I just finished my Yak-55 Flight-flex, but I'm still waiting to maiden it, crappy weather. It's got an eflite park 370 1320 kv outrunner in it, with, at the moment a 640 mah 3S LiPo in it. When I next get money I'll buy it a 1500, or 1320. From testing it though it looks like it'll torque roll at like 1/3 throttle lol. I can't wait to get this thigh airbourne, it's been windy, and/or rainy ever since I finished it, but I imagine it'll fly something like the U-can-do ep. I'll let you know once I get it in the air!