[MV=PY]

Opposing props spin in opposite directions. This allows control of yaw (slowing down one set and speeding up the other maintains height while altering rotational energy).

They are very stable.

This one has a gps, compass, 3 linear and 3 rotational accelerometers. It carries a GoPro 3. If it loses radio contact it goes to 60' and returns to the takeoff spot.

Highly recommended (it's a blast!). ;-)

For real fun, google FPV.

[mylife]

Amazing technology!

Lot’s of science and physics behind that.

[Carriage Hill]

I dropped one in my Amazon Cart. I’ll do the research on it tomorrow, and either get/dump it.