Proping a OS 25LA
Hi!
A 9x7 is a little too large for the OS .25 LA , though it could spin a 11x4 with ease if used on a light highwinged trainer ...on a low winged sport aircraft from which you demand a little more performance a 9x5 or a 9x6 APC is much better...that is if you fly at sea-level.
Regards!
JanK