Category FLIGHT and M ОТІOIM

In the last few months of World War II, the first jet fighter, the German Me-262, zoomed into combat. Much faster than any Allied propeller plane, it was power­fully armed with a 30-millimeter gun and rockets. Fortunately, the Me-262 was not used effectively-most Me-262s were used to carry bombs, and a bomb load reduced its speed. The Germans devel­
oped other jet airplanes and the rocket – powered Me-163, which was designed to intercept high-flying Allied bombers.

The only Allied jet to see combat in World War II was the British Meteor, a twin-engine fighter fast enough to destroy German V-1 flying bombs. The first U. S. jet in service, the XP-80 Shooting Star, was built in just 143 days and first flew in January 1944. Too late to fight in World War II, it saw combat in 1950 during the Korean War.

After World War II, it was clear that propeller-driven, piston-engine fighters were obsolete. Air forces hastened to equip themselves with jets, which were armed with missiles rather than machine guns. The U. S. Air Force had its first swept-wing fighter, the F-86 Sabre, in

1947 and its first all-weather interceptor, the F-94 Starfire, in 1949.

Jet fighters flew in combat during the Korean War, and the first victory gained in an all-jet air combat came in 1950 when Lieutenant Russell J. Brown, Jr., flying an F-80, shot down a Chinese MiG-15 fighter. Jet fighters also demon­strated their ability to fly nonstop across the ocean, when in 1950 an F-84 Thunderjet flew from Britain to the United States, refueling in the air three times on the way.

STEALTH

Although the F in the F-117 Nighthawk’s name designates it as a fighter, the stealth aircraft is a primarily a ground attack plane. Developed in secret, the F-117 became operational in 1983. Its unusual shape and construction help "blind" an enemy’s radar. It relies on stealth, not speed, to surprise an enemy. The Nighthawk has been used in war­fare by the United States in Panama in 1989, in the 1991 Gulf War, and in Iraq.

A Key Role

In the 1950s, some experts believed mis­siles could replace fighters. Experience in later conflicts (Vietnam, the Gulf War, Bosnia, and Iraq) has shown that the fighter plane still has a key role. Its tasks are now varied: Besides fighting enemy airplanes, it also flies reconnaissance, electronic warfare, and strike missions.

Over time, the fighter pilot’s job has become technically and physically more demanding. Some planes, such as the Russian MiG-31, need a second crew member to operate the weapons systems. The Russian MiG family of warplanes is one of the most famous in aviation history. It began with the Mikoyan – Gurevich MiG-1, a propeller-driven fighter of 1940. The MiG-15 jet (1950) was followed by a succession of faster MiGs, including the MiG-25, which set speed and altitude records. MiG fighters led the air forces of many Communist nations in Eastern Europe during the Cold War, and these fighter planes also were built in Chinese versions.

For many people, long-distance flying is a tedious ordeal, not a pleasure. Airplane designers of the future may make flying more comfortable by fitting fewer, big­ger seats, maybe arranged diagonally instead of in rows. Larger airplanes with fewer seats would offer passengers the chance to stretch their legs during the flight. Passengers should be able to surf the Internet on a laptop (Internet access on airlines was approved by the FAA in 2005). They may even be able to order meals and drinks from a virtual flight attendant who pops up onscreen at the click of a button or mouse.

In the twenty-first century, air travel will feature a mix of aircraft types: large- and medium-size, very fast and relatively slow, and some with VSTOL (vertical/short takeoff and landing) capability. There might be a return to

Designs for supersonic aircraft of the future include HyperSoar, a large air­plane flying at Mach 10, or 6,700 miles per hour (10,780 kilometers per hour). A major problem at such hypersonic speeds is heat from fric­tion. HyperSoar is designed to avoid this problem by skipping along the upper edge of the atmosphere, just as a flat rock skims when thrown across a pond. It would climb to 210,000 feet (64,000 meters), then turn off its engine and descend to 105,000 feet (32,000 meters). The engine would be turned back on again, and HyperSoar would skip back up to the fringes of space. It would repeat the process until it landed like a normal airplane.

HyperSoar also could become the first stage of a two-stage launch sys­tem for space satellites.

