It rises with the ascending power of hot air contained in a “quasi-tight” envelope. The more heated, the higher up. Less heated, it descends. The pilot may operate the rope to open the piece of cloth on top of the envelope (commonly known as the valve or parachute). Hot air is leaking then out of the balloon which goes down, more or less rapidly. To move in the desired direction, it’s necessary to find a suitable wind.
A hot air balloon has three essential elements: a wicker and rattan basket or gondola (size varies depending on the volume of the envelope) attached to the envelope with steel cables at the load frame which supports a burner. The “fireplace” is connected to 4 cylinders of gas (most often propane). The envelope, usually 1,500 to 5,000 m3, is made of polyurethane-coated nylon, which guarantees around 600 hours lifetime i.e. a decade of normal use, if the balloon is controlled and stored with care to put away all risk of porosity and lacerations which endanger piloting the balloon.
In addition to the basket, the stove system and the envelope, the pilot has radio communication and navigation instruments: an altimeter (used to mesure altitude), a rate-of-climb indicator (vertical speed) and a temperature probe. A quite useful sensor, because the higher the temperature outside, the higher it is necessary to heat (not above 100°C inside, beyond fabric’s coating is destroyed). A flight (from hedgehop to altitudes of 1,000 to 2,000 m) usually lasts around an hour, but preparation and return to take-off place requires an amplitude of three hours.
Born in 1783, hot-air balloon had not survived the French Revolution. It was not until the 1960s in the United States and then in Europe, so that the balloon will redo its modern appearance. There are also “special shape” balloons that is to say specially patterned after the appearance of a house, a statue, a car, motorcycle, or any other object. These balloons, exceeding sometimes fifty meters high, are more difficult to fly. Still, they are extraordinary and never miss to delight the public.
Other special range includes small balloons with basket that consists of little more than a seat for the pilot and perhaps one passenger. Those one-man balloons (or cloudhoppers) can sometimes accommodate a fan supporting horizontal displacement at slow speed.
Reference : Pilâtre de Rozier Organisation