Jumat, 02 April 2010
Dreaming of wings
People have dream and wishing they could fly as bird. This dream has inspired many people to invent ways to leave the ground.
In 1783, two brave Frenchmen became the first people to fly. They knew that hot air rises. So they climbed into a basket fastened to a large balloon. They used a fire in an iron pot to heat the air inside the balloon. The balloon rose at least 300 feet (91 meters).Balloons fell short of these early fliers' dreams, though. Balloons drifted with the wind and did not go where the pilots wanted. They wanted to have more control over their flights. So, inventors started looking at birds as a model for a brand new kind of flying machine
In 1799, Sir George Cayley, a British engineer, built a small aircraft with curved wings. It was called a glider because it glided on the air.
Otto Lilienthal, German engineer devoted years to perfecting a glider. Lilienthal piloted his craft by swinging his body from side to side as he hung from its large, lightweight wings.
Meanwhile, Octave Channute, an American engineer, heard about the experiments that Lilienthal was doing. Channute developed a double-winged glider-or biplane-that several pilots flew successfully.
In 1900, people's dreams of flight really started to take off. Two bicycle makers, Wilbur Wright and his brother Orville, began testing a glider near Kitty Hawk, North Carolina. Before long, the Wrights worked out a way to control their glider in flight. Then the brothers turned their attention to building a powered glider-an airplane. They tried out different wing shapes. They also discovered that propellers added lift by acting like spinning wings. To turn the propellers, they designed a lightweight gasoline motor. Finally, they finished their plane, named Flyer. In 1903, The Wrights hauled Flyer to Kitty Hawk. There they laid sixty feet (18 meters) of track and placed a wheeled platform on it. Then they set Flyer on the platform.
Orville stretched out on Flyer's lower wing. With its propeller whirring, Flyer rolled along the track. The plane picked up speed and then lifted about ten feet (3 meters) into the air. For the first time , a heavier-than-air machine flew under its own power. The dream of flight had come true!