Category FLIGHT and M ОТІOIM

In the pioneer days of aviation, a pilot relied on eyesight and navigated with a map, following ground landmarks such as highways and railroads. Rules to reg­ulate air navigation were first introduced in the 1920s. The first air traffic con­troller began work in 1929 in St. Louis, Missouri. English became the interna­tional language of air traffic control, and agreed-upon words were adopted to prevent misunderstandings. At this time, radio was used to communicate with planes, but there was no radar to track aircraft movement until the 1940s.

The International Civil Aviation Organization (ICAO) was set up in 1947. Today, this agency of the United Nations regulates air traffic control worldwide as well as the boundaries of national airspace. It allocates call signs to each airline flight, usually an abbreviated form of the airline name (such as GLA for Great Lakes Airlines) followed by the number of the flight—for example, GLA 674 for flight 674. The call signs appear on radar screens, on flight plans, and on information boards at airports. Other civilian aircraft are usually identi­fied by their registration numbers, a combination of letters and numbers dis­played on the tail and wings—N3761P, for example. (The “N” is the interna­tional designation for the United States.)

ilitary aircraft are the airplanes and helicopters used by the world’s military forces. They are used for combat and for other military operations, including carrying supplies and troops, reconnaissance, training, and search and rescue.

In the United States all branches of the military (not just the U. S. Air Force) use aircraft. The United States has the world’s most powerful air force, and the U. S. Navy, Army, Marine Corps, and Air National Guard also have their own aircraft. Other major air forces include those of Russia, China, the United Kingdom, and France. Canada does not have a separate air force but has the Canadian Forces Air Command (AIRCOM) within the unified Canadian Forces.

The nerve center of a larger airport is the control tower. Air traffic controllers use radar, computers, and radio to direct the movement of airplanes in and out of the airport and on runways. The design and layout of runways is regulated by the government and by the International Civil Aviation Organization, to which most nations belong.

Early airplanes were light enough to land on a grass airfield. Modern passen­ger and cargo planes are so heavy that they need hard runways, constructed of concrete or tarmacadam. Because most modern jet planes need a lot of space to take off and land, runways have become longer, and airports now take up a lot of ground.

A typical airport today has a single main runway, often over 13,000 feet (3,960 meters) long. The runway must be long and wide enough for the largest

WIND FACTORS

Aircraft usually land and take off into the wind. For this reason, older airports had three or four runways, arranged in the shape of a triangle or box, so aircraft could land and take off no matter which direction the wind was blowing. Modern air­planes are so powerful that they are less affected by wind, and a modern airport can often operate efficiently with just one main runway. It may need extra runways, however, to cope with the number of passengers and amount of air cargo.

_____________________________________________ /

planes flying into the airport to take off and land safely. A runway has a clear space at each end in case a pilot requires extra distance when taking off or land­ing. Numbers on or beside the runway identify it by compass direction. For example, on a north-south runway, the numbers are 18 (short for 180°) at the north end, and 36 (short for 360°) at the south end. White lights mark the edges of the runway, and green lights are placed where the runway starts. There is an additional set of red and white approach lights, which pilots see as they prepare to touch down.

pollo was the name given to a project launched by the United States to fly astronauts to the Moon, land them, and return them safe­ly to Earth. The spacecraft built for the project were also named Apollo. The name comes from Greek and Roman mythology-Apollo was the god of light, of healing and medicine, and of poetry and music.

The Political Background

Project Apollo involved a series of spaceflights to increase knowledge of the Moon and of manned spaceflight. The program was carried out at great speed and high cost in the 1960s. Many people doubted it would succeed.

In 1961, President John F. Kennedy announced to the U. S. Congress that the United States should aim to land astro­nauts on the Moon before 1970. At that time, the United States was in competi­tion with the communist federation of nations then called the USSR, or Soviet Union. The Soviet Union had launched the first Earth satellite (Sputnik 1) in 1957, and in 1959 it had sent three unmanned Luna spacecraft to the Moon. Luna 2 crashed onto the Moon’s surface, while Luna 3 flew around the Moon to photograph its far side, never before seen on Earth. The Soviet Union had clearly taken the lead in what the media called the space race.

U. S. space scientists knew the Soviets were capable of launching heavy

manned spacecraft using powerful booster rockets developed for the Soviet Union’s military missile program. The Soviets put the world’s first astronaut, Yuri Gagarin, into Earth orbit in April 1961. They followed this historic space­flight with a 25-hour flight by Gherman Titov in August 1961. Many experts predicted that the Soviets would land on the Moon within a year or two.

