what is the envelope of a hot air balloon made of
Hot air balloon Modern hot air balloons are usually made of materials such as ripstop nylon or dacron (a polyester).[19]
Hot air balloon In the 18th century the Portuguese jesuit priest Bartolomeu de Gusmão envisioned an aerial apparatus called Passarola which was the predecessor of the hot air ballon. The purpose of Passarola was to serve as air vessel in order to facilitate communication and as a strategical device[5]. In 1709 John V of Portugal decided to fund Bartolomeu de Gusmão's project following a petition made by the jesuit priest [6] and an unmanned demonstration was performed at Casa da India in presence of John V, the queen Maria Anna of Austria, having as witnesses the Italian cardinal Michelangelo Conti, two members of the Portuguese Royal Academy of History, one Portuguese diplomat and one chronicler. This event would bring some European attention to this event and this project. A later article dated on October 20, 1786 by the London Daily Universal Register would state that the inventor was able to raise himself by the use of his prototype. Also in 1709, the Portuguese jesuit wrote Manifesto summário para os que ignoram poderse navegar pelo elemento do ar (Short Manifesto for those who are unaware that is possible to sail through the element air). Persecuted by the Inquisition he was prevented to continue his research, however, he left designs of a manned air vessel.