RE: RCS 150 and Ziroli Hellcat overheating?
I use the Saito 450 3 cylinder in my 1/5 Wildcat. I used dummy engines to create a baffle for in coming air. Very tight to the cooling fins. I think you should consider a 1 to 2 ratio of air coming in to air leaving. I opened up the cooling flaps on my cowl and have not had problems this summer in 95 degree humid Virginia air.