I fly a GP Cub ARF on floats w/ST90 and TF Spitfire with MVVS 91, 3 bladed Graupner 15/8 prop that looks almost scale size.

I like the scale sound, and how else could I get a 19 oz engine to swing a 3X 15/8 prop? And with the rear exhaust header, it doesn't even need a muffler!