times felt pant, vent, strut for excess heat, and I'm not one to go easy on the brakes. Haven't noticed any excess heat. Where did you get pants? Central States has several sets of molds and good instructions available. From: SWrightFLY@aol.com Date: Fri, 3 Sep 1999 21:27:50 EDT Subject: Re: COZY: Wheel Pants In a message dated 9/3/99 7:57:47 PM Central Daylight Time, cdenk@ix.netcom.com writes: << I have top slots, one per pant. In plan view they are 1" wide x about 3" long, centered sideways, >> this method will "squirt" air up 90 degrees to the relative wind and cause excessive in flight drag along with disturbed air going into the prop.............Best low drag method is an oval exit at the rear of the pants. This will cool your breaks just fine. Carl will probably be the last one to arrive at Rough River due to all this drag................ :-) Steve Wright Aircraft Works LLC: Electric Nose-Lift for EZEs From: cdenk@ix.netcom.com Date: Sat, 4 Sep 1999 07:21:40 -0500 (CDT) Subject: Re: COZY: Wheel Pants was said <"squirt" air up 90 degrees to the relative wind and cause excessive in flight drag> The way I see it the low airflow generated from other openings in the pants (wheel opening is the only) is introduced into the air stream parallel to the bottom sloped surface around 1 vertical/ 4 horizontal. I concur with Nat's comments that this ventilation if/is required only on the ground, the only exception might be a "stop and go" landing, and I have only done one of those with the Cosy. Our landing/takeoff combined distances are long enough that exceptionly long runways are needed to do them safely. There probably is a more drag efficient way to shape a top vent, but this was a simple way. Cut a slot, shape a tapered scrap of styrofoam, duct tape release, hot glue inside of slot, 2 plys bid, a little bit of finishing, and done. Date: Tue, 07 Sep 1999 23:10:23 -0400 From: Jim Sower Subject: COZY: Wheel pants Hey all, I have just emerged from the 'annual from hell'. Made a lot of upgrades and replaced two bad jugs and etc. Now I'm examining wheel pants. I don't think I'm ready for the leap to Lamb tires just yet. At least I have to get my breath from working on this beast all summer. Sooooooo. If there's anyone out there who has recently upgraded to Lamb tires and the appropriate pants, and has a decent pair of 'regular' wheel pants in fairly good shape laying around his shop, how about making me an offer (no, I'm not ready to make any right now - probably when I move to lambs sometime down the road). I am looking for something that will pretty much bolt on, and be an improvement over what I have (MASSIVE tear-drop type pants). Thanks, Jim Sower From: "Nat Puffer" Subject: Re: COZY: Wheel Pants Date: Fri, 3 Sep 1999 18:00:01 -0500 Builders, The purpose of vents in the wheel pants is to allow the discs to cool without causing an oven which cooks your landing gear struts. Obviously, this problem is most likely to occur after landing, taxiing, and parking. It is also obvious that the best way to allow convective cooling of the brake discs is to put one or more vents in the top of the wheel pants, so cool air can come in the bottom, take up heat from the discs, and the exit from the top. Best regards, Nat