Fast flight times are still regarded as a key selling point for some new airplanes. Experts are not sure how passengers would react to the skip­ping motion of HyperSoar (it might feel like a giant theme park ride), but the flight would be quick. Allowing for time and distance to take off and land, a HyperSoar flight from Chicago

to Tokyo (just over 6,000 miles, or about 10,000 kilometers) would require twenty-one skips and last 65 to 72 minutes. A cross-country trip from New York City to Los Angeles would need nearly ten skips and be completed in about 35 to 37 minutes.

airships, which have been absent from the skies since the 1930s. Airships are slow, but they give passengers a tranquil view of the scenery below as they glide through the air at around 100 miles per hour (160 kilometers per hour).

Looking farther ahead, the airliner of the future could be a flying wing or blended wing body (BWB). The BWB is a more efficient shape for high-speed flight at altitude. The plane would have no windows. To avoid claustrophobia, passengers would be given a “view”
through artificial windows or on screens of a simulated sky outside. A BWB air­liner could be flying by 2020.

A glider has the same basic shape as a powered airplane, but its wings are longer and very narrow. Narrow wings produce less drag than wide wings. The longer the wings, the more wing area the glider has to generate lift. A competition sailplane may have wings that are 70 feet (21 meters) long but less than 3 feet (1 meter) wide. Just like a powered air­plane, gliders’ wings have ailerons-and sometimes flaps as well-for control in flight. Many gliders carry water as bal­last in the wings. The ballast, which pro­vides additional weight for extra control in fast rising air currents, is jettisoned (dropped) before the glider lands.

The fuselage (or body) of a glider is slim, again to reduce drag. It is often so

slim that the pilot has to lie almost prone in the cockpit. Trainer gliders, designed for two people-an experienced pilot and a student-have slightly wider bodies and cockpits in which the passen­gers can sit upright.

Gliders are made of lightweight materials, usually aluminum, fiberglass, metal, and wood. The outer skin is smoothed and polished to reduce air resistance. Landing gear on a glider usu­ally consists of one landing wheel that folds away after the glider is airborne.

Launching

Most gliders are launched by a towing airplane. A towrope or wire, usually 150-200 feet (46-61 meters) long, is fastened from a hook on the towing

GLIDER CLASSIFICATION

The French Federation Aeronautique Internationale (FAI) is recognized as the world’s air sports association. It classes gliders for competition in various ways.

The classes include:

• Standard class: no flaps, wingspan 49.21 feet (15 meters).

• 15-meter (49.21-feet) class:

flaps allowed.

• 18-meter (59.06-feet) class:

flaps allowed.

• Open class: no restrictions.

• Two-seater class: maximum wingspan 65.62 feet (20 meters).

• Club class: open to a range of types, including older gliders.

__________________________________________ )

airplane to another hook on the nose of the glider. As the towing airplane takes off, it pulls the glider after it, and the two airplanes gain height. Once a glider has gained sufficient altitude-usually between 2,000 and 3,000 feet (610 and 915 meters)-the glider pilot frees the glider from the towrope by using a con­trol in the cockpit.

Gliders also can be launched by cat­apulting them off hillsides or by towing them behind a vehicle, but the most usual alternative to tow launching is to use a winch. This process is similar to launching a kite. A power-operated winch is set at one end of the takeoff

О The Duo Discus is a high-performance glider used in fast cross-country flying. Built in the Czech Republic, the two-seater used for high-level training and often is seen in competitions.

Powerful air currents, known as mountain waves, are found on the lee (sheltered) side of steep, high mountains. Flying a glider in mountain waves is sometimes called ridge running. A glider also will soar when it flies into a shear line, or convergence zone, where a mass of cool air has forced a block of lighter, warm air to rise. Experienced glider pilots learn to take full advantage of these air currents and other favorable flying conditions.

New records are frequently set by gliders for height, distance, and speed. Gliders have climbed to heights of over

49,0 feet (14,940 meters) and have made straight-line flights of more than 1,240 miles (1,995 kilometers).

A glider pilot has four basic flying instruments: an airspeed indicator, an altimeter (to show altitude), a compass, and a vario/altimeter that indicates the rate at which the plane is rising or falling. The vario/altimeter helps the pilot determine the glider’s position in relation to nearby rising air currents. The pilot also can use computers and GPS systems to keep track of the air­craft’s position and course.

