Date: Wed, 30 May 2007 11:06:57 -0400
From: Finn Lassen <finn.lassen@verizon.net>
Subject: Re: [FlyRotary] James Cowl - RV-7a - Renesis - Cooling
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
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Hi Dennis,

Hans already mentioned this in passing, but I want to emphasize it:
How well are the radiators sealed against the cowling and in between 
each other?

Seeming small cracks or openings can make a big difference.

Finn

Dennis Haverlah wrote:
> I had very marginal cooling on my first and second flight - RV 7A, 
> James cowl, Griffin Scirocco aluminum double pass water radiator with 
> a Mazda 1989? RX-7 oil cooler.  Water radiator fin size - 22LX13WX2.5T 
> inches. Oil - 19LX4.5WX 2T  inches.  The radiators are mounted 
> side-by-side under the engine and are at about 25 - 30 degree to the 
> inlet air flow. (The air must turn 60-65 deg to flow through the 
> radiators)   See photos 1 and 2.  After my first 2 flights, I 
> constructed a divider/duct to provide a duct for the engine combustion 
> air to make the sharp turn 90 deg. up after the inlet to get to the 
> filter.  The bottom of this duct was also supposed to provide a duct 
> wall for the air going to the radiators.  See photo 3.  Two flights 
> demonstrated this really hurt - not helped  - my cooling.  Now I can 
> barely take off and fly the pattern before getting up to 210 - 215 on 
> oil and water.  The divider duct took out about 8-10 sq. in. of inlet 
> area but removed the engine combustion air requirement form the 
> remaining inlet air going in the larger inlet.