i have a 9x7x3 and a 10x6e on the way shoudl be here monday.
to fly you need a lot less than 1:1 ratio power to weight. to take off or loop or other aerobatics needs a bit more.
here are some figures i quickly searched for a moment ago. take with a bit of salt. i do not know of thier validity
50-70 watts per pound; Minimum level of power for decent performance, park flyer/slow flyer models
70-90 watts per pound; Trainers and slow flying scale models
90-110 watts per pound; Sport aerobatic and fast flying scale models
110-130 watts per pound; Advanced aerobatic and high-speed models
130-150 watts per pound; Lightly loaded 3D models and ducted fans
150-200+ watts per pound; Unlimited performance 3D and aerobatic models
if i assume 12.4 v (likely lower) on my best test with the 9x4.7sf and 3s. it was 288 watts