Comment on Can someone explain to me how a ventilation fan can suck LESS when on high compared to low?

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litchralee@sh.itjust.works ⁨1⁩ ⁨day⁩ ago

I like this answer. The only thing I would add is that when the fan blades are all stalled, it might seem then that drag and energy consumption should reduce, since there’s not much air moving. But in a cruel twist (fan pun intended) of aerodynamics, the useless spinning of stalled fan blades still causes parasitic drag. So not only does the fan not move air, it’s also consuming more energy than spinning a solid disk of the same moment-of-inertia.

When the engine fails for certain single-propeller aircraft, there’s sometimes a mechanism to lock the propeller to make it stop rotating, since it would otherwise “windmill” in the air and waste the previous kinetic energy that’s keeping the plane aloft. Or so I’m told.

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