Category FLIGHT and M ОТІOIM

In a hot air balloon, the heat comes from a propane gas burner. The pilot turns on the burner to send hot air into the balloon. The balloon is made of a tough, nonflammable material such as nylon

BALLOON JUMP

The world’s longest delayed-drop parachute jump was made from a balloon. On August 16, 1960, Captain Joe W. Kittinger jumped out of a balloon 102,800 feet (31,333 meters) above New Mexico. He fell 84,700 feet (25,817 meters) before his para­chute opened. In 1984, Kittinger became the first person to fly the Atlantic Ocean alone in a balloon.

He flew from Maine to Italy in about 86 hours.

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or polyester. The bigger the bag, the more weight (payload) the balloon can lift. Passengers ride in a basket or similar structure hanging beneath the balloon. To descend for landing, the pilot releases air from the top of the balloon. Hot air balloons are popular with sports balloonists.

Gas balloons are usually filled with helium. This gas is safer than hydrogen because it does not catch fire. Gas bal­loons have more lifting power than hot air balloons. They can also go higher and stay aloft longer.

The largest type of gas balloon is a superpressure balloon. The pressure of gas inside the bag is higher than the pressure of the outside air. At launch, a superpressure balloon is only partly filled with gas. As the balloon rises, the gas expands and fills the bag. The

largest such balloons have a volume of more than 70 million cubic feet (2 mil­lion cubic meters), and they are unmanned aircraft.

Today, scientists find unmanned gas balloons useful for studying the weather and the upper atmosphere. Weather bal­loons carry radiosondes—instruments that measure temperature, humidity, and air pressure—which send back data by radio.

There are two kinds of bird flight: flapping and gliding. During flapping flight, the bird beats its wings up and down. The large primary feathers in the wing do most of the propulsion; the smaller secondary feath­ers help to maintain lift. The wings move in two directions while flapping: up and down and in a circular or figure 8 move­ment. The wingtips move faster and farther than the rest of the wings. The smaller the bird, the faster its wings flap.

The downbeat is the power stroke. On the downbeat, the wing feathers overlap closely so that air cannot pass through them but is instead pushed downward. The wing moves downward and forward. The primary feathers are bent back at their tips so the wing performs like a
propeller, pulling the bird forward. Power is produced on the upbeat, too, although less so than on the downbeat. As the wing moves upward, the primary feathers are bent back and move apart a little, fanning open to allow air to slip through the gaps between them. This reduces wind resistance and saves energy.

THE SPEED OF BIRDS

Peregrine falcon: 200 miles per hour (320 kilometers per hour) in a dive.

Spinetailed swift: 105 miles per hour (170 kilometers per hour). Canvasback duck: 65 miles per hour (105 kilometers per hour).

Pigeon: 60 miles per hour (96 kilometers per hour).

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bomber is a military airplane designed to attack targets on the ground or at sea by dropping explosives. A bomb, a metal case filled with high explosives, is just one of the weapons that a bomber can drop. These airplanes also may be armed with mis­siles, rockets, and guns.

Types of Bombers

Most air forces have bombers of two main types: fighter-bombers, also called strike fighters, and strategic bombers. Strike fighters, such as the U. S. Navy F/A-18 and the British Royal Air Force Tornado, can fly as fast as a fighter plane, although how they perform is affected by the weight of the weapons they carry. Their main role is to carry out tactical (battlefield) attacks on troop
concentrations, airfields, bases, ships, and supply routes. Some bombers oper­ate from naval aircraft carriers, while ground-attack airplanes such as the A-10 Thunderbolt fly over a battlefield to destroy tanks, artillery, or other small targets.

Strategic bombers, such as the B-52 and B-1B, are bigger planes. They can fly for 10,000 miles (16,090 kilometers), and even farther when refueling in the air from tanker planes. They are used to attack targets such as factories, military bases, ports, and cities. Even when they fly above 50,000 feet (15,240 meters), these planes are relatively easy to pick up on radar and so risk being shot down by fighters or ground-to-air missiles.

