Josie Nielson
Igor Sikorsky did.
All of the early helicopters were developed during WW2
Helicopters were developed to provide flight where conventional aircraft could not operate.
France developed the first model of the helicopter. It was first invented by Paul Cornu, a french inventor. Some say the invention of the helicopter was inspired by Leonardo Da Vinci's flying machine.
Henrich Focke from Germany developed the first fully operational helicopter in the world: the FW 61 with its maiden flight in 1936.
As a result of hindsight from helicopter operations during the Vietnam War era, the T700 was developed in 1967 to power the beginning of the military Blackhawk helicopter line.
In 1907 Paul Cornu was experimenting with a vertical lift rotor blade system and performed the first VTOL (vertical take off and landing) flight, thus inventing the first helicopter. The helicopter was initially an idea by Leonardo Da Vinci. he developed an ornithocopter which set the basis for the structure of the modern Helicopter
igor sikorsky developed the first practical and usable helicoptor after emigrating to america.
Igor Sikorsky developed the first practical helicopter, capable of taking off and landing vertically with a usable payload.
Helicopters were developed and built during the first half-century of flight, with the Focke-Wulf Fw 61 being the first operational helicopter in 1936.
You can't really invent the same thing several times. The Blackhawk helicopter isn't rated as an invention, as it's note really doing anything hugely new. IT was developed by a team of engineers from a company called Sikorsky.