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Date: Wed, 22 Jul 2009 14:07:31 -0500
From: Dennis Haverlah <clouduster@austin.rr.com>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: Water spray supplimental cooling
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I'm still contemplating installing a water spray for use during high 
power climb-out. 
I used Ed's cooling spread sheet and estimated I need about 200 
Btu/minute additional oil cooling during climb..  I also calculated that 
5 qts of oil need about 288 Btu to gain 40 deg. F during the first 2 
minutes of take-off and climb  This translates to about 150 Btu/ 
minute.  I believe I need about 200 Btu/minute additional cooling to 
keep my oil cool on a 100 + deg. day.
 The Latent Heat of Evaporation for water is 970 Btu/# or 8050 Btu/gal.  
For a 10 minute climb I'd need 200 Btu X 10 or 2000 Btu.  This is 
approximately  1 Qt or 32 oz/10 minutes.  My water flow rate would than 
be 3.2 oz/minute.

I found some "misting" spray nozzles at Home Depot and found they work 
well at 30 psi.  I have a 12 V Schure RV water pump that can be used for 
initial testing.

Next week the afternoon temperatures will be above 100 deg again.  I 
hope to get the water mister installed so I can try it.

If the medical water pumps David Leonard has will provide 30 psi or more 
I'd be interested in trying them.

Dennis Haverlah