How does an alpha (AoA) vane work? The alpha vane (also called AoA vane) is an external probe used to measure the angle of attack. I have been trying to understand how exactly it works, but I can't find any clear explanation or simulation. 



Is the vane static or dynamic i.e. does it rotate along its central axis?

Given that it has a significant surface area, I think that it would either:


Rotate because of the force/drag exerted by the airflow, and give an angle of attack proportional or equal to its angle of rotation
Measure the force being exerted on it via a force sensor embedded in the surface


Is either of these correct?



In short, how does an alpha vane work?
From what I have studied at my instrumentation course, it rotates and reads the angle between the current position and the reference position.

You then have several (3-4) of them around the fuselage because a roll maneuver (for example) will alter the measurements asymmetrically and in this way you can compensate for this effect.