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Date: Tue, 29 May 2012 14:23:11 -0400
From: Ernest Christley <echristley@att.net>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Injector balancing
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Mark Steitle wrote:
> Ernest, 
> 
> Not sure you intake and mine are very similar.  I assume that you have a
> single TB.  Since I'm running a p-port motor, I needed to have the
> throttle plates as close to the intake ports as possible.  So, I'm
> running three separate 46mm throttle bodies.  The primary injectors are
> between the butterflies and the intake ports.  The primary injector
> bungs are cast into the TB's.  They share a 1-piece throttle shaft.  
> 
> The secondary injectors are located further out on the runners ahead of
> the butterflies.  Each runner connects to a single airbox.  The #1
> intake is at the rear of the airbox, #2 in the middle, and #3 in the
> front.  Air is fed in from the front corner with a 4" SCAT.  I could
> test your theory by removing the airbox.  This would make all three
> intake runners identical.  May be worth a try.  
> 

For the purposes of my theory, your setup is nearly identical to what I started with.  The air came in the front, blew
past the first rotor, and the rotor in the back wound up with its fuel and part of the front's.  The plate I put in made
it so that the incoming air did not blow past the front rotor's intake toward the second.  Instead, it now has to
pressurize the manifold, and then roll around the plate to approach both runners directly.  I had idle EGT differences
of 400* to 500*, and only evened out when the speed got really fast.  They now hang within 100* at idle, and are dead
even over 2000rpm.

Verifying even flow is a necessary exercise, but from your description I strongly suspect that you have a pressure
distribution problem in your plenum.