Quad Quad copter build

SF stands for Slow Fly, the P stands for Pusher so it spins ccw instead of cw. The two types of props are needed to have torque in two directions. Then as you want to turn left or right, two motors slow and two speed up, this causes uneven torque so the quad turns.
Hope this helps, its 2am here and i'm not thinking straight :D
 
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