So I just finished my 1.5m span pattern plane scratchbuild which flies much better than I had hoped for and have progressed to the point that I feel I can tackle what I have always wanted, a yak 3. I have already done much of the foam fabrication, in fact the airframe is 90% complete, built almost entirely from foam, will post pictures if you like. So far the specs that I aiming for are;
Span 1.38m
Weight all up 2.0kg including retracts etc
Battery 4000mah 3s
80A esc
Turnigy 790kv 35mm motor with a 15/5 3 bladed prop which according to ecalc will give me around 750 watts

Now my question; which needs more cooling, the motor, esc or battery? Secondly, do you think it is possible to use the machine gun ports to direct air for cooling inlet, and then use the under fuselage scoop(for want of a better word, its structure is similar to a mustang) as the exit? Also, what dimensions for cooling inlet and outlet would be needed for this setup? The reason I would like to use the machine guns as cooling inlets is that I am loathe to start opening up the cowl, I am trying to make this as scale as possible (a foam warbird but not a 'foamy')
The scale cooling inlets on a yak 3 are the wing roots but I really cannot see how I could use those. Any help would be appreciated.