ࡱ;  Root Entry F˺CompObjbWordDocument,ObjectPool˺˺ 4@   FMicrosoft Word 6.0 Document MSWordDocWord.Document.6;  Oh+'0$ H l   D h(C:\MSOFFICE\WINWORD\TEMPLATE\NORMAL.DOTHistory of Flight Cecilia Chi Cecilia Chi@Ǭ$ܥe3 e%,"*j*jj*j*j*j*j******* * *,1********++++&+f+f+A,T,;,j******,*j*j*******j**j**+~**,j*j*j*j**+*-*History of Flight Stories up to 4000 years old tell about flying machines and men in flight. None of these myths were true, but they prove that man has always dreamed of flying. The stories that were true were all about men who failed, killing or injuring themselves-until 1783. Two brothers, Etienne and Joseph Montgolfier ran a paper factory. One of them noticed that the paper envelopes seemed to get lighter and lift up when they were above a flame. They started making little paper bags and put them above the fire, and they floated. The brothers thought it was the smoke that made the bags rise, but it actually is that hot air is lighter than cold air. When a bag is filled with hot air, it becomes lighter than the air around it, and floats. Anyway, they made a huge bag, and announced all over town that they would make it fly. Most of the people did not believe them, but they were proved wrong as the bag filled up with hot air from a big fire below, and rose up into the air. Soon after this experiment, many people wanted to fly in the balloon. Before any person went up in a balloon though, they put up three animals: a duck, a rooster, and a sheep. They came back safely. Then the brothers made a new balloon, their biggest, for a man. It was 50 feet wide and 75 feet high. Around the neck of it, they made a place for the person to stand. An iron pot hung right below the mouth of the balloon to fill it up with hot air. Two men, Pilatre de Rozier, and Francois dArlandes were the first people to fly on November 21, 1783. They stayed in the air for about 25 minutes. After this flight many people became interested in hot air balloons. They realized that hot air was not very safe though, because sparks from the fire could easily set the balloon aflame. Jacques Charles solved this problem. His balloon was filled with a gas lighter than air: hydrogen. Many people went up in the safe hydrogen balloons. By the 1800s, flying balloons were common. There were some problems with them, though. They couldnt be controlled; they just went with the wind. Sir George Cayley made the first heavier than air flying machine. These had more potential to be controlled than lighter than air crafts. It was reliant on the wind to fly, but Cayley believed that if he could find a lightweight engine and propeller, his aircraft could stay in the air for a long period of time. At the time though, there were no such engines. Some inventors concentrated on trying to control balloons. They had ideas like rowing through the air with big paddles, manual propellers, or other things. In 1852, Henri Giffard designed a balloon shaped like a football with a steam engine and propeller mounted below. His airship could fly at 5 miles per hour, and could be steered. These airships were called dirigibles. It still needed improvements though. It could not go very fast and had a huge turning radius. Thirty-two years later, two French soldiers designed an airship that could go up, down, steer left, right, or around in a complete circle. It could go at 14 miles per hour. Count Ferdinand Zeppelin invented an airship with a metal skeleton. His airships never lost their shapes when the gas was let out. They were called zeppelins, after him. Otto Lilienthal experimented with gliders around 1891. His gliders were made of cotton cloth supported by bamboo. They were like hang- gliders. He made over 2000 flights, but on 1896 he crashed and died. Many people learned from his ideas though. Octave Chanute was inspired by Lilienthal. He was an engineer and bridgebuilder, and he used his knowledge from this to construct gliders with six wings, one above the other. This didnt really work though, so he tried three wings, and then two wings. These were very successful. He never flew them himself; he had assistants that flew them, and they never had any accidents because the gliders were built so well. Around the same time, two brothers, Wilbur and Orville Wright became interested in flying. They studied all they could about aircrafts, and they figured that they should build one that doesnt rely on the wind, and would be maneuverable. They needed a lightweight gas engine, but none was available. So they built their own. They hooked it up to two propellers. This was mounted on their plane, which was made of cloth, strips of wood, and wire. On December 