Mike Wills wrote:

   No expert advice here. But the trend that I see with these airplanes as
 they start test flying is that most tend to start with undersized inlets
 that get hacked to bits to get the cooling under control during the test
 phase. IMHO its easier/better/safer to start with an inlet area thats too
 large. You can more easily reduce the inlet during testing as need be while
 avoiding overheating early in your test program. My inlets will be approx
 55 sq. in. for the rad and approx 25 sq. in. for the oil cooler initially.

 > Mike Wills

I agree Mike.

BTW I gave up on my custom rad. I bought a 16 by 27 by 2.25 thick Howe rad

>from Summit Racing for $199.95. The core itself is actually 15 by 24 inches.

It looks like a mass produced 2 tube row core designed for plastic end tanks
and Howe just welded on aluminum end tanks. It does indeed look like the
tubes are aluminum furnace brazed into the header plates.

I tried tig welding on a stock 2nd gen Mazda core and it can be
done, no problem.
No melting of the brazed tubes takes place due to the convoluted shape
of the stock header plates dissipating the heat before it can reach the tubes.

The labor involved is high however as you must clean the header plates
thoroughly. Preferably with a caustic etch. Using stock cores would make
my custom rad too thick for the space under the cowl so I gave up.
Perhaps I could find thinner cores that would work but they would
no be cheap.

This Howe rad is a quick, simple and cheap solution. Took two days
for Summit to get it to me. I will have to weld custom inlets
and outlets on it but what the hey.

Given the 25% rule for relatively thin rads the opening would be about
90 square inches.

Paul Lamar

Mike, Thanks for the good advice.

  Paul,   You must have changed your mind.   810 cu in of core!!   I
like it.  Jerry

           Jerry

It was cheap and I have a turbo looking for 250 HP or more :-)

Smallest one you can get for under $200. Most are 27 by 19  for
that price.

Paul Lamar
 
The AirCraft Rotary Engine NewsLetter.              Powered by Linux.
ACRE NL web site.
http://home.earthlink.net/~rotaryeng/            http://www.linux.org