Straightforward physics suggests the lift is a function of how fast you spin them. I'm sure with a fast enough spin you could get enough lift. Maybe rocket engines on the tips?

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chopin a day ago | parent [-]

The tips need to stay subsonic. A bigger rotor must turn slower. AFAIK the tips of current wind turbines are already close to this limit.

	▲	tim333 a day ago \| parent [-]
		Still subsonic speeds can produce a lot of lift. I mean jet aircraft weighing 200 tons lift off at about 160 mph. But googling wing tip thrust, jet engines are probably more practical than rockets.