From: "Stephen Izett stephen.izett@gmail.com" <flyrotary@lancaironline.net>
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Subject: Re: [FlyRotary] Updates on Muffler Experiences?
Date: Mon, 30 Oct 2023 07:05:58 +0800
References: <list-2550628@lancaironline.net>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
In-Reply-To: <list-2550628@lancaironline.net>
Message-Id: <FD5FABDF-5D44-4365-B774-560154E04023@gmail.com>

Hi Andrew

Do you have a photo of your engine/mufler?

Steve Izett


> On 29 Oct 2023, at 10:31=E2=80=AFpm, Andrew Martin =
andrew@martinag.com.au <flyrotary@lancaironline.net> wrote:
>=20
> Hi Doug,=20
> My setup is for a Renesis so bit different to an 86 13b, what I found =
worked well is a short & compact muffler, all homemade, a 60mm =
perforated ss tube welded to the mazda renesis exhaust manifold that was =
shortened as much as possible. I perforated the 60mm tube with 10mm =
drilled holes, enough so area of drilled holes is same as pipe inlet.  A =
100mm ss tube covers the 60mm tube and outlet of 100mm is at same end as =
inlet of 60mm, this is important to send sound waves back to source =
(works similar theory to ANR headset apparently). muffler is short, =
approx 150mm to keep it rigid & fit the space next to the psru. end =
plates of muffler were cut from 6mm plate & fully welded to both inner & =
outer tubes and covered with lightweight tin can as heatshield.
>=20
> If I was using p port exhaust I would mount individual mufflers =
directly to each port, inner pipe same size same as port, would look =
like 2 cans protruding from side of engine, connect short tailpipes =
(same volume as inner perforated pipe) as close to engine end of outer =
pipe as possible to exit cowl. Idea is to send sound waves straight back =
to where they come from without restricting gas flow.
> Probably as clear as mud, but my 2 cents worth, works a treat.
> Cheers
> Andrew Martin