Mailing List flyrotary@lancaironline.net Message #36151
From: Ernest Christley <echristley@nc.rr.com>
Subject: Re: [FlyRotary] Engine noise and changes in timeing and mixture.
Date: Tue, 13 Mar 2007 12:53:25 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
WRJJRS@aol.com wrote:

For Tracy,
 When I was actively tuning race cars we had a truism that I often used, "everything changes everything". This was a drastic oversimplification, but none the less was true. If you have an engine running very well, a seemingly minor change WILL change exhaust note or timber. On the dyno you would find some adjustments did little, others a great deal. The fact is as you get the mixture closer to right I am afraid you will hear the exhaust not come back up in volume.
Bill Jepson

Maybe not, Bill.  Without the snubbers, there would be some unknown and possibly variable delay in the closing.  There would also possibly be varying delays between different injectors.  This variability might not be enough to feel a vibration, but the exhaust pulse would be slightly stronger from one chamber than the other.  It would only be detected as more noise and would express itself as a slop factor in tuning.  Remove the variability and the tuning can be more exact since the same amount of fuel will be delivered every time, giving Tracy that extra 100RPM.

Possible?

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        ,|"|"|,              Ernest Christley       |
----===<{{(oQo)}}>===----    Dyke Delta Builder      |
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