Mailing List flyrotary@lancaironline.net Message #12374
From: Ed Anderson <eanderson@carolina.rr.com>
Subject: oil cooler duct suggestion
Date: Sun, 24 Oct 2004 00:24:43 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Rusty,
 
   Glad to hear its all working well.
 
 I've looked at some oblique ducts in K&W and believe your first duct may just need some refining.  I've tried to draw (in blue) some suggested curves.  I think part of the problem is the blunt end of the duct opposite the intake make be causing the last 1/3 (perhaps more) to be less effective.  That back section of air in your duct  might be blocking/hindering  good flow into the last 1/3 or so of the cooler.  Also, I think with as flat as the airflow is to the core, you may need an airflow divider to force at least some of the inlet air to all parts of the cooler.  As it is - I suspect most of the airflow is going through the first 1/2 of the cooler with lesser amounts through the back half. 
 
The problem I see with your suggested revision is the losses you will encounter by having so much of the air having to make a pretty tight 90 degree turn to go through the core.  But, have not tired a duct this oblique so don't have any real data to go by. 
 
FWIW
 
Ed
 
Ed Anderson
Rv-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com
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