Using airbrakes to slow its descent, a glider can land on almost any flat field, often miles from its launch. Most are designed to be taken apart so they can be loaded on a trailer for the trip home.

Regulations for glider pilots are simi­lar to those for other airplane pilots. In the United States, the Federal Aviation Administration is responsible for regu­lating pilots and gliders.

SEE ALSO:

• Aerodynamics • Aeronautics

• Cayley, George • Lift and Drag

• Lilienthal, Otto • Wright, Orville

and Wilbur

_____________________________________________ J

Interest in helicopters increased rapidly after World War II. In 1946, the first experimental delivery of U. S. airmail by helicopter was made in Chicago. A Sikorsky S-51 began the world’s first scheduled helicopter passenger service in Los Angeles in 1947. A helicopter landing station, or “heliport,” was opened in New York City in 1949, and the first international helicopter passen­ger flight was made in 1953 between Brussels, Belgium, and London, England.

For the military, too, the helicopter was soon in everyday use. During the Korean War (1950-1953), helicopters took on a variety of tasks, including observation, transporting supplies and troops, and evacuating casualties.

By the 1960s, the helicopter had a combat role-attack helicopters called “gunships” targeted enemy troops and tanks on the ground. Helicopters were used a great deal in the Vietnam War. The first combat helicopter widely employed by the U. S. military was the Bell Model 209 HueyCobra (1967).

Helicopters found useful roles with the U. S. Navy: they flew reconnaissance missions and hunted submarines with

guns, missiles, depth charges, and torpe­does. They were used to rescue pilots downed in the ocean and to retrieve spacecraft and astronauts. Large, troop­carrying helicopters flew soldiers and marines into combat zones. Even a rela­tively small ship, such as a destroyer, is able to carry a helicopter, and this type of aircraft is now an essential compo­nent of a modern navy fleet.

Hughes’s subject in Hell’s Angels reflected his other passion in life: flying. He was devoted to flying-and to flying fast. In 1934, Hughes flew a Boeing air­plane at 185 miles per hour (300 kilometers per hour), a new record. The next year, he flew the H-1 Racer, a plane he and an associate had specially designed.

Built for speed, the plane had landing gear that could retract into the wings. More important, all rivets holding the metal pan­els of the plane were set flush into the structure to produce less drag. With these features along with a powerful engine, Hughes shattered the old speed record by flying more than 352 miles per hour (570 kilometers per hour).

Hughes continued working on the H-1 to improve its per­formance. In 1936, he flew the air­plane across the country. Flying from Los Angeles to New York, he arrived in less than 91/2 hours-2 hours less than the previous record. On that flight, the H-1 averaged 322 miles an hour (520 kilo­meters per hour). In 1937, Hughes shaved a further 2 hours off that speed.

In 1938, Hughes and a team of four pilots attempted a round-the-world flight. They modified a twin-engine Lockheed 14, stuffing it with extra gas tanks, radios, and navigational equip – ment. Hughes wanted to prove that safe, long-distance flying was possible, and
he spent $300,000 of his own money to do so.

The trip was so well planned that the plane never made any unscheduled stops. In the end, the team circled Earth in 3 days, 19 hours, and 14 minutes, cut­ting the old round-the-world record in half. Hughes was hailed as a hero and was given a tickertape parade in New York City. The following year, he received a gold medal for his achieve­ment from the U. S. Congress.

The simple HHMU gas guns led to the bigger maneuvering units worn by astronauts in later years. One of these was NASA’s manned maneuvering

unit (MMU). The unit clipped onto the back of an astronaut’s spacesuit. The MMU enabled the astronaut to fly freely in space, without a tether, like a one – person spacecraft.

The MMU was propelled by puffs of nitrogen gas from twenty-four thrusters pointing in different directions. It was flown by means of two hand controllers. The controller in the astronaut’s right hand was used for pitch, roll, and yaw motions. The left controller moved the astronaut in a straight line forward and back, up, and down, or left and right. The MMU also could fire jets to keep the astronaut in the same position.

MMUs were used by Space Shuttle astronauts between 1984 and 1986. Cosmonauts at the Russian Mir space station tested a similar jetpack for per­forming extra-vehicular activity (EVA).

