View Poll Results: Is Vy flight path angle greater than Vx?

Voters
9. You may not vote on this poll
  • Vy flight path angle is greater than Vx

    1 11.11%
  • Vx flight path angle is greater tha Vy

    7 77.78%
  • Other opinion / no opinion

    1 11.11%
Results 1 to 10 of 52

Thread: Vy flight path angle greater than Vx ???

Threaded View

Previous Post Previous Post   Next Post Next Post
  1. #1

    Vy flight path angle greater than Vx ???

    A while back I decided to analyze runway design for obstacle clearances (angle to 50' vs distance vs climb rate vs speed, etc.) using my trusty spread sheet.
    In so doing I decided to incorporate data from various POHs.
    In so doing I found that in all cases Vy yielded a steeper flight path angle than Vx.


    Apparently Vx is NOT the "airspeed for best climb angle" it is the airspeed to use at LIFT OFF to give the shortest ditance to 50' of altitude.
    In other words; the sortest distance to 50' from the BEGINNING OF THE GROUND ROLL is attained by lifting off at the Vx speed.
    The basic idea to clear 50' on takeoff is to get off the ground as soon as possible and establish an IAS of Vx.


    This is very different from being "the best angle of climb speed" since while inflight if you need to clear the obstacle above you, you would go to Vy, not Vx.


    Comments, agree/disagree welcome.

    Poll is: agree Vy angle > than Vx
    disagree, Vy angle not > Vx, Vx is greater than Vy
    Other: ?
    Attached Files Attached Files

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •