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See the images of several of the best paper-planes. Notice that their wings are slightly elevated, than a normal paper-plane. That is just what happens with me as well, a little elevation on the wings of a paper-plane makes it go faster and farther. Why does this happens?

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    $\begingroup$ please define what you mean by "elevated" $\endgroup$
    – Federico
    Jul 20, 2015 at 11:33
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    $\begingroup$ see this image and notice the slight elevation in wings. $\endgroup$
    – anshabhi
    Jul 20, 2015 at 11:35
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    $\begingroup$ elevation, noun: the height of a place above the level of the sea you mean that the photo has been taken on top of Mt. Everest? $\endgroup$
    – Federico
    Jul 20, 2015 at 11:37
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    $\begingroup$ @Federico I just thought that you have that much common sense :). $\endgroup$
    – anshabhi
    Jul 20, 2015 at 14:22
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    $\begingroup$ OK, seriously though, are we talking about the "trimming" of the trailing edge of the wings, or are we talking about the "dihedral" of the entire wing angling up from the fuselage? There are different reasons that both contribute to stability. $\endgroup$
    – KeithS
    Jul 20, 2015 at 14:38

1 Answer 1

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Most paper planes are nose-heavy and for a very good reason. Basic aerodynamics tells us that putting the centre of gravity forward of the centre of lift, makes any plane (paper or not) more longitudinally stable.

The trade-off is that this configuration tends to cause a nosedive. The trailing-edge elevation counteracts this.

Note that, for the very same reason, all conventional-configuration self-stable aircraft are designed with negative tail-lift.

Aside

A not unheard-of cause of air accident for small commercial planes is pilots ignoring the loading specifications in order to please a customer. If the positioning of the load puts the C of G too far back, the plane becomes unstable. This may result in an unrecoverable spin.

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    $\begingroup$ The aside is counter to the question. Moving the CG forward makes it more stable (but hard to land bc of inability to flare). Moving the CG back makes it more unstable, making stall recovery difficult to impossible. Adding elevator doesn't changed the CG. It changes the center of lift. $\endgroup$
    – rbp
    Jul 20, 2015 at 17:32
  • $\begingroup$ I said that elevator counteracts the tendency to nosedive. I didn't anywhere claim it changed the CG. Not, that is, unless the baggage is so loosely stowed that it is sliding about. I've reworded that paragraph slightly to be clearer. $\endgroup$ Jul 20, 2015 at 21:56
  • $\begingroup$ Yes much better. Although the instability applies to any stall not just s spin $\endgroup$
    – rbp
    Jul 21, 2015 at 1:31

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