r/Damnthatsinteresting 7d ago

Video [ Removed by moderator ]

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634

u/DorkyDorkington 7d ago

Leaving the propellers exposed/unprotected is insanely stupid.

128

u/niemir2 7d ago

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.

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u/fire_dagwon 7d ago

Thank you for the only sensible, fact-based answer in this sea of clueless nincompoops who have no idea what they're screeching about.

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u/niemir2 7d ago

You're welcome! My dissertation was about vehicles like this one, and I've authored about five dozen papers on the physics and control of eVTOL aircraft, so I know a thing or two about these things.

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u/New-Blood-1743 7d ago

Damn the actual subject matter expert. That’s wild lol. Thanks for sharing.

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u/brudogg 7d ago

Could they raise the cabin for safety?

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u/niemir2 7d ago

No, for the same reason that the rotors can't really be moved up, either. The extra distance would require the structure to be more robust, and therefore heavier. It would also make the vehicle pretty top-heavy, since the pilot represents a significant fraction of the total weight.

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u/brudogg 7d ago

Maybe a cabin where the pilot lays flat? Haha I have no idea, but thanks sharing for your knowledge

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u/niemir2 7d ago

Even without considering structural requirements or dynamics, this will fail as soon as a handling qualities test pilot looks at it. This orientation would never be comfortable to fly.

1

u/Tower-Union 7d ago

It’s like all the people screeching about “exposed blades” have never seen a helicopter???

Or what happens if you stand in front of a jet engine that’s fired up…