A few months back, I saw the pictures of this prototype aircraft.
As I understand it, it’s difficult to make an aircraft like this maintain level flight because you control your orientation by changing the speed of the various propellers.
So, that night, I had a dream. Each engine would have a high power electric motor in series with the fuel burning engine. In order to keep the aircraft level, some motors would act like generators, and the current would flow to motors that act to increase the speed of the corresponding blade. There would be an ultracapacitor and a resistor bank for supplying surges of current or disposing of unwanted energy.
For a quadcopter :
Pitch is controlled by increasing and decreasing the rpms of the front and back rotors causing a moment which causes the copter to pitch up or down.
Roll Same mechanism as pitch but using left and right rotors instead of front and rear.
Yaw In a quadcopter the rotors are counter rotating. Two of the rotors rotate in one direction and two rotate in the other. If the rpms of all rotors are the same then no moment about he yaw axis is created. By altering the rpms of the sets of counter rotating rotors, a moment will be created and the copter will yaw.
All 3 of these critical maneuvers, you speed up 2 propellers (on a quadcopter) and slow down 2 others.
So this is a hybrid in the sense that you’re using electricity to distribute engine power more rapidly and as a source for huge changes in blade speed.
To keep the weight down, the motors might have to be superconducting.
In theory, this would still be simpler than the complex apparatus that helicopters use to govern blade pitch. Each engine module would be the engine, electric motor, power controller, and possibly a clutch. It would probably end up being an octacopter or more for some redundancy.