subject: Flight above the Clouds "It's Fun to Fly" [print this page] Flight above the Clouds "It's Fun to Fly"
Easier - Flight is the ability to fly. It is the act of traveling or moving through the air. Harder - Humans first observed flight in other animals in the natural world. Birds have wings and most have the ability to fly. Many insects can fly. Only one mammal can fly, the bat. However both the flying squirrel and the flying lemur can glide. Humans experimented and developed ways of flying. Lighter-than-air methods that have successfully been used include hot air balloons and blimps. On December 17, 1903, brothers Wilbur and Orville Wright made the first successful heavier-than-air flights near Kitty Hawk, North Carolina. They had built their airplane after studying the writings of other aviation pioneers and experimenting with gliders, kites, and wind tunnels. Helicopters and gliders are the two other types of heavier-than-air craft. Four basic forces are involved in the flight of an airplane:
(1) gravity,
(2) lift,
(3) drag, and
(4) thrust.
Thrust is created by a plane's propeller or its jet engines. Drag is the natural force of air that resists an airplane's forward movement. Lift is created by the plane's wings as they move through the air. And gravity is the natural force that pushes a plane toward the ground.
Gravity and lift are opposing forces, as are drag and thrust. When the plane's lift equals the force of gravity and the force of thrust equals the drag, the plane remains in level, cruising flight. When one or more of these four forces change, the plane begins to change its altitude, direction, or speed.
