Mailing List flyrotary@lancaironline.net Message #36815
From: Al Gietzen <ALVentures@cox.net>
Subject: RE: [FlyRotary] Re: Cooling area drag
Date: Thu, 3 May 2007 17:12:36 -0800
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>

 

I had a local hydraulic wizzard calculate my coolers and lines. He thinks the stock pump will handle it. #8 lines, coolers inseries

 

Bob Mears

Bob;

 

How many feet of line?  Lots of -8 lines, and two coolers in series could have significant pressure drop, certainly before the temp comes up.  With the pressure control at the far end, it is subjecting the coolers and the upstream line to that much higher pressure.  I don’t know for certain that it is a problem, but my engineering judgment suggests it’s not the best.  I did some sort of analysis on mine with my 2-3 ft of line on each side of the cooler, and looking at the 16 gpm oil flow we measured on the dyno, I went to -10 lines.  Rotaries have significantly higher oil flow rates than their piston cousins.

 

I think someone else suggested tipping the rad the other way, and moving the inlet scoop forward and up.  In addition to reducing the corners the air has to make, it could have the advantage of better flow and lower drag because it puts the inlet more into the ‘compression’ zone at the front (external diffusion).  May allow a smaller inlet.

 

FWIW,

 

Al

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