Mailing List flyrotary@lancaironline.net Message #63032
From: <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Exhaust setups
Date: Sun, 22 Jan 2017 03:57:29 +0000 (UTC)
To: Fly rotary blog, e-mail <flyrotary@lancaironline.net>
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The SS flex we used has that same bellows inside the webbing, the bellows is very loose without the webbing. On your basic auto/truck/suv, when the webbing breaks loose from the end holdings the pipe usally fails soon after. If you catch it before pipe fails just add worm type hose clamps to both ends, will last for many more years.  David R. Cook RV6A Rotary
From: "Matt Boiteau" <flyrotary@lancaironline.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Saturday, January 21, 2017 8:32:40 PM
Subject: [FlyRotary] Exhaust setups

I'd personally (and I did) stay away from the woven stainless and go with the flex bellow. On my turbo car (non-rotary), I've melted the stainless mesh into a ball and closed up the exhaust. Airplane rotary has an flex bellow (like below), but I have't ran it yet.
Share a photo of your exhaust.


Inline image 1

- Matt Boiteau


On Sat, Jan 21, 2017 at 5:21 PM, Dennis Havarlah <flyrotary@lancaironline.net> wrote:
After about 700 hours and 8 years flying I have decided to design and build a new exhaust system for my RV-7A powered by a 4 port RX 8 Renesis engine.  Bobby Hughes has offered advice and greatly assisted me in this endeavor.
 
The new exhaust was designed with three header pipes routed into a 3 to 1 collector that is 3 inches in diameter.  The headers and collector direct the exhaust toward the firewall.  A combination of 3 inch and 2.5 inch pipe take the exhaust down and out the bottom of the cowl and the exhaust exits about 12 inches back from the firewall.
 
I have flown with the new exhaust and discovered it causes a lot more vibration to the airframe than the old exhaust.  (I have a ball joint in the down pipe at the firewall).  I want to add a flexible joint down stream of the 3 to 1 collector and have about 3 inches space for it.  MY Question  -  Has anyone used a flex coupling or a flex bellows as seen on Summits web site?  The flex coupling is a woven stainless joint with a liner inside and weldable ends.  The flex bellows looks like a metal bellows on the outside and has a slip joint built inside. 
 
Anyone  have any experience with these on the rotary?
 
Thanks,
 
Dennis Haverlah
 


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