The Physics of Airplane Flight
There are several aspects involved in the dynamics of airplanes and what makes them fly. This report will address the wings of airplanes, lift, propellers, jet engines and steering and stability of an airplane. Essentially these are main topics of airplane flight.
The wing of an airplane is an airfoil, very similar to that of a Frisbee. The wing of an airplane is shaped so that the air moves faster over the top part of the wing than on the bottom surface of the wing. Due to “Bernoulli’s” effect, the pressure is greater below the wing than above it, thus the wing has an upward “ lift”.
This brings us into the dynamic of lift. The lift is what keeps the airplane in the sky. As an airplane travels down the runway, the air striking the front of the wing separates into two air streams. At first, both air streams travel at the same speed, but as the airplane increases its speed, the airstreams adopt different speeds. Because of the shape and orientation of the airplanes’ wing, the air going over the top of the wing has further to travel than the air below the wing .The air stream below the wing reaches the back of the wing first, finds an empty space and proceeds to meet the oncoming top air stream. This creates instability, because as the plane travels faster, the airstream’s momentum has to change as it goes around the rear of the wing. The turning point extends further and further behind the wing until the airstreams form a vortex and peel away from the wing. Now a stable air pattern begins to develop, in which the top airstream travels faster than the bottom airstream. This allows the air particles to arrive at the front of the wing together and flow back separately and meet at the rear of the wing. The pressure is now lower above the wing than below it and this produces lift, which supports the plane so it can fly.
The force produced on the wing is not upward, but slants downstream somewhat. This component is known as “Induced drag”, which is produced whenever an airfoil gets lift. By deflecting the airstream, the airplane’s wing pushes down on the airstream, causing the airstream to travel downward. The force that slows the airplane down is the induced drag. In order to decrease the drag, an airplane must exert as little work as possible on the passing airstream. Because the downward force is comparable to the airplane’s weight, it can reduce it’s work by pushing the air downward a smaller distance. The distance is dependant upon how much the airplane pushes on the air. If the airplane applies the same force down on the air, the airplane can reduce that air’s downward acceleration. Air then goes downward more slowly and goes less of a distance while the airplane is pushing on it. Therefore, if the wing size is increased, it allows the airplane to deflect more air a smaller distance, which will allow the airplane to experience less induced drag.
In order to sustain a constant altitude, the...