Mailing List flyrotary@lancaironline.net Message #9248
From: Mike Robert <pmrobert@bellsouth.net>
Subject: Re: [FlyRotary] Re: Oil cooler air velocity was : [FlyRotary] Visit
Date: Thu, 24 Jun 2004 12:47:12 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Haywire wrote:

then your air velocity through your cooler will be
 

approx 0.1 - 0.3
of your airspeed.  So for a 200 MPH speed you might have 20 -60 mph air
velocity through your cooler fins not 200.  Just though I would
mention it.
   


Hi Ed;
Do you really think that it will be this fast? Even say through the Evap
cores? The reason I ask is that I've just installed a fan on the back side
of one of my evap cores to be used in conjunction with one of my EWP's to
reject cowl/engine heat after shutdown. I assumed/guessed that the airflow
exiting through the evap core will be slowed down to <5mph. I don't have any
data to support this, it just seemed reasonable.
I didn't add a shroud around the fan as I didn't want to hurt in-flight
cooling by forcing all of the air through the fan blades, even though this
will make the fan less efficient. But I think if it does see up to 60 mph
airflow then it's lifespan will indeed be short.
 

Auto experience: The RX-7 first gens place the oil cooler directly in the incoming air flow, no ducting or anything special to slow the air down, it's just sitting right there under the front bumper. I have a 12 volt fan from a 19" computer rack cooling system bolted to the back of it and it hasn't exploded/debladed/etc. yet after numerous miles at 80 mph. I power the fan only when stuck in traffic after a heat soaking fast run and the oil temp is creeping past 200F. I'm quite surprised at it's longevity. YMMV, obviously. Doesn't John Slade use a Ferrari fan for his coolant radiator app?

S. Todd Bartrim   (completing panel modification/upgrade)
Turbo 13B RV-9Endurance
C-FSTB
http://www3.telus.net/haywire/RV-9/C-FSTB.htm

  "Whatever you vividly imagine, Ardently desire, Sincerely believe in,
Enthusiastically act upon, Must inevitably come to pass".

 


      -Mike


 


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