# Paper Airplane Anatomy How a single sheet of paper folds into a dart, and how its nose, wings and back edges shape lift, balance and steering in flight\. By quiet\-moon\-c68d68bb Topic: Physics & Chemistry [Open the interactive Jig](https://ask.jig.com/j/UgNU5t8D4K1q) ## Transcript ### 1. One sheet of paper This classic dart is a single sheet of paper: no engine, no glue, no tape\. Yet every fold gives part of the sheet a job, just like the parts of a real aircraft\. Drag anywhere to turn the desk and look at it from every side\. Scroll or pinch to move closer\. ### 2. Built from four folds Fold the top corners to the middle, then fold the new slanted edges to the middle again\. Fold the sheet in half, and fold each side down to make a wing\. Press the button to watch a flat sheet become a dart\. A letter\-size sheet is about 22 by 28 centimetres and weighs only about four and a half grams\. ### 3. Meet the parts The pointed front is the nose\. The narrow fin underneath is the body, also called the keel: it is where you pinch to throw\. The two big flat triangles are the wings, and their back edge is the trailing edge\. Real airliners have the same parts, plus an engine and a separate tail\. ### 4. Why the nose is heavy Count the layers\. Near the nose the paper is folded up to 8 layers thick, while most of each wing is a single layer\. All that paper packs weight up front, so the balance point, called the centre of gravity, sits ahead of the wings' middle\. A nose\-heavy plane points itself into the wind like a dart, which keeps its flight steady\. ### 5. Four forces in flight Four forces act on a flying plane\. Lift pushes up and weight pulls down\. Thrust pushes forward, but on a paper plane it comes only from your throw\. Drag is the air pushing back, slowly using up that push\. With no engine, a paper plane is really a glider: it always trades a little height for distance\. ### 6. How a flat wing lifts A paper wing is flat, not curved like an airliner's\. It flies tilted slightly nose\-up, an angle called the angle of attack\. The tilted wing pushes air downward, and the air pushes the wing up\. Tilt it too far and the air tumbles off the wing: it stalls\. Try a small angle first, then a big one, and watch lift and drag change\. ### 7. Trim the back edges Small bends at the back of the wings, called elevons, steer the plane\. Bend both up and the nose lifts; bend both down and it dives\. Bend one up and one down and the plane rolls into a turn\. Small bends work best, because big ones add drag\. The dashed line shows roughly how each trim changes the flight path\. ### 8. Dihedral keeps it level Seen from the front, the wings tilt up in a shallow V called dihedral\. When a gust tips the plane, the lower wing gets more lift and the plane rolls back to level\. Now you know every part of the dart: fold one and fly it\! Record throws have carried paper planes more than 69 metres, and others have stayed aloft for nearly 30 seconds\.