Paul et al,

For what it's worth, a classic formula for cooling air inlet area in
low-to-moderate performance aircraft is .35 sq. in. per climb
horsepower. This is usually applied to air-cooled engines, but I suppose
the heat rejection per horsepower is not that different for a
liquid-cooled one. There is much dispute about outlet area; one
suggestion is 10% greater than inlet.

For air-cooled engines the cooling air requirement is a function of
delta-p, that is, the pressure drop across the engine. I have never
worked with a liquid-cooled installation, but I assume there is some
such factor for a radiator as well. Delta-p is in turn a function of
forward speed; if the dynamic pressure is below the required delta-p,
the expected cooling performance will not be obtained.

What strikes me about the photos is that if the central radiator is the
coolant radiator, there seem to be surprisingly large alternate routes
for the incoming air. The wind bloweth where it listeth, as the prophet
quite correctly pointed out. If the cowling provides an alternate route
with lower impedance than that of the main radiator, the air will follow
it and avoid the main radiator.

Peter Garrison

Yes I agree. Sealing around the rad is extremely important.

Thanks Peter.


Paul Lamar

Is this the Peter Garrison of Flying Magazine?  His recent writeup
about the CG range of Melmoth II was especially interesting..


Regards,

Matt-

Yes.

Paul Lamar