Paul

Can you spin this @ 600rpm and suck air thru the radiator?

http://cgi.ebay.com/ebaymotors/Hughes-269-A-helicopter-cooling-fan-and-flywheel-assy_W0QQitemZ150242985379QQihZ005QQcategoryZ26437QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

tonys longez

Sure but I don't know about 600 RPM. Sounds low by a factor of five or ten.
There is no free lunch. That is going to suck HP and fuel burn.