Mailing List Message #65319
From: Andrew Martin <>
Subject: Re: [FlyRotary] Exhaust setups
Date: Mon, 11 Nov 2019 13:56:18 +0800
To: Rotary motors in aircraft <>
Matt. Did I read that right. Your 4" tube is open at the end? Would that not make it try to emulate a trumpet.
I would close the outlet end completely then cut an outlet in the 4" at the inlet end. You end up with a very effective Schertz pipe exhaust.

On Mon, 11 Nov. 2019, 11:38 am Matt Boiteau, <> wrote:
What are you guys running for exhaust? The thing is stupid loud and can barely talk on radio. Headset is LightSpeed wireless Tango's. Their ANR does not work well with the pitch of the rotary. Will try a Bose headset tomorrow.

I have 2.5" exhaust leaving the cowl. (ex1.jpg)  It comes down and centers the bottom of the plane into a 4" outer pipe. (ex2.jpg) The 4" outer pipe (5ft long) is open to the free air and exits behind the rear bulkhead. The 2.5" converts to a 3ft long perforated pipe (ex3.jpg) and exits inside the 4" outer pipe. For fun, I filled it full of ceramic fiber insulation mat, which did help a little until it blew all out.

- Matt Boiteau
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