Speaking of  a rad under the engine Tracy mentioned at Shady Bend
     that the air temp inside his cowl was 50 degrees F higher than
     outside air temp. I was a bit skeptical about this as I knew
     the rad only heated the air 10 degrees F or so. The rest of
     the heat must be coming from the engine block and the exhaust.

     I just realized part of the reason we have had so much
     trouble cooling the rotary is most people have the rad
     in the cowl dumping hot air into the cowl. Duh! The heat transfer
     rate between rad and air is a strong function of the difference
     in temp. If the rad is 220 and the air going through it is
     100 the difference ie 120. All well and good.
     However if the rad is immersed in air that is 150 F the
     difference is only 70F!!!!!!

     Ding Dong!!!

     Wait a minute; am I missing something here?  The air coming into and going through the
     rad is the air from outside.  The rad is not seeing the in-cowl air, and it should not
     be a factor.  Looks like one of those great insights that is wrong in hindsight :).

     Al

Oh damn I guess I was wrong. I thought for sure I was on to something
there.

Paul Lamar
 
The AirCraft Rotary Engine NewsLetter.  Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/            
Copyright 1998-2002 All world wide rights reserved.