Prop height

[grdev]

I will be using a 72" prop on my XL with the center of the Prop hub 8" above the crankshaft center line. Using the center of the firewall as a reference for the center of my crankshaft, that raises the center of the prop almost even with station one top cross member, or just at the bottom of the wind screen.  Will having the prop raised to that height  cause any adverse effects?. I could always lower the engine 8" but then I would need to build longer gear legs  to have at least 8" of clearance on the prop with the fuselage in a level position.

[rockiedog2]

I put my thrust line 6" below the top long(what I call the longitudinal axis) thinking that will make the pitch response correct when adding/reducing power. when adding power the nose rises; when decreasing power the nose lowers. seems like I read that in some manual long ago. well, it works on mine. I think that's a requirement on certified planes.
I expect the thrust line has been tried all over on homebuilts and there are large variation in the results...like those planes with the motor on top of the wing. Gene/Larry Smith has all those planes with redrives...might give him a call and see what he says. he oughta know