I’ve got the idea to add a prerotator to my DC autogyro (see pics) to achieve a very short take off running even in no wind conditions.
In my opinion, there are two solutions:
1) A mechanical prerotator (see pics)
A servo controlled clutch is driven from the engine shaft by reduction gears. Bevel gears lead the motion upwards. Two universal joint couple the bevel gears with the reduction gears in the rotor head by a length compensating shaft. The rotor axis is driven by a one way bearing.
2) An electric prerotator (see pics)
An electric motor is coupled by two universal joints and a length compensating shaft to the reduction gears in the rotor head.

What do you think of these ideas? Which one is more realistic?
Problems: What kind of clutch to use? Reduction ratio? What electric motor to use? Change the receiver battery to lipoly battery (7,2 V) to drive the motor and reduce the voltage to 5 V for the receiver?