Category FLIGHT and M ОТІOIM

Responsibility for the attacks was lev­eled at al-Qaeda, a secretive Islamist ter­rorist organization led by Osama bin Laden. U. S. President George W. Bush announced a “war on terror,” and U. S. warplanes were ordered to shoot down any hijacked airliner that might pose a danger. No-fly zones were enforced.

Some of the 9/11 terrorists had been living in the United States and had even taken flying lessons there. The 9/11 attacks led to a review of the nation’s security. Stricter antihijacking regula­tions were introduced to prevent explo­sives or weapons from being taken onto airplanes. Air marshals disguised as pas­sengers traveled on flights, ready to dis­arm potential skyjackers. Within a few weeks, President Bush had signed a new law, the Anti-Terrorism Act, giving the U. S. government increased powers.

Other suicide attacks were foiled. Later in 2001, for example, law enforce­ment agents seized al-Qaeda terrorist

Richard Reid (a British citizen), who had been planning to blow up a U. S. airliner with a bomb hidden in his shoe.

Today, passenger and baggage screening systems are provided by the Transportation Security Administration (TSA), part of the Department of Homeland Security. Under new secure flight arrangements, airlines and securi­ty services exchange information to identify all persons buying airline tick­ets, checking identities against those of known terrorists. Counterterrorist intelli­gence in the United States is spearhead­ed by the National Counterterrorism Center, which took over the State Department’s responsibility in that area.

SEE ALSO:

• Airport • Pilot

In the 1940s, some scientists believed that rockets held the key to exploring space. Much postwar space research involved testing missiles to carry nuclear weapons, and this research was carried out in secret. Although little was known about the Soviet program, American scientists suspected that Soviet rockets were bigger than those being tested in the United States, which included the Viking and WAC Corporal. In 1949, however, the United States fired the world’s first two-stage rocket, using a V-2 as the first stage and a Corporal for the second stage. This two-stage rocket was capable of reaching space.

July 1957 to December 1958 was designated International Geophysical Year. As part of this worldwide science program, the United States planned to launch the first artificial satellites into orbit around Earth. With the Cold War still at its height, there was little exchange of information between the United States and the Soviet Union. Apart from releasing some information about radio communications for con­trolling a satellite, the Soviets gave no hint of what was to come.

Finally, on October 4, 1957, Moscow announced that Soviet scientists had launched Sputnik 1, the world’s first space satellite. With Sputnik 1 bleeping its radio signals from orbit, the Soviets had grabbed the lead in the space race.

With the successful orbit of Sputnik 1, the space race between the United States and Soviet Union had begun. President Dwight D. Eisenhower sent congratula­tions to the Soviet leadership, but the success of the Sputnik program caused surprise-and dismay-in the United States, especially among space scientists.

О Sputnik missions were launched from Tyura – Tam in the Soviet Union. The launch of Sputnik 2, shown here, took place in November 1957. The spacecraft carried a dog named Laika into space.

Many scientists had attended a science symposium in Washington, D. C., the week before the launch, at which Soviet space scientists had been present. Not a hint had been given that a satellite launch was pending.

The Sputnik program was a blow to U. S. scientific prestige. Sputnik 1 was over fifty times heavier than Vanguard. Its weight, the Americans knew, must have required a powerful launch vehicle and suggested a dangerous technology gap. The Soviets were taking the lead with more powerful space rockets and, presum­ably, bigger bomb-carrying missiles.

The National Aeronautics and Space Administration (NASA) was created in 1958 to oversee a new program of U. S. space flights. Explorer and Vanguard satellites were successfully launched in 1958, showing that the United States also had a space capability, and further success soon followed.

When anything flies through air very fast, it heats up due to the increased fric­tion with the air. The higher the speed, the higher the temperature climbs. Concorde cruised at a speed of 1,345 miles per hour (2,160 kilometers per hour), or Mach 2.04. At this speed, its body and wings heated up to more than 195°F (91°C). The tip of its nose reached 260°F (127°C)-hotter than boiling water. Planes designed to fly faster than this must be made from materials that can withstand such high temperatures.

The Space Shuttle returns from space at a speed of about Mach 25. As it descends into the atmosphere, it heats up. The hottest parts of the spacecraft are the nose and the leading edges of the wings, which reach 2,750°F (1,510°C). Heat-resistant tiles and other materials are vital to protecting the Space Shuttle’s aluminum structure.

