Anyone experience this on an Alpha or other plane? Once the engine gets hot, the muffler spins (muffler, screw & nut become one). When its cold, it's tight as can be. It's making quite the mess. I believe the aluminum is actually breaking down (Gray/black matter) and spraying along with the exhaust. Also, when i took it apart, the disk inside (bear with me, my terminology is not so good) is broken. Does that make any difference as far as how the muffler works?

There are several grades, (temperature sensitive), of Loktite. You can find these at most Auto Parts stores. Check the labeling and go for the most "potent" stuff. I have been away from St. Rodding for a while, but I think the blue is the "mild" one. (easier to break the seal).... lownslo

Do I put the Locktite between the 2 parts of the muffler too? Or just on the threaded parts? Because the screw is tight and it turns with the end piece of the muffler as one unit.
thanks all!

A buddy of mine told me that that plane runs better if you take the baffle out of the muffler. Makes it a little louder but it gives it a little more power

Hello greenpilot, If I can picture your description correctly, something is not normal with the fitting of these parts and / or, the length of the bolt and/or, it's thread length.
To answer your question about Loktite between the parts.... I guess you could dab some on there.... BUT that will not be the solution to this problem. Do the muffler parts EVER get tight OR do they work themselves loose? It just seems that the bolt and nut that ties the two pieces together may be the problem. What I am saying is... the nut may "SEEM" to get tight. Is it possible that it has "runs out of treads" and the nut can't go any further?? (THUS leaving the muffler parts still slightly loose) Try to add a couple more washers as spacers if this is the case. You can take the baffle out (?), but that again I feel is not going to solve the problem. (not sure how it fits in your muffler..but it could actually increase the problem if it makes the total length of the muffler shorter in length. Now your bolt may not tighten it at all.
Keep us posted..... I would like to know what is going on here.

PS. When using the LOKTITE, be sure to clean the parts first with alcohol or acetone etc. Also... some types Loktite is meant to "creep in" the threads, and some has to be applied. (check the directions)

....lownslo....

Bob

Lownslo - That's what we thought originally. At first, I noticed the plane came down and the muffler 'exhaust pipe' was pointing a different direction than when it went up. Assuming it was loose, tried to turn it back and found it tight as could be. A club member suggested as you did, I added some washers. Still did it. He added some washers, still did it. Last time out, the engine was running on the ground for a while, we actually saw the whole back end spinning. The back end spins as does the long screw itself.
Did notice when I took it apart last time that there is a very thin rubber washer/gasket?? (looks like a rubber band) between the two muffler parts. Could that have been larger originally and wore down to where it's not doing its job? Someone suggested sealant from an auto parts store.

I take my mufflers apart, and re-assemble them using rtv (silicone) on all mating surfaces. I use the blue lock tite on the threads of the bolts, the red stuff is more permanent. I also chuck the gasket, and use rtv there instead. No leaks yet... Good luck, Loren

I've lost the back of my muffler to the loosening of the nut. I was in about my 8th loop, went vertical, and the engine quit. The plane immediately stalled, and I choked, and said help to the guys at the field. One of them said "what? You can handle that". I then glided it it for the best landing of the day.

greenpilot hi there i'm new too but with the help of vegas mossie and the gang here(las vegas nv), my alpha is still flying great. we did turn the exhaust to point at 5 o'clock when looking from behind. it hasn't moved yet. ok have fun. spooner

heres the deal buddy...the long screw threads into the rear muffler peice. If thats not tight before you tighten the "locknut", it will spin. Loosen the lock nut, aim the muff where you want it to point, Tighten the screw as tight as you can, then tighten the nut. This will solve the problem.
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If that was the problem, a few of us at the field made the same mistake. I did put the sealant on it yesterday, and hope to fly it within the next few days (too much rain this morning). But I will remember to tighten the screw first from now on!

Hey bignasdy, Do a lot of us out here feel dumb about now!!!
I know I do !!!
I only had 2 strokes for a couple months and I only loosened, and turned the outlet, one time. It never did loosen up on me. I just flat out forgot how I did it. I have all 4 stokes now.
It is really amaZZZing that the thread went this far without someone jumping on it like you did.
Nice going!!!!......lownslo