I am using an OS 70 FourStroke engine
on my GP Ultimate...
Excellent flyer with engine, almost unlimited
verticals and still is a good floater relatively
to a bipe!
I love flying this plane, have casted a fiberglass
cowl as well as wheel pants.!
Have changed to two seperate servos (in the wings)
for the ailerons and fibergalssed the fire wall
as well as the adjacent fuselage walls.
Have placed the battery in the middle of the fuselage
and am just on the recommended CG....
Regards
Hisham.