AY Honors/Hot Air Balloons/Answer Key

Jacques Étienne Montgolfier

The Montgolfier brothers, Joseph Michel Montgolfier (August 26, 1740 – June 26, 1810) and Jacques Étienne Montgolfier (January 6, 1745 – August 2, 1799), invented the montgolfière, or hot air balloon. Their invention was the first aircraft to carry humans into the sky.

Early years

The brothers were born into a family of successful paper manufacturers in Annonay, south of Lyon, France. Their father, Pierre (1700-1793), established his eldest son Raymond (1730-1772) as his successor. As a result, the younger sons were initially sent away to school to learn other professions.

Joseph possessed a typical inventor's temprement -- a maverick and dreamer but impractical in terms of business and personal affairs. Clever and highly inventive by nature, he was rebellious towards his formal education -- twice running away from school. Nonetheless, his natural curiosity led him to a very successful self-education in the then emerging physical sciences. He eventually returned to the family homestead, but was only peripherally involved in the family paper-making business.

Étienne (as Jacques Étienne was more generally known) had a much more even and businesslike temperament than Joseph. He was initially sent to Paris to train as an architect. However, after the sudden and unexpected death of Raymond in 1772, he was recalled to Annonay to run the family business (no serious consideration was given to the elder Joseph in this role, given his uneven behaviour.) In the subsequent 10 years, Étienne applied his talent for technical innovation to the family business (papermaking was a high tech industry in the 18th century.) He suceeded in incorporating the latest innovations of the day into the family mills. His work led to recogonition by the government of France and the award of a research grant to foster further development in papermaking.

Initial experiments

Of the two brothers, it was Joseph who first contemplated building flying machines.

There is no definitive account of when Joseph first started contemplating lighter-than-air flight. Some accounts put it as early as 1777 when Joseph observed laundry drying over a fire incidentally form pockets that billowed upwards.

Joseph made his first definitive experiments in November of 1782 while living in Avignon. He reported, some years later, that he was watching a fire one evening while contemplating one of the great military issues of the day -- an assault on the fortress of Gibralter, which had proved impregnable by both sea and land. Joseph mused on the possiblity of an air assault using troops lifted by the same force that was lifting the embers from the fire.

As a result of these musing, Joseph set about building a box-like chamber (3 foot by 3 foot by 4 foot) out of very thin wood and covering the sides and top with lightweight taffeta cloth. Under the bottom of the box he crumpled and lit some paper. The contraption quickly lifted off its stand and colided with the ceiling.

Joseph then recruited his brother to balloon building by writing the prophetic words: "Get in a supply of taffeta and of cordage, quickly, and you will see one of the most astonishing sights in the world." From that point forward, the brothers worked as a team.

Early in next month, December 1782, Joseph repeated his experiment out of doors in a garden near the family homestead with his entire family as witness. On this ocassion, the box-like balloon lifted to some 70 feet in the air and remained aloft for a full minute.

The two brother then set about building a contraption 3 times larger in scale (9 times larger in volume). The lifting force was so great that they lost control of their craft on its very first test flight on December 14, 1782. The device floated nearly 2 kilometers (about 1.5 miles). It was destroyed after landing by, what Etienne later called, the "indiscretion" of passersby.

Public demonstrations

Given these initial successes, the brothers decided to make a public demonstration of a balloon in order to establish their claim to its invention.

They constructed a globe-shaped balloon (there are no reports as to whether the balloon was plain or decorated) of sackcloth with three thin layers of paper inside. The envelope could contain nearly 28,000 cubic feet of air and weighed 500 lbs. It was constructed of 4 pieces (the dome and 3 lateral bands) held together by some 1,800 buttons. A reinforcing "fish net" of cord covered the outside of the envelope.

On June 4, 1783 (many sources incorrectly fix the date as June 5), they flew this craft as their first public demonstration at Annonay in front of a group of dignitaries from the Etats particuliers. Its flight covered 2 km, lasted 10 minutes, and had an estimated altitude of 1600 - 2000 m.

Word of their success quickly reached Paris. Etienne went to the capital to make further demonstrations and to solidify the brothers' claim to the invention of flight. Etienne had studied in Paris and was much more at home with the dress and habits of the city. Joseph, given his unkempt appearance and shyness, remained with the family.

There was an intense competition between the brothers and Jacques Alexandre César Charles who had already made a public demonstration of a balloon using hydrogen as its lifing gas.

In collaboration with the successful wallpaper manufacturer, Jean Baptiste Réveillon, Etienne constructed a 37,500 cubic foot envelope of taffeta coated with varnish. The balloon was covered in brigh colors and flourishes to distinguish it from the rather plain design of the Charles balloons. The bold design was no doubt the influence of Réveillon, the wallpaper maker.

There was some concern about the effects of flight into the upper atmosphere on living creatures. Some reports say King Louis XVI of France forbade human flight until the effects on animals had been determined. However, there is no written evidence of this edict. Rather it is most likely that the inventors themselves decided to send animals aloft first.

On September 19, 1783, the Aerostat Réveillon (as Etienne referred to it) was flown with the first living beings in a basket attached to the balloon: a sheep, a duck and a rooster. This demonstration was performed before a huge crowd at the royal palace in Versailles, before King Louis XVI of France and Queen Marie Antoinette.

The flight lasted approximately 8 minutes, covered 2 miles, and obtained an altitude of about 1500 feet. The flight would have been longer but the craft was unstable. It tipped wildly just after launch which allowed a considerable amount of hot air to spill from the mouth. The animals survived the trip unharmed.

One of the first people at the site of the landing was Pilâtre de Rozier who had already volunteered to be one of the first humans aloft when the time came. (Pierre Montgolfier, father of the inventive brothers, had given his permission for his sons to work on balloons rather than the family papermaking business only on the condition that neither of the brothers ever go aloft in a balloon themselves.)

An ascent in a tethered balloon took place around October 15 (on the 12 or 14 according to Montgolfier), to an altitude of 26 m.

Human flight

On November 21, 1783, the first free flight by humans was made by Pilâtre de Rozier and the marquis d'Arlandes, who flew aloft for 25 minutes about 100 metres above Paris for a distance of nine kilometres.

(A flight by Karl Friedrich Meerwein in 1781 with his "ornithopter", a flapping device, probably preceded this event, but it never became a generally used viable means of flight.)

The ascensions made a sensation. Numerous engravings commemorated the events. Chairs were designed with balloon backs, and mantel clocks were produced in enamel and gilt-bronze replicas set with a dial in the balloon.

Following years

Only one of the brothers (which one is unknown) ever flew in a balloon himself, and then only once.

In 1766, the British scientist Henry Cavendish had discovered hydrogen gas, by adding sulphuric acid to iron, tin, zinc shavings, and hot air balloons were superseded by hydrogen gas balloons. This was followed by further flights, including a crossing of the English Channel on January 7, 1785, by Jean-Pierre Blanchard and John Jeffries.

Revival of the hot air balloon

Balloons using heated air rather than lighter-than-air gasses did not return until the 1960s, when Ed Yost improved the safety of the classic Montgolfier design by using ripstop nylon for the envelope and propane gas as the burner fuel.

External links

• "Lighter than air: the Montgolfier brothers"
• "Balloons and the Montgolfier brothers"
• "Karl Friedrich Meerwein"