FROM GLIDERS TO ROCKETS

At the beginning

To be able to fly is one of the oldest human ambitions. Icarus, who was a legend, flew with feathers and wings out of wax too near the sun. So the wax melted and Icarus died. People in the ancient world tried to copy him, but all with disastrous results.

First, people thought that the way to fly would be to design a machine with flapping wings like a bird's. But the first people who took to the air did it with the help of a hot air balloon. Those people were the brothers Montgolfier from France. That happened at the end of the 18^th century.

But balloons were at the mercy of the wind for their direction and speed, so they were no use as a means of transport. So Sir George Cayley designed the first successful passenger-carrying glider in the middle of the 19^th century. He worked out the principle of 'lift', which is obtained by making the upper surface of the wing convex and keeps the wing airborne.

The greatest glider pioneer of the age, Otto Lilienthal, died after nearly 2000 flights in a glider he built himself.

Flying by steam

Other inventors tried making steam-powered aircraft. But the flights which could be made were only a few metres long. The people, who were responsible for the breakthrough in flying were two American brothers: Orville and Wilbur Wright. They lived in the 19^th century.

The Wright-brothers ran a bicycle business. In their spare time they directed all their attention to aeronautics.

The Wrights saw that there were three problems in realizing their dream of a machine which could fly:

The first problem was to make wings large enough to lift the weight of the engine and the passenger, and to keep the aircraft in the air.

The second problem was to find the right engine.

The third and most important problem was to work out ways of balancing and steering the aircraft in flight.

The Wrights saw that the solution was to provide their aircraft with controllable surfaces similar to those found on aircraft today. They fitted a movable elevator in front of the wings, and a movable tail fin which acted as a rudder. In the beginning of the 20^th century, the Wrights began to build a powered flying machine.

Failure at Kitty Hawk

One year later the flying machine was ready to take off. Its name was Flyer I. The wingspan of Flyer I was twelve metres. It was powered by a four-cylinder petrol engine. The engine drove two wooden propellers fitted behind the wings. The pilot lay on his stomach. Flyer I had no wheeled undercarriage. It would take off from a set of wheels mounted on a rail track, and land on skids shaped like skis.

On a December-day, Wilbur Wright tried to take off. But he made a disastrous mistake. Flyer I could not take off and crashed into the sand hills near Kitty Hawk in North Carolina.

When the damages of Flyer I were repaired, it was Orville Wright's turn to take off. His try was successful and the first powered flight was fourty-two metres long. On the same day they tried it again and again. The result was a 260 metres-long flight by Wilbur Wright. The top speed was forty-eight kilometres per hour. On the end of this day, the first powered aircraft was taken by the wind and crashed without a pilot. So the Wright's went back to their drawing board to design Flyer II.

But the successful flight did not make headline news all over the world. Most people thought that it would be impossible for small-town enthusiasts. If it was possible, it would be done by trained engineers. If engineers were not able to realize the dream of powered aircraft, how could it be done by people who were not engineers? But the Wright's continued improving their aircraft. With Flyer II and Flyer III, they increased the length of their flights and the manoeuvrability of their aircraft in the air. A few years later Flyer III flew for a total of thirty-eight minutes, covering thirty-eight kilometres. The flight included demonstrations of turning, circling and flying a figure.

At that time the Wrights wanted to go into business. But they had found no one who wanted to buy a powered aircraft. The United States Army was also not interested. So Wilbur Wright travelled to Europe by ship with a demonstration machine. The kings of some European countries watched the demonstration. The Daily Mail, an English newspaper, reported about the aircraft. Everyone was talking about flying. So the Wrights had all the publicity they needed - the air age had arrived.

In World War I aircraft, which could reach speeds approaching 161 kilometres per hour, were used. They played a small but important part in that war. The aircraft were needed to make weapons more efficient, for example to carry heavy bombs deep into the enemy territory.

