Thanks for the nice words!Hi, Jeff!!! What a nice job you guys are doing!!!
a. what is the minimun powerplant requirement for the P85 (if possible, list hp/prop figures)?
b. fuselage lenght (prop spinner included) and wing spam?
Minimum engine: I would say 350 HP as a minimum. The plane will certainly fly and perform "OK" on less power, but you would be wasting the airframe structural strength, as well as engine weight. Since the P85 is meant to use an LS engine, I can't imagine putting a decent LS engine together that would not make at least that much power. The engine currently bolted to the plane is a 402 cid stroker LS2 block with LS3 heads and intake. Dyno'd way over 400 hp at 5000 rpm (and even more at the 5400 peak HP rpm), but we are propping it to use about 380-400 hp out of the box.
Prop: On this first P85 we are using an 80 inch diameter, 3 blade prop. The 1.8:1 re-drive ratio results in 2800 prop rpm at 5000 engine rpm. Seems like a high helical tip speed at 5000 rpm, although Catto says it will work - I am sure he knows more about his props than I do. Entirely possible to use a higher numerical re-drive ratio with a larger diameter prop, up to 98 inches diameter will fit with adequate ground clearance.
Wing span 26.8 ft
Length 22.3 ft