Paul Cornu lifted a twin rotored helicopter without assistance for a few seconds with no assistance from the ground on Nov 13, 1907. A 24hp Antoinette engine that raised him about one foot oﬀ the ground for 20 seconds powered his design. The rotors operated in opposite directions to oppose the torque created by each of them. This design was not maneuverable so it was eventually abandoned.
Paul Cornu in his aircraft
The next major advancement came in 1924 when Etienne Oehmichen ﬂew a helicopter in a closed circuit for 7 min 40 sec for a distance of one kilometer. For this, he won prize money of 10,000 Francs (approx $2200)
Advances kept coming, but the ﬁrst practical and controllable helicopter came from the Germans in 1936. Built by Focke-‐Wulf, the FW61 was produced on a biplane trainer design. It maintained a front rotor, but was cut down and was only used to help cool then engine.
This machine set records for altitude of over 11,000 feet, straight line ﬂight of 143 miles, speed, and ﬂight duration. It also accomplished the ﬁrst autorotation landing with the engine oﬀ!
This design is now the most prominent design in modern helicopters. The Sikorsky Company is still around and is one of the leading helicopter companies in the world.
Sikorsky builds many helicopters for the US Military including the BlackHawk, SeaHawk, SuperHawk, amongst others and builds many civilian helicopters including trainers.