Brésil (spherical balloon)

After seven years living in Paris and having already performed several ascents in other balloons, Santos Dumont decided to develop his own aircraft to gain experience, as it would be more economical than renting balloons from other builders. He commissioned the constructor Henri Lachambre, of the firm Lachambre & Machuron, to build what he aimed to be the smallest free balloon ever built, with a 113 m³ hydrogen chamber, 6 metres (20 ft) in diameter and a total weight of 27.5 kilograms (61 lb).[1][2][3]

Before flying in Brésil, Henri Lachambre's team let Santos Dumont make ascents in both France and Belgium as a way of gaining experience.[4] According to Godin da Fonseca, Santos Dumont was influenced to build his first balloon when he followed the Paris-Amsterdam car race in 1897.[5]

One of Santos Dumont's main innovations in this aircraft was the use of Japanese silk for the envelope: Japanese silk, despite having 70% of the resistance per unit area of Chinese silk, still had 70% more resistance than necessary. However, the other balloonists feared that the delicacy of the material would cause tears in flight, and Santos Dumont only began to trust the material after several laboratory tests.[6] To maintain stability, Santos Dumont employed a longer length of rope, as shown in the schematic above, where the first figure represents a traditional balloon and the second represents Brésil.[7]

Everything involved was kept as small as possible, even though there was no experience with such a tiny balloon. However, Santos Dumont had to study everything that had been accomplished so far to have confidence in the project.[8] The chamber net was reduced to a mere 2 kg (4.4 lb), while the basket was reduced from 20 kilograms (44 lb) to 6 kg (13 lb).[9] Instead of an anchor, he used a small 3 kg (6.6 lb) harpoon.[10] His critics said the balloon would have no stability, nor any success.[2]

Its first flight took place on 4 July 1898,[3] in the Jardin d´Acclimatation.[11] Santos Dumont described that the balloon "...very maneuverable in the air and very smooth." and that it would not be wrong to say that he carried it in his briefcase.[12] The aeronaut also described that the balloon was "...beautiful in its transparency, like a big soap bubble."[13]

Its use in over 200 flights made Santos Dumont one of the best aeronauts in France and gave him the due flight experience that resulted in the development of other balloons and his airships,[14][3][15] as well as attracting attention from other inventors and the European press.[16] The performance of its first two models, "Brésil" and "Amérique", impressed experienced balloonists.[17] Its first airship, the "Nº1", had its first test run on September 18, 1898, three and a half months after the first flight of the "Brésil".[18]

Dias 2006 describes that because of his innovations in developing a balloon of reduced size and cost, Santos Dumont "...would have made a great contribution to aeronautics," even if he had only created the Brésil.[9]