Paul,

I DO NOT have experience with the engine, but if you ever believe published info about a product,

Keith had his test pilot fly around with on of the engines with NO DUCTING to test the heat issue....SUPPOSEDLY even without ducting, BECAUSE OF THE THINNER FINS, the engine ran cooler than his other engines.........

This makes some sense.....the thinner fins would absorb heat really fast and as long as there is adequate airflow, they will cool FASTER as well

Let me throw this analogy out to you......

I do a lot of metal work and can relate to it this way.........If you take some steel sheet stock, let's say 1/8" and 1/2" (just to show what I am saying), put a rosebud to it and start heating, the 1/8 will heat up faster than the 1/2....Remove the heat once both parts are cherry red and the 1/2" will stay hot longer......This is what an engine does....it applies heat when combustion occurs and that's it. HEAT AND COOL.....HEAT AND COOL. the fins are really going to absorb the heat and then they will cool even faster than a "STANDARD" fin