Hello! I just got back from the flying field with my 1/4 Cub. It is powered with a Saito 91 spinning an APC 15x4 prop. The plane weighs 13 3/4 LBS. ready to fly. As far as the comments on "scale power" goes........ The 91 is WAY more power than a full size Cub! I have about 34 hours in the full scale Cub. I am a Private Pilot. With the 91 it takes off in about 35 to 40 feet and climbs at about a 20 degree angle at a pretty decent speed. It does loops and rolls at half throttle. It also (much to everyones suprise at the field) does knife edge from one end of the field to the other without losing altitude! The knife attitude is at about a 45 degree angle. I have maximum throw on the rudder and quite a bit on everything else. Also the CG is at almost 5 inches back from the leading edge. I know you will not believe it but those are the facts. Some people at the field thought it was imoral to see a Cub do that! So, to anyone who does not think a 91 will power a 1/4 Scale Cub and do a good job at it...... you are dead wrong! I think it is the correct engine for the plane. This is a Balsa USA kit. ............... Jeff