shuttlepilot
Well-known member
- Joined
- May 9, 2003
- Posts
- 59
I was at the dentist this morning and read this in the May 08 Popular Science magazine,pg10.
Question: ... stated that an airplane rises because air underneath the wing pushes it upwards. But I thought that it was because the wings shape creates low air pressure above it and the wing lifts...
PS reply:This is a common misconception. although the pressure difference you mention does exist (and is described by a physical law known as Bernouilli's principle) it is not nearly large enough to lift an airplane. Instead lift is achieved mostly by a process called "flow turning". As a wing moves forward, it pushes air downward. Per Newton's third law of motion-everey action has an equal and opposite reaction-that push generates a force in the opposite direction, which in this case is upward.
So what happened to the 4 forces of flight? Are there 5 now?
Question: ... stated that an airplane rises because air underneath the wing pushes it upwards. But I thought that it was because the wings shape creates low air pressure above it and the wing lifts...
PS reply:This is a common misconception. although the pressure difference you mention does exist (and is described by a physical law known as Bernouilli's principle) it is not nearly large enough to lift an airplane. Instead lift is achieved mostly by a process called "flow turning". As a wing moves forward, it pushes air downward. Per Newton's third law of motion-everey action has an equal and opposite reaction-that push generates a force in the opposite direction, which in this case is upward.
So what happened to the 4 forces of flight? Are there 5 now?