Balloon

 

lighter-than-air craft without a propulsion system, lifted by inflation of one or more containers with a gas lighter than air or with heated air. During flight, altitude may be gained by discarding ballast (e.g., bags of sand) and may be lost by releasing some of the lifting gas from its container.

Although interest in such a craft dates from the 13th cent., the balloon was not actually invented until the late 18th cent., when two French brothers, Joseph and Jacques Étienne Montgolfier, experimented with inverted paper and cloth bags filled with heated air and, in 1783, caused a linen bag about 100 ft (30 m) in diameter to rise in the air. In the same year the Frenchmen Pilâtre de Rozier and the marquis d'Arlandes made one of the first balloon ascents by human beings, rising in a hot-air-filled captive balloon (i.e., one made fast by a mooring cable to prevent free flight) to a height of 84 ft (26 m). In 1766 the English scientist Henry Cavendish had shown that hydrogen was seven times lighter than air, and the usefulness of this gas in balloon ascension was demonstrated in Dec., 1783, by J. A. C. Charles of France, who with his associates successfully ascended in a hydrogen-filled balloon and traveled 27 mi (43 km) from the starting point.

The first ascent in England was made by James Tytler, a Scottish writer, in 1784, and in 1793 the French balloonist J. P. Blanchard made an ascent at Philadelphia. Blanchard, with Dr. John Jeffries, an American physician, also made the first sea voyage by balloon, crossing the English Channel in 1784. Among the noted balloon voyages of the 19th cent. was that made by the Swedish engineer S. A. Andrée, who, in 1897, attempted unsuccessfully to reach the North Pole by balloon. In the American Civil War and World War I, captive balloons were used to observe troop movements and to direct gunfire. Captive balloons, called barrage balloons, were used as obstacles against low-flying aircraft in World War II.

The helplessness of the free balloon in controlling direction led to the development of the dirigible balloon (see airship). In 1932 the Swiss physicist Auguste Piccard, one of the major figures in 20th-century ballooning, ascended in a balloon with a sealed spherical gondola to a height of 55,500 ft (17,000 m); since then manned balloons have reached heights of 100,000 ft (30,500 m) and unmanned balloons have exceeded 140,000 ft (42,500 m). The Americans Ben Abruzzo, Maxie Anderson, and Larry Newman made the first transatlantic crossing in 1978, and in 1981 Abruzzo, Newman, Rocky Aoki, and Ron Clark crossed the Pacific. In Mar., 1999, Jacques Piccard, Auguste's grandson, and Briton Brian Jones made the first nonstop balloon flight around the world; the American Steve Fossett completed the first nonstop solo circumnavigation in July, 2002. Today high-altitude hydrogen balloons carry aloft radios and other instruments, used to transmit meteorological readings or to take photographs free from atmospheric distortion.

In contemporary sporting balloons, which use air heated by a small gas-fired burner, altitude is controlled by varying the temperature of the heated air. Hot-air balloons represent the fastest-growing segment of ballooning. Gas bags made with space-age materials are more durable and weigh far less than the traditional silk; heaters have similarly become more efficient. While ballooning remains dangerous, the hot-air balloon's slow response time offers a unique sensation of effortless motion through the atmosphere.

Bibliography

See A. Hildebrandt, Balloons and Airships (1976); J. P. Jackson and R. J. Dichtl, The Science and Art of Hot Air Ballooning (1977); B. Piccard and B. Jones, Around the World in 20 Days (1999).

Ballooning redirects here. For the behavior of spiders and other arthropods, see Ballooning (spider).

A balloon is a type of aircraft that remains aloft due to its buoyancy. A balloon travels by moving with the wind. It is distinct from an airship, which is a buoyant aircraft that can be propelled through the air in a controlled manner. It is also distinct from aerostat, which is a balloon that is moored to the ground rather than free-flying.

Types of balloon aircraft

There are three main types of balloon aircraft:

• Hot air balloons obtain their buoyancy by heating the air inside the balloon. They are the most common type of balloon aircraft.
• Gas balloons are inflated with a gas of lower molecular weight than the ambient atmosphere. Most gas balloons operate with the internal pressure of the gas being the same as the pressure of the surrounding atmosphere. There is a special type of gas balloon, called a superpressure balloon, that can operate with the lifting gas at pressure that exceeds the pressure of the surrounding air, with the objective of limiting or eliminating the loss of gas from day-time heating. Gas balloons are filled with gases such as:
  • hydrogen - not widely used for aircraft since the Hindenburg disaster because of high flammability (except for some sport balloons as well as nearly all unmanned scientific and weather balloons).
  • helium - the gas used today for all airships and most manned balloons.
  • ammonia - used infrequently due to its caustic qualities and limited lift.
  • coal gas - used in the early days of ballooning; it is highly flammable.
• Rozière balloons use both heated and unheated lifting gases. The most common modern use of this type of balloon is for long-distance record flights such as the recent circumnavigations.