In 1989 the B-2 Spirit stealth bomber gave the bomber a new edge. Its revolu­tionary technology (a flying wing shape and special materials used in construc­tion) enabled it to sneak through radar defenses. Most early bombers had crews of eight or more, but the B-2 needs only two crew members and can

DROPPING BOMBS

A bomber’s weapons may be carried inside the aircraft, in a compartment known as the bomb bay, or attached to the outside of the aircraft. In the early days of air warfare (1914 to 1939), bombs were simply dropped from airplanes over the target area, frequently scattered to increase the chance of actually hitting the target. During World War II, large groups of bombers flew together in formation, often guided to the target by a pathfinder plane that marked the location of the target with flares. Accuracy improved as bombing and navigation equipment became more sophisticated, but bombs still were dropped in a fairly haphazard man­ner. A modern bomber can attack targets many miles away, using elec­tronic guidance systems to send its weapons precisely to their targets. Laser-guided bombs fly along a laser beam directed at the target either from the bomber or from another plane flying nearby.

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Date of birth: January 26, 1892 or 1893.

Place of birth: Atlanta, Texas.

Died: April 30, 1926.

Major contributions: First American woman to gain international pilot’s license; first African American woman to fly in the United States.

nown as “Queen Bess,” Bessie Coleman was the first African American woman to fly and a well-known early stunt pilot. Her example inspired other African Americans to take up flying.

Coleman was one of thirteen chil­dren born to a father who was part Native American and a mother who was African American. When she was nine, her father decided to move to Indian Territory—now the state of Oklahoma-hoping to escape the discrimination that he faced in Texas. Bessie remained behind in Texas with her mother and several sisters. Soon after, she finished elementary school and began working as a laundress. Bessie hoped to continue her education, but she could only afford to attend school for one more semester.

In 1915 Bessie Coleman moved to Chicago, where she joined a brother who lived there. Working in a barbershop as a manicurist, she became friends with Robert S. Abbott, publisher of the Chicago Defender, an important African American newspaper.

Newsreel and magazine stories about the new field of aviation interested Coleman. She applied to flight schools across the United States but was turned down because of her race and gender. Abbott suggested that she obtain the needed training in France, where there was less racial prejudice. Taking his

advice, Coleman learned French and saved her money to pay for lessons. She sailed for France in November 1920.

After several months of training, Coleman received her license to fly and returned to the United States. Black newspapers across the country hailed her as the first female African American pilot. To earn a living, Coleman decided to become a stunt pilot. To be success­ful, however, she needed to learn more tricks. Once again unable to find anyone in the United States to teach her, she returned to Europe early in 1922 for a few more months of training.

Back in the United States once again, Coleman took part in her first air show in September 1922. She was sponsored by Abbott’s newspaper and dazzled the crowd. A few weeks later, she appeared in another show in Chicago and went on to take part in several more.

Coleman dreamed of launching a fly­ing school for African Americans, but she could not afford to buy an airplane until early 1923. The plane she bought was an older model, and it stalled and crashed during a flight. Seriously injured in the crash, Coleman needed eighteen months to recuperate.

In the middle of 1925, Coleman began stunt flying again, putting on a spectacular show in Houston, Texas. Coleman also began touring to give lec­tures to black audiences about the thrill of flying. She hoped to use the fees she received to launch her flying school.

Early in 1926, she managed to buy another plane. Once again, it was an

BESSIE COLEMAN’S LEGACY

Coleman’s bravery and determination inspired African Americans in a time when they suffered from segregation and other forms of dis­crimination. In 1929, pilot William J. Powell and other African American aviators formed the first Bessie Coleman Aero Club. On Labor Day 1931, the club organized an all-black air show in Los Angeles, California. Similar aero clubs were founded in many cities across the country. Also in 1931, a group of African American pilots flew over Coleman’s gravesite in Chicago, a tradition still carried on today. Powell continued to honor Bessie Coleman by promoting avia­tion in the black community.

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older plane, one left over from World War I. The day before an air show in Jacksonville, Florida, Coleman and her mechanic took the plane aloft to test it. A loose wrench fell into the plane’s gears, causing the mechanic-who was piloting the plane-to lose control. The plane flipped over, throwing Coleman to her death. The plane then crashed, killing the pilot.

SEE ALSO: • Aerobatics • Barnstorming • Pilot

When World War II came to an end, hundreds of DC-3s no longer required by the military were quickly snapped up by airlines desperate for aircraft with which to start postwar passenger services. The DC-3 continued to do a valuable job even in the jet age, being used in civil avia­tion, in the military, and in scientific work. In 1956, a DC-3 flown by the U. S. Navy became the first airplane to land at the South Pole, while assisting an Antarctic expedition named Operation Deep Freeze. The DC-3 design was so effective that it never had to be radically altered. The plane did not change much during its sixty-plus years of service.

