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Date: Fri, 04 Mar 2005 09:27:34 -0500
From: Ernest Christley <echristl@cisco.com>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: EWP Test Results/DRAG
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David Carter wrote:

>I like dyno data for engine performance, but a "cooling SYSTEM" can't be
>simulated unless you put the dyno in a NASA wind tunnel and replicate the
>two main stages of flight - takeoff and climb at full throttle (need
>everything right for that speed) and cruise (don't need much coolant flow or
>pump) - - - and WOT top speed (for us racers or racer wunnabe's)
>
>David
>  
>

And a dyno won't tell you how the engine will perform in a race car as 
it is subject to high G side loads.

A dynometer is not for testing an entire system.  It's a way to 
conviently isolate parts of the system so that one part at a time can be 
optimized.  It's impossible to engineer ANYTHING with different sections 
changing all over the place at the same time.

The question Rusty stated was, "what effect does water flow have in a 
real engine?"  You can't reliably answer this question in flight, 
because everything else is changing around it.  But with a dyno, you 
install a variable speed water pump that circulates water through a 
static system (same radiator, engine and fan).  With a graph of the 
results you have some authority to state that reducing/increasing the 
flow will have such-n-such an effect.  If you increase/reduce the flow, 
you will have to compensate for the *effect* elsewhere.