Balloon (aeronautics) they are popular for balloonist sport activity. The first balloon which carried passengers used hot air to obtain buoyancy and was built by the brothers Josef and Etienne Montgolfier in Annonay, France in 1783: the first passenger flight was 19 September 1783, carrying a sheep, a duck, and a rooster. The first tethered manned balloon flight was by a larger Montgolfier balloon, probably on 15 October 1783. The first free balloon flight was by the same Montgolfier balloon on 21 November 1783. When heated, air expands, so a given volume of space contains less air. This makes it lighter and,
Hot air balloon course) stated in the previous section. Liftoff would require a slightly greater temperature, depending on the desired rate of climb. In reality, the air contained in the envelope is not all the same temperature, as the accompanying thermal image shows, and so these calculations are based on averages. For typical atmospheric conditions (20 °C, 68 °F), a hot air balloon heated to (99 °C, 210 °F) requires about 3.91 m³ of envelope volume to lift 1 kilogram (62.5 ft³/lb). The precise amount of lift provided depends not only upon the internal temperature mentioned above, but the external temperature, altitude above