Project Apollo was America’s answer to that challenge. The program went ahead despite skepticism from some scientists that manned exploration of the Moon was too risky and not worth such a vast expenditure of time, money, and expertise.

Today’s avionics include sensors, radio communications equipment, computers, and control and naviga­tion systems. They also include the displays in the cockpit.

The job of sensors is to collect information. Sensors on the outside of an aircraft collect information about its speed and height. Other sensors in the engines monitor temperature, pressure, and speed. Yet others measure tire pressure. Sensors inside the plane monitor the air pressure and temperature. Radar in an airplane’s nose searches the sky ahead for storms.

Radio equipment lets the crew talk to air traffic controllers on the ground. Radios are also able to receive signals from navigation beacons on the ground and some­times from satellites in space. Devices called transponders send out radio signals that identify each plane to air traffic controllers. Military aircraft have even more avionics for their weapons and defense systems.

Computers and other electronic sys­tems process all the information arriving from the sensors. A huge amount of information floods into an aircraft’s
cockpit. The plane’s avionics help cut it down to a level that pilots can manage. Displays show the information pilots need on screens and other instruments.

It is possible that an airliner will be struck by lightning one or more times in a year. A lightning bolt produces millions of volts, and avionics can be put out of action by just a few volts too many. When lightning strikes an airplane, however, it flows around the plane’s metal body. It does not get inside the plane, and so the avionics are safe. The crew and passengers are protected from lightning in the same way.

Some parts of a plane’s body are now being built from light materials, such as carbon fiber, instead of metal. The new materials are used because they are lighter and stronger than most metals, but they do not keep lightning out in the way that metal does. One way to protect the delicate avionics in these aircraft is to cover the plastic or carbon fiber parts of the body with a thin metal mesh. If lightning hits the airplane, the metal layer stops it from reaching the computers and electronics inside.

Control systems enable the crew to control the aircraft. Some control systems, such as the autopilot, are auto­matic: They work by themselves. Others are manual and are operated by the crew. Actuators, for example, are an air­craft’s mechanical muscles. They move parts of the plane, such as the rudder in the tail, the moving parts of the wings, and the landing gear.

Dates of birth: Benz: November 25, 1844; Daimler: March 17, 1834.

Places of birth: Benz: Karlsruhe, Baden, present-day Germany; Daimler: Schorndorf, Wurttemberg, present-day Germany.

Died: Benz: April 4, 1929; Daimler: March 6, 1900.

Major contributions: Pioneers in auto­mobile engines and founders of a company that advanced airplane and airplane engine design; Benz: inventor of the gasoline-powered automobile; Daimler: co-inventor of the first powered balloon to fly successfully.

arl Benz and Gottlieb Daimler were engineers who designed pioneering automobiles and car engines. Their work produced advanced designs that paved the way for aircraft engines. The two men never met, but the company that formed by merging their two businesses later produced important German aircraft engines.

Trained as an engineer, Karl Benz took an interest in developing an engine for a horseless carriage, or automobile. Another German, Nikolaus Otto, invent­ed an internal combustion engine using a four-stroke piston in 1876. Two years later Benz invented a two-stroke version that improved on Otto’s design. Benz also designed several other key features of an automobile, including the spark plug, carburetor, clutch pedal, and gearshift. In 1885 he invented a vehicle run by a gasoline-powered engine. Although it had only three wheels, it is considered by historians to be the first practical, purpose-built automobile.

By 1899, the company Benz had formed was making more than 600 cars-now with four wheels-each year. For several years, his company was a leading automaker. A racecar it built in 1909 set a land speed record of 142 miles per hour (228 kilometers per hour).

Gottlieb Daimler also studied engi­neering and then partnered with Wilhelm Maybach, another mechanical engineer, to develop better engines. In 1885 they placed an engine on a bicycle, creating the world’s first motorcycle. Two years later, Daimler and Maybach

produced the first speedboat. The next year, they placed an engine on a balloon, which was flown over the town of Seelberg. In 1890 Daimler and Maybach formed a company, but they often fell into conflict with other managers. Maybach himself left the company in 1891, and Daimler at one point lost his job as technical director. In 1900, after several years of ill health, Daimler died.

