Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Aerospace Lift of wings

  1. Apr 20, 2004 #1
    Dragonflies can create 20 times the lift/weight ratio of an aircraft by using turbulent air which passes from one set of wings to another.Why don't we give airplanes a second set of wings to do the same?
  2. jcsd
  3. Apr 20, 2004 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Because dragonfly wings flap.

    Research into ornithopters is currently going on. I'm not sure if they are sophisticated enough yet to have a control system to take advantage of two sets of wings.
  4. Apr 20, 2004 #3
    Because dragonflies utilize the movement of the wings to generate vortices that travel down the LE of their wings. Its more than just the turbulent flow passing from one wing to the next.

    watch the gif at the top of this site:

    And read this:
    http://www.physicstoday.com/pt/vol-53/iss-12/p22.html [Broken]

    Would you fly in an airplane with wings that moved like that?

    BiPlanes are an old concept but they have a limiting flaw--drag. Without the figure 8 motion to produce and utilize the turbulent air the second set of wings would add a substantial amount of drag.

    P.S. I'm not an aeronautical engineer or physicist so take the above with a grain of salt.
    Last edited by a moderator: May 1, 2017
  5. Jun 25, 2004 #4

    Attached Files:

  6. Jun 25, 2004 #5

    Planes with two wings were developed in the early part of last century, though the wings themselves didn't flap like an insect.
    Some early experimenters with flight tried the flapping method for flight to no avail. Using flapping wings to try and create lift is very inefficient method for heavy objects such as airplanes. I don't know where you got these ratios but
    a dragonfly is much much lighter than a human.
    Last edited: Jun 25, 2004
  7. Jun 26, 2004 #6
    Flapping Wings

    Objective is to prove by a model that flight with flapping wings is practicable.
    Leonardo da Vinci had no current materials composits (Carbon, fiberglass etc.)
    The already model shows that it is possible .The necessary power is lower than that of a classic plane of the same weight by disregarding the Cx.
    For the human transport it is still UTOPIA.
    Robert Korobelnik
  8. Jun 26, 2004 #7
    Can they hover? Can they be made fast? Cab they be made big?
  9. Jun 27, 2004 #8
    Can they hover? yes
    Can they be made fast? Yes and so bought ready to fly
    Cab they be made big? Certainly in a few years
  10. Jun 27, 2004 #9


    User Avatar

    Staff: Mentor

    Aerodynamics for small airfoils is different than for large ones. Structural loadings scale as well. Because of these two issues, flapping wings will not scale to human-sized craft.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook