Hot air balloon Montgolfier brothers, and had its first public demonstration on 4 June 1783 with an unmanned flight lasting 10 minutes, followed later that year with manned flights. The 1785 Rozière balloon, a type of hybrid balloon, named after its creator, Jean-François Pilâtre de Rozier, has a separate cell for a lighter than air gas (typically helium,) as well as a cone below for hot air (as is used in a hot air balloon) to heat the helium at night. Hydrogen gas was used in the very early stages of development but was quickly abandoned due to the obvious danger of introducing
Hot air ballooning forecasts. The pilot will also send up a helium pilot balloon, known as a "met-balloon" in the UK and "pibal" in the USA, prior to launch to get information about what the wind is actually doing. Another way to determine actual wind directions is to watch other hot air balloons, which are the equivalent of a large "met-balloon". The direction of flight depends on the wind, but the altitude of the balloon can be controlled by changing the temperature of the air inside the envelope. The pilot may open one or more burner blast valves to increase the temperature inside