A hot air balloon is a lighter-than-air aircraft that consists of a balloon full of heated air with a basket underneath. The air is heated in most cases using an open flame.
A hot balloon is an aircraft that uses heated air as buoyancy. Hot air is trapped in a large bag known as an envelope. The first hot air balloons were used in China as a method for signalling between soldiers during wars.
The largest part of the balloon is the envelope. This is a large bag that is most often made of nylon which is filled with heated air. The envelope normally looks like an inverted teardrop, but they can be made in a variety of shapes and are often used by companies for advertising and marketing. The basket hangs underneath the envelop and carries the passengers along with any fuel needed for the burner above. The burner burns fuel, normally propane and butane, to heat the air in the envelope. The pilot can use the burner to gain altitude. To lose altitude, some balloons have large vents at the top which can be opened to allow some of the hot air to escape. Hot air balloons are different to other lighter-than-air aircraft, like blimps, as they are not sealed at the bottom and use heated air for buoyancy.
The Montgolfier brothers became interested in balloon flight after seeing clothes billowing over an open flame. They first demonstrated balloon flight in the summer of 1783. The flight wasn’t manned but instead had a sheep, a duck, and a rooster as passengers. The first untethered and manned flight was later in 1783. The flight lasted 25 minutes and the passengers traveled about five miles. News quickly spread about the Montgolfier brothers and many people around the world became interested.
Montgolfier style balloons only use the buoyancy of heated air, but there are hybrid balloons. These hybrid balloons get buoyancy from hot air and also from lighter-than-air gases such as hydrogen or helium. With the discovery of helium and hydrogen, hot air ballooning became less popular. These new balloons could stay in the air indefinitely and could reach incredibly high altitudes. They are named Rozière balloons after their inventor Jean-François Pilâtre de Rozier.
Ed Yost designed and created a balloon that could carry its own heat source and fuel. This would allow the balloon to fly for longer and further than before. Yost had his first successful flight in 1960. These are the most common type of hot air balloon now used all over the world.