RE: How much motor to fly this?
I had two Sterling Stearmans. The first one I flew with a glow HP61. The second one I flew with an Enya 120 4 stroke. The extra power did not seem to make much difference but it used a lot more fuel. Between the 2 I would guess I had about 1000 flights Be careful to set the wing incidences correct. The plans are wrong.
I am currently flying a 11lb, 62 in Lazy ace witch is about the same size and is also a biplane. I power it with 9 A123 cells,a 60 amp ESC and 40 size Scorpion motor. It will fly about 6 minutes on a charge and take about 15 minutes to recharce. I have been flying for about 5 years.
The batteries are arranged to resemble a 5 cylinder motor. see the picture