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Date: Mon, 12 Oct 2009 13:06:04 -0500
From: Charlie England <ceengland@bellsouth.net>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] FlyRotary] where's the missing power?
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Lynn Hanover wrote:
>  1) The engine is a Bruce Turrentine built. Turbo housings and high
> >> compression NA rotors. No porting.
> >> 
> >> 2) The exhaust is a true 2 - 1 header with equal length primaries.
> >> I'm a little sketchy on dimensions but my recall is 1 3/4" primaries,
> >> 32" long and equal length into a Burns merge collector  2 1/2".
> >> Muffler is 4" behind the collector, 2 1/2" inlet and outlet, 28"
> >> long, 4 1/2" diameter. It's a spiral flow design, homebuilt, with a
> >> relatively large straight tube through the middle. I dont believe it
> >> presents any significant restriction. Internals are Inconel and it
> >> was in good shape when I had it off the airplane a couple of weeks ago.
>  
>  
> Your exhaust system sounds to be near perfect. I would not suspect 
> problems there.
>  
> Perhaps TDC mark may be in error. Actual ignition advance between 20 
> and 25 degrees?
>  
> Poor inlet shape on TB. Needs trumpet bell. 
>  
> F/A around 12.7. EGTs 1600 to 1675?
>  
> Lynn E. Hanover 
>  
>  
Or poor inlet shape on the intake tubes leaving the plenum, or one other 
possibility....

The normally aspirated 2nd gen engines were from 135-160 hp.  You 
mentioned that it performs better than your old 160 hp Lyc; maybe you're 
already getting all there is, short of a 2.85 redrive and retuning the 
intake.

Charlie