THE ADAPTABLE AIRLINER

Very few aircraft have been built in as many versions as the DC-3. It is truly one of the great multipurpose aircraft in aviation history, with about 100 different versions developed over the years for dif­ferent tasks. Some of those versions are:

• TC-47B Navigator trainer.

• XC-47 Experimental floatplane.

• AC-47D 1965 version with three 7.62-millimeter machine guns.

• SC-47D Search and rescue model.

• C-53 Skytrooper with twenty-eight seats and glider-towing hook.

• C-53B 1942 version with special Arctic equipment.

• E4D-4 U. S. Navy model, later adapted for electronic countermeasures.

О In 1946, a C-47 is used to take paratroopers on a practice jump at Fort Benning, Georgia.

The flywheel worked well, but it added a lot of extra weight to the engine. Another type of engine, the rotary engine, solved this problem. The engine’s massive cylinders spun around like the spokes of a wheel. The spinning cylinders did the same job as the fly­wheel, so the heavy flywheel was no longer needed. Famous World War I fighter planes, such as the Sopwith Camel, were powered by rotary engines.

The rotary engine was popular because it produced a lot of power for its weight, but it caused some problems. A heavy weight spinning on the nose of an aircraft affects the way it flies. Pilots who flew the Sopwith Camel found that it turned swiftly to the right, but it was much slower to turn to the left.

It also was difficult to build increas­ingly powerful rotary engines. As the cylinders tried to spin through the air, the air pushed back against them. This air resistance, or drag, slowed the cylin­ders down. The engine had to use some of its power to overcome this drag.

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Spinning the cylinders faster or adding more cylinders to produce more power caused even more drag and wasted more of the engine’s power.

orces are pushes or pulls that can cause objects to accelerate or change shape. Aircraft fly because they produce forces that overcome grav­ity and allow them to rise into the air. They move through the air because of the forces produced by their engines. Spacecraft, which are not traveling in air once they leave Earth’s atmosphere, use the force of gravity to move in a circle.

Basics of Force

In everyday language, acceleration means speeding up. To a scientist or engineer, however, acceleration can mean speeding up, slowing down, or changing direction.

If a force acts on an object that is free to move, it makes the object accelerate. The larger the force, the greater the acceleration. Acceleration also depends on mass. A small mass accelerates faster than a big mass pushed with the same force.

Every force has size and direction. Quantities such as these are called vec­tors. Forces acting in the same direction combine to produce an even larger force. When forces act in opposite direc­tions, they produce a force equal to the difference between them. If the forces acting on something exactly balance each other, there is no overall force, and the forces are said to be in equilibrium.

Some forces, such as friction, act when objects touch each other. These are contact forces. Other forces, such as gravity and magnetic forces, work at a distance. The objects that experience these forces need not touch each other. These are noncontact or distance forces.

Date of birth: March 9, 1934.

Place of birth: Gzhatsk, Soviet Union.

Died: March 27, 1968.

Major contributions: First person to fly in space; first person to orbit Earth. Awards: Order of Lenin; Hero of the Soviet Union.

uri Gagarin was born on a farm in a region west of Moscow in the Soviet Union (now Russia). He learned how to fly as a teen and
began training as a military pilot at the age of twenty-two. Just two years after Gagarin graduated from flight school, the Soviets began looking for candidates to become cosmonauts (the Soviet term for astronauts). Out of 3,000 applicants, they chose twenty men. Gagarin was one of them.

Training in the program was intense. It involved not only technical study and flight training but also physical and psy­chological tests. In January 1961, Gagarin was one of six candidates cho­sen for final testing. As the hopeful cos­monauts prepared for the tests, tragedy touched the Soviet space program. One of the candidates died when fire broke out during a training session. Gagarin and the other four candidates continued with their training.

On April 8, 1961, Soviet offi­cials chose Gagarin to be the first cosmonaut in space. His warm personality was a deciding factor. Officials thought Gagarin would make a good impression in his ensuing wave of public appear­ances as the first person in space. The next day, Gagarin was told of the decision.

On April 12, 1961, Gagarin entered a Vostok spacecraft to fly

О Like many American astronauts, the Soviet cosmonaut Yuri Gagarin trained first as a military pilot.

He returned to aviation after his famous journey into space.

on his mission, named Vostok 1. At 9:07 a. m., the command to ignite the booster rocket was given. Over the radio Gagarin said, “Poyekhali!” (“Here we go!”). The rocket began to rise and the booster was ejected. Gagarin and his capsule were in orbit.

Gagarin orbited Earth once, complet­ing the trip in a little less than an hour – and-a-half. Radio communication was lost briefly between tracking stations, and the lack of contact worried officials. However, communication was soon resumed-to everyone’s great relief.