The years after World War I were a time when aviators competed with each other to score 'firsts'. But aircraft were not only used for record-breaking. They were very useful as a profitable means of transport. For example, the first airmail service began a few years after the invention of Flyer III in Britain.

The first airlines were also founded at that time, for example in countries like Britain, France and the Netherlands, which had large empires scattered across the world. The first passenger planes were tiny. They could usually carry only eight passengers. Often bombers of World War I were fitted with seats for carrying passengers. But soon the aircraft industry began to build planes specially designed for comfortable passenger travel.

Because of the long distances in the United States, air travel really took off. American aircraft builders moved into the lead. They built the Douglas DC3, also called the Dakota. It became the most widely used plane among the world's airlines, carrying mail or passengers over short distances.

Meanwhile, an entirely different kind of aircraft had appeared: the helicopter. Helicopters use spinning rotor blades to move forward and also to hover. Sir George Cayley began to work on the idea of the helicopter some 300 years after Leonardo da Vinci, who made unrealistic plans of helicopters. In the middle of the 19^th century, Cayley produced a steam-powered design, but it was never built. A real helicopter had to await the invention of the internal combustion engine.

The JET ENGINE

The idea of an engine producing power by shooting out a stream of gases and compressed air is old. It is said that Sir Isaac Newton thought about at the end of the 17^th century. Two hundred years later, an aeroplane driven by steam jets was designed, although it was never built. Then, at the beginning of the 20th century, the gas turbine was invented. This works by using hot exhaust gases to drive a turbine, in a similar way to the jet engine. Gas turbines were used in industry, and some people began to wonder if they could be adapted to power aircraft.

Jet-engined aircraft flew fast and moved swiftly into action. So they were a very efficient weapon in surprising the enemies. The first jet-engined aircraft of Britain was the Gloster Meteor. The first German jet-engined aircraft was the Messerschmidt 262 and the first aircraft of Russia using the powerful jet-engine was the MiG 15.

After World War II the jet technology that had been developed for use in warplanes could be applied to civilian aircraft. Piston engines needed a huge amount of fuel and they could not fly very high. Jet-airliners need less fuel and they are able to fly high above the clouds, so flying is more comfortable because of avoiding bad weather.

When the aircraft were able to carry larger numbers of passengers, the cost of air travel fell. So more people could afford travelling by plane.

The jet engine developed more and more. Aircraft became faster and faster. The world's major airforces had a new target: They wanted to break the sound barrier, which is about 1160 kilometres per hour. The first plane which broke the sound barrier was an American Bell X-1 aircraft.

But not only military aircraft are able to fly at supersonic sounds. Also airlines wanted to use such fast planes. But as a means of transport, such aircraft are very expensive. Only two have ever gone into service - the Concorde and the Tupolev 144. Both planes were disappointments. The Tupolev 144 had technical problems and the Concorde has never earned the money that was spent on it.

Rockets

Like a jet engine, a space rocket uses the backward rush of exhaust gases to propel itself forward. A jet engine uses the oxygen which exists in the atmosphere to burn the fuel. A space rocket contains its own supply of oxygen.

A major problem was to make the rockets powerful enough to leave the atmosphere of our earth. The solution of that problem was the liquid fuel. The main parts of those liquid fuels were oxygen and hydrogen.

Germany was the world leader in rocket-technology. The USA and the USSR got German specialists. The division of knowledge about rockets led to the 'space race' of the 1960's and 1970's between the two superpowers.

The first target was to break free of the earth's gravitation pull. The USSR's Sputnik 1 became the first satellite to achieve this. Russia scored first and so America's rocket team, led by Wernher von Braun redoubled its efforts. The first American satellite was the Explorer 1.

The first living passenger in space was a dog named Laika in the Sputnik 2. The first human in space was Yuri Gagarin from Russia. The first humans landed on the surface of the moon were the US-astronauts Neil Armstrong, Edwin Aldrin and Michael Collins.