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From: "Al Gietzen" <ALVentures@cox.net>
To: "'Rotary motors in aircraft'" <flyrotary@lancaironline.net>
Subject: RE: [FlyRotary] Re: FW: Phase 1 completion
Date: Tue, 3 Jul 2007 09:19:35 -0800
Message-ID: <000501c7bd96$5441a200$6400a8c0@BigAl>
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Subject: [FlyRotary] Re: FW: Phase 1 completion

Al Gietzen wrote:
>
> The other is that there is something strange about the timing. At low 
> power things appear fine; switching off leading ignition has more 
> effect than switching off trailing, as expected. At operating power 
> levels, however; switching off leading has almost no noticeable 
> effect; whereas switching off trailing drops the rpm by 400+ rpm - 
> which suggests that the timing is very late. Yet advancing the timing 
> via mode 8 does not make any improvement. What is wrong with this 
> picture? It is possible that the added filters caused a delay in the 
> timing, although analysis suggests the effect would be small. Why 
> doesn't advancing the timing improve the power? Is there a timing 
> change to one set of coils associated with disabling the other? We are 
> removing the filtering capacitors from the ignition circuits as a test 
> to see what the effect is.
>
Just a shot in the dark, but is it possible that you are too far 
advanced and are reaching peak pressure to soon? Just a slight alignment 
or measurement error could mess you up, and the rotary's resistance to 
detonation would mask the problem. A test would be to retard the 
ignition 1 degree, then disable the leading and trailing to compare the 
numbers to what you have now.
--------------------
Unless I am mistaken, spark too far advanced would diminish the effect of
the trailing plug and increase the effect of the leading plug.  What I am
seeing is the opposite.

Al