Category FLIGHT and M ОТІOIM

German and Japanese Innovations

The V-1 was one of several innovative weapons developed by the Germans. These included the V-2 ballistic missile, anti-aircraft missiles, guided bombs, and the rocket-powered Me-163 interceptor, capable of speeds of 620 miles per hour (1,000 kilometers per hour). The Dornier Do-335 Pfeil “Arrow” was a twin-engine fighter, with one propeller in its nose and another in its tail. This unique air­plane was almost as fast as a jet, but only a handful reached the Luftwaffe before the war ended.

The Germans were the first to use remote-guided rockets, in 1943, firing HS-293 missiles against British ships

KAMIKAZE MISSIONS

As the war swung against Japan, the nation resorted to kamikaze attacks, which started in October 1944. The word kamikaze means "divine wind." Volunteer pilots crash-dived their planes packed with explosives onto U. S. Navy ships, killing themselves and creating as much destruction as possible. Japan even built a rocket-powered suicide plane, the Ohka, which was launched from a carrier plane. An estimated 3,000-4,000 pilots flew kamikaze missions for Japan, sink­ing between thirty and eighty U. S. ships and damaging many more.

German and Japanese Innovations

о Jet engines and rockets both advanced during the course of World War II, as scientists rushed to develop new and lethal instruments of war. The Japanese Ohka suicide plane, shown here, used rocket and jet technology.

in the Atlantic Ocean. Similar radio – controlled missiles, air-launched from Dornier 217 bombers, sank the Italian battleship Roma following Italy’s surren­der to the Allies in 1943.

The Japanese proved resourceful in building robust fighting airplanes, such as the Mitsubishi Zero. The Japanese, like the Germans, had no long-range heavy bombers, but in 1944 they did attack the West Coast of the United States by flying balloons carrying small bombs across the Pacific. About 9,000 balloons were launched; around 1,000 reached the United States, causing 285 recorded incidents and six deaths.

Launch and Reentry

Spaceflight became possible with the development of rockets that had suffi­cient power to break free of Earth’s gravity. To break free, a rocket must reach escape velocity, which is just over

25,0 miles per hour (40,200 kilome­ters per hour). Takeoff and reentry are the two most dangerous times in a spaceflight. Before the 1950s, some sci­entists argued that the human body could not survive the stresses of a space launch. The earliest flights by astro­nauts proved such views wrong. Astronauts have flown faster than any humans have before and have returned back to Earth unharmed.

Conventional rocket motors work both in air (for takeoff) and in space. Most rockets used to launch spacecraft are multistage vehicles propelled by chemical fuel burned in liquid or solid

form. The propellants must include oxy­gen, or the fuel will not burn, because there is no air in space.

Booster rockets provide extra thrust during takeoff. In a multistage rocket, boosters and lower stages separate and fall away as soon as their fuel is burned up. Only the topmost stage reaches space. The load a rocket lifts into space is called its payload-this could be a satellite, a manned spacecraft, or a robot space probe.

A rocket is streamlined for efficient, controlled, high-speed flight through the air. A spacecraft designed to return to Earth, like the Space Shuttle, also is streamlined, but it has wings. The wings help the Space Shuttle land like a con­ventional airplane after it has reentered Earth’s atmosphere.

Returning to Earth from space is potentially as dangerous as leaving it. A spacecraft must decelerate (slow down), using braking rockets, and approach at a precise angle so it does not hit the Earth’s atmosphere too fast. Reentry is accompanied by a rapid rise in tempera­ture. Air gets trapped in front of the spacecraft, which is moving so fast the air cannot escape. Compression (squeez­ing) of the air raises the temperature to more than 10,000°F (5,540°C). Spacecraft would burn up unless protected by a heat shield of tough, insulating material.

Working Together

The Apollo triumph persuaded many people that the United States had won

Подпись: О In 1995, U.S. Space Shuttle astronaut Robert Gibson met and shook hands with cosmonaut Vladimir Dezhurov during the first international docking mission of the Space Shuttle with the Russian space station Mir. The mission, STS-71, commemorated the Apollo-Soyuz Test Project twenty years earlier, which brought the space race to a symbolic close. the space race. No Soviets flew to the Moon, although unmanned Zond space­craft may have flown test flights for a Moon mission. Soviet plans for a Moon landing were abandoned, prob­ably because of serious problems with the rocket launcher and the lunar space­craft. The closest the Soviet Union came to the Moon was when two small robot vehicles crawled over the dusty lunar surface. Instead, the Soviets turned their attention to orbital space stations, such as Salyut 1 (1971) and later Mir. In 1975, on the Apollo-Soyuz Test Project, American and Soviet astronauts flew together in space. A new era of cooperation had begun.

