Thanks everyone for the advice. Looks like big dia lower pitch to increase thrust. I've tried an APC 14-6 and Master Airscrew 13-8. APC was slightly better. I will try the 15-6 and see how it goes.

I also just 'borrowed' a tank of 25% Nitro off a friend. Holy S*^# what a difference from the 10% I've been burning. Vertical is about double what it was before it peters out. That was a pleasant surprise, altho my wallet will suffer. Like everything else about this hobby, spend more, get more!

Sprink, you have a 91FX in yours?? Wow, that thing must scream! Mine with the 91 4-stroke is REALLY fast. I have the throws about double the book high rates recommendation and snap rolls are blinding. I'm waiting for the wing to rip off one day, already cracked both wing mounts, luckily not on the same day. Its beefed with tristock now so if it breaks it will be somewhere else. If I put a bigger engine in I'm sure I'd kill the airplane. Also, can you get yours to flat spin? Mine wont come close yet but the CG could safely come back a little more.