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Date: Fri, 30 Apr 2010 18:54:30 +0800
From: Marc de Piolenc <piolenc@archivale.com>
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To: flyrotary@lancaironline.net
Subject: Eductor scavenging of radiator outlet
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Ejector cooling (not sure why the posters are calling the device an 
eductor - that term is reserved for machines that use a current of fluid 
to move bulk solids) is well worth pursuing. It isn't much pursued because:

1. people follow plans, even if a design has a history of cooling problems

2. ejector cooling is poorly documented in textbooks even though it's 
been worked on for decades, and research on unsteady-flow ejectors is 
ongoing.

Bruce Carmichael, Mr. Low Speed Aerodynamics, comments in one of his 
books that cooling drag in typical light aircraft is MANY TIMES what 
theory predicts it should be, so as other aspects of light airplanes 
become cleaner and more efficient cooling is the obvious drag abatement 
target.

The immediate benefit of ejector cooling is reliable static cooling 
during taxi and runup, without stealing precious shaft power for an 
auxiliary cooling fan.

Marc de Piolenc