I just finished getting the bugs out of my Rascal 40. I have a YS 63 for power. It is like a snake ready to strike! With the YS63 it has no problem doing any manuver except unlimited vertical climbs. However I did have to lower the wing incidence by adding 1/8 of a inch at the back or the fusaladge just below the wing to keep it level with full power. I have a 11 x 6 zinger prop and it has plenty of pull.