I used a Himax 2025-4200 with a GWS C (5.33:1) gearbox, APC 10x7SF prop and Kokam HC1500 3S packs. It has unlimited vertical, top speed is in the high 50mph range and flight times are in the 15 min range with very little throttle control. At full throttle it really isnt a park flyer anymore...lol!