Welcome Guest. Sign in or Signup

4 Answers

Manuevering speed : Va

Asked by: 2167 views Aerodynamics, Commercial Pilot, Flight Instructor

Hi.

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

Ace Any FAA Written Test!
Actual FAA Questions / Free Lifetime Updates
The best explanations in the business
Fast, efficient study.
Pass Your Checkride With Confidence!
FAA Practical Test prep that reflects actual checkrides.
Any checkride: Airplane, Helicopter, Glider, etc.
Written and maintained by actual pilot examiners and master CFIs.
The World's Most Trusted eLogbook
Be Organized, Current, Professional, and Safe.
Highly customizable - for student pilots through pros.
Free Transition Service for users of other eLogs.
Our sincere thanks to pilots such as yourself who support AskACFI while helping themselves by using the awesome PC, Mac, iPhone/iPad, and Android aviation apps of our sponsors.

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.

    0 Votes Thumb up 0 Votes Thumb down 0 Votes



  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.

    0 Votes Thumb up 0 Votes Thumb down 0 Votes



  3. John D Collins on Oct 04, 2014

    Kris, I think you meant to say:

    Therefore, Va decreases with reduced weight.

    0 Votes Thumb up 0 Votes Thumb down 0 Votes

  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.

    +4 Votes Thumb up 4 Votes Thumb down 0 Votes


The following terms have been auto-detected the question above and any answers or discussion provided. Click on a term to see its definition from the Dauntless Aviation JargonBuster Glossary.

Answer Question

Our sincere thanks to all who contribute constructively to this forum in answering flight training questions. If you are a flight instructor or represent a flight school / FBO offering flight instruction, you are welcome to include links to your site and related contact information as it pertains to offering local flight instruction in a specific geographic area. Additionally, direct links to FAA and related official government sources of information are welcome. However we thank you for your understanding that links to other sites or text that may be construed as explicit or implicit advertising of other business, sites, or goods/services are not permitted even if such links nominally are relevant to the question asked.