After the MMU, NASA developed a much simpler space maneuvering unit. Astronauts working outside the Space Shuttle or the International Space Station wear a device called the simplified aid for EVA rescue, or SAFER. Tested in space for the first time

in 1994, the unit fits around an astro – propulsion. The SAFER is much smaller naut’s life-support backpack. Like the than the MMU and it holds less gas, so it MMU, the SAFER uses nitrogen gas for is intended for emergency use only.

When a plane cruises at a steady speed, the thrust of its engines forcing it for­ward is exactly balanced by drag pulling it backward. If the drag can be reduced, the plane can go faster or farther or burn less fuel.

One way to reduce drag is to make the wings thinner. The Lockheed F-104 Starfighter was a very fast fighter built in the 1950s. It had very thin wings to reduce their drag and make the plane as fast as possible. In fact, its wings were so thin and the leading edges were so sharp that soft covers had to be fitted to them on the ground to protect engineers from injuries if they walked into a wing.

Gliders

Gliders have long, thin wings that create a lot of lift and a slim, streamlined body that causes little drag, so they have very high L/D ratios.

For gliders the L/D ratio is the same as the glide ratio. This is the distance a glider flies forward compared to the height it loses. A glider with a glide ratio of 70:1 flies 70 feet (21 meters) forward for every 1 foot (0.3 meters) it descends.

It is important to know the L/D ratio of a powered aircraft, because it tells the pilot how far the plane can glide before it has to land if the engines fail. While it is gliding, drag is slowing it down. As it slows down, its wings produce less lift, so it loses height.

In 1982, a Boeing 747 flew into a cloud of ash rising from a volcano in Indonesia. The ash damaged the engines.

All four engines failed at an altitude of 37,000 feet (11,278 meters). With an L/D ratio of 15:1, the 747 could glide a distance equal to fifteen times its altitude, or up to about 105 miles (170 kilometers). Luckily, the crew was able to restart three of the engines and land the airliner safely.

The Space Shuttle returns to Earth without engine power and glides down to a landing. Compared to an airliner or glider, the spacecraft has a very poor L/D ratio. It drops like a stone as it glides, approaching the runway at an angle six times steeper than that of an airliner.

issiles are self-propelled weapons that fly toward their targets at high speed, armed with an exploding warhead. There are many different types of missiles.

The Basic Types

Small missiles are used for attacking tar­gets, such as tanks, just a few hundred or thousand feet away. These small bat­tlefield missiles used by armies are also called tactical missiles. There also are longer-range missiles carried by ships and helicopters for attacking enemy ships, aircraft, and land targets. The biggest and most powerful missiles can fly thousands of miles and do enormous damage to a whole city. These missiles are known as strategic missiles.

Nearly all missiles have a guidance system that steers them toward their tar­gets. For this reason, they are called
guided missiles. There are different types of guidance systems. Some use the heat of the target (for example, the heat gen­erated by the jet exhaust of an enemy fighter plane). Other guidance systems are radar seeking, using the radar reflec­tion of an oncoming missile to find and destroy it. Missiles aimed at a stationary target on the ground can use GPS as their guidance system.

Missiles also are defined by where they are fired from and what their target is. Surface-to-air missiles (SAMs) are launched from the ground at aircraft. Air-to-ground missiles (AGMs) or air-to – surface missiles (ASMs) are fired by air­craft at targets on the ground.

Air-to-air missiles (AAMs) are fired by aircraft at other aircraft. The AIM-9 Sidewinder is a short-range missile used by fighter planes in combat with each other. AIM stands for air intercept mis­sile. When a Sidewinder is fired, its solid fuel rocket accelerates it to more than twice the speed of sound. Fins on the nose and tail provide lift and steer the mis­sile. The missile’s nose

О A view of the wing of a U. S. Navy Hornet shows two laser-guided bombs and (on the outside) an AIM-9 Sidewinder missile. The Sidewinder is an air – to-air missile, which means it is used by aircraft to attack enemy aircraft.

The world’s first ballistic missile was the V-2, developed in Germany during World War II. It stood 47 feet (14 meters) high and weighed about 29,100 pounds (13,200 kilograms). The V-2’s nose contained 1,600 pounds (about 725 kilograms) of explosives. Its rocket

engine, burning alcohol and liquid oxygen, boost­ed it to a height of about 50 miles (80 kilometers), and then the V-2 fell toward its target, up to 200 miles (320 kilometers) away. The V-2 arrived with­out warning because it flew faster than the speed of sound. Even if a V-2 was spotted, it was flying too fast to be shot down.

The V-2 was not a very accurate weapon. It could be fired at something as big as a city with a good chance of hitting it, but it could not be counted on to hit smaller targets, such as bridges or runways. About 4,000 V-2s were launched during the war-more than 1,000 fell on London. After the war, the United States and the Soviet Union captured scores of unused V-2 rockets. Many of the ballistic missiles and space rockets built in the 1950s were based on the V-2.

О A V-2 rocket is prepared for launch by technicians in Germany in the early 1940s.

4___________________________________ _________________________________________

contains an infrared (heat) seeker. This detects the heat of the target plane and steers the missile toward it.

Kings and emperors often appear in leg­ends about flying. The earliest known story of a flying person-about 4,500 years old-is the legend of King Etana of Sumer in Mesopotamia (modern-day Iraq). The king and his wife were not able to have a child, and he desperately wanted an heir. Following the instruc-

tions of the sun god, he freed a captured eagle. The bird carried King Etana to heaven, where he begged the goddess Ishtar for a child. She gave him a plant that both he and his wife ate, and the treatment worked.

Nearly as old is the Chinese legend of the emperor Shun. He used two over­sized hats to fly. Once he employed this device to escape a burning tower. On another occasion, he used it to fly around his empire.

The Persians also told of a king who flew. The vehicle that King Kai Kawus used was of ingenious design. Workers attached long poles to the four corners of this throne. They tied meat to the top of each pole, and at the bottom of each pole they chained an eagle. When the eagles grew hungry, they beat their
wings in an effort to reach the meat. That motion carried the throne aloft. This method worked, and the eagles car­ried the king into the sky. Unfortunately, they grew tired and stopped flapping their wings. When that happened, the throne tumbled to the ground.

A similar story involves the Greek conqueror Alexander the Great. He tied hungry griffins to poles attached to his throne. Griffins were half lion and half eagle. Alexander’s story ends with a more direct moral than that of Kai Kawus, however. His vehicle stayed in the air for a week and brought him near the heavens. An angel then appeared and asked him why he wanted to see the
heavens when he did not yet understand everything about life on Earth. Humbled, the conqueror returned to land.

Britain also has an ancient legend of a king who flew. King Bladud, who reigned in the ninth century b. c.e., had great intelligence and practiced magic. He fashioned a pair of feathered wings and launched himself into the air.

However, the king’s flight ended in dis­aster. In some versions of the story, he plunged to his death. In others, he slammed into a wall. Either way, he lost his life and his kingdom, which was then inherited by his son—Lear. King Lear then became the subject of another leg­end, which was immortalized in a tragic play by William Shakespeare.

parachute is a canopy that slows the fall of an object or person through the air. The word parachute means “against a fall.”

Parachutes have saved the lives of many pilots who needed to eject from damaged airplanes. Parachutes are used to drop supplies and paratroopers (para­chuting soldiers) from airplanes. Sports parachutists enjoy freefall skydiving. Yet another use for a parachute is as an air­brake, to slow an airplane, spacecraft, or other vehicle as it lands.

A personal parachute is packed in a bag or body pack worn by the para­chutist and attached to a strong harness or supporting rig. After exiting the air­craft, the parachutist opens the para­chute by pulling a handle called the rip­cord. Parachutes also can be opened automatically. When a pilot ejects from a jet plane, for example, the ejector seat mechanism opens the parachute. Brake parachutes for slowing down an airplane are stowed in the tail and open only after the plane has touched down on the runway. A spacecraft parachute opens after reentry into the atmosphere. Other brake parachutes may be automatic or manually deployed.

The canopy is made of a tough, light fabric-silk was traditional, but nylon and other synthetic materials are used today. The traditional shape for a para­chute canopy was a circle, but modern parachutes are usually square or rectangular. The parachutist’s harness

is attached by straps, called risers, to suspension lines around the edge of the canopy. As parachutists float to the ground, they can make turns by tugging on steering lines.