awat65

My Feedback: (17)

I have had 3 muffler bolts break on my TT 40 Pro. Does anybody have anysuggestions how I can stop this. I am tired of buying new mufflers. Somebody suggested I JB weld the two muffler halfs together, but is this legal in 424?.

Tony Watkins

[email protected]

I have reduced the breakages on the TT46 by using a solid mount eg metal, preferably a backplate mount, and ensuring the prop is suitably balanced eg horizontal, then vertical. Even wiring it together does help to reduce the cantilever on the muffler componennts ALSO check where the outlet tube is on the muffler- ensure it is, when viewed from the front, parallel with the wing. If not when you land with a side mounted engine potentially you can, with a hard landing land on the outlet pipe if the undercarriage has spread quite wide. I mount on the VIPER q500 aircraft and you will need to relocate the outlet pipe position. regards trevor h[sm=bananahead.gif]

SSAN

Tony,

You can either JB Weld the joint parts together for a permanent fix or you can use high temp silicon around the joint areas as an alternative. These two methods works fine for me when I started racing several years ago and never had any issue like others did. However, make sure you don't screw in the srew too tight or the silicon method will still break on you. Also, make sure to scuff the joint parts with sand paper and spray it with break cleaner before installing.

Hope this helps.

djlyon

I assume you are talking about the long through bolt on the muffler. If so replace it with a 6/32 threaded rod with nylon locking nuts on each end. thread the back half of the muffler to 6/32.

awat65

My Feedback: (17)

Thanks guys!

Tony Watkins

PortCityFlyer

My Feedback: (1)

I called ACE hobbies and complained about this problem. Believe it or not their tech guy said I was the first to report a problem and evidently was not operating the motor properly. I was astonished at his response. After much bantering he agreed to sell me a muffler for 1/2 price. I told him that the purpose of my call was to encourage a redesign not to save $15 on a muffler. I never took him up on his offer. Please do me a favor and call ACE with your muffler troubles so we can get them to stregthen the design.

daven

My Feedback: (1)

I've had the same problems with the OS muffler of similar design.

The best solution I have found was stated above, use 6/32 threaded rod all the way through with nylon lock nuts on each end. Before locking it tight, I clean up the joint real good and use JB Weld at the seam, I save a bit and dab it on the ends of the threaded rod overlapping the nylon nuts.

Do not over tighten the nuts. The threaded rod will not expand as much under heat as the muffler itself. If you overtighten the nuts you risk breaking the threaded rod in the air.

When that is all dry, I take some baling wire and wrap it around the front of the muffler back around the exhaust hole as a safety precaution. Doesn't look pretty, but will save you a new muffler if the back half does find a way of breaking loose.

djlyon

I suspect ACE considers operating the engine over 17000 rpm with a 9/6 prop as abuse. I'm sure they feel it should be operated in sport planes that just kind of toddle along. The many many orders they have recieved for replacement mufflers, that they never fill, should tell them something.

Denis

johnnychimpo

I emailed Thunder Tiger and they had a dealer ship me replacement bolts for my broken ones. The bolts breaks when you overtighten too. A permanant fix is gettting some 4-40 rods to replace the bolt.

fancman

My Feedback: (16)

I believe like stated above that this problem is now unique to just ACE. The same thing happens with OS mufflers and the first thing I do when I get a muffler of this type is take it apart and rough up the contact surfaces and use JB Weld to glue them together. I then put the bolt back in with red locktite and the problem is solved forever. I've also drilled and tapped the muffler and the mating band and have equally good results with that. In any case I think of you do nothing with any of these type mufflers it's almost a sure bet you're going to loose half of it in flight one day.

grubs4flyn

My Feedback: (1)

I say let them break. You can stay in shape walking the fields nearby looking for the baffle and back half. I did everything people said and still had one break the 6/32 bolt and JB weld. A piece of shielded wire will get you through a race day. I did everything all over, but this time I just barely tightened the bolt. I think the heating up streaches the bolt to breaking point if the thing is too tight. This last job seems to be holding pretty well, but I'm sure it's going to wait til race day. Just and FYI, several only last a few flights.

DHG

My Feedback: (7)

grubs,

Please explain? How are you using the wire, and do you need to drill any holes in the parts?

Thx

Duane

Lewis S.

My Feedback: (229)

Hello,
There is a real good soloution we found a few years back. W use 4-40 BMX spokes. They are soft and won't fail with the vibration. We run a dye on the one end and then silver solder on the nut, Then we double nut the other end and use high temp Loctite on it. Used the same muffler for 3 years that way.
PS, if you are turning up that high, find an APC 9x6 to pull it down to the 16,300 range, you will go faster.

Happy New Year
Lewis

grubs4flyn

My Feedback: (1)

Any kind of sheilded or coated wire that will fit into the bolt holes, then twist it tight on the outside. Not pretty, but will get you by the day.

awat65

My Feedback: (17)

A friend of mine is just going to weld the 2 muffler halfs together for me. It should solve the problem permanently.

Tony Watkins

daven

My Feedback: (1)

Tony, you may want to talk to the people that run the races in your area. Some don't permit welded muffler because it restricts inspection. I've had a couple welded and it does work well if the person doing the welding knows what their doing.

awat65

My Feedback: (17)

Thanks Dave for the tip, I will check.

Tony Watkins

awat65

My Feedback: (17)

Thanks Dave for the tip, I will check.

Tony Watkins