Comment by Gibbon1
8 hours ago
I'm curious about using a hybrid system where you have multiple electric fans. For instance 2 turbines and 4 fans. Advantage is smaller diameter for the same mass flow. And more redundancy. A negative is the weight of the electric motors and generators. If you added a battery you have some other advantages. Less pucker when you lose an engine. And better throttle response.
Another advantage is you can place the fans all along the wing getting you better stall resistance as the flow doesn't detach as easily. There's already a prototype of a hybrid plane that does this:
https://www.electra.aero/
You can go one further and just mount a squirrel cage fan in place of or on the front or top of the wing. https://en.wikipedia.org/wiki/FanWing
Or go further and use rotating drums: https://en.wikipedia.org/wiki/Flettner_airplane
Or you can use a horizontal-axis style helicopter rotor with variable pitch, and it gets you omnidirectional thrust (VTOL) https://en.wikipedia.org/wiki/Cyclogyro
There are a lot of interesting possible alternate histories (only requiring a few tweaks to physics) where fixed wings never really work and horizontal rotorcraft dominate, especially in a world where lighter-than-air craft are common - something like a hybrid between a zeppelin and a paddleboat.
There was never any possible alternate history where those alternative lift or propulsion approaches could dominate. The fundamental flaw is that in case of power loss they can't really glide or autorotate. Perhaps useful for some limited drone applications but not safe enough for humans.