Computer drawings of several wing planforms. The wing shapes
 are rectangular, trapezoidal, triangular and compound.

This slide shows the wing shapes for a variety of aircraft as viewed from above while looking down on the wing--a view called the planform of the wing. For all of the wings shown above, we are looking at only one of the two wings. The Wright Brothers stacked their two wings one on top of the other, while modern aircraft typically have wings on either side of the fuselage.

You can see that wings come in many different planforms: rectangular, triangular, trapezoidal, or even in complex combinations like the Space Shuttle. To figure out how much lift a wing will generate, you must be able to calculate the area of any of these shapes--a skill learned in high school and used every day by design engineers. For the rectangular wing the area is equal to the span (s) times the chord (c);

A = s * c

For a trapezoidal wing, we need to know the semi-span (s), which is the distance from the root to the wing tip, and the chord length at the root (cr) and at the tip (ct). Then from the equation for a trapezoid, the area is one half the sum of the tip and root chords times the semi-span;

A = .5 * [ ct + cr ] * s

For the triangular planform the area is equal to one half of the root chord times the semi-span;

A = .5 * cr * s

For a compound configuration like the Space Shuttle, you have to break up the wing into simple shapes which you can compute.

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Guided Tours


Beginner's Guide to Aerodynamics
Beginner's Guide to Propulsion
Beginner's Guide to Model Rockets
Beginner's Guide to Kites
Beginner's Guide to Aeronautics

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byTom Benson
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