Originally Posted by slipstick
As far as it goes NASA's part of that is all perfectly reasonable. Of course it fails to explain how or why the "moving flow of gas is turned by a solid object" and that's always where most of the debate comes in
The rest of the debate is caused when people paraphrase things incorrectly e.g. converting the accurate statement "Lift occurs when a moving flow of gas is turned by a solid object" into the incorrect "it's the air being shoved down that causes
lift". That's isn't what NASA says nor is it what they mean
NASA isn't quite as specific as I'd like, on the turning vs shoving air down either. Their turning link refers to a Newtonian response to turning a fluid, not a Newtonian response to shoving air down.
Can we trust them?
Or do we have to look at the "helicopter won't lift if a flat plate is attached to its skids" experiment?
Because to me, what NASA's saying, is that the lift is generated at the rotor, which means a chopper with it's downwash blocked should still rise - but it doesn't.
There are scientists claiming that lift is both - Newton response to downwash at low speeds, and Bernoulli at high speeds.
The chopper experiment intrigues me no end though - and I've yet to see a Bernoulli only, or a turning only, demonstration of lift in a chopper.