Some jet planes are able to take off and land verti­cally by swiveling their engine nozzles downward. This is called vectored thrust. Fighter planes increasingly use vectored thrust for steering. VTOL aircraft use it to generate lift. The Harrier Jump Jet uses this method.

The jet of gas from the Harrier’s engine comes out through four nozzles instead of just one. There are two noz­zles at the front of the aircraft and two more at the back. The pilot can rotate all of the nozzles together by moving one control in the cockpit. The nozzles are pointed downward for vertical takeoff, landing, and hovering, and turned back­ward for normal forward flight. They even can swivel forward a little, so the Harrier can fly backward.

When a jet plane is taking off verti­cally, hovering, or flying slowly, air does not flow around it fast enough for its control surfaces (the rudder, elevators, and ailerons) to work. The plane has to control its attitude, or position in rela­tion to the horizon, in a different way. A small amount of air from the engine is piped to small nozzles in the aircraft’s nose, tail, and wingtips. Blowing air out of these nozzles can turn the aircraft about all three axes-up and down, rolling side to side, and turning to the left or to the right.

An airplane needs big wings to produce large amounts of lift when it is flying slowly during takeoff and landing. Big wings that produce a lot of lift, howev­er, also produce a lot of drag. Excessive
drag makes the wings inefficient when the plane is cruising at high speed, because the engines have to burn more fuel to overcome it.

Designers solve this problem by cre­ating the best wings for high-speed cruising but changing their size and shape for takeoff and landing. As an air­liner prepares for takeoff or landing, flaps slide out from the trailing edges of its wings, and strips called slats slide out from the leading edges. Flaps and slats are called high-lift devices because they produce extra lift. Flaps produce more lift by making a wing bigger and more curved. When slats are extended, they make the leading edge of a wing more curved. This shape enables the wing to be tilted to a greater angle of attack without stalling. The higher angle of attack produces extra lift.

The simplest flaps hinge downward from the wing’s trailing edge. Fowler flaps slide backward and then tilt down.

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THE ANATOMY OF AN AIRPLANE WING

The front edge of a wing also is called its leading edge, and the back edge is the trail­ing edge. The measurement from the leading edge straight back to the trailing edge is the wing’s chord. The length from one wingtip to the other is the wingspan. The curvature of the top and bottom of a wing is called its camber. The part of a wing where it joins a plane’s fuselage is the wing root. A wing’s aspect ratio is a measure of how long and slender it is. A wing that has a high aspect ratio (long and slender) causes less drag, so it is good for gliding. Wings usually tilt up from an airplane’s body toward the wingtips, forming a shallow V shape. The angle of this tilt is called the dihedral, and the wing’s dihedral makes an airplane more stable.

They increase the size and curve, or camber, of a wing. Flaps are nearly always on a wing’s trailing edge, but Krueger flaps are on the leading edge.

The increased curve in the wing shape produced by flaps may cause a wing to stall and lose lift if the smooth airflow over the wing breaks away from the drooping flaps.

When a slotted flap slides out, a gap opens up between the flap and the rest of the wing. Air from below the wing comes up through the slot and flows over the top of the flap. This extra air­flow helps to stop the wing from stalling. There are also slotted slats. Air coming up through the slot from below flows over the top of the wing and

enables the wing to work safely at a higher angle of attack without stalling. A blown flap is a device that blows air from the engine over the flaps. The extra airflow produces more lift and delays stalling even more.

In May 1942, RAF Bomber Command launched its first “1,000-bomber” raid, targeting the German city of Cologne. Bombs were unguided, but aim was more accurate, thanks to the U. S.-

designed Norden bombsight. This device had a gyroscopically stabilized telescope for the bombardier to sight the target during the bombing run. The bombsight computer automatically made course corrections to ensure that the bombs were released over their targets.

The weight of bombs increased. In 1943, the first 12,000-pound (5,440- kilogram) bomb was used. The first 22,000-pound (9,990-kilogram) “grand slam” bomb followed in 1944. The size of airplanes also grew. The B-29 of 1944 was twice as heavy as the earlier British Lancaster. The B-29 could cruise at

30,0 feet (9,140 meters) during a mis­sion that might last 15 hours, driving off enemy fighters with thirteen defensive guns controlled by a computer system.

