Timeline for Are wings any more efficient at creating lift, versus orienting the engine's thrust downwards?
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13 events
| when toggle format | what | by | license | comment | |
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| May 4, 2017 at 14:04 | comment | added | Koyovis | Airplanes do fly by throwing air down. A flat plate can create lift. | |
| Apr 19, 2017 at 14:29 | comment | added | Philip Roe | @reirab: Oops, apologies. I did indeed mean to reply to Simon. | |
| Apr 19, 2017 at 4:53 | comment | added | reirab | @PhilipRoe What would be news to most aerodynamicists? Having worked with several of them at an aerodynamics testing facility, I'm pretty sure they're generally aware of Newton's Third Law. Maybe you meant to reply to Simon instead? | |
| Apr 19, 2017 at 4:51 | comment | added | reirab | Unfortunately, a lot of the material even that's taught to pilots in flight training is wrong in regards to how lift generation works. Both Bernoulli's Principle and Newton's Third Law are both true at the same time. It's not a matter of some of the lift being generated by one and some by the other. All of the lift follows Newton's Third Law. The force applied in the downward direction to the air is equal and opposite to the force applied to the upward force applied to the airplane. When the vertical speed is not changing, this force is equal in magnitude to the airplane's weight. | |
| Apr 18, 2017 at 22:13 | comment | added | Anthony X | Doesn't matter how you analyze it, some basic facts don't/can't change. Air is fluid; you push on it, it moves. Air has mass, so if you push on it and it moves, work is done. Wings never "pull" on air; if, as you say, the wing reduces air pressure on the upper surface, ambient air pressure pushes air down in response to the unbalanced forces. So, as a wing is generating lift, air is being displaced downward, which requires an input of work. You can still consider the wing as generating vertical thrust, via large masses of air accelerated to very low downward velocity. | |
| Apr 18, 2017 at 18:39 | comment | added | Peter Kämpf | @Simon … yet at supersonic speeds it is partially true. And in ground effect, too. | |
| Apr 18, 2017 at 15:30 | comment | added | Simon | @PeterKämpf Yes, I was pointing out that the high pressure "lifts the wing up" myth has been abandoned. | |
| Apr 18, 2017 at 15:24 | comment | added | Peter Kämpf | @Simon: Thick airfoils have suction on both sides, but there is always a pressure difference when there is lift. | |
| Apr 18, 2017 at 15:23 | comment | added | Simon | You might want to read up on the theory of lift. The high pressure below, low pressure above theory has been well and truly laid to rest. Lift is the opposite and equal reaction to the air being accelerated downwards. | |
| Apr 18, 2017 at 15:22 | comment | added | Peter Kämpf | So what happens to the air flowing over the wing? The suction on the upper surface pulls the air above the wing down and the pressure on the lower side pushes more air down. As a result, the air is accelerated downwards when it flows off the wing. Yes, airplanes fly by pushing air down; this is not a simplification but a consequence of the pressure field around a wing or helicopter rotor. | |
| Apr 18, 2017 at 14:53 | review | Low quality posts | |||
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| Apr 18, 2017 at 14:09 | review | First posts | |||
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| Apr 18, 2017 at 14:07 | history | answered | Suncat2000 | CC BY-SA 3.0 |