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4 Answers

Manuevering speed : Va

Asked by: 2209 views Aerodynamics, Commercial Pilot, Flight Instructor


Why Va is varies with Weight??(how can i answer?)

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4 Answers

  1. Kris Kortokrax on Oct 04, 2014

    Put simply, at Va, the airplane will stall before it bends.
    Stall speed decreases with a decrease in weight
    Therefore, Va decreases with weight.

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  2. Nibake on Oct 04, 2014

    To add to that, the more weight the wing has to lift, the harder it has to work (higher AoA at any given speed) hence the increase in unaccelerated stall speed and Va.

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  3. John D Collins on Oct 04, 2014

    Kris, I think you meant to say:

    Therefore, Va decreases with reduced weight.

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  4. Best Answer

    John D Collins on Oct 04, 2014

    Va is a design speed and is defined only at maximum gross weight. At this speed, the wing will generate the same amount of lift just before the stall, regardless of the weight. At maximum gross weight, an accelerated stall at Va will generate a G loading equal to the certified G loading limit. At lighter weights, the lift is the same at Va, but the G loading can exceed the G limitation. Event hough the wing will only experience the same lift forces, this can over stress structures other than the wing. To keep the maximum G loading to not exceed the G limit, the maximum speed at which a rapid pitch control input may be made by the pilot is adjusted down by the square root of the ratio of the actual weight divided by the maximum gross weight. In common discussion, this is termed as reducing Va for the weight, but I think it is more accurate to say that Va is fixed as a design speed, but at lighter weights we use a lower speed calculated to not exceed the maximum G loading.

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