Clément Ader (April 2, 1841 – March 5, 1925) was a French inventor and engineer, is remembered primarily for his pioneering work in aviation.
Ader was an innovator in a number of electrical and mechanical engineering fields. He originally studied electrical engineering, and in 1878 improved on the telephone invented by Alexander Graham Bell. After this he established the telephone network in Paris in 1880. In 1881, he invented the “théâtrophone”, a system of telephonic transmission where listeners received a separate channel for each ear, enabling stereophonic perception of the actors on a set; it was this invention which gave the first stereo transmission of opera performances, over a distance of 2 miles (3 km) in 1881. In 1903, he devised a V8 engine for the Paris-Madrid race, but although three or four were produced, none were sold.
Following this, he turned to the problem of mechanical flight and until the end of his life gave much time and money to this. Using the studies of Louis Pierre Mouillard (1834–1897) on the flight of birds, he constructed his first flying machine in 1886, the Éole. It was a bat-like design run by a lightweight steam engine of his own invention, with 4 cylinders developing 20 horsepower (15 kW), driving a four-blade propeller. The engine weighed no more than 4 kg/kW (7 pounds per horsepower). The wings had a span of 14 m (46 ft). All-up weight was 300 kg (650 lb). On 9 October 1890, Ader attempted a flight of the Éole. It is accepted that the aircraft took off, reaching a height of 20 cm, (8 in) and flew uncontrolled for approximately 50 m (160 ft), 13 years before the Wright Brothers.
The Avion III (sometimes referred to as the Aquilon or the Éole III) was a primitive steam-powered aircraft built by Clément Ader between 1892 and 1897, financed by the French War Office.
Retaining the same basic bat-like configuration of the Éole, the Avion III was equipped with two engines driving two propellers. While the earlier aircraft had no means of directional control at all, this one was equipped with a small rudder.
Trials of the aircraft began at the Satory army base near Versailles on October 12, 1897, with the aircraft taxiing along a circular track. The first flight was attempted on October 14 and most sources agree ended almost immediately in a crash without ever leaving the ground. Late in his life, Ader would claim that there had been a flight of 100 m (328 ft) on this day, and said he had two witnesses to confirm it. Whatever actually happened, the French military was unimpressed with the demonstration and cancelled any further funding.
The machine is preserved at the Musée des Arts et Métiers in Paris. It underwent extensive restoration in the 1980s.