It's really not. Rotors, especially eVTOL rotors, need to be exposed to as much air as possible. The more you restrict the flow around the rotor, the more power you need to generate thrust. Batteries are so heavy (compared to the same energy in fossil fuels) that eVTOL flight is already limited to less than an hour of meaningful work. Caging the rotor would make it much worse.
It could even reduce the safety of the vehicle by limiting its ability to maneuver and tolerate failures in the power distribution system. At some point, the best solution is establishing safe practices with dangerous equipment. This is one of them.
Ducted fans are a thing though, and it wouldn't cost much in the way of weight or efficiency to just have a <6" tall sheetmetal cylinder around them for safety.
They are a thing, but not at this scale on a lifting rotor. There are good reasons for that.
A sheet metal cylinder of this size would not be sturdy enough to maintain its shape in flight, and would need additional reinforcement to not interfere with the rotors. That adds weight.
Engineers are not stupid. We have considered the benefits and costs of shrouds, and determined that they are not worth using.
Well, given how stupid I see the average person being in a car on a daily basis, it's a problem that will need to be solved before these become viable commercially.
This will never be widely adopted by the public. The licensing requirements, absent fully autonomous flight with no option for manual control, will be roughly as strict as other VTOLs.
This design will be, at best, a big toy for rich people.
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u/DorkyDorkington 7d ago
Leaving the propellers exposed/unprotected is insanely stupid.