New answers tagged angle-of-attack
0
A cambered, or "airfoil-shaped" wing cross section will have a significant curve (bulge) on the top surface, usually with the thickest part nearer the leading edge, while the bottom surface will have no or minimum curve. The result of this is that air passing over the top surface of the airfoil has a longer distance to travel than air passing over the bottom ...
2
symmetric wings don't produce any lift at 0° AOA whereas cambered wings do.
Yes, that's correct.
Usually, the most important difference is that a cambered wing is optimised for a positive angle of attack. It produces less drag for the same amount of lift, and can produce more lift before stalling.
Obviously that assumes that the wing is the right way up - ...
1
Leading-edge stagnation point moving down with increasing angle of attack is true for inviscid flows, however the same does not always hold for viscous (or more realistic) flows, especially around stall. For a given airfoil, if angle of attack increases, the leading-edge stagnation point could move up or down from the leading-edge depending on the flow state ...
5
This depends very much on what the AOA sensors are used for.
Traditional airplanes
Traditionally, AOA sensors are only used for stall warning and stall barrier (i.e. stick pusher). In this case, you can get away with only two AOA sensors. A sensible design would trigger the pilot/copilot side stall warning with the onside (or opposite side) AOA sensor, ...
0
Let's start from the fact that nearly all airplanes have 'AoA protection' in the form of stall warning.
For automatic stall prevention, strictly speaking, one doesn't need FBW: this can be achieved with traditional automatic control means (the infamous MCAS is, in essence, an example of such a system). On the other hand, FBW does not have to have stall ...
2
Your answer is correct. The pressure distribution from the xfoil simulation on a NACA 0012 are shown below for AOA 0 and AOA 5. As you can see, the lower side pressure does increase. However, most of the lift is generated by the suction on the upper surface, which is typical of subsonic flight.
2
I'm pretty sure you were right. More angle of attack means more lift. More lift is caused by higher pressure under the wing and lower pressure on top. More lift causes more induced drag.
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