raynman

My Feedback: (3)

Hi,
I would like to see some of this forums ideas about securing the back half of the Muffler
(silencer) to the engine - or front half of the muffler - in case of separation during flight.
I just lost my new 46ax back half of muffler this weekend. That's my second muffler loss during my 2+ year flying career. Can one drill/tap tie-wire, zip tie? what are some thoughts? What do you guys/gals do?

FHHuber

I have resorted to "Spiking" the threads behind the nut on the muffler's long screw. You just deform an exposed thread a LITTLE and the nut can't vibrate past, but with a screwdriver and wrench you can remove the nut if needed. If you spike a thread a turn or so from the nut when its tight, you can losen the nut and screw enough to rotate the back section of a round muffler without having to turn the nut onto the spiked thread. If it vibrates loose in flight.. you will hear it but you won't loose half the muffler.

Ross Kean

After the first time I lost the back half of a Magnum 40 muffler two years ago, I started double nutting the rod and then adding a dab of JB weld to the nut and threads. Didn't have a problem after that until last week. I had the muffler from my Magnum 61 apart and reassembled it in the usual fashion with a lock washer and double nut. I was in a hurry and the JB weld takes some time to harden so I skipped that step. Lost the back half after two flights!!!!! I find that the JB weld works better than Locktite for this application and can easily be removed if it has to come apart (give the bead a squeeze with pliers and it will break up so the nut(s) can be removed.

Ross

twostroke

My Feedback: (6)

Use the red loctite #271 that way you can get thm apart again will a small torch.

Bob Yeager

My Feedback: (5)

I'm not sure why it works, but I have had good luck using a bead of "Permatex Sensor-Safe Ultra Copper High Temp RTV Silicone" between the muffler halves. Apply the bead to the flange, assemble, tighten the screw and bolt, wipe off the excess. I'm not even sure where I got this idea. It seems to me, it was a hint or an article in RC Report a few years back.

Ed_Moorman

My Feedback: (1)

I hit mufflers with a triple whammy.
1. use the Permatex hi-temp silicone on the center joint as has been mentioned.
2. Use Lock-tite on the rod threads and nut
3. Use Zap-A-Dap-A-Goo or JB weld on the outside of the nut and rod extension.

The parts have to be clean for these items to work and they work best when the muffler is new and doesn't have any oil on it.

If you are replacing your AX muffler, buy a Tower .46 muffler for $15 and the Tower muffler bolts (they are slightly longer). The Tower will give you 700-800 more rpm forless cost than an OS replacement.

J_R

Macs makes a one piece muffler that is more expensive than the tower muffler, but it is lighter and adds about 500 rpm. The only real advantage is the weight.

You can drill the exhaust tip and use fine copper wire run to an engine mount bolt to keep from losing it, but, that does nothing for losing the nut or bolt. As Ed suggested, use lockers on all the parts.

Bob Yeager

My Feedback: (5)

And then there is the ultimate solution:

http://www.pspec.com/html/muffler.html

tommy157

My Feedback: (1)

I had the same problem I use a nylon inserted locknut..get them at Ace Hardware..$.29 ea for 6-32 threads...

daveopam

My Feedback: (9)

The JB weld works good for me. Also have you thought about a safty strap. Drill a small hole in the muffler at the exit or through a gusset on the muffler. Then attach a steel fishing leader to the engine mount screw. One end of the leader has a clevis and one end has a loop. This also works well on those gray Hobbico exhaust deflectors. It may ding the plane a little if it comes off, but you wont loose it.

david

FLYBOY

My Feedback: (11)

Geez, I have never lost one. Tighten the nut and haven't ever had it come off. Are you checking it once in a while?

Shouldn't have said that, now I will end up loosing 2. [X(]

taurus02914

usualy if you degrease the bolts and or nuts before reassembling them they shouldnt fall off .
We have one guy here who looses them regularly, he resorted to attaching a piece of wire to the muff and the other end to the firewall, hasnt lost another one yet.

aimmaintenance

I welded mine on a webra. Of course the Webra engineers had the brainstorm of a press fit.[:@]

pauluk2w

My Feedback: (7)

i always secure my muffler's with lock wire and secure it to the engine then if it does come off during flight i wont lose it.