Clément Ader (French pronunciation: [klemɑ̃ adɛʁ]; 2 April 1841 – 3 May 1925) was a French inventor and engineer. He was born near Toulouse in Muret, Haute-Garonne, and died in Toulouse. He is best known for his early work in aviation. In 1870, he was also one of the first people to help start the sport of cycling in France.

Electrical and mechanical inventions

Ader was a pioneer in electrical and mechanical engineering. He first studied electrical engineering and in 1878 made improvements to the telephone created by Alexander Graham Bell. In 1880, he set up the telephone network in Paris. In 1881, he invented the théâtrophone, a system that sent sound through separate channels to each ear, allowing listeners to hear performances as if they were in a theater. This was the first time stereo sound from an opera was transmitted over a distance of 2 miles (3 km). In 1903, he created a V8 engine for the Paris–Madrid race. Although three or four of these engines were made, none were sold.

Aircraft prototypes

After working with V8 engines, Ader focused on the challenge of mechanical flight. He spent much of his life studying and funding this effort. Using research by Louis Pierre Mouillard on how birds fly, Ader built his first flying machine in 1886, called the Ader Éole. It had a bat-like shape and used a lightweight steam engine of his own design. The engine had four cylinders and produced 20 horsepower (15 kW), powering a four-blade propeller. The engine weighed 51 kg (112 lb), and the wings spanned 14 m (46 ft). The total weight of the machine was 300 kg (660 lb). On 9 October 1890, Ader tried to fly the Éole. Historians note this attempt as the first powered take-off and uncontrolled flight in ground effect, covering about 50 m (160 ft) at a height of about 20 centimeters (8 inches). Ader also claimed he successfully lifted the Éole off the ground.

Ader began building a second aircraft, named the Avion II, also called the Zephyr or Éole II. Most sources say this project was never completed and was later replaced by the Avion III. Ader later claimed he flew the Avion II in August 1892 for 100 m (330 ft) near Paris, but this claim was not widely accepted.

Ader’s work interested Charles de Freycinet, the French minister of war. With support from the French War Office, Ader built the Avion III. This machine resembled a large bat made of linen and wood, with a 15 m (48 ft) wingspan. It had two four-bladed tractor propellers, each powered by a 30 hp (22 kW) steam engine. On 12 October 1897, Ader tested the Avion III on a circular track at Satory. Two days later, he tried to fly it. After a short run, the machine was hit by a gust of wind, turned sharply off the track, and stopped. Following this failure, the French army stopped funding the project but kept the results secret. In November 1910, an official report stated that Ader’s flight attempts were unsuccessful.

Book on aviation

Clément Ader continued to support the progress of aviation. In 1909, he wrote L'Aviation Militaire, a widely read book that had 10 editions published over five years before World War I. The book is known for describing how airplanes might be used in war and for predicting the design of a modern aircraft carrier, including a flat flight deck, a structure on top of the carrier, elevators to move planes, and a space to store planes. His concept for an aircraft carrier was shared by a United States naval officer in Paris and led to the first tests in the United States in November 1910.

— Clément Ader, L'Aviation Militaire, 1909

Influence

Clément Ader is still respected for his early work on powered flight. His aircraft contributed to the French word avion, which means a heavier-than-air aircraft. In 1938, France released a postage stamp to honor him. The company Airbus named one of its aircraft factories in Toulouse after him. Clément Ader has been called "the father of aviation."