History

The hot air balloon Kongming lantern was developed for military communication service around the 2nd or 3rd century AD in China. Later, this kind of hot air balloon was very popular among children and at carnivals.

It has been proposed that some ancient civilizations developed manned hot air balloon flight. For example, it has been proposed that the Nazca lines (which are best seen from the air) presuppose some form of manned flight, and that a balloon was the only possible available technology that could have achieved this.

In 1709 in Lisbon, Bartolomeu de Gusmão made a balloon filled with heated air rise inside a room. He also made a balloon named Passarola (Portuguese: Big bird) and attempted to lift himself from Saint George Castle in Lisbon, but only managed to harmlessly fall about one kilometre away. This was the first man ever to fly in human history.

Following Henry Cavendish's 1766 work on hydrogen, Joseph Black proposed that a balloon filled with hydrogen would be able to rise in the air.

The first recorded manned balloon flight was made in a hot air balloon built by the Montgolfier brothers on November 21 1783. The flight started in Paris and reached a height of 500 feet or so. The pilots, Jean-François Pilâtre de Rozier and Francois Laurent (the Marquis of d'Arlanders), covered about 5 1/2 miles in 25 minutes.

Only a few days later, on December 1 1783, Professor Jacques Charles and Nicholas Louis Robert made the first gas balloon flight. Like the first hot air balloon flight, this flight left from Paris. The hydrogen filled balloon flew to almost 2,000 feet (600 m), stayed aloft for over 2 hours and covered a distance of 27 miles (43 km), landing in the small town of Nesle.

Once flight was shown to be possible, the next great challenge was to fly across the English Channel. The feat was accomplished on January 7 1785 by Jean-Pierre Blanchard, a Frenchman, and American John Jeffries, who sponsored the flight.

The first aircraft disaster occurred in May 1785 when the town of Tullamore, County Offaly, Ireland was seriously damaged when the crash of a balloon resulted in a fire that burned down about 100 houses, giving the town the unusual distinction of being home to the world's first aviation disaster. To this day, the town shield depicts a phoenix rising from the ashes.

Blanchard went on to make the first manned flight of a balloon in America on January 9 1793. His hydrogen filled balloon took off from a prison yard in Philadelphia, Pennsylvania. The flight reached 5,800 feet (1,770 m) and landed in Gloucester County, New Jersey. President George Washington was among the guests observing the takeoff.

Gas balloons became the most common type from the 1790s until the 1960s.

The first steerable balloon (also known as a dirigible) was attempted by Henri Giffard in 1852. Powered by a steam engine, it was too slow to be effective. Like heavier than air flight, the internal combustion engine made dirigibles – especially blimps – practical, starting in the late 19th century. Alberto Santos Dumont made the first application of an internal combustion motor in aviation's history. He produced and flew in a dirigible using a gas engine.

Ed Yost reinvented the design of hot air balloons in the late 1950s using rip-stop nylon fabrics and high-powered propane burners to create the modern hot air balloon. His first flight of such a balloon, lasting 25 minutes and covering 3 miles (5 km), occurred on October 22 1960 in Bruning, Nebraska.

Yost's improved design for hot air balloons triggered the modern sport balloon movement. Today, hot air balloons are much more common than gas balloons.

Events in the early history of ballooning; collecting cards from the late 19th century.

Balloons as flying machines

A balloon is conceptually the simplest of all flying machines. The balloon is a fabric envelope filled with a gas that is lighter than the surrounding atmosphere. As the entire balloon is less dense than its surroundings, it rises, taking along with it a basket, attached underneath, that carries passengers or payload. Although a balloon has no propulsion system, a degree of directional control is possible through making the balloon rise or sink in altitude to find favorable wind directions.

The first balloons capable of carrying passengers used hot air to obtain buoyancy and were built by the brothers Josef and Etienne Montgolfier in Annonay, France.

Balloons using the light gas hydrogen for buoyancy were flown less than a month later. They were invented by Professor Jacques Charles and first flown on December 1 1783. Gas balloons have greater lift and can be flown much longer than hot air, so gas balloons dominated ballooning for the next 200 years. In the 19th century, it was common to use town gas to fill balloons; it was not as light as pure hydrogen gas, but was much cheaper and readily available.

