I have a modeltech funfighter P-51. I'm running an OS .46 LA with a MAS 9X8 prop. on the bench tuned for flight it's taching 14200 RPM. do you think if I swapped out the LA for a .46 AX and put an 9x10 prop on it, I would get a noticeable gain in the top speed or the added weight would defeat the purpose of the swap? right now the plane is an estimated mid 80's in level flight. I'd like it to be faster!!!

I would, I think you will notice quite a difference.

i'm putting a NELSON 40 on mine

Put in a GMS 47 and a 9x7 prop. Around 15K rpm

i would say 8.8x9.0 @ 19000 +

Seems a bit high for a .46 AX, I'm thinking it's not going to turn that prop past 14k or so on the ground. Did I miss something?

I know, old thread. I've been out of action for 7 months, catching up on old subscriptions (all in this forum).

i meant those rpm with a nelson

The Nelson will test to see how well the Fun Fighter is put together.

use a 10x7 APC prop with the OS AX, you should be somwhere around 105 mph.

I don't think the 9x8 will be any faster.

it might turn a 9x9....but not a 9x10 at that RPM

but you really need is a Nelson or a JETT.