Gabriel and Charles Voisin built aircraft at the dawn of aviation, even possibly making their first flight before the Wright brothers. The Voisin brothers went into aircraft manufacture and even though Charles Voisin was killed in 1912 the aircraft was successful during The Great War. However, after 1918 sales of aircraft plunged and Gabriel decided to go into car production. The Voisin Type C1 was based on a Citroen design, but given a Voisin 4-litre four cylinder engine using Knight sleeve-valve technology. This was the recipe for all future Voisins. Also part of the Voisin format was the use of aluminium construction and unusual body designs, some typified by Art Deco styling. Voisin also threw down the gauntlet with advanced design, giving this first car 4-wheel brakes and a 4-speed gearbox. Voisin's first 6-cylinder engine was introduced for the C11, and this evolved for the later C14 'Charmant' which was a big seller in spite of its high price. In 1929 Voisin launched a 4.9-litre V12 car as the C18 'Diane'. Gabriel Voisin lost control of his company in 1937 at the time that the 6-cylinder C28 was announced but only four were produced. Avions Voisin was nationalised in 1945 and the nanme was lost at that time.