Both companies suffered in the 1920s. Germany’s economy was shattered after the nation’s defeat in World War I, and few people had the money to buy automobiles. In 1926 the companies merged to form Daimler – Benz. The new company achieved some success. It named its car the Mercedes – Benz, combining Daimler’s most popular model with the Benz name. Three years after the merger, Karl Benz died.

The company’s gains were partly fueled by a new field-developing aircraft engines. In the late 1920s, Daimler-Benz developed a powerful twelve-cylinder aircraft engine. In 1934, the company produced a landmark air­craft engine, the DB600. With more power and greater endurance than other engines, it was quickly adopted by German airplane manufacturers.

By the late 1930s, Germany’s leaders were ignoring a World War I peace treaty that had banned Germany from manufacturing military airplanes. Many of the aircraft built by the Germans

Bleriot’s next design, the XI, showed promise. In July 1909, he set out for northern France to try the English Channel crossing.

There, he found two other fliers hoping to win the prize. Count Charles de Lambert crashed his plane, built by the Wright brothers, in a test run and

withdrew from the contest. The sec­ond flier, Hubert Latham, took off on July 19, 1909, but crashed into the Channel. After being rescued, he called for another plane to be brought so he could try again. Several days of bad weather pre­vented anyone from flying, however.

Early on the morning of July 25, the weather cleared and the wind eased. While Latham slept, Bleriot decided to make the attempt. At 4:35 a. m., with dawn breaking, he took off. Latham was awakened, but by the time he was ready, the wind had picked up, and he could not fly.

Flying without a compass, Bleriot could only guess that he was heading north. After about thirty minutes, Bleriot spotted southeastern Britain. He landed on a field in triumph. In thirty-seven minutes, Bleriot had conquered the English Channel.

OPEN TO ATTACK

Bleriot’s flight across the English Channel provoked anxiety in the United Kingdom. For centuries, the English Channel had been a barrier to invasion. After Bleriot’s flight, newspaper editorials warned that the country would no longer be safe.

In time of war, they said, planes could fly from the Continent to attack the island.

_____________________________________________ /

Later Life

Bleriot’s feat gained him great fame and success. Very quickly, orders for his monoplanes poured in, helping him build another fortune. He took part in forming a company that made one of the most popular fighter planes of World War I, the SPAD. After the war, Bleriot manufactured commercial planes.

Bleriot’s flying career did not last much past his English Channel crossing. Later in 1909, he suffered an injury in another crash that forced him to give up flying. He continued to promote aviation and improvements in aircraft design until his death in 1936.

N

SEE ALSO:

• Aileron and Rudder • Biplane

• Fighter Plane • World War I

_________________ J

Date of birth: December 27, 1773.

Place of birth: Scarborough, Yorkshire, England.

Died: December 15, 1857.

Major contributions: Developed the science of aerodynamics; built first glider that successfully carried a person in flight; developed designs for a pow­ered dirigible and helicopter.

eorge Cayley grew up in a noble family in northern England. When he heard, at age nine, of the balloon flights of the Montgolfier brothers, he became fascinated by the idea of flight.

By 1796 and the age of thirteen, Cayley had made a model helicopter. At the time, some people believed that air­craft would need movable wings to reproduce the flapping motion of birds. Cayley concluded that a fixed-wing air­craft was superior. He drew a sketch in 1799 that shows the basic configuration of a modern airplane, with fixed wings, a long fuselage, and a tail that includes elevators for controlling motion up and down and a rudder for steering. A draw­ing on the other side of the paper shows

an understanding of drag and lift, forces of air that contribute to flight. Five years later, Cayley built a model glider follow­ing his ideas. Although small, the glider was successful-released from the top of a hill, it flew down to the ground.

Between November 1809 and March 1810, Cayley published a three-part essay presenting his findings. Called “On Aerial Navigation,” the essay set forth basic principles of aviation. Key conclu­sions included the ideas that low air pressure above a wing produces lift and that curved wings generate more lift than flat ones. Cayley also described how to use angled wings and tail wings to make flight more stable.

In 1816 Cayley published another paper that explained how to build an airship that could be moved through the air by steam-powered propellers. An air­ship, like a balloon, is a bag filled with gas that is lighter than air, but unlike a balloon, it can be steered.

Much later, in 1843, Cayley sketched a helicopter design. Late in his life, he had more success with gliders. In 1849 Cayley built a small glider with three wings that carried a ten-year-old boy through the air for several feet. Four years later, he built a larger glider that carried his coachman more than 420 feet (128 meters) before crashing. This marked the first time a person flew in a full-size heavier-than-air craft.

