Hi mate,

I don't think the Yak would be well suited to that motor, unless you could find a 3:1 gearbox that fits. Yaks are borderline 3D models - even in aerobatic setup they are the most fun when they have plenty of thrust for long vertical uplines, knife edges etc. With a prop that wont nuke your motor you would have to fly that thing using energy rather than thust - and there are some things you just can't do with that (like sustained knife etc).

I'm guessing even on 2s you wont be able to swing anything bigger than 7" safely (maybe 8" maybe - but you would need to measure to check).

Cheers,
Oz.