Yup. I mis understood completely, still a 72 pulling near 4.5 kilos is a lot of work. I had an Aeromaster bipe that went 9 lbs and I had an OS 90 4 stroke on it. totally different type with symetrical airfoils and such but even with the scale like airfoil it seems like more would be better. My rule for power is if enough is good then more is better and too much should be given serious consideration. My 1/3 scale Nieuport 28 weighs 37 lbs dry (about 4 times your snipe) and has a DA 100cc engine. I fly around at something less than 1/2 throttle and seldom exceed 1/2 even taking off but if I need to pull the nose up in a hurry a big dose of throttle makes it go as high as needed.
Doc