The third balloon type was invented by Pilâtre de Rozier and is a hybrid of a hot air and a gas balloon. Gas balloons have an advantage of being able to fly for a long time, and hot air balloons have an advantage of being able to easily change altitude, so the Rozier balloon was a hydrogen balloon with a separate hot air balloon attached. In 1785, Pilâtre de Rozier took off in an attempt to fly across the English Channel, but the balloon exploded a half-hour into the flight. This accident earned de Rozier the title "The First to Fly and the First to Die". It wasn't until the 1980s that technology once again allowed the Rozier balloons to become feasible.

Jean-Pierre Blanchard made the first piloted balloon flight in North America on January 9 1793.

Both the hot air, or Montgolfière, balloon and the gas balloon are still in common use. Montgolfière balloons are relatively inexpensive as they do not require high-grade materials for their envelopes, and they are popular for balloonist sport activity.

Light gas balloons are predominant in scientific applications, as they are capable of reaching much higher altitudes for much longer periods of time. They are generally filled with helium. Although hydrogen has more lifting power, it is explosive in an atmosphere full of oxygen. With a few exceptions, scientific balloon missions are unmanned.

There are two types of light-gas balloons: zero-pressure and superpressure. Zero-pressure balloons are the traditional form of light-gas balloon. They are partially inflated with the light gas before launch, with the gas pressure the same both inside and outside the balloon. As the zero-pressure balloon rises, its gas expands to maintain the zero pressure difference, and the balloon's envelope swells.

At night, the gas in a zero-pressure balloon cools and contracts, causing the balloon to sink. A zero-pressure balloon can only maintain altitude by releasing gas when it goes too high, where the expanding gas can threaten to rupture the envelope, or releasing ballast when it sinks too low. Loss of gas and ballast limits the endurance of zero-pressure balloons to a few days.

A superpressure balloon, in contrast, has a tough and inelastic envelope that is filled with light gas to pressure higher than that of the external atmosphere, and then sealed. The superpressure balloon cannot change size greatly, and so maintains a generally constant volume. The superpressure balloon maintains an altitude of constant density in the atmosphere, and can maintain flight until gas leakage gradually brings it down.

Superpressure balloons offer flight endurance of months, rather than days. In fact, in typical operation an Earth-based superpressure balloon mission is ended by a command from ground control to open the envelope, rather than by natural leakage of gas.

For air transport balloons must contain a gas lighter than the surrounding air. There are two types:

• Hot air balloons: filled with hot air, which by heating becomes lighter than the surrounding air; they have been used to carry human passengers since the 1790s;
• Balloons filled with:
  • hydrogen - highly flammable (see Hindenburg disaster)
  • helium - safe if used properly, but very expensive.

Large helium balloons are used as high flying vessels to carry scientific instruments (as do weather balloons), or even human passengers.

Cluster ballooning uses many smaller gas-filled balloons for flight (see An Introduction to Cluster Ballooning).

Balloons in the military

Main article: History of military ballooning

See also: Observation balloon

The first military use of a balloon was at the Battle of Fleurus in 1794, when L'Entreprenant was used by French Revolutionary troops to watch the movements of the enemy. On April 2 1794, an aeronauts corps was created in the French army; however, given the logistical problems linked with the production of hydrogen on the battlefield (it required constructing ovens and pouring water on white-hot iron), the corps was disbanded in 1799.

American Civil War

The first major-scale use of balloons in the military occurred during the American Civil War with the Union Army Balloon Corps established and organized by Prof. Thaddeus S. C. Lowe in the summer of 1861. The balloons were inflated with coke gas from municipal services and then walked out to the battlefield, an arduous and inefficient operation as the balloons had to be returned to the city every four days for re-inflation. Eventually hydrogen gas generators, a compact system of tanks and copper plumbing, were constructed which converted the combining of iron filings and sulphuric acid to hydrogen. The generators were easily transported with the uninflated balloons to the field on a standard buckboard. In all, Lowe built seven balloons that were fit for military service.

The first application thought useful for balloons was map-making from aerial vantage points, thus Lowe's first assignment was with the Topographical Engineers. General Irvin McDowell, commander of the Grand Army of the Potomac, realized their value in aerial reconnaissance and had Lowe, who at the time was using his personal balloon the Enterprise, called up to the First Battle of Bull Run. In a later exercise, Lowe was called to act as a Forward Artillery Observer (FAO) from which aerial station he was able to direct artillery fire by a set order of flag signals, from an unseen position, onto a Confederate encampment. FAO is still used today from either ground or aerial positions.

Lowe's first military balloon, the Eagle was ready by October 1 1861. It was called into service immediately to be towed to Lewinsville, Virginia, without any gas generator which took longer to build. The trip began after inflation in Washington, D.C. and turned into a 12 mile (19 km), 12-hour excursion that was upended by a gale force wind which ripped the aerostat from its netting and sent it sailing to the coast. Balloon activities were suspended until all balloons and gas generators were completed.

