How does an alpha vane work?

AsheeshR
  • How does an alpha vane work? AsheeshR

    The alpha 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?

  • For what I have stutied at my instumentation 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.

Related questions and answers
  • The alpha 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

  • I'm interested in short, or trick, take-offs - such as from platforms, tall trees, etc. I think that I should have a wind speed and direction measure an understanding of my wing surface area This will let me add to my intuition from regular launches (from sites with known-good launch conditions), and estimate how much velocity I need to add via a run / push. The methodology to count the wind measure seem a bit more grey, right now. I can have a sense of the wind where I am, but it may quickly change beyond my launch site. Since I'm considering how to launch from a stationary

  • translate to a deflection of the surfaces, mimicking the "old" mechanical control setup. It is my understanding that this is the design choice of Boeing in its new aircrafts. I do not wish to discuss how Airbus and Boeing made their design decisions, but rather see if there has been performed a study on what interface is preferred by pilots, eventually differentiating among private/commercial pilots...Provided an aircraft with a fly-by-wire system, there are basically two possible choices when it comes deciding how to let the pilots interface with it: rate control / attitude hold: a deflection

  • Air Force One is obviously a big deal. We close terminals and implement other seemingly crazy safeguards against terrorist attacks while the president is en-route to an airport. How does ATC protect the president whilst in the air? I have heard of TFRs for "VIP in the area" reasons — is that for AF1? I am guessing that the aircraft identification is blocked, but wouldn't they still need to have the transponder on for TCAS? Specifically, the Wikipedia page on Air Force One has the following quote: Air traffic controllers gave Air Force One an ominous warning that a passenger

  • In a full motion Level C or D simulator like those used by the airlines and for jet type ratings: How should a pilot log the simulator time in their logbook? I.e. Can you log: Total Time Instrument Time Time in Type Cross Country Time Night Time Landings (including night landings) Dual given/received Anything else?

  • radars confirmed this weird behavior from FlightRadar24. Also A/C before and after this one did not exhibit this behavior. Does anybody have any thoughts as to what may be happening??? Why is the "skew" at seemingly same angle? Is that anything? In light of MH370, does this happen often, how reliable is that GPS data? Tail # N657UA Boeing 767-300 Typical route between EGLL and KORD Time of occurrence is approximately: 3/16/2014 6:09pm CST I have also verified FlightAware is ALSO showing the same weird glitch. See below "yellow" highlighted airplane: Same A/C from FlightRadar24

  • Here is a $C_L$ / $AoA$ curve that I took from Wikipedia. The better textbooks say that a stall is that condition in which a further increase in angle of attack will result in a reduction of lift. The point at which that transition happens is known as the critical angle of attack. Theoretically, sustained flight is possible at angles beyond the critical angle of attack - take a look... curve without an angle of attack indicator? Or to ask the question another way, Is there a practical way to tell when an airplane has exceeded the critical angle of attack without an AoA meter?

  • How much the pitch (horizontal orientation) can differ from the angle of attack? I am trying to understand the claim that "angle of attack indicator was unfortunately not available", contributing to problems during Air France Flight 447. Attitude indicator most likely was available?

  • ? Apart from pilot workload and fuel efficiency (I know that trimming an aircraft can produce drag), what other benefits does trim offer? Without trim tabs, how is trimming accomplished? ...I know that historically pilots used to trim an aircraft to relieve continuous application of force during climb/cruise/descent, and at that trim tabs existed on control surfaces (elevator, ailerons, etc) which could be used to hold the position of the control surface without the pilot applying any force. But now, we don't usually have trim tabs, and with fly-by-wire systems forces have been

  • When I extend my flaps to 10 degrees, what exactly is the 10 degrees measuring? Is this referring to the angle of the flap blades themselves, the new angle of the wing chord, the change in the new critical angle of attack or something else?

Data information