While the idea of vertical flight and helicopters has challenged inventors since at least the days of Leonardo da Vinci, some of the earliest success occurred at College Park in the 1920s.
When Emile Berliner became interested in helicopters in 1908, he was already a successful inventor, having invented the gramophone, the telephone transmitter (mouthpiece) and other devices. In 1912, Berliner came to College Park as a sponsor of the Washington Aeroplane Company. However, Berliner continued working on his helicopter ideas at his home and factory in Washington, DC. In 1919, his son, Henry, joined Emile on the helicopter project. Henry took over most of the experimental operation when they moved the project to College Park the next year.
The initial machine (see right) had two contra-rotating propellers, a four-wheeled chassis, engine, shutter-like vanes, rudder, a seat for the pilot, and little else. While the machine rose quite easily from the ground, there was still a need for more lateral control and a more powerful engine.
The US Navy became interested in the Berliners’ work and provided a Nieuport 23, a World War I French fighter plane, and a British Bentley 220hp engine. The Berliners used them to test various design ideas between 1922-24. Among their modifications was adding the vanes from earlier designs and turning the biplane (two wings) into a triplane (three wings). They hoped this would increase vertical lift when moving forward. On February 24, 1924, Henry Berliner flew their helicopter to an altitude of 15 feet with a maneuvering radius of 150 feet while maintaining a speed of about 40 mph. This flight, made in front of Navy officials and media, was acclaimed as the first controlled helicopter flight.
The 1924 Berliner helicopter (below) demonstrated a vertical lift aircraft could be controlled in numerous directions. This proved a helicopter was possible, but it would be another 15 years of work before Igor Sikorsky produced the first practical helicopter.