14, 1903, This plane, along with Wilbur Wright, made an unsuccessful flight. They repaired it, and on December 17, the same year, Orville Wright made a 12 second flight at 30 miles per hour, in the first engine-powered, heavier-than-air aircraft. During World War I, airplanes were used for spying and scouting. Pilots usually brought along weapons to fight while flying. Soon, the generals realized that planes could be used for fighting. They became equipped with machine guns, and each side was busy making better and faster planes. There were then observation planes, pursuit planes, and bombers. This period, from 1914 to 1918 was a time for many improvements in airplanes. At the beginning of the war, most planes could go about 60 miles per hour, and by the end of the war, most planes could go up to 130 miles per hour. The shapes of planes started to change around the 1920s to 1930s. Before this, most planes were made of wood and cloth, which was not very safe. In 1924, the first all-metal plane was made. It had three engines. The pilots discovered that they had breathing problems at high altitudes, so the pressurized cabin was invented. Engineers began to learn more about aerodynamics, so they began to streamline airplanes. Airlines were introduced around this time, but they were not very successful. Helicopters had been experimented with a lot since the 1800s, but the first successful one was built in 1937. Helicopters can go straight up and down, forward, backward, left right, stay still, and turn around in place. The helicopter is controlled by the pitch or angle of the rotor. In 1939, the first airplane with a jet engine was built. The gas-powered planes had propellers, but jet engines didnt need them. The jet engine burns the fuel to make the whole engine move, whereas the gas engine only makes part of the engine move, to turn the propeller. When the jet engine is mounted on an airplane, the whole plane moves forward as fuel is burned. World War II began soon after the invention of the jet engines, so most of the airplanes in the war were still gas-powered. Around the end of World War II, the fastest plane could go about 600 miles per hour. Many scientists and pilots didnt think airplanes could go much faster. Planes were capable, except that the air could not get out of the way. It piles up in front of the plane, and tears them apart. A few test pilots died in the attempt to break the sound barrier. Then, the Bell Aircraft Company built a plane shaped like a bullet. The leading edge of the wing and tail were very sharp, to minimize drag. This airplane was called the XS-1, which stood for Experimental Supersonic One. On October 14, 1947, the XS-1, also called the X-1, was carried into the air by a Superfortress bomber, with Air Force Captain Chuck Yeager as the pilot of the X-1. It was released, and Yeager turned on the jet engine. The X-1 was successful, breaking the sound barrier with only a little shaking. There were few remarkable improvements in aircrafts after the sound barrier was broken. The first large commercial airline began in 1952. Planes were made to go up to 5 times the speed of sound, or Mach 5, like the X-15. The F-100 was the first plane to break the sound barrier without shaking. The Boeing 747, the first jumbo jet, began service in 1970. Supersonic planes were used basically only in the military, until 1976, when the worlds first supersonic transport, the Concorde was introduced. All airplanes have 4 forces acting upon it. There is gravity, lift, drag, and thrust. An airplane wing is flat at the bottom, and round at the top. Since the air above the wing has greater distance to travel, it must travel faster. When air travels at faster speeds, the pressure drops. This is lift. Gravity is the natural force that keeps it on the ground. When the pressure above the wing is low enough to overcome gravity, the plane will take off. For this to happen, the plane must be traveling forward at a high enough speed. The engine creates thrust. In jet engines, air is taken in, compressed and heated by the combustion of the fuel, and thrust out through a turbine. The action-reaction law says that the engine will move forward from the backward thrust. Propellers lower pressure in front of the plane, causing the plane to move forward. ࡱ; SummaryInformation(2%@qj%@M ˺@l7/Microsoft Word 6.010ࡱ; %ccU^c 5 MUDdS!%!t! !!!! !! !!!!! !! !hK@Normala "A@"Default Paragraph Font"!    ",E%%- Cecilia ChiC:\MSOFFICE\WINWORD\FLIGHT.DOC@Epson Stylus 800+LPT1:epepstEpson Stylus 800+ D"'hhEpson Stylus 800+ D"'hh44 441Times New Roman Symbol &Arial"hϓ$z R$;History of Flight Cecilia Chi Cecilia Chiࡱ;