I have been flying my 1/3 Sopwith Pup for 16 years on an old Quadra 50 that was used when I put it in. I use a 24-6 Zinger to get out past that big cowling plus I want low speed lugging ability, which is what I would imagine he would want for that Super Cub to look realistic. Smaller diameter props are more for speed than slow, realistic flight.

Tom