With his ability to inflate balloons from remote stations, Lowe, his new balloon the Washington and two gas generators were loaded onto a converted coal barge the George Washington Parke Custis. As he was towed down the Potomac, Lowe was able to ascend and observe the battlefield as it moved inward on the heavily forested peninsula. This would be the military's first claim of an aircraft carrier.

The Union Army Balloon Corps enjoyed more success in the battles of the Peninsula Campaign than the Army of the Potomac it sought to support. The general military attitude toward the use of balloons deteriorated, and by August 1863 the Balloon Corps was disbanded.

Confederate Army uses

The Confederate Army made use of balloons, but they were gravely hampered by supplies due to the embargoes. They were forced to fashion their balloons from gaily colored silk dress-making material, and their use was limited by the infrequent supply of gas in Richmond, Virginia. By the summer of 1863, all balloon reconnaissance of the Civil War had ceased.

In other countries

In Britain during July 1863, experimental balloon ascents for reconnaissance purposes were conducted by the Royal Engineers on behalf of the British Army, but although the experiments were successful it was considered not worth pursuing further because it was too expensive. However by 1888 a School of Ballooning was established at Chatham, Medway, Kent. It moved to Stanhope Lines, Aldershot in 1890 when a balloon section and depot were formed as permanent units of the Royal Engineers establishment.

During the Paraguayan War, balloons were also used for observation by the Brazilian Army.

Balloons were used by the Royal Engineers for reconnaissance and observation purposes during the Bechuanaland Expedition (1885), the Sudan Expedition (1885) and during the Anglo-Boer War (1899-1902). On October 5 1907 Colonel John Capper (late Royal Engineers) and team flew the military airship Nulli Secundus from Farnborough round St Paul's Cathedral in London and back with a view to raising public interest.

Hydrogen-filled balloons were also widely used during World War I (1914-1918) to detect enemy troop movements and to direct artillery fire. Observers phoned their reports to officers on the ground who then relayed the information to those who needed it.

Because artillery was such an important factor in World War I, balloons were frequent targets of opposing aircraft. Though balloon companies were protected by antiaircraft guns and patrolling fighters, casualties were frequently heavy. One reason for this was the hydrogen that filled the balloons was highly flammable, and planes assigned to attack enemy balloons were often equipped with incendiary bullets, for the purpose of igniting the balloon.

The Aeronaut Badge was established by the United States Army in World War I to denote service members who were qualified balloon pilots. Observation balloons were retained well after the Great War, being used in the Russo-Finnish conflicts (1939-40 and 1941-45).

The Japanese launched thousands of balloon bombs to the US and Canada, carried in the jet stream; see fire balloon. The British used balloons to carry incendiary devices to Germany between 1942 and 1944; see Operation Outward.

Records

On May 27 1931, Auguste Piccard and Paul Kipfer became the first to reach the stratosphere in a balloon.^[1]

On August 31 1933, Alexander Dahl took the first picture of the earth's curvature in an open hot air balloon.^[2]

The altitude record for a manned balloon was set at 34,668 meters on May 4 1961 by Malcolm Ross and Victor Prather in the Stratolab V balloon payload launched from the deck of the USS Antietam in the Gulf of Mexico.

The altitude record for an unmanned balloon is 51.8 kilometres, reached by a Winzen balloon with a volume of 1.25 million cubic metres. The balloon was launched in October 1972 from Chico, California, USA. This is the greatest height ever obtained by an atmospheric vehicle. Only rockets, rocket planes, and ballistic projectiles have flown higher.

Balloons in space

The Echo satellite was a balloon launched by rocket in 1960 and used for passive relay of radio communication.

In 1984 the Soviet space probes Vega 1 and Vega 2 released two balloons with scientific experiments in the atmosphere of Venus. They transmitted signals for two days to Earth.

See also

• Balloon Flight Contest
• Balloon-carried light effect
• Cluster ballooning
• First flying machine
• High altitude balloon
• Hopper balloon
• List of altitude records reached by different aircraft types
• List of early flying machines
• Blimp
• Observation balloon
• Project Manhigh
• QinetiQ 1
• Skyhook balloon
• Thermal airship
• Zeppelin

References

External links

• Hot Air Balloon Simulator - learn the dynamics of a hot air balloon on the Internet based simulator.
• Stratocat Historical recopilation project on the use of stratospheric balloons in the scientific research, the military field and the aerospace activity
• Royal Engineers Museum Royal Engineers and Aeronautics
• Royal Engineers Museum Early British Military Ballooning (1863)
• Balloon fabrics made of Goldbeater's skins by Chollet, L. Technical Section of Aeronautics. December 1922
• Tripod

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