well, i really have no intentions of buying a liquid cooled engine (although it crossed my mined), and i want to use the engine i already have.

hi "old man", thank you for your answer.
It seems that i have a problem, isnt there any other way cooling the engine while hovering?
the plan is to build a shroud that will surround the prop, kinda like a ducted fan... a prop ducted fan,
if the walls of the shroud will be high enough to contain both the prop and the engine itself, wouldnt it be sufficient to force enough air over the cylinder and keep it cool?
p.s, while serching RCU for some VTOL information, i came across some of your threads, a lot of useful information, thank you.

Raviv.