I know we’re here for the gas-motor free aspect of the ppg, but I think it’s worth looking into for the efficiency.
There’s statements about that a hybrid system can run a drone 20x longer than lithium. They’re just the size we’d be looking for! So instead of stocking up on heavy batteries for sustained flight. Or an inefficient larger motor, perhaps this is an option for longer flight.
I know these are about half the output needed, but it’s all easily scaleable and as stated by the Tech Ingredients guy, it wouldn’t be much more in weight.