Bud:

The Saito 180 in this plane was flown before in a CAP and I tried different props including the 18x6. The 18x6 works well too but a bit less forward speed; the 17x6 works better for aerobatics. I din't have any 18x6 around so I put the 17x6 in the Cub. Performance on this plane is not an issue compared with the CAP.
Teryn