Hot air balloon is a subset of balloon aircraft, which is the oldest successful human-carrying flight technology. Jean-Francois Pilatre de Rozier made first untethrered manned flight on November 21, 1783 in Paris, France and on December 14, 1782 Francois Laurent d’Arlandes, which was created by Montgolfier brothers.
In current scenario, balloon envelopes have been prepared in various types of shapes, such as shapes of commercial products, rocket ships and hot dogs.
Envelope of hot air balloon is capable of containing heated air and just beneath the envelope there is a gondola, which is used to carry passengers and also a source of heat. Hot air balloon is made buoyant by heated air inside the envelope; as it has less density than relatively cold air outside the envelope. The envelopes of sport balloons are made up of nylon fabric and the mouth of balloon is made from fire resistant material known as Nomex.
Ed Yost pioneered modern hot air balloons, with an onboard heat source, in the beginning of 1950s. On October 22, 1960 his work resulted in his first successful flight. Bristol Belle in the year 1967 built a hot air balloon in United Kingdom. In current scenario, hot air balloons are used for the purpose of recreation.
Vijaypath Singhnia on November 26, 2005, set the world record for uppermost hot air balloon journey, reaching 21,027 meters. From Mumbai, India he took off, and landed 149 miles south in Panchale. Previous record was made by Per Lindstrand on June 6, 1988 in Plano, Texas, who flew 19,811 m. The flight, which exceeds an altitude of more than 15,000 ft, requires oxygen for all crew and passengers. Virgin Pacific Flyer balloon accomplished the longest air travel in a hot air balloon on January 15, 1991, when Per Lindstrand and Richard Branson flew 7,671.91 km from Japan to Northern Canada.
Construction-
A hot air balloon is made up of single coated fabric gas sack, which has an opening called as throat or mouth. A basket or gondola is attached to an envelope to carry passengers. The burner is mounted above the basket and centered in the mouth of hot air balloon, which injects the fire into envelope for the purpose of heating. Propane, a liquefied gas is used as a fuel in hot air balloon.
Envelope-
Envelope is made up of tough synthetic fabrics such as nylon, dacron or ripstop.
Seams-
French felled is a most common method used for stitching panels together.
Coatings-
The fabric of hot air balloon is coated with silicon or polyurethane, to make it impermeable against air.
Sizes-
Smallest hot air balloon has a size of 21,000 ft cube of envelope volume and radius of 5.22 m. The large balloons have envelope volumes up to 600,000 ft cube.
Vents-
At the top of the balloon there is a vent, which enables the pilot to release hot air to slow an ascent, start a descent, or increase the rate of descent, for landing.
Shape-
Most often the shape of hot air balloon is hemispherical.
Basket-
The baskets of hot air balloons are made up of rattan or woven wicker.
Burner-
Liquid propane is converted to gas by burner, which mixes air in it, ignites the mixture, and directs the flame and exhaust into the mouth of envelope.
Fuel Tanks-
Fuel tanks are pressure vessels, which are made from aluminum, stainless steel or titanium with a valve at one end to feed the burner and to refuel.
