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Thread: does shape cause levity

  1. #1
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    does shape cause levity

    does shape cause levity

    def: levity
    lift
    ant: gravity

    def: topspin
    the up surface rotating into the headwind

    from another thread

    Quote Originally Posted by rwjefferson
    unsupported assertions
    the shape of the wing is the force that lifts bumblebees and birds and planes
    Quote Originally Posted by billvon View Post
    The shape of a wing helps create lift, yes. That's easily provable in a wind tunnel.
    Levity is already present in verse initial inertial pressure differential. Shape only makes lift more or less efficient. Shape or warp is not the same as force. What is true for space holds true here on earth.

    easily provable in a wind tunnel
    airplanes can fly upside down
    all shapes can provide lift
    a sphere with a shiny smooth surface topspinning exhibits lift
    rough balls not so much

    Name a shape that cannot exhibit lift.
    Name the force that lifts shiny topspin.
    Name the force that sinks a baseball.

    peace
    ron

  2. #2
    Sweep your hand through some smoke. Your hand is quite a good wing shape. Your palm skates across the smoke. Your knuckles throw the smoke up. You are creating a hole of less resistance.. like a little cave. Easier to move up than down. Fill a bath with water, slide your hand through the bath water. The small curvature in your hand causes a vector angle rotation. You can twist your hand to change the rotation angle, you hand can become a rudder.

    Vector angles combined with areas of less resistance... that's your answer in the end.

  3. #3
    Arguing with a crank - useless AlexG's Avatar
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    This thread belongs in pseudoscience.

  4. #4
    Penguinaciously duckalicious. Dywyddyr's Avatar
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    This thread belongs in the Cesspool.
    And the first two posters in this thread with it.

  5. #5
    Quote Originally Posted by rwjefferson View Post
    does shape cause levity

    def: levity
    lift
    No. A difference in pressure, or a redirection of the air flow, or buoyancy, causes lift.

    No need for the term "levity", either, if all you mean is "lift".

    Levity is already present in verse initial inertial pressure differential.
    I can't parse that.

    Shape only makes lift more or less efficient.
    More efficient than what?

    Shape or warp is not the same as force.
    Obviously. Otherwise we wouldn't need three words - one would do.

    easily provable in a wind tunnel
    airplanes can fly upside down
    all shapes can provide lift
    Explain how a non-rotating sphere can provide lift.

    Name the force that lifts shiny topspin.
    Topspin tends to sink, not lift. The force is a result of different airflow above and below the ball.

    Name the force that sinks a baseball.
    Same thing as with tennis.

  6. #6
    Empirical Skeptic Trippy's Avatar
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    Quote Originally Posted by rwjefferson View Post
    does shape cause levity
    Certainly:


    lev·i·ty
    noun \ˈle-və-tē\
    1: excessive or unseemly frivolity

    Another example: Tim Minchin: Storm
    (some language may offend).

  7. #7
    Levity is already present in verse initial inertial pressure differential.
    Quote Originally Posted by James R View Post
    I can't parse that.
    It is an engineering explanation of laughter.

  8. #8
    I forgot to add angular momentum to the vector interpretation. So you have a vector angle of momentum, which would be the rudder, or the bend of a wing, or the bend of your hand in bath water, or the spin of the object.

  9. #9
    Valued Senior Member origin's Avatar
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    Quote Originally Posted by rwjefferson View Post
    does shape cause levity
    easily provable in a wind tunnel
    airplanes can fly upside down
    all shapes can provide lift
    You do realize that the lift of aiplane flying upside down is completely different than a plane flying right side up.

    It is a horribly inefficient way to fly because the lift is provided by the force of the air on the bottom side of the wing giving an upward force which causes a huge amount of drag.

    The normal way that a wing works is that the low pressure on top of the wing lifts the entire body with very little drag.

    By the way if you want to see how inefficient it is to fly upside down try this experiment - mount the wings upside down on an airplane and try to take off. I highly recommend that you do this by remote control so no one is killed.

  10. #10
    As Trippy noted, "levity" means "inappropriate lack of seriousness." The use of the word to mean "lightness" is archaic.

  11. #11
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    Quote Originally Posted by origin View Post
    You do realize that the lift of aiplane flying upside down is completely different than a plane flying right side up.
    Depends on the aircraft! Aerobatic aircraft (like the Extra) have symmetric airfoils that generate lift efficiently in both directions.

  12. #12
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    some may find this site illuminating

    http://www.grc.nasa.gov/WWW/K-12/airplane/wrong1.html

    a series of incorrect theories of lift.

