Leonardo never attempted to make this helicopter, because he had no engine.
In France in 1783 a toy helicopter was presented, named “Chinese tern”, although no one knew
from where this device actually originated. In 1796 George Kelly experimented with similar Chinese terns, and gave a blueprint for steam helicopter.
Over the next hundred years, many have tried to construct a helicopter. Some of these projects were fantastic, others almost practically feasible, but only a few helicopters took off.
The problem was the lack of powerful engine that could lift the helicopter. During the First World War, when such engines were made, it has become possible to construct helicopters that were able to loft a man above the ground.
Designer Igor Sikorsky made two helicopters in 1909th and 1910th. Toward the end of 1917, two Austro-Hungarian officers constructed a helicopter designed for observation of the front, a task that was previously carried out by air balloons. This helicopter was able to repeatedly lift up to greater heights, but in all ended there.
Work on the construction of the helicopter continued in many countries, but without any major success. However in 1936 news came from Germany that the company “Focke-Wulf” managed to produce a good helicopter.
This helicopter in 1937 managed to fly long distances at speeds of around 110 kilometers per hour and at altitudes greater than 3,300 meters.
In year 1940 the designer Igor Sikorsky demonstrated his helicopter which could be used in the practice, which was supplied to the U.S. Army in 1942.