It seems that a big problem with electric controll line is burnt out motors and speed controllers with a nose over that stalls the prop.  It seems to me me that this should be an easy problem to solve.  I am thinking an air pressure switch that interupts the controll signal to the speed controller.  It would be held in the on or the run state by the air blast from the prop.  I am not sure how much time you have between motor stall and burn out.  I don't know if speed controllers react fast enough to a loss of signal to save every thing.  I am sure the motor would be OK, not sure about the speed controller.  By putting the switch in the controll signal line you would not be degrading performance by adding resistance to the high power battery input side.  Should weigh less than 1 oz. Any thoughts?

I am suprised that top of the line speed controllers don't have auto shut down on high current.

       

Hi John,
The better ESC models do.
In general, you should set the current limit/shutdown to FAST or SENSITIVE, but the ESCs do have provisions that protect in most cases.

Regards,
  Dean P.