By the 1980s, the space race was over. Relations between the United States and the Soviet Union improved, with the signing of treaties agreeing to bans on nuclear weapons testing and cut­backs in the production of missiles.

The United States introduced the Space Shuttle in 1981. Although they launched their Buran shuttle in 1988, the Soviets never seriously competed with the new, reusable spacecraft.

In 1989, the Soviet Union broke apart into separate countries. Since then, Russia has worked as a partner with the United States to build and operate the International Space Station. New partic­ipants in space include the European Space Agency (ESA) and China. (China became the third nation to launch an astronaut, in 2003.)

The space race provided significant technological spin-offs (especially in electronics) and led to an increase in sci­ence education. A future space race might be a commercial contest between companies offering space tourism, but most people believe that the future of scientific space exploration lies in inter­national cooperation rather than in a race for the stars.

SEE ALSO:

• Apollo Program • Astronaut

• Gagarin, Yuri • Glenn, John

• Spaceflight • Sputnik

Подпись: ~Подпись: ГV.

Directional Stability

Directional stability keeps a plane flying in a straight line without veering to one side or the other. Early airplanes had lit­tle stability. The pilot had to concentrate extremely hard and constantly make adjustments to keep the plane under control. A gust of wind or a careless maneuver could send the plane spiraling to the ground. Many early aviators died in crashes caused by poor stability and control problems.

A modern plane’s tail fin, or vertical stabilizer, helps to provide directional stability. If the plane’s nose is pushed to one side by a gust of wind, the airflow around the tail fin moves the tail back in line with the nose, so that the plane keeps flying in the same direction instead of veering off course. (Weather vanes keep pointing into the wind for the same reason.)

Testing and Using SVS

Подпись:
Testing and Using SVSПодпись: The TIFS aircraft is a modified C-131 Samaritan military aircraft, which is itself based on a Convair 580 turboprop airliner. It was built in the 1950s and converted to a flying simulator in the late 1960s. TIFS has two cockpits. One is used to test new developments. The other (standard) cockpit can take over at any point if necessary. This double cockpit is an important feature, because it allows a test pilot safely and repeatedly to push a system all the way to failure, which is risky to do in a conventional flight test, especially near the ground. The research cockpit can be programmed to make the plane fly like other kinds of aircraft. In its test flights, it has doubled for a variety of airliners, experimental aircraft, the B-2 Spirit stealth bomber, and even the Space Shuttle. As well as simulating other aircraft, it also is used to test new avionics systems. In this case, the second cockpit can be replaced by a nose section containing the new avionics, and the research pilot sits at a crew station in the aircraft's cabin. Pilots say it is more realistic to fly TIFS than a simulator on the ground because it sounds, feels, and performs like the real airplane. The TIFS plane entered service as a military transport on March 22, 1955, so it cele-brated its fiftieth anniversary in 2005. к J
In 1999, synthetic vision was tested in flight by a modified C-131 military aircraft named the Total In-Flight Simulator (TIFS). For the tests, TIFS was fitted with screens to try a variety of dif­ferent images and data. The research flights were made out of Asheville Regional Airport in North Carolina.

Подпись: О A pilot testing SVS in 1999 was able to compare the virtual world on his screen with a view from the cockpit.Testing and Using SVSПодпись: — SEE ALSO: Testing and Using SVSResearch pilots using the synthetic vision system reported that they soon forgot they were looking at a computer-generated image and not at the real world.

System designers are already thinking about other ways in which SVS might be used in the future. One possible application is in air traffic control systems at airports.

Airport traffic con­trollers work in a con­trol room that looks out across the airport, but some parts of an airport may be obscured by buildings or bad weather. SVS could provide con­trollers with a clear, computer-generated view of the entire air­port in all conditions. Although synthet­ic vision has been developed for civil aviation, military forces also are interest­ed in the systems. Synthetic vision already has been flight tested in military airplanes and helicopters.

• Air Traffic Control • Avionics

• Cockpit • Global Positioning System • Pilot

Naval Service

The main advantage of a VTOL aircraft is that it does not need a runway, and so it can operate from any small patch of ground, from a road, or even a ship’s deck. One version of the Harrier, the Sea Harrier, was developed for naval use. It could operate from the smallest aircraft carriers. The decks of these ships are too short for most naval jets that require runways, but they are big enough for helicopters and VTOL aircraft.

A Sea Harrier with full fuel tanks and a large weapons load is too heavy to take off vertically, and the deck of a small aircraft carrier is too short to use a normal takeoff run. So small carriers are fitted with a ramp at the end of the deck, also known as a ski jump. As an aircraft accelerates toward the end of the deck, the ski jump gives it an extra push upward into the air.

