Mailing List Message #65373
From: Andrew Martin <>
Subject: Re: [FlyRotary] Re: Mufflers
Date: Wed, 20 Nov 2019 09:46:09 +0800
To: Rotary motors in aircraft <>
Yep. Thats the picture I was trying to upload, mine is the same but lots shorter so suspect louder than Garys. whole thing fits in cowl alongside the PSRU. it fits inside a baby formula milk tin that I used as heat shield. If doing again I would make it a bit longer, but it surprised me how good this is. 5mm end plates are fine so far, I actually think they are overkill but that is what I had available when I knocked this up, they are fully welded to both inner & outer pipes, bit like a puzzle to put together but possible. Some of the other pictures posted are misleading. Most important detail is that gas must enter and exit at same end.
I will go to airport today, take photo and post better description.

Neil. no turbo yet, I do have one I rescued from one of our tractors when it was re-powered. turbo specs escape me for now but gas flow rate between applications did match. but that will have to wait until I have finished my phase 1. I've sworn to no more mods until this plane is signed off.

On Tue, Nov 19, 2019 at 11:36 PM Matt Boiteau <> wrote:
Here is the picture from Andrew's email. 

My exhaust is stupid loud. I've tried a few things which didn't work. Getting noise complaints around the airport while testing.

Just reading this Gary Schwarz's link, looks promising. Andrew, did you fit yours inside the cowl? I'm surprised 5mm endplates are holding up.

- Matt Boiteau

On 2019-11-19 12:57:36 AM, Andrew Martin <> wrote:

Kelly, I would if I had some, really did not expect it to work as I deviated from the design a bit. Will be back at airport on weekend to take photo, too late for construction photo. But nothing to it.

I read about the idea by Gary Schwarz in this thread, post #7 , post #58 for his testing and post #142 sums up his findings.
Someone on here may know him as he was doing it for a rotary. Mine is much shorter than his drawing below due to space constraints but the theory works.
edit: Ahh!!! deleted his picture as too big to post. it is in his post #7 mentioned above though.

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