Leonard Greene

Leonard Michael Greene (June 8, 1918 – November 30, 2006) was an American inventor and aerodynamics engineer who held more than 200 patents, many of which are aviation-related.

He is most well known for his contributions to aviation technology, including his invention, the Aircraft Stall Warning device, which warns pilots when a deadly aerodynamic stall is imminent.

Leonard M. Greene was born in New York City on June 8, 1918.

Max Greene, his chemist father, and Lyn Furman Greene, his artist mother, encouraged their son to create his own toys.

His parents made him a gift of their old stove, which he could take apart.

Greene experienced poverty as a youth during the Depression and never forgot it.

When Leonard was 16, his father had passed away.

Greene first married Beverly Kaufman, with whom he had three children; this, however, ended in divorce.

Then, he adopted four children of his second wife, Phyllis Saks Greene, with whom he had another child.

Leonard Greene graduated in 1938 from the City College of New York with a B.S. in Chemistry, and went on to receive a M.S. in aeronautical engineering.

He received a pilot license at the age of 19 and later did postgraduate work in aeronautics at the Guggenheim School of Aeronautics at New York University.

In the mid-1940s, Greene developed the first practical way to warn the pilot of the aerodynamic stall.

His first design and apparatus included threaded bolts, a bicycle horn and other odd components, all powered by flashlight batteries.

Greene filed his device for a patent in 1944, and the patent was issued in 1949.

To build the device, Greene established the Safe Flight Instrument Corporation in 1946.

Apart from his inventive life, Greene also served as the founder and president of the Institute for Socioeconomic Studies, a think tank to address issues such as poverty and social awareness.

Additionally, he co-founded the Corporate Angel Network, a charitable organization that flies patients in corporate aircraft.

In order to develop his design, Greene founded the Safe Flight Instrument Corporation in White Plains, NY, in 1946.

There, he refined and marketed the stall warning indicator.

Basically, his device sounded an alert when the plane was in danger of not having enough lift to stay flying.

This alert would allow time for the pilot to take corrective measures.

Since its invention, this device became standard equipment for all aircraft and has also helped reduce the number of accidents due to stalling.

The Stall Warning Indicator was called “the greatest lifesaver since the invention of the parachute”[14] by the Saturday Evening Post and the device received the Flight Safety Foundation’s first Air Safety Award.

After developing the Stall Warning Device, Greene continued developing aviation inventions.

He and his engineering staff at Safe Flight went on to conceive devices now commonplace in aircraft, including an automatic throttle system in 1956 and a wind-shear warning system that warns a pilot if an aircraft enters a dangerous microburst and provides escape guidance.

Phyllis Saks Greene, an heiress of the Saks Fifth Avenue department store family, died in 1965.

Greene's third marriage was to Joyce Teck Meller in 1967, which also ended up in divorce in 2005.

He developed the latter in the late 1970s after a series of wind-shear-related crashes that claimed hundreds of lives.

In 1977, he was awarded the degree of Doctor of Civil Law honoris causa by Pace University.

During World War II, Greene joined the Grumman Aircraft Corporation in Bethpage, NY, as an aerodynamicist and engineering test pilot.

There he witnessed an aircraft crash caused by stall.

In aviation, a stall occurs when the airflow over the wings is no longer sufficient to provide lift – essentially, a stalled wing ceases to function.

This happens when the wing exceeds its critical angle of attack.

Greene realized that the accident could have been avoided if the pilot had been warned of an imminent stall.

Aerodynamic stalls caused the majority of aviation deaths at the time.

In 1991, he was inducted into the National Inventors Hall of Fame.

A son from the second marriage, Donald Greene, died September 11, 2001, abroad United Airlines Flight 93 when it crashed in Pennsylvania.

In his 2001 book Inventorship: The Art of Innovation, Greene described finding "creative ideas in the simplest things."8 To address a key problem of supersonic aircraft – window-shattering sonic booms when they break the sound barrier – he turned to the earthworm for inspiration.

Greene died on November 30, 2006, at the age of 88 in Mamaroneck, New York.

The cause was complications from lung cancer.