  13. #13
    Valued Senior Member origin's Avatar
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    Quote Originally Posted by billvon View Post
    Depends on the aircraft! Aerobatic aircraft (like the Extra) have symmetric airfoils that generate lift efficiently in both directions.
    Interesting, I did not know that. I assume that there is some way to adjust the wing angle, otherwise there would be no net lift one way or the other, right?

  14. #14
    Valued Senior Member origin's Avatar
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    Quote Originally Posted by Boris2 View Post
    some may find this site illuminating

    http://www.grc.nasa.gov/WWW/K-12/airplane/wrong1.html

    a series of incorrect theories of lift.
    Nice little site.

  15. #15
    C'mon, get happy! chimpkin's Avatar
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    I am in good shape, so mine does not cause levity anymore.

  16. #16
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    Quote Originally Posted by origin View Post
    Interesting, I did not know that. I assume that there is some way to adjust the wing angle, otherwise there would be no net lift one way or the other, right?
    At a zero angle of attack a symmetric airfoil generates no lift, so aerobatic aircraft use one of several methods to get lift:

    -Angle of attack change via flight surface trim. Basically you trim the airplane so it always flies nose up, which gives you a greater AOA and more lift.

    -Angle of incidence change. You can tilt the entire wing relative to the airplane to give it a positive AOA when the aircraft is level; that does the same thing.

    -Flaps (used primarily for landing and low speed flight.) They change the effective AOA of the wing so you can fly level with the nose not raised as much.

  17. #17
    Valued Senior Member origin's Avatar
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    Quote Originally Posted by billvon View Post
    At a zero angle of attack a symmetric airfoil generates no lift, so aerobatic aircraft use one of several methods to get lift:

    -Angle of attack change via flight surface trim. Basically you trim the airplane so it always flies nose up, which gives you a greater AOA and more lift.

    -Angle of incidence change. You can tilt the entire wing relative to the airplane to give it a positive AOA when the aircraft is level; that does the same thing.

    -Flaps (used primarily for landing and low speed flight.) They change the effective AOA of the wing so you can fly level with the nose not raised as much.
    Thanks! Interesting stuff.

  18. #18
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    def: bernoulli
    fluent flowing faster over a boundary forces lower static pressure
    and vice versa
    lower pressure over a wing accelerates air mass back and downwards

    def: newton
    a measure of mass acceleration
    action~reaction
    equal in verse opposite

    def: fluent
    all that flows over time
    everything

    A non rotating sphere "lifts" just like all other shapes and gliders and sizes. Make it as light as possible, launch into an up draft.

    incorrect theory of lift
    an airfoil lifts at neutral angle of attack

    self evident truth
    an airfoil lifts at downward angle of airmass departure
    airplanes with can lift upside down
    all shapes can provide lift
    all shapes are subject to stall
    soapy spheres exhibit lift without rotation
    top spinning bowling balls force airmass downwards
    top spinning golf and tennis balls force airmass downunder and upwards in verse fuzzy boundary layer
    even wikipedia is behind in publishing the truth

    ItS
    peace
    ron

    a wing harnesses a segment of vortex
    a vortex is the dance of newton in verse bernoulli

  19. #19
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    Quote Originally Posted by rwjefferson View Post
    def: bernoulli
    A non rotating sphere "lifts" just like all other shapes and gliders and sizes.
    No, it doesn't. A nonrotating sphere does not generate lift.

    Make it as light as possible, launch into an up draft.
    If it rises it will be due to drag, not lift. (Same reason thermals pick up leaves, grass, petals etc.)

    incorrect theory of lift
    an airfoil lifts at neutral angle of attack
    Some airfoils do indeed generate lift at zero angle of attack.

    self evident truth
    an airfoil lifts at downward angle of airmass departure
    airplanes with can lift upside down
    All agreed.

    all shapes can provide lift
    Incorrect. Some, as mentioned above, cannot.

    all shapes are subject to stall
    Strictly speaking yes, as turbulent flow can be caused with any shape.

  20. #20
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    dogma dies hard

    incorrect theories of lift
    lift is the same as minimal drag
    a nonmoving wing generates lift

    strictly speaking
    a wing that forces airmass downwards is in deed attacking the headwind
    shape only makes lift/drag more or less efficient
    shape only redirects force
    redirection is not the same as force
    shape is not the same as force

    Name a shape that lifts without force.
    Name the force that generates lift.

    peace
    rw

    force is inertial pressure differential

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