Thanks for your query and your comments.

Firstly with regard to the Tigercat - the RCV60SP engine has a 2:1 reduction gearing, therefore the speed at the prop is half of the engine speed. You therefore need much larger propellers than conventional engines. We recommend the use of a 13.4x13.5 propeller (or similar). You can get this actual size from www.apcprop.com. Obviously you will need to check that you have enough clearance for these propellers. Without having specific experience with these models we cannot give you definitive advise however a couple of 60SPs should have the power to pull the Tigercat.

Assuming clearance on the P-38 was okay, you could also use this size prop for this application. Another RCV user has put a couple of 58CD's in a P-38 if you are interested, see www.rcvengines.com/gallery_58cd_p38.htm

With regard to the B-25, one of our customers has actually put a couple of 90SP engines in his plane and it looks fantastic. He has cut down 15.75x13 3-bladed APC props to 15x13 and you can view this plane on www.rcvengines.com/gallery_90sp_b25.htm

I hope this information helps
If you have any more questions, please don't hesitate to contact me.

Best regards
Laurenne