How did WWI Planes Fly?

  1. Hello. I've just been curious as to the answer to this question. Modern aerofoils are fine due to the geometry that allows for a pressure difference between the upper/lower surface. But as I remember WWI planes, they all have 4-5 levels of straight wings. Does that serve the same purpose? How? I tried googling it but couldn't sort through the irrelevant topics. I'd appreciate anyone who can feed my curiosity!
     
  2. jcsd
  3. Pilots were much stronger back then.
     
  4. The airplanes had airfoils.
     
  5. Hi, interesting question. I don't know the answer but I googled some pictures of WWI planes. A lot of them had two layers of wings that look like they have some curvature. This combined shape looks like a silhouette of sections of an airfoil, (from Cyrus) probably because each wing is an airfoil.
    [​IMG]
     
    Last edited: Mar 29, 2009
  6. russ_watters

    Staff: Mentor

    Just an fyi, even a flat plate will fly if it has a positive angle of attack...but I don't think anyone has ever tried to fly one. Even the Wright Flyer had a real airfoil.
     
  7. Vanadium 50

    Vanadium 50 17,542
    Staff Emeritus
    Science Advisor
    Education Advisor

    A plane works by pushing air down. That's exactly what the WW1 vintage planes did - and as pointed out, they do have an airfoil.
     
  8. DaveC426913

    DaveC426913 16,128
    Gold Member

    4-5 levels? The most was 3 really (Fokker Triplane) the large majority had 2 wings. I think the reason they were bi-wings rather than the later mono-wings has more to do with the strength of materials and how much lift a wing of a given length could support.
     
  9. mersi kurosh
    Thanks, good to know!
     
  10. :wink:
     
  11. Adding vertically stacked layers improves lift, but with diminishing returns with each added layer This is due to interference. There's no improvement in aspect ratio by stacking wings; the drag increases with each layer, as the lift advantage slows.

    You're right, the box construction was for strength. The Fokker triplane has an additional small foil between the wheel. Any structural members such as the carriage axle produce drag. Wrapping an aerodynamic shape around it reduced drag. So presumably, it's a source of free lift if you give it an angle of attack.

    Even the cross wires where teardrop shaped, eventually. A teardrop shape half an inch across has about the same aerodynamic drag as a wire of about 100 mils diameter.
     
    Last edited: Mar 29, 2009
  12. DaveC426913

    DaveC426913 16,128
    Gold Member

    OK so, 3 1/2 wings.:approve:
     
  13. I did find one example of a stack of 4 wings as pictured here.
     
  14. Is that really so or are you speaking whimsically? I'm sure a helicopter works by pushing air down, but a plane?

    I thought planes worked because the shape of the wing decreases the air pressure above the wing's surface, giving it a net lift.
     
  15. A plane works because of Bernoulli's principle the air flows faster on top
    because of the shape of the wing thus creating a low pressure on top
    and the high pressure on the bottom of the wing pushes the plane up , I mean yes it can climb by moving the aileron's .
     
  16. <Raises my eyebrow> ...............um, no.
     
  17. rcgldr

    rcgldr 7,451
    Homework Helper

    The old "dime store" type balsa gliders have flat wings and glide just fine. Rubber powered balsa planes with flat wings also fly well.

    http://www.retroplanet.com/PROD/24887
    http://www.retroplanet.com/PROD/24886

    The point is to accelerate the air downwards. The air is drawn downwards towards a low pressure zone above a wing, and/or pushed downwards away from a high pressure zone below. Technically the air accelerates away from higher pressure zones to lower pressure zones in all directions, except that air can't flow through a solid wing, so the net result of a wing moving forwards with an effective angle of attack is to accelerate the air downwards (corresponding to lift), and somewhat forwards (corresponding to drag).
     
    Last edited: Mar 29, 2009
  18. ok then how does it work cyrus , learn me
     
  19. I provided you a link to an online book. I would recommend reading it. Ailerons cause pure rolling moment (ideally). They do not make the aircraft climb, that would be the elevator.
     
  20. ailerons can do both roll and elevate , when you pull back
    on the stick the elevators and the ailerons move down so I wasn't completely wrong but you wouldn't have known based on your comment and the B-2 bomber doesn't even have elevators
     
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