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Bob, while combining exhaust headers of the proper length can provide scavenging - you can also get it with the single headers - self scavenging. The powerful exhaust pulse when it hits the atmosphere (or a larger cross section muffler) returns back up the pipe as a refraction (negative?) wave. If the pipe is of the correct length (rpm dependent among other factors), this refraction wave will reach the exhaust port as it opens and the lesser pressure it causes can help scavenge the combustion chamber.
The benefit of mutual scavenging is that the length of tubing to make that happen is shorter (by approx 1/2) than the self scavenging approach. The reason is there is approx 120 rotor degrees between two exhaust port openings on one rotor, whereas there is only approx 60 deg rotor degrees between port opens between the two rotors permitting a shorter tube to get the timing right which is rpm dependent as well as exhaust gas temp dependent.
FWIW
Ed
----- Original Message ----- From: <btilley@mchsi.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Saturday, July 28, 2007 9:03 AM
Subject: [FlyRotary] Re: Individual Exhaust
Joe,
Several people have done just that. The one concern I have is that there isn't any scavaging
between rotors( one exhaust pulse pulling the exhaust out of the other rotor).
Bob
---------------------- Original Message: ---------------------
From: "Joe Ewen" <jewen@comporium.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: [FlyRotary] Individual Exhaust
Date: Sat, 28 Jul 2007 12:05:18 +0000
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