RE: Motor/esc/Prop
I have a SPEED 480 motor in my Cessna running direct drive with a 8x4E prop and it is pulling 18 amps. So I would venture a guess that your 400 motor, if it is direct drive with no gearbox, should be around a 7x4, 7x5, or maybe at the most an 8x4 to be around 12 amps.