19. BERNOULLI As the speed of a fluid increases, the pressure in the fluid decreases. As air passes below the wing it also passes above the wing. The air on top of the wing moves a longer distance over the curved surface of the wing and moves at a faster speed. This reduces the pressure above the wing. The air below the wing moves slower than the air above the wing. This causes the air pressure to be increased. This difference in pressure above and below the wing causes a kite to fly or lift. NEWTONS For every action there is an equal and opposite reaction. Kites excert a downward force upon the air. Air passes over the top edge of the kite and goes down the upper surface of the kite. As the kite pushes downward on the relatively heavy air it gets an equal push upwards. This causes the kite to have an upward counterforce and to fly.
20. 3 MAIN FORCES LIFT Like an airplane, a kite is heavier than air and relies on the motion of the wind past the kite to generate the aerodynamic lift necessary to overcome the weight of the kite. DRAG The movement of the air is generating an aerodynamic drag which is overcome by constraining the kite with a control line. GRAVITY The aerodynamic lift is overcoming the weight of the kite and the person hanging. (both a downward force)
22. UPDRAFTS AND TERMALS A kite also gets higher by updrafts and thermals. Updrafts are formed when the wind rises over the kite's surface. Thermals are rising bubbles of hot air.
