X-Mozilla-Keys:                                                                                 
charles.harbert wrote:

Vlad, I'll make this short because I'm not an expert on this by any means, but I
can tell you what I've done to date. I started out with just the factory nose
mounted cooler (180 hp design) which was totally inadequate for a turbocharged
20B (300 hp), particularly during ground idle. I then added a 2nd nose cooler of
approx the same size on the other side, but again still inadequate (oil temp
225-235 F). I then added the 3rd oil cooler (same size) in a belly scoop which
solved the problem (temp 175-200). I now have totals of  250 sq in of frontal
area and 485 cu in of volume. I got my oil coolers from Griffin. They're
aluminum so be careful with them and inspect for shipping damage. UPS damaged 2
that were sent to me.

What I learned is that you're better off putting a 2nd larger oil cooler in the
rear in front of the water rad near the engine. I'd suggest you use a single fan
pulling thru both water and oil coolers because of  ground taxi time. If I don't
have the fan on, my temps really go high quickly. It will cool better when your
flying. This is an inherent problem for all pushers, even for a/c engines. Oil
cooling is vital for the rotaries and approx a third if the engine cooling is
thru the oil vs 20% for a piston engine. On top of that rotaries make more heat
than a piston engine per hp, so you need bigger rads than normal. Same is true
for water radiators. You'll need about 500 -600 sq in and 1100-1300 cu in for
them (assuming good in/out ducting).

Try to put your oil cooler on the cold side of the engine, so that if it leaks,
the oil won't be blown onto the exhaust and cause a fire.

 
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