Category FLIGHT and M ОТІOIM

he space race was a period of rivalry between the United States and the Soviet Union during which the two nations competed in the exploration of space. The race was at its height in the 1950s and 1960s.

The Cold War

The space race had its origins in the Cold War, a time of mutual suspicion between the United States and the Soviet Union that began after World War II (1939-1945). The hostility resulted from the deep divide between two political systems: Soviet communism and U. S. capitalism, or free enterprise. The two nations became the world’s military super-powers, each building up huge stocks of weapons, including rockets.

In 1945, after Germany’s defeat in World War II, both the United States and the Soviet Union acquired German rock­et technology. The German V-2 rocket could fly faster than sound and reach a height of 60 miles (96 kilometers). German scientists were taken to the Soviet Union and the United States, where they worked on more advanced rockets for their adopted countries.

On October 4, 1957, the rocket carrying “Elementary Satellite 1,” or Sputnik 1, took off from the desert near Tyura-Tam, in what is now the Kazakh Republic. All went well, and the first radio signals from space told the waiting Soviet sci­entists that Sputnik 1 was in orbit. They announced their success to the world, and almost every newspaper, radio, and television network carried the story. Sputnik 1 was headline news. Astronomers trained radio telescopes on the tiny satellite. Amateur radio enthu­siasts in many countries picked up the satellite’s “beep beep” radio signals as it passed overhead.

Sputnik 1 had a brief working life, but its historic flight proved that a human-made craft could survive launch and fly in orbit. The scientific data gath­ered from the flight was limited, but Sputnik 1 did help to identify the density of the layers in the upper atmos­phere and provided useful information on how radio signals from space were received on Earth.

Scientists had feared that space dust or meteoroid impact might damage the spacecraft. Even a minute hole in the satellite would have caused a detectable drop in pressure and temperature. However, Sputnik 1 continued to orbit Earth undamaged. The spacecraft’s radio batteries ran out before the end of October, after which no more signals were received. The satellite stayed in orbit until January 1958, when it burned up as it reentered Earth’s atmosphere, having traveled about 37 million miles (60 million kilometers).

Shock waves explain why World War II pilots lost control of their aircraft in high-speed dives. As shock waves devel­op over the wing, they disturb the air so violently that the smooth flow breaks up into a swirling turbulent flow. The air­craft’s control surfaces are trapped inside this chaotic air. Robbed of the smooth airflow they need, they cease to work. The turbulence caused by shock waves is the reason for the violent shak­ing that World War II pilots experienced.

Modern supersonic aircraft do not suffer from these problems because of their shape. Their wings are thinner and more swept back, so they cut cleanly through the air and delay the formation of shock waves. When the aircraft goes faster than the speed of sound and the shock wave cone forms around it, the swept-back shape of the wings means that the whole aircraft fits neatly inside the shock cone and flies more smoothly.

he capability of a fixed-wing air­craft to take off and land vertical­ly is known as vertical takeoff and landing, or VTOL. Some aircraft have the ability to take off and land on a very short runway-these are V/STOL aircraft. V/STOL stands for vertical or short takeoff and landing. Still others are STOVL aircraft-they are capable of a short takeoff and vertical landing. The terms are used to describe a small group of fixed-wing aircraft. They do not include helicopters, airships, or rockets, all of which also have the ability of vertical takeoff.

Propeller Planes

Fixed-wing aircraft normally need a long takeoff run to get airborne. They cannot take off until their wings are moving through the air fast enough to create enough lift to overcome the plane’s weight. If a fixed-wing aircraft is to take off vertically, it needs to direct its engine power downward with enough force to overcome its weight.

Propeller planes can do this by tilting their engines and propellers so they work like helicopter rotors. The V-22 Osprey, a V/STOL aircraft, swivels its propeller engines up for takeoff and landing and angles them forward for regular flight. Its propellers work like helicopter rotors for vertical flight and like propellers for forward flight, so they are called prop-rotors. They are made bigger and stronger than normal pro­pellers because they must support the entire weight of the aircraft for takeoff and landing. Aircraft such as the V-22 Osprey are called tilt-rotors.

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.

——————————————————————- £——————————————————————

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.

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.