Gagarin did not actually fly the spacecraft during his trip. Soviet officials worried that the first cosmo­naut might do something wrong, and they locked the controls. He did have a code to unlock them if anything went wrong.

The spacecraft’s reentry into Earth’s atmosphere was difficult. The last set of booster rockets was discarded just before reentry, but they did not completely sep­arate. That caused the spacecraft to jos­tle as it headed back to the ground.

As the spacecraft neared Earth, Gagarin opened a hatch and ejected from the capsule. He opened a parachute and reached the ground in a gentle descent. The historic first spaceflight by humans had been achieved.

After the successful landing, Soviet leaders rushed Gagarin to Moscow. On May 1, 1961, he stood on a platform next to the Soviet leader Nikita Khrushchev as thousands of people paraded on the streets below.

TRIBUTE TO A COMRADE

In 1969, Americans Neil Armstrong and Buzz Aldrin became the first humans to set foot on the Moon. They carried tokens with them to honor three U. S. astronauts and two cosmonauts who had died during the early days of spaceflight. One of those symbols-a medal-honored Yuri Gagarin. The medal is still on the Moon today.

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Fearing losing Gagarin in a fatal space accident, Soviet officials banned him from any more spaceflights. He remained in the space program, helping to train new cosmonauts. In the middle 1960s, Gagarin was promised he could go into space once more, and he began flying planes again to regain his status as a pilot. He died in a training flight in 1968 when his airplane crashed.

The people of the Soviet Union mourned the death of their hero. The Soviet training center for cosmonauts was named for him, and the town of his birth, Gzhatsk, was renamed Gagarin in his honor.

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SEE ALSO:

• Apollo Program • Astronaut

• Spaceflight • Space Race

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The development of the human body was shaped by the conditions on Earth’s surface, including gravity. On Earth, muscles and bones grow strong by working against gravity. Fluids in the body, mainly blood, are pulled down­ward by gravity.

Astronauts in orbit are pulled by gravity almost as strongly as they are on Earth, but the effect of gravity vanishes in orbit because the astronauts and their spacecraft are in a state of free fall. The combination of their speed with the downward pull of gravity means that their curving fall exactly matches the curve of the Earth’s surface. Astronauts in their spacecraft fall without getting any closer to the ground. This effect explains why astronauts float in space.

Gravity tells us which way is up and which way is down. Down is the direc­tion in which gravity pulls us, so down is toward the center of Earth. Up is the opposite direction. When the effect of
gravity is removed, up and down have no meaning. Astronauts sometimes have to take a moment to figure out which is the floor and which is the ceiling because they lose their sense of up and down. When they are in space, they can work, eat, or sleep just as comfortably with their heads pointing at the floor as any other way.

An astronaut’s body is affected by spaceflight. Without gravity to push against, muscles waste away and bones lose calcium. Fluids that are normally pulled downward spread out through the body, making astronauts’ faces fatter and their legs thinner. The balance mechanism in the ear does not work properly, so astronauts can feel dizzy and sick for the first days of a mission.

The Hindenburg had a control car that held the control room or bridge (as in a ship), the navigation room, and an observation area. The control room crew operated rudder and elevator controls. They could also release hydrogen gas (to make the airship lose height) or water ballast (to gain height).

The Germans used hydrogen, which was highly flammable, as a lifting gas. A safer alternative was helium gas, but the

only major producer of helium was the United States. The sale of helium to Germany was prohibited at the time because of political disagreements between the U. S. government and Germany’s Nazi regime. German airship engineers knew that hydrogen gas could be dangerous; there had been many accidents with balloons and airships caused by hydrogen catching fire. Only a spark was needed. To minimize the risk of fire, engineers had built in safety measures that included treating the skin of the airship to prevent any sparks caused by electricity or metal contact. Passengers were permitted to smoke, but only in a pressurized smoking room.

The passenger accommodation was inside the metal body of the airship. The Hindenburg had beds for fifty passen­gers, although more than 100 people could be carried, including the crew. Passenger cabins were small, measuring 6.5 feet by 5.5 feet (1.98 by 1.68 meters). Each was equipped with a sleeping berth, a folding washbasin, and a fold­ing writing table. Passengers spent most of their time in the public areas of the airship, looking out of the windows at the view of mountains, cities, and ocean passing beneath them. At one point, the giant airship even had a grand piano, but this was removed to save weight on the 1937 flights.