Подпись: О A Sea Harrier heads for the ski jump during its takeoff from an aircraft carrier.

A Sea Harrier pilot has to calculate the aircraft’s takeoff speed very careful­ly by using its weight and the current wind speed. If takeoff is too slow, the plane might not get airborne. If it is too fast, the Sea Harrier might hit the ski jump too hard and damage its undercar­riage. The Sea Harrier uses a short take­off and vertical landing, making it a STOVL aircraft. It was the first opera­tional STOVL combat aircraft to use vectored thrust.

Подпись:FLYING BEDSTEADS

When NASA was preparing to send astronauts to the Moon in the 1960s, they developed a strange – looking aircraft to prepare astro­nauts for the task of landing on the lunar surface. The lunar lander, called the Apollo Lunar Excursion Module (LEM), would descend to the Moon balanced on the fiery jet of gas from a rocket engine. The first training vehicle for this event balanced on the jet exhaust from a jet engine instead of a rocket. Called the Lunar Landing Research Vehicle, it led to the development of three Lunar Landing Training Vehicles. Astronauts called them "flying bedsteads" because of their strange appearance.

When the U. S. Marines were looking for a light attack plane, they developed the Harrier to suit their needs. Their work resulted in a new Harrier, the AV – 8B Harrier II. It had bigger, thicker wings and was able to carry a bigger payload over a greater distance.

Other Kinds of Wings

Fixed-wing airplanes are not the only aircraft that use wings. A helicopter’s rotor blades are actually long, thin wings. High-performance parachutes called parafoils are really inflatable wings. The parachute is made of two layers of fabric with dividers between them, forming a line of pockets, or cells. As the parachute moves along,
air fills the cells and forms a wing shape. The parachutist con­trols and steers the parafoil by pulling control lines that change the wing’s shape.

A flexible fabric hang glider is yet another type of wing. Called a Rogallo wing, this early hang glider was developed in the 1940s by hus­band and wife, Francis and Gertrude Rogallo. When space exploration began, NASA investigated the Rogallo wing as a way of landing the Gemini manned spacecraft. Round parachutes eventually were used instead, but the Rogallo wing was used by other designers, who devel­oped it into the modern hang glider.

Racecars also use wings. However, racecar wings do the opposite job of air­craft wings. They produce a downward force, called downforce, when they cut through air. This pushes the car down harder against the ground, giving its tires better grip, and enabling it to take corners faster without loss of traction.

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SEE ALSO:

• Aerodynamics • Aileron and

Rudder • Bernoulli’s Principle

• Lift and Drag • Stall

Industrial Production

Prewar theories that bombing would destroy civilian morale and halt factory production proved inaccurate. The British did not crumble during the Blitz; the Russians moved their factories east out of range of German planes; and German and Japanese workers contin-

Подпись: О The U.S. aerospace industry boomed during World War II. Mass production methods became more efficient, and Americans worked around the clock to build aircraft. Industrial Production

Industrial Production

Подпись:WORLD WAR II AVIATION ADVANCES

World War II was a war of air power. During the course of the war, top speeds of fighter aircraft rose from about 350 to 450 miles per hour (563 to 724 kilometers per hour). Bombers flew higher to escape interception: up to 35,000 feet (10,700 meters) by 1945. Naval battles among ships were replaced by long-range air battles between planes flying from aircraft carriers. Factory production methods speeded up manufacture, and technology greatly improved the range, nav­igation, gun power, and bombing accuracy of warplanes. Air transports, such as the C-47 and C-54, carried troops and supplies, and parachutes were used to land them. Radar was the key air invention: It aided ground defenses and also helped pilots locate enemy targets. Air weapons became more destructive as bombs laid waste to cities, and guns and rockets could blow planes apart in midair. For protection, planes had armor plating and self-sealing fuel tanks. By 1944 to 1945, air warfare had been changed forever by new weapons and tech­nology: jet planes, helicopters, the V-1 flying bomb, the V-2 missile, and the atomic bomb.

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N

SEE ALSO:

• Aircraft, Military • Aircraft Carrier

• Bomber • Fighter Plane • Missile

• Parachute • Radar

Industrial Production

Industrial Production

Traveling in Space

After being launched, a spacecraft leav­ing Earth for the Moon or Mars does not need to keep burning fuel. Spacecraft can make use of other methods of propulsion, such as solar sails or ion engines. Once on course and free of Earth’s gravity pull, the engines can be switched off to save fuel as the space­craft coasts through space. This is how the Apollo astronauts traveled to the Moon, a trip that took two-and-a-half days. They fired their engines only to slow down the spacecraft and during their return to Earth.

