I would have to say the 91FX will have little or no vertical performance. 10 pounds is a bit heavy for it. It may actually hover, but it will be at 100% throttle to do so. BUT, It will fly quite nice, much better than scale flying. The 91FX is pretty much topped out at 9 pounds. IMHO of course. I had one on a 8.5 pound Ultimate and was very dissappointed. 90% power to hover (10% nitro, 15x6 TF prop) very sluggish pull out. No transition on a 15 inch prop. No hovering on a 14 inch prop.