Instant Access To 100,000+ Essays!

The Four Acting Forces In order for airplanes or birds to fly two things are needed, lift and thrust. Unfortunately, these forces don’t come out of the blue; they must be created. Humans create them by adding wings for lift and engines for thrust. Thrust is the force that takes you forward. Engines create thrust by burning the plane fuel until it gets extremely hot. Then the hot air is pulled to the front of the engine by fans. Since the only opening in the engine is the back, the hot air builds up and turns into pressure in the front; rushes out of the back, moving the plane forward thus creating thrust. Given that birds don’t have engines, they have adapted to a different way. Instead of making pressure, they angle their wings forward and thrust them back with superior strength thus moving their bodies forward. Once thrust is created, all that is needed to get into the air is lift. Lift is the force that takes you upward. Unlike the engine, lift for both the airplane and bird works the same way. As a wing rushes through wind lift is created, by fast air going on top of the wing and slower air on the bottom thus creating lift. When these two forces are working there are two other force acting against them, drag