Keep the weight of the plane below 1 lb if you can, it will stunt better. The Fox 15x is very light weight, it weighs the same as many .09 engines and is much more powerful than the .09. Compared to a modern .15 it is not very powerful but when you compare it to engines of the same weight it really shines! Even the old Fox steel fin works well on this plane. I use a 7x5 prop on mine with a Fox steel fin .15 and 10% nitro fuel with 29% castor.

I shortened the nose about 3/4 inch on mine to get it to balance without adding weight.

A great flying plane to learn the pattern! Fly it on 45 to 50 foot .012 lines.