Quick****w, I've had no problem at all with cooling; note that I did cut out two additional holes on the bottom of the cowl for better cooling. Note also that initially I had a problem with the exhaust pipe joints staying tight--the vibration and heat would loosen the joints no matter how tight I made them. There may be a better solution but JB Weld did the trick; now if I ever want to undo it that could prove interesting! Take a look at geocities.com/jbrundtz/st-m.html for a good website for how to put together this model with the exhaust completely enclosed. One thing's for sure--GP's estimate that this ARF can be properly put together in as little as 15 hours is conservative! It took me a lot longer.