how wings work? Smoke streamlines around an airfoil

What people said

Recommends Peter Kämpf · 2017-07 · Aviation Stack Exchange · on “What causes pressure disturbances ahead of the wing?”

An approaching body needs to push air out of the way. Directly ahead of it, it will compress the air such that the local pressure [LINK] increase will push the air out of the way. When the body is a lift-producing wing, the lower pressure on the upper side will suck the air towards it. So what can be observed are two effects: Air gets compressed ahead of any body approaching at subsonic speed, the more the faster the body moves, and When lift is created, this pattern will be distorted such that the flow will turn in the direction of the lift-producing suction. The propagation speed of small pressure changes can be observed with your ears. Sound is just that: Small fluctuations in pressure. A

Recommends Izak the coder · 2018-03 · Aviation Stack Exchange · on “If both propellers and wings are airfoils, then why do propellers deflect air perpendicularly to the rotor, but wings not?”

Here is my dilemma. I have seen a lot of videos of airfoils in wind tunnels, and I've noticed how the airflow always moves away from the trailing edge parallel to the wing, or at a very small angle away from the wing as in this video: I've also heard that propellers are nothing more than rotating wings (airfoils), producing lift sideways as opposed to upwards. What confuses me is that in the case of the propeller, the airflow leaves the propeller at a much higher angle, and not straight as is with the wing. In other words, the airflow is deflected backwards from the prop. I just can't understand how the wing and propeller, which are two very similar shapes (maybe not that similar, but they o

Recommends TomMcW · 2019-01 · Aviation Stack Exchange · on “How does Bernoulli's principle contribute in lifting airplane?”

Please see this smoke test video: [this video] The air above the airfoil reaches the trailing edge before the air below and at a higher velocity. What you’re stating here is the “equal transit theory” which is incorrect. See NASA website [LINK] for why it is incorrect.

Cites Electric Pilot · 2017-12 · Aviation Stack Exchange · on “Is it possible to maintain horizontal flight with the angle of attack above critical value by increasing speed?”

In this video [this video] a stall happens at 1:40 upon reaching the critical angle of attack. The air flow is now detached from the upper part of the wing, resulting in higher pressure above the upper part of the wing, thus eliminating the major factor of lift. [LINK] Let's imagine that we have extremely powerful engines and enough tail stabilizer authority to maintain horizontal flight with any speed. Is it possible to maintain horizontal flight when: wings have high angle of incidence (let's assume some experimental design)* aircraft has zero pitch condition (straight and level flight) permanent state of high angle of attack (as the consequence of the 1 and 2) *high angle of incidence is an an

Cites mins · 2018-01 · Aviation Stack Exchange · on “What is the physical meaning of circulation found in Kutta condition?”

The Kutta–Joukowski theorem is applicable for 2D lift calculation as soon as the Kutta condition [LINK] is verified. When this is the case, there is a circulation $\small \Gamma$ around the airfoil [LINK] . My question is related to this circulation: What is the physical meaning of the circulation $\small \Gamma$, often represented like this ( example 1 [LINK] , example 2 [LINK] , example 3 [LINK] ): [LINK] (Own work) I'm interested in a simple explanation of the circulation (is air moving around the airfoil? for dummies) and how does this circulation relate to a view of the airflow in a wind tunnel, where there is no apparent air flowing clockwise around the airfoil: [LINK] Source: [this video]