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Date: Wed, 08 Feb 2006 15:35:45 -0500
From: Ernest Christley <echristley@nc.rr.com>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Six port bolt-on manfold progress (was:  RX-8)
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BillDube@killacycle.com wrote:

> In the car, all the intake valves are open at something like 6500 RPM 
> (maybe even lower.) My manifold emulates the stock manifold in this 
> condition. Should work OK for the expected RPM operating range.
>
>         With a 2:85 PSRU, the max prop RPM will be 3157. As I 
> understand it, this should not be a problem for a 72 inch prop.  You 
> just have to pitch it correctly to absorb 243 HP at that RPM (at 
> altitude.)
>

Bill, I think Ed was saying that if you pitch the prop to absorb 243HP 
at 3157, then it will be producing ?160HP? at ?2000RPM?.  You're engine 
will be turning 5700 with the prop at that RPM.  The question is, "Will 
5700 engine RPM produce 160HP or greater?"  If you don't get >160HP at 
5700 RPM, you'll never be able to get TO the 243HP that is sitting there 
waiting for you.  A CSprop would let you feather it  past the lower RPMs 
and bring you into the sweet nirvana where you manifolds tuning works at 
its maximum.  With a fixed pitch prop, it may be questionable until you 
build one and try to run it.

How'd I do, Ed?


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