Pratt & Whitney Canada Developing Hybrid Electric Power - AVweb

Somehow I can’t see the energy advantage of inserting a generator-motor conversion step into the middle of the power generation and application chain. In ground vehicles such as trains or construction equipment the added flexibility of precise power control & application is an advantage, but in an aircraft, not so much. Mostly you just want to feed everything you’ve got directly to the props. Probably some aerodynamic advantages, but that seems to be about it.