How do wings generate lift when flying upside down?
In: 91
The force from the wings depends on the direction that they deflect air. Angle em up, they deflect air down. Angle em down, they deflect air up. You can adjust the wing angle by adjusting the orientation of the whole plane.
To keep lift when the plane is upside down, it just needs to be angled up slightly.
[deleted]
[deleted]
This is a great question and has often been answered incorrectly by experts. This Wikipedia article sorts through the various interpretations, and incorrect ones can still be found in physics textbooks they say.
[https://en.wikipedia.org/wiki/Lift_(force)](https://en.wikipedia.org/wiki/Lift_(force))
My follow-up question is how did the Wright Brothers figure lift out in just a few years?
AoA, or angle of attack. If you point your nose upward enough, and apply enough thrust, literally anything will fly.
So…this is partially the fault of the Bernoulli’s Law explanation of lift and flight, and how the only thing that ends up being emphasized is the “sHaPe oF tHe wInG” to the detriment of everything else involved in how lift works.
Drive around in your car. Get up to a reasonable speed and stick your hand out the window. Notice that as if you angle your hand upwards or downwards you can cause your hand to be pushed by the moving air in those directions.
That’s literally all lift is; the aircrafts wings deflect air downwards, and due to the conservation of momentum the amount of force applied on the air to push it downwards ends up pushing the aircraft *upwards*. If you want more lift, you change your angle of attack, and so deflect more air downwards.
Flying upside down is identical, but now you’re having to deflect the air downwards with the top of your wings, rather than the bottoms. Assuming your plane is built to structurally handle the loading, everything works the same way, just with the directions reversed.
[deleted]
Air moves around a wing, the design makes sure the air underneath serves as a cushion with more pressure and the air above as a lesser one but not entirely as a void, you still need some air pressure above the wing so it’s not constantly forcing the wing to up with speed and make the controller struggle to keep it where it’s intended to be.
When it’s upside down, the control surfaces still work albeit not as well as the air is meant to be slipping as easily from that side.
We’ve had a basic knowledge of aerodynamics for centuries so even in early wing design with powered flight the wings already had a shape meant to differentiate air pressure influence but you can still find in some models in the RC plane community where the wings are identical top and bottom and they’ll have similar control flying either direction.
[THIS](http://airfoiltools.com/airfoil/details?airfoil=n0012-il) is the page for a website called AirfoilTools, for an airfoil called the NACA0012. Look at the graph labeled Cl v Alpha. This is Coefficient of Lift vs angle of attack. Look at the y axis, and you’ll note that the numbers can go negative. Literally, if you tilt the wing down, you will generate a force of lift towards the bottom of the plane.
If you fly upside down, and tilt your wing such that you are generating lift *towards the bottom of the plane*, but the bottom of the plane is pointed *towards the sky*, you are generating lift in the upwards direction. Enough of that, and you can fly.
Can a plane choose to fly down? Yes. When a plane is upside down and they fly down which direction are they going? Up.
Latest Answers