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Date: Fri, 09 Jul 2010 11:09:57 -0400
From: Ernest Christley <echristley@nc.rr.com>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Dyno
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Lynn, the dyno sheet looks like a standard dyno run where the engine was 
run from idle to WOT.  In this case, it looks like the carb started to 
be a restriction between 5500 and 6000 RPM, due to the drop in manifold 
pressure.

The question I have is if anyone has made dyno runs using the engine as 
we're more likely to use it in an airplane.  Has anyone made a run at 
WOT, and then use the mixture control to vary power?  At 5500 RPM, the 
sheet shows 174 Hp and a BSFC of .55 lb/Hphr.  At 6500 RPM, the Hp goes 
to 195 and the BSFC is back at .55.  The airflow is obviously increased, 
because the Mp dropped.  What would happen to the BSFC if the airflow 
for 6500 RPM is maintained, but the fuel is cut from the 108 lb/hr to 
the 98 lb/hr used at 5500 RPM?

I may (most likely?) just be completely confused about how it all works, 
but I know that Ed has mentioned that he controls power with mixture;  
however, I've never seen a dyno sheet that explicitly stated that it was 
a power curve generated by varying mixture at WOT.