Cayley dreamed of powered flight, but he lived at a time when that was not yet possible. The steam engines of the early 1800s were too heavy to carry

A BOLD PROPHECY

George Cayley was convinced that humans would be able to fly. His essay "On Aerial Navigation" included the following prediction: "I feel per­fectly confident, however, that. . . we shall be able to transport ourselves and families, and their goods and chattels, more securely by air than by water. . . . To produce this effect it is only necessary to have a first mover [power source], which will generate more power in a given time, in pro­portion to its weight, than the animal system of muscles."

______________________________________________ /

a flying machine and occupants aloft. Still, his pioneering 1853 flight and his important writings paved the way for later aircraft designers. Because of his research, Cayley is widely considered a pioneer of aviation.

In 2003 flying enthusiasts celebrated the 150th anniversary of Cayley’s 1853 glider flight. Sir Richard Branson, a British businessman and adventurer, wore period clothes and flew a glider following Cayley’s design. Branson, unlike Cayley’s coachman, managed to land without crashing.

N

SEE ALSO:

• Aerodynamics • Glider • Helicopter

• Lift and Drag • Wing

Challenger and Columbia

ASA’s Space Shuttles began fly­ing into space in 1981. Since that time, two of the Space Shuttles, Challenger and Columbia, have been destroyed in accidents that caused the deaths of both crews. On January 28, 1986, the Space Shuttle Challenger broke up 73 seconds after liftoff. Then, on February 1, 2003, while returning to Earth, Columbia broke up.

A control system links the flight controls of an aircraft (and some spacecraft) with its control sur­faces. An aircraft’s control surfaces are the ailerons, elevators, and rudder.

Cables and Hydraulics

The simplest control system uses cables. When the pilot moves one of the controls in the cockpit, the control pulls a cable. The cable is threaded through the plane to a control surface in a wing or the tail. Moving a control pulls a cable, and the cable moves a control surface.

Early airplanes used a simple control system of this kind. Today, only the smallest and slowest aircraft are con­trolled with cables. Bigger and faster air­craft are harder to control with muscle power. When the pilot tries to move the controls, the control surfaces resist because of the greater force of the air pushing back against them.

The biggest and fastest aircraft, including most airliners, have mechani­cal muscles that are much more powerful
than any pilot’s. An airplane’s engines drive pumps that force an oily liquid through pipes. The pipes go from the pumps to machinery in the wings and tail that moves the control surfaces. The flow of oil through the pipes is con­trolled by valves. The valves work like faucets-opening a valve lets oil flow through it, while closing it stops the flow of oil. Moving the flight controls in the cockpit opens or closes valves and sends the oil to the actuators, the machines that move the control surfaces.

This sort of control system, operated by liquid in pipes, is called an hydraulic control system. Aircraft usually have three or even four separate hydraulic control systems. If one fails, there are always more to take its place.

Earhart added to her celebrity in 1930, when she set a women’s speed record of 181 miles per hour (291 kilometers per hour). In 1931 she set a new women’s altitude record of 18,451 feet (5,624 meters). Still, some women had criticized Earhart for being only a passenger on the 1928 transatlantic flight. Those criticisms stung, and she was determined to prove her worth.

On May 20, 1932,

Earhart set out from New­foundland, Canada, in a twin-engine Lockheed Vega to fly solo over the Atlantic Ocean. The flight was not easy. Gasoline leaked into the cockpit, the altimeter broke, and a storm buffeted the plane. At one point, the plane plunged 3,000 feet (914 meters) and then began to spin before Earhart could regain control. Never­theless, she landed the plane safely in Ireland about 15 hours after taking off. It was only the second solo crossing of the Atlantic Ocean-no one had dupli­cated Lindbergh’s feat until then.

Earhart also set a distance record for women, flying more than 2,000 miles (3,218 kilometers).

Earhart’s trip made her one of the world’s most famous women. She pub­lished a book about the trip called The Fun of It, which furthered her image as a plainspoken charmer. Earhart used the

book to continue her campaign to bring women into aviation.

Her next exploit came the following year. On August 24 and 25, 1932, she flew solo across the United States from California to New Jersey. The flight took a little more than 19 hours, setting a record. The next year, Earhart made the same trip in two hours less time.

In 1935 Earhart became the first pilot to fly solo from Hawaii to California. Later that year, she made the first non­stop flight from Los Angeles to Mexico City and, after a few weeks, carried out the first flight from Mexico City to Newark, New Jersey.