Received-SPF: none
 receiver=logan.com; client-ip=24.25.9.102; envelope-from=echristley@nc.rr.com
Message-ID: <41C307E8.8040007@nc.rr.com>
Date: Fri, 17 Dec 2004 11:23:04 -0500
From: Ernest Christley <echristley@nc.rr.com>
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040113
MIME-Version: 1.0
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Dynamic balance
References: <list-567069@logan.com>
In-Reply-To: <list-567069@logan.com>
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Transfer-Encoding: 7bit

Perry Mick wrote:
> I did that too way back when. I was told I need to run it's output 
> through a spectrum analyzer. Audio frequencies so an audio spectrum 
> analyzer would work. You could input to the audio card in a PC and use a 
> PC audio spectrum analyzer.

Ed,

You were calculating the position of your discs by estimating the 
temperature in the exhaust and such.  Have you thought about using 
Perry's method?  Record the sound and analyze that to get the exhaust 
frequencies that are actually present.  It seems that it would also have 
the advantage of telling precisely which ones were stongest and in need 
of attenuation.


-- 
http://www.ernest.isa-geek.org/
"This is by far the hardest lesson about freedom. It goes against
instinct, and morality, to just sit back and watch people make
mistakes. We want to help them, which means control them and their
decisions, but in doing so we actually hurt them (and ourselves)."