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Date: Wed, 07 Jan 2009 22:42:10 -0500
From: Ernest Christley <echristley@nc.rr.com>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] FAW and the Phonoic gap  [FlyRotary] Re: Muffler
 design (was 20B isssues . . )
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Ed Anderson wrote:
> Ernest, keep in mind that the results you get with your sound recording may
> not be indicative of what real exhaust pulse would give you.  The reason
> -the exhaust pulse is a Finite Amplitude Wave - and they do behave
> differently in reflecting and refracting than standard sound waves.  
>
> The math is not too intimidating {:>)
>
> http://www.wikiwaves.org/index.php/Finite_Amplitude_Wave_Theory
>
>   
OK.  You're just making fun at my expense now.

I'd be upset if that page wasn't so dang funny 8*)

Another factor that will affect the experiment will be the difference in 
temperature between the test I do with PVC pipes on the bench, and the 
steel that is in the rotary's exhaust.  I'll probably end up with five 
or six mufflers before I'm done, but I hear that is what you've got to 
do before you can be considered hairy-chested.

-- 

http://www.ernest.isa-geek.org