The most destructive weapons in history were the two atomic bombs dropped by B-29s on the Japanese cities of Hiroshima and Nagasaki (August 1945). The bombs destroyed the cities and killed an estimated 200,000 people.

he aerospace industry makes and services aircraft, spacecraft, and associated equipment. Aerospace manufacturers make airliners, airfreight carriers, warplanes, helicopters, and general aviation airplanes. They also build guided missiles, engines, and other equipment, including electronics and air traffic control systems. The industry’s space activities include making commercial telecommunications satel­lites, navigation satellites, and science satellites. Aerospace companies build and adapt launch vehicles, such as multistage rockets, the Space Shuttle, and the ground systems that control spaceflights. The industry also takes care of the overhaul, rebuilding, and conver­sion of air and space vehicles.

Industry Overview

The United States has the world’s biggest aerospace manufacturing sector. Its biggest customer is the federal govern­ment. Military airplanes, missiles, and other equipment are ordered by the U. S. Department of Defense. The main purchaser of space vehicles (satellites and launch vehicles) is the National Aeronautics and Space Administration (NASA), also a federal agency.

Passenger and cargo-carrying air­craft form the biggest sector of the civil part of the industry. These planes are supplied to air transportation busi­nesses, such as airlines and airfreight businesses. Smaller businesses buy air­craft of many kinds. Satellites are sold to television companies and other commu­nications businesses. The aerospace manufacturing industry also supplies airports and space centers with all kinds of service equipment—everything, in fact, that keeps airplanes and space­craft flying.

Every large aerospace corporation works with a network of smaller compa­nies. These businesses supply all types of components, from weapons and avionics to airliner seats and carpets. On major projects, corporations often cooperate with partners to cut costs and share expertise. For example, the European Aeronautic Defence and Space Company (EADS), which makes the Airbus airliner, was originally a consortium of British, French, Spanish, and German companies.

U. S. aerospace companies are pri­vately owned. In some other nations, however, the government controls the aerospace industry. Before the breakup of the Soviet Union in the 1990s, all Soviet military and civil aircraft were built by the state-controlled aerospace sector. There are other examples of national aerospace firms, such as Saab of Sweden. Government industries, such as those in Israel and China, usually build airplanes for their armed forces.

he term air traffic refers to all air­craft in the air, about to fly, or just landed. Air traffic control is per­formed by people on the ground whose job is to ensure air safety at all times. Safety is a matter of concern for all fliers, whether they are piloting private airplanes, military jets, or airliners. Pilots have the final responsibility for the safety of any aircraft, but they must also follow instructions given by con­trollers on the ground.

Air traffic controllers make sure that aircraft of all sizes move safely around in the sky. Their work is of special importance around airports, where the sky is often crowded with airplanes. Air traffic control makes sure that planes taking off and landing do so in a safe, orderly, and efficient manner.

From the 1940s to the 1960s, U. S. engi­neers built a series of research airplanes to explore supersonic flight. These craft included the Bell X-1, Bell X-2, Douglas Skyrocket, and X-15—all were record breakers. Their flights helped engineers design supersonic jet fighters and manned spacecraft. The British Fairey Delta 2 (FD-2) set a world airspeed record of over 1,000 miles per hour (1,609 kilometers per hour) in 1956. The small FD-2 had the same delta wings

SECRET EXPERIMENTATION

Research flying is often secret. Developed in secret between 1975 and 1982 by Lockheed for the U. S. Defense Advanced Research Agency, the F-117 Nighthawk was in U. S. Air Force service years before it was revealed to the public.

Phantom Works, a project division of McDonnell Douglas (now part of Boeing), tested a different aircraft, the Bird of Prey, from 1996 to 1999. Termed an "invisible airplane," the Bird of Prey was hard to detect because of its shape, the way it was painted, and stealth specifications similar to those of the F-117.

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and drooping nose made familiar by Concorde in the 1980s.

Not all experimental airplanes fly higher or faster. The Altus is a civilian version of the military Predator, a U. S. drone used after 2000 in wars in Afghanistan and Iraq. Altus carries scientific instruments to sample the atmosphere, flying at only 80 miles per hour (129 kilometers per hour), but it is able to stay in the air for up to 24 hours. The Proteus airplane can also stay in the air for up to a day. It is designed by Burt

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Rutan, innovative designer of Voyager, an airplane that flew nonstop around the world (in 9 days) in 1986. Rutan also produced SpaceShipOne, the world’s first successful private spacecraft.

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SEE ALSO:

• Bell X-1 • Concorde • Engine

• Glider • Jet and Jet Power • Kitty Hawk Flyer • Rocket • Wright,

Orville and Wilbur

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