Nice little Kobra

prop selection has everything to do with how you pipe is set up.

What prop are you using now? What rpm? What is the pipe length set at ?

In general (without knowing the above info), the OS 32 likes rpm. I'd tend to work with an 8x7, 8x8, 9x6, and maybe even try the APC 8.5 x 7.25 q-500 prop - all depends on how the plane resonds to it.

Bob