He invented a great number of devices, designed a "flying saucer" and discovered the Coandă effect of fluid dynamics.

[2] In the 1950s, Coandă inflated his importance in aviation history, describing falsely how he had invented the air-breathing jet engine and incorporated that design into the Coandă-1910 aircraft.

His inventor's spirit did not comport well with military discipline and he obtained permission to leave the army, after which he took advantage of his renewed freedom to take a long automobile trip to Isfahan, Teheran, and Tibet.

In 1910, in the workshop of Gianni Caproni, he designed and built an aircraft known as the Coandă-1910, which he displayed publicly at the second International Aeronautic Salon in Paris that year.

[4] According to Charles Gibbs-Smith: "There was never any idea of injecting fuel; the machine never flew; it was never destroyed on test; and Flight noted that it was sold to a Monsieur Weyman.

"[3] Gibbs-Smith continued, "The claim said that after a disastrous crash (which never happened) Coandă wished to begin a 'second aircraft', but 'his funds were exhausted.'

Within a year he was ... exhibiting (in October 1911) a brand new propeller-driven machine at the Reims Concours Militaire..."[3] Other aviation writers accepted Coandă's story of his flight tests with the Coandă-1910.

Although eventually unsuccessful for aircraft propulsion, this effect has been widely used on a smaller scale, from packaging machinery for small pills through to the Dyson Air Multiplier bladeless fan.

In 1969, during the early years of the Ceauşescu era, he returned to spend his last days in his native Romania, where he served as director of the Institute for Scientific and Technical Creation (INCREST) and in 1971 reorganized, along with professor Elie Carafoli, the Department of Aeronautical Engineering of the Polytechnic University of Bucharest, spinning it off from the Department of Mechanical Engineering.