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Vendor for RV-12 Exhaust?
- Thread starter scsmith
- Start date
Van's makes them in-house.
Yes, it appears that at one time they had that capacity, and for all I know they still do. They just don't seem to be doing it, at least not for the non-is RV-12.
The issue at hand is that my RV-12 muffler has a #3 input bell where one side is worn almost all the way through, and has cracked through, resulting in an exhaust leak. Also the ball on the corresponding exhaust pipe is badly eroded.
The cause appears to be the misalignment of the #3 exhaust tube such that the ball doesn't properly align with the bell, causing excessive side-loading at that joint and resultant abrasion and erosion. I don't know how it became so badly misaligned, but it might be due to a repair on the #2 exhaust tube.
And, yes, I could order the RV-12is exhaust for RV-12, price tag $4k+. And, yes, I spent supercar money for a puddlejumping airplane, so I guess I should have expected that kind of exorbitance; that's on me.
So anyhow, what to do?
After studying the available resources and technologies, for the short term I've ordered a new muffler from Sideslip aviation, a new joint ball from Motive, new spring bails from I forget where, and some 1-1/4" ID and 1-1/4" OD 304SS tubing from a racing exhaust supplier. My plan is to cut away the offending portion of the #3 exhaust pipe, fabricate a replacement, and splice it on with a beveled or fishmouthed external sleeve. I figure I can do most of this with MIG welding, or what TIG I can scare up from the local usual suspects.
Long term, I'll probably order an entire exhaust system kit from Aeroweld in CZ, and fabricate an end-to-end replacement. I designed and tooled about 50 weldments for my kit gliders, and have done a bit of exhaust fab for my 24 Hours of Lemons team, so this isn't exactly a first rodeo for me.
The RV-12 ULS exhaust is $3383, but yes, it shows currently unavailable.
Thanks! I already had the male on order (they're relatively easy to find) but this is the first I've seen of the female parts available in the US.
I called Lockwood and spoke with their welder, and did not get warm fuzzy feelings about their ability to help in my case.
The root cause of the failure on my exhaust is the misalignment of the ball on the pipe and the bell on the muffler; that is clear by inspection. The proper fix is to adjust the alignment of the pipe so the ball fits properly into the bell. To do that requires access to either an actual Rotax 912 engine, or to a jig that accurately replicates the spatial relationships between the four cylinder exhaust outlets. I naively expected Lockwood to have such tooling available, but when I spoke with their welder that did not seem to be the case.
Don't get me wrong, their welder sounded quite competent at welding, and I'm sure their facilities are top-notch. But having tooled up about 50 complex weldments in my ill-spent youth, I have some idea how it's done, and I didn't hear what I needed to in our telephone conversation.
Piper J3
Well Known Member
My friend had socket on muffler and ball-end on stack replaced. Welding was done on a bench without fixtures. When reinstalling muffler, the four exhaust stacks must to loosened at the cylinders to allow all the pieces/parts to self-align.
Once parts are aligned and tightened in position, spring tension becomes the key for longevity. Bend each spring clip “up” so the extension spring has more preload stretch. This will keep the lubricated ball/socket tightly in place and prevent movement/chaffing in the joint.
I am considering replacing my wimpy Rotax springs with heavier motorcycle exhaust springs that have swivel ends. Several spring lengths are available from Amazon. Not sure if 58mm or 55mm is correct length…
Once parts are aligned and tightened in position, spring tension becomes the key for longevity. Bend each spring clip “up” so the extension spring has more preload stretch. This will keep the lubricated ball/socket tightly in place and prevent movement/chaffing in the joint.
I am considering replacing my wimpy Rotax springs with heavier motorcycle exhaust springs that have swivel ends. Several spring lengths are available from Amazon. Not sure if 58mm or 55mm is correct length…
The joints at the cylinder heads allow pivoting around the axis of the port, so loosening them can accommodate lateral alignment. But they're not ball joints, so they can't accommodate the kind of misalignment I have.
Thanks, I'll look into those stronger springs!
RandomSquawk
Member
I too have been looking. Vans may list it, but good luck getting them to make one. Took me over a year and a half to get just the #2 exhaust tube (the subject of their own service bulletin), and it doesn't even fit; not even close. After verifying the part #, their tech's answer was to loosen all the nuts. As @Bob Kuykendall pointed out, that only allows pivoting on 1 axis. Even with all 8 nuts completely removed there is no way to force close this gap. I eventually gave up, partly because the much cheaper repair weld I got all those years ago is still holding. Fingers crossed. Eventually the day will come when I have to source a whole new exhaust, so I'll keep watching.
By the time I get mine fixed, I'll probably be able to manufacture complete systems. But only for EABs and ELSAs
