Thrust and Drag

Thrust

Throwing the airplane is what gives it the ability to move anywhere at all. If there was no wind and you let an airplane go, it would simply fall to the ground. Depending on the angle the plane is thrown, the thrust could be either purely horizontal or partially vertical as it acts on the plane. If the plane is thrown purely horizontally, then it should gradually fall to the ground as it glides forward. This is because the only forces working on it vertically are gravity and lift, which are addressed on their own page.

Even so, the thrust has control over the plane’s altitude, because the thrust is what allows the plane to generate lift.


Drag

Like all fluids, air has viscosity. As a plane glides through this fluid, air particles rub against it. The rough surface of normal printing paper can cause a large amount of drag, as particles get “caught” in the texture of the wings. This is why origami paper is so excellent for building paper planes: The texture is very smooth, and the light weight allows the plane to fly longer without falling as much. Minimizing drag on your airplane will let thrust have a stronger effect, and thus allow the plane to get more lift.