Muffler help

DaveJaksha

Gold Supporter
Joined
Feb 14, 2016
Messages
186
Location
Tucson
Aircraft
Sportcopter Vortex
Total Flight Time
100
Hey, guys. I am thinking about mufflers for my Yamaha genesis 3 cyl project. After looking around at other projects, I was thinking the solution shown in the picture below would be a nice clean installation. This is the muffler used on the Tangogyro. I talked to the guys at Tango, but they are to busy to supply me with one, so I was hoping someone in the group could suggest where I might get something similar fabricated? I check with a couple of muffler shops in the Tucson, AZ area, but they won’t touch it since its a aircraft. Other options would be welcome also.

Cheers,

Dave
 

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I've done some work with using a tuned exhaust on a 4 cyl. Lycoming. This muffler doesn't look like it comes close to using the HP increasing effects available from a tuned exhaust.
 
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Any racing car or motorcycle fabricator should be able to help.

Race cars have had mufflers for years and the fast guys have learned a lot.

I would have to see what was inside to know how good the muffler in the picture is. My first reaction is the primaries are too short and the outlet is too large.

I use to race a Triumph Trident in endurance races and their early space ship mufflers worked the best. It was a three into two with lots of tricks to keep the cylinders from talking to each other and bleads for specific frequencies.

Good muffler design is a complex art and overhead cams with fast ramps exacerbate the challenge.
 

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Talk to Richard Hawkinberry (HAWK) on this forum. He's a principal at Millennium Helicopters and a really great guy.

smiles,
Charles
 
DaveJaksha;n1131618 said:
...I check with a couple of muffler shops in the Tucson, AZ area, but they won’t touch it since its a aircraft. Other options would be welcome also. Cheers, Dave

Dave: It is an "off-road vehicle project", since you would be off the roads. And the engine is a snowmobile one.
 
The last I heard from Heath Lowery in SD, (who has the green-colored Kermit The Frog Aviomania single place open/enclosed gyroplane powered by the YG-4 engine), he was changing to longer primaries and secondaries than what he initially installed on that machine. He said the original exhaust basically allowed idle and then full-power, with little mid-range performance. He had rather short pipes.

I went from a home-built muffler on a longer pipe pointed aft along the keel under the prop (at the end of the regular Yamaha pipes) to using the original, heavy muffler (approximatel 20#). The resulting quieter exhaust tones enabled me to hear the intake being louder to my left behind me, than the new exhaust noise from my right while flying. It ran fine all the way up through an extra 500 more rpms here locally (200' ASL).

But when I took it to Rotors Over The Rockies in Utah, where the density altitude was +5K' ASL and higher, those extra 500 rpms only gave sputtering/ stumbling. I've gone to just straight pipes, which sounds about like the original loud exhaust note of that home-built muffler, and have back the crispness in all throttle responses. Tested by flying it quite a bit @ Alvord Desert dry lakebed in far SE Oregon (@ 4K' ASL), and it performs like B/4.
 
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