Paul
I am building a Bear Hawk which has a aluminum wing.
I was thinking if you attached .375 O.D. .250 I.D. tubing to the under
side of the wing skin running from the front spar to the rear spar
and coupled the .375 O.D. to a 1" I.D. tubing running parallel with the
front and rear spar to make a large heat sink and let the aluminum wing
radiate the heat. How hot do you think a wing would get? The Bear Hawk
has 222 sq ft. of wing area. I figure it would require 16 .375 O.D.
tubes, 30 inches long (8 for the upper skin and 8 for the lower skin)
for each wing. The heat exchanger would weigh 17.25# if it were made
from "M" cooper tubing for each wing. Plus a little over 1.6 gal of
coolant per wing. If the wing didn't get to hot and cause problems from
expansion, and heating the fuel takes, the cooling drag could be reduced
considerable.
Just an idea and thought I would throw it out to see what every one
thinks of the idea.
Would the boundary layer prevent any significant cooling?
Here is how you can compare. Calculate the surface area of
radiator exposed to the air and the surface area exposed to the
coolant. That will give you a rough idea if a skin surface radiator
will work. The Schneider cup people did this surface rad trick in
1930 and had a lot of trouble. Also Lockheed tried it
with the P38 for the intercoolers and also gave up
and went to a conventional inter coolers.
-- Paul Lamar ...No rotor no motor.
Paul,
Peter Garrison did an article on exactly this idea with the calculations
of available surface area etc...
His conclusion was that it won't work. If you have a lamilar flow
airfoil also, things just get worse due to boundry layer effects. It
always seems like this might work though, too bad. A real plumbing
nightmare though.
Bill Jepson
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I'm sure that if it could be made to work, someone, somewhere would have
done it successfully by now. I always wondered if the exhaust heat could
be used to de-ice the wings-2/3 of the heat energy of the rotary goes
out the exhaust. Wouldn't you just need to get the wings over 33 degrees
to de-ice them? Just wondering, I've got no intention of ever flying in
ice on purpose.
Brian Trubee
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