AWI 4 in 1 exhaust

[N53LW]

Have the AWI 4 n 1 exhaust on the RV-8, was wondering if anyone else is having problems with the collecter cracking? Have 230 hrs on the plane and it has cracked 3 times so far. AWI has made us a new collector , it also has cracked. We have the exhaust supported ahead of the collector, but have no real solution for supporting the 4 n 1 collector itself. Any ideas would be appreciated. Thanks.

[Bubblehead]

I have about 200 hrs on this system with no problems. I supported the collector off the rear two bolts that connect the collector to the 4 pipes. I used a system similar to the Vetterman system. I will post pictures over the weekend.
I did cut the collector a little at the rear to get a more rearward opening. I also cut the two top pipes from the cylinders so that the collector would move up a little closer to the fuselage. Perhaps you are trying to pull it up toward the fuse and putting some stress on the system.

[DanH]

Originally Posted by N53LW

Have the AWI 4 n 1 exhaust on the RV-8, was wondering if anyone else is having problems with the collecter cracking? Have 230 hrs on the plane and it has cracked 3 times so far. AWI has made us a new collector , it also has cracked. We have the exhaust supported ahead of the collector, but have no real solution for supporting the 4 n 1 collector itself. Any ideas would be appreciated. Thanks.

Hmmm.....mine is supported aft of the pipe join, in the middle of the collector section, using cable loop hardware supplied by AWI. I really like the design. However, no flight time yet.

[DanH]

Follow-up report...cracked collector here, 144 hours in service. One socket was splitting away from the collector body. The cracks seem to originate at the interior welding (the "cone" area). Don't think it has anything to do with the support method. AWI has made weld repairs; we'll see how it holds up.

Phil, had any further problems?

[Jerry Cochran]

begs the question. What is the advantage? Faster speed/lower drag, cost, esthetics?

[Adam]

I have 240 hrs on mine and have no signs of any cracks! My exhaust is unsupported as that was the way the original company told me to install it.

[DanH]

Look up inside the tailpipe. There was less than 1/2" of crack visible anywhere on the outside, probably 2-1/2" inside at the interior welds where all the pipes come together.

[gnuse]

Originally Posted by Jerry Cochran

begs the question. What is the advantage? Faster speed/lower drag, cost, esthetics?

If you had ever heard a 4 into 1 you wouldn't be asking this question.

[Wicked Stick]

Today while performing my condition inspection, I found the following:



My RV-8 has 123 hours tach time on it.
Seems to me that since the other 3 pipes are fine, that this one might have been defective or mis-aligned when welded at the factory causing stress in that area. I have read others having collector issues, but thought I'd post this to see if anyone else has experienced an issue with theirs in this area.

[DanH]

Dave, does that pipe bottom out in the collector socket, i.e. with the link disconnected you can't shove it in any further?