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Date: Thu, 15 Jun 2006 12:55:52 -0400
From: Ernest Christley <echristley@nc.rr.com>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Remove Turbo
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Ed Anderson wrote:

> Anything you can do to reduce the power and therefore heat your engine 
> is developing will reduce the BTU of waste heat your cooling system 
> must deal with.  Leaning would reduce the heat load - but, whether 
> sufficiently to materially affect your cooling is another story.  My 
> calculations shows the following:
>
> Rpm    A/F ratio    Fuel Flow   BTU
> 1000   12:1            2.9            1417
> 1000   14.7            2.3            1157
> 1000   17.4            2.0            987
>
> However, keep in mind that at lower  idle RPM  you need a richer 
> mixture to keep the engine turning over, so you can not lean the 
> engine as much at idle as you can up in the air at cruise.
>
> My 0.02 worth

If it were possible, cutting the BTU by 30% would just have to help.  
'Course, that's just an semi-educated opinion.  I was thinking a little 
more throttle and a little less fuel, with the goal of having the excess 
air carry off a disproportionate amount of heat. I've heard you say that 
in cruise you can use the mixture knob to very effectively control 
power.  Why not on the ground?  Set the throttle to quarter or even half 
open and bring the mixture down till it will barely keep turning.

Note:  I still don't have an engine running, or I'd be experimenting 
with this myself and reporting the results.

-- 
         ,|"|"|,              Ernest Christley       |
----===<{{(oQo)}}>===----    Dyke Delta Builder      |
        o|  d  |o        http://ernest.isa-geek.org  |