When I realized that the SunnySky 380KV motors were not powerful enough to power the Santa Cruz Project, I ordered one of each of 3 other motors.  That way, I could test them without spending a fortune.

One of the motors I ordered was the Turnigy AeroDrive 4240 - 530KV from Hobby King.  When I first looked at this motor, I noticed that it was big - bigger than I had imagined.

It wasn't too heavy, and it looked nice.  Best of all, it looked to have much better construction quality than most of the hobby motors I have bought.  The bearings were very tight and smooth. The windings looked good.  

So, I bolted on a 16" X 5.5" propeller and screwed it to one of the frames I have.  I connected to a 40A Turnigy PLUSH ESC, which can handle batteries up to 6-Cell.  I have a 5000mAH 4Cell battery (on bigger machines, I like to go with 4 Cell = 16.8V  batteries because for the same amount of power, the current is less and all the wiring has less loss). 

I used a "Servo Tester", an invaluable little accessory.  It is about 1" X 1", has a knob on the top and can be connected to any ESC and send the proper signals.  The knob allows you to adjust the PWM from 1ms to 2ms - full range.

So I held onto the frame tightly, and slowly turned the knob on the servo tester.  The motor started winding up.  There was very little motor "whine" - only the sound of the big 16" prop slapping the air.  I turned it up more and was astonished at how little throttle I had to give it before it REALLY started to pull.  So I connected it to my digital fish scale and put a DC current probe on the ESC input wire to measure the current.  By the time I got to 10 Amps, the motor/prop combo was pulling about 2lbs. I turned the knob more and the motor just kept winding up.  By the time I got to 30 Amps, the scale read 6lbs 5oz !!!  At 40 Amps, it was 6lbs 13oz!  4 of those could lift 27 LBS !  

40A at 16V is 640 Watts.  Since there are 745 Watts in one Horsepower, the little motor was probably putting out a little more than 3/4 HORSEPOWER!!! I admit that it could not do this forever, but I ran it at 30A for several minutes and it barely got warm. Best of all, it had a 4 ounces more pull when drawing 10A than my 28mm X 16mm NTM 800KV did (the NTM was spinning a 12" prop).

I ordered 3 more.  They should be here by next Monday.

Just to think... If I powered it with several 4-cell batteries in parallel (I would need 120 Amps),  I could probably lift 14 pounds of payload with a quad - and still fly decently.