Traveling in Space

О The Apollo 10 crew sped home at 24,790 miles per hour (39,890 kilometers per hour) on their return from the Moon in 1969. The astronauts’ capsule splashed down safely in the Pacific Ocean.

Traveling in Space

О Helios A and Helios B were space probes sent in the 1970s to orbit the Sun. They reached the highest speed of any spacecraft. A 1974 photo­graph shows Helios A on top of a launch vehicle.

Although there is no air in space, space is not empty. It contains dust, chunks of minerals, space junk, and streams of radiation flowing out at great speed from the Sun and from other stars.

Stretching into space around Earth is a magnetic field. This magnetism attracts electrically charged particles that form belts, or zones, of radiation. Named the Van Allen radiation belts, these radia­tion zones were unknown until the first U. S. satellite, Explorer 1, encountered them in 1958. The Van Allen belts were the first important scientific discovery made by a spacecraft.

The fastest spacecraft sent from Earth so far have been the solar probes Helios A (1974) and Helios B (1976). Helios B traveled about 150,000 miles per hour (241,350 kilometers per hour) as it orbited the Sun. Although spacecraft are the fastest vehicles ever flown by humans, they are snail-like in space terms, where the distances are unimag­inably immense. The nearest star is 4.2 light years from Earth. So even if a future spacecraft could reach light speed of 186,000 miles per second (299,280 kilometers per second), it would take 4.2 years to get there.

To fly astronauts to Mars and back using existing spacecraft would take eighteen months. Keeping astronauts alive, healthy, and able to work during such a long mission poses great chal­lenges to space science. Humans are not designed for an airless, weightless environment. A manned spacecraft must provide everything needed for human life support-air, water, food, fuel, energy, waste disposal, and exercise. Long periods of spaceflight weaken the body’s muscles. So great are the chal­lenges that some scientists believe that

Space Shuttle

T

he Space Shuttle was the world’s first reusable spacecraft and the first spacecraft with wings. The Space Shuttle can carry seven astronauts into space, stay in orbit for about two weeks, and then fly back to Earth to land on an airstrip.

The Shuttle Concept

Until the first Space Shuttle flew in 1981, all spacecraft (manned craft, satel­lites, and space probes) were launched by multistage rockets. Such rockets and the spacecraft they carried could be used just once. Only the spacecraft itself reached space; the discarded rocket stages fell into the sea or burned up in the atmosphere. The Space Shuttle was planned as a more economical vehicle
that could make regular trips into space. It has no rival. The Soviet Buran shuttle spacecraft, similar in appearance, made only one flight, without a crew, in 1988; it was thereafter canceled.

In 1969, a Space Task Group set up by President Richard Nixon’s adminis­tration suggested several new space projects. One was a reusable spacecraft, capable of flying one hundred or more missions. The result was the Space Shuttle, known to NASA as the Space Transportation System (STS). The main contractor was North American Aviation (later part of Rockwell International, now part of Boeing). Other contractors responsible for supplying the engines

О A view inside the Space Shuttle shows the giant engines, the cargo bay, and the flight deck and mid-deck where the astronauts live.

Space Shuttle

Rudder and speed brake

Main engines (3)

Maneuvering engines (2)

 

Forward

control

thrusters

 

Hydrazine and nitrogen tetroxide tanks

 

Space radiators (inside doors)

 

Manipulator arm

 

Cargo bay

 

Flight

deck

 

Space Shuttle

Space Shuttle

Подпись: Unite'Подпись: Nose Mid-deck gear Air

control

thrusters

Electrical system fuel cells

Body flap Elevon

 

Main gear

 

Space Shuttle

and fuel tanks, were Morton Thiokol, Martin Marietta, and Rocketdyne.

The first Shuttle to fly was Enterprise, which was used for prelimi­nary flight and landing tests from 1977. These tests included flights on top of a modified Boeing 747 airplane. Enterprise never actually went into space. Five Space Shuttles have flown in orbit. The first operational Space Shuttle, delivered to NASA in March 1979, was Columbia, which made its first space flight on April 12, 1981, and remained in service until it was destroyed in a tragic accident in 2003. Challenger, which arrived at Kennedy Space Center in July 1982, was the first Space Shuttle to be lost in an accident, in January 1986. The three Space Shuttles currently operational are Discovery, delivered in November 1983; Atlantis, delivered in April 1985; and Endeavour, which was built to replace Challenger and arrived at Kennedy Space Center in May 1991.