First, thinner is a winner for paper airplanes. Very flat wings have less drag than thicker or curved wings. This is not true for full-sized airplanes, but more on that later. For paper airplanes, there tend to be two basic wing shapes: rectangular and triangular. The former world-record holder for duration (that is to say, the longest time aloft) had a very rectangular shape. The current world- record holder for duration, on the other hand, is more triangular shaped at the nose, with the tail very rectangular. One thing to consider in designing a paper airplane is its ASPECT RATIO, or, more simply, the ratio of the length of the wing to its breadth.
The absolute best shape for a glider is a very long, narrow set of wings-like those of a seagull or albatross. This wing con figuration has a HIGH ASPECT RATIO-in other words, the distance from wing tip to wing tip is much greater than the distance from the front of the wing to the back. Creating a paper airplane with a wing like a seagull, however, is a tall order for a designer. Paper wings need to with- stand a mighty throw and still perform well. High aspect ratio wings are tough to make structurally sound for paper airplanes.
Let's return to our discussion of the basic wing shapes: triangular and rectangular. The advan-
tage to a triangular-shaped paper aircraft is that layers of paper can be moved toward the middle of the plane, which will help with overall stiffening (resulting in a stronger, sturdier plane that will hold up when you throw it). The advantage of a rectangular shape is that it's a more efficient glider, meaning it will fly farther forward for each
foot it loses in height.
The shape of a paper airplane determines where its CENTER OF LIFT will be. The CENTER
OF GRAVITY needs to be a bit in front of the center of lift to keep the plane moving forward after your throw. A rectangular-shaped plane needs almost half of the paper weight at or near the nose in order to keep the center of gravity in front of the center of lift. A triangular-shaped plane can have the weight moved further back because there's less wing area (or LIFTING SURFACE) at the nose. This dance between shape and center of gravity makes paper airplane inventing endlessly fun. The tradeoffs work like this: a really efficient glider won't need to be thrown as high to travel far, designer could give up some structural support in favor of wider wings (which will allow the glider to stay in the air longer). A great distance plane needs to be thrown
very hard, so more layering will be critical in the leading edges of the wings and the fuselage. Flying in a straight line matters for distance planes, so a taller tail may be the way to go. How much layering? How broad can I make the wings? How tall should the tail be? How hard will I throw? These are all strategic questions for your specific goals. My world-record plane is simply one set of compromises for a goal. Other solutions are certainly possible, perhaps even preferable.
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