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From: "Bill Schertz" <wschertz@comcast.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-2070151@logan.com>
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Subject: Re: [FlyRotary] James Cowl - RV-7a - Renesis - Cooling
Date: Sun, 27 May 2007 17:27:34 -0500
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Dennis,
1. Can you put a pressure probe in front of and behind the radiators to 
measure how much delta-P you are getting?

2. How close to the back side of the radiator is the oil pan? Too close can 
cause the air to not want to go through the rad.

3. Are the oil and water radiators sealed to one another to prevent air flow 
between them?
----- Original Message ----- 
From: "Dennis Haverlah" <clouduster@austin.rr.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Sunday, May 27, 2007 1:11 PM
Subject: [FlyRotary] James Cowl - RV-7a - Renesis - Cooling


>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.
>
> My inlet is about 50 sq. in. and the outlet is about 67 sq. in.  This
> cowl was used successfully on the Power Sport a/c so I believe the inlet
> and outlet are at least big enough for 160 + hp.  When I first posted
> pictures of the radiator installation someone suggested I may need
> turning vanes to improve flow to the radiators.  I am now ready to try
> the turning vanes below the radiators.
>
> Does anyone have info. I can use to design the turning vanes?  The K&W
> document on page 273 mentions guide vanes but does not go into detail.
> I am thinking of 2 inch wide vanes long enough to go from the left to
> right side of the radiators and spaced 4 inches apart  with the top of
> the vanes about 3/4 inch below the radiator  fins.
> Comments or -- Any other ideas?
>
> Dennis H.
>
>
>
>


--------------------------------------------------------------------------------


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