RE: Engine upgrade for Super Skybolt ARF?
I replaced an OS91 S-II with a Saito 100 (same bolt pattern) in a TF Corsair and there was a very noticeable difference in power. I didn't think the Saito would be that much stronger but it was. The 125 should be even better. Try both the Saito 125 and OS 120 AX and let us know your results.
Fred