not only the low pressure zone.
The article was annoying me a little bit because it threw all these references to 'aerodynamic experts' that were all puzzled by a low pressure force sitting on top of the curve of the wing and couldn't explain what it was.
And I'm sat here, a layman by comparison, going 'isn't that just drag being generated by the over-wing airflow because it doesn't move in nice straight lines and will swirl about when told to move. Especially at high angles of attack, which is what eventually causes wing stall.
It's what leading edge slots were designed to combat, but what do I know?'.
Generally they can't. But some are able to, see aerobatic aircrafts for example. Symmetrical wing profiles exist, and still they are able to generate lift (though they are not the most efficient). What matters in this case is the angle of attack.
Ha, I mean properly fly upside down. Most aircraft can operate 'inverted'
And I'd never say otherwise
But as you say, that depends massively on an increased angle of attack than normal and newton rather than bernoulli to stay airborne.
Their lift may degrade upside down but they don’t fall as if lift has been inverted, would be something like falling at double gravity
Upsidedown wings generate downforce, not lift. They
do act as if gravity has been doubled (or even increased by a factor of 5). That's how F-1 cars work.
If the article was correct and wings operate the same regardless of orientation, then helicopters could fly upside down without issue as long as you could rotate the blades sufficiently to a positive angle of attack.
Aaaanndd they can't. Yeah, there are helicopters that can go upside-down. Lynx for example is fitted with a rigid rotor hub (no 'blade sail' when maneuvering) which means it's one of the few helicopters that can do rolls and loops etc. It's also the fastest true helicopter (Osprey is not a helicopter) in the world, and will always hold that title cos physics.
But even that doesn't really fly upside-down. The loops are more like stall turns and rolls are done safe in the knowledge that you'll
never be at the start altitude when you finish. If it did work, then trust me the pilots would do it. I've been in Lynx many times when it was in service and the pilots are
not shy.
Look at any aircraft upside down. The nose is much higher, especially at low speeds. That's because the engines are having to push the aircraft up, rather than the wings lifting the aircraft up. Helicopters generate little to no lift thrust and only fly because of lift generated by the rotors.
Which is why being upside-down in a helicopter for any length of time ends in a crash. Always.
The article goes on to explain that wings without curves are also used to generate lift. Yeah, speak to any pilot who flew the F-104 Starfighter and ask him about the lift generated by the less than a centimetre thick blades attached to the side of his aircraft.
There's a reason why they were nicknamed flying coffin nails.