Quote:
Originally Posted by winkosmosis
Read the NASA article. The Bernoulli Effect is not what makes the plane fly. The air flows faster over the top of the wing, yes, because of the angle and the downward curve at the rear-- airflow on the bottom is compressed because it hits the underside and slows down relative to the plane. But the air speed difference is a tiny tiny contributor. It's not the majority or even a major portion of lift.
Redirection of flow is what creates lift.
If you know of a plane that can fly at 0 degrees wing pitch, post it.
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The de Havilland DHC-7 climbs with a five degree nose DOWN attitude because of the large camber (curve) of the upper surface of the wing. The "downflow" of airflow at the trailing edge of the wing does not exist. Upward pressure at the back of the wing would deform the structure and most of the lift is generated at the center of pressure, usually in the first third of the airfoil.
The airflow on the top surface of the wing does not "arrive later" at the trailing edge. It accelerates due to the longer distance it must travel in sub-sonic flight. The airflow below the wing does not "compress" and is nearly the same as atmospheric pressure. The difference in the pressure above and below the wing is what creates lift. Purely Bernoulli.
The effect of deflecting airflow is Newton's theory. That is how you see RC aircraft with completely flat wings fly. Symmetrical airfoils still use Bernoulli to create lift because the angle of attack causes the airflow to travel faster over the "top" of the wing.
The propeller of a powered airplane is also an airfoil and it produces thrust (lift) based on exactly the same prinicipal.
Drag producing devices such as trailing edge flaps and spoilers use Newton's law to redirect airflow for increased lift during takeoff and landing. They are still increasing the speed of the upper airflow and thus, creating lift.
I can go into much more detail with regard to rotary-wing aerodynamics, but that is not germaine to this thread.