Short answers, pulled from the story.
Igor Sikorsky designed the VS-300, the first viable American helicopter, which first flew tethered on the 14th of September 1939 and made its first free flight on the 24th of May 1940. He then refined that design into the R-4, which became the world's first mass-produced helicopter in 1942. The single main rotor and antitorque tail rotor configuration he pioneered is now standard on most helicopters worldwide.
Igor Sikorsky was born on the 25th of May 1889 in Kiev, in the Russian Empire, now Kyiv, Ukraine. He was the youngest of five children of Ivan Alexeevich Sikorsky, a professor of psychology, and Mariya Stefanovna Sikorskaya, a trained physician.
Sikorsky fled Russia in early 1918 after the Bolshevik Revolution, having been warned that the Bolsheviks intended to shoot him for being the Tsar's friend and a popular public figure. He moved to France, and when French military contracts ended in November 1918, he emigrated to the United States, arriving in New York City on the 30th of March 1919.
The Russky Vityaz, designated S-21, was the world's first successful four-engine aircraft to take flight, developed by Sikorsky while he served as Chief Engineer of the aircraft division at the Russian Baltic Railroad Car Works in Saint Petersburg. Sikorsky piloted its first flight on the 13th of May 1913. The design experience led directly to the Ilya Muromets, the world's first four-engine bomber.
When Sikorsky founded the Sikorsky Manufacturing Company in Roosevelt, New York in 1923, composer Sergei Rachmaninoff introduced himself as a supporter by writing a check for five thousand dollars. Those funds helped Sikorsky repair a damaged prototype after its first test flight and persuade other backers to continue investing.
Sikorsky was inducted into the International Air and Space Hall of Fame in 1966, and entered both the National Inventors Hall of Fame and the Junior Achievement U.S. Business Hall of Fame in 1987. A main-belt asteroid designated 10090 Sikorsky was named for him in 1990. Sikorsky Memorial Airport in Stratford, Connecticut, and the Sikorsky Memorial Bridge carrying the Merritt Parkway over the Housatonic River also bear his name.