This period was marked by small numbers of limited projects achieving limited success. Very little technology transfer occurred between projects. The primary efforts occurred in France, Spain, Austro-Hungary and the United States.
This period marked the first significant attempts at manned rotary-wing aircraft. Though some examples achieved limited flight, control and stability were lacking in all designs and rotors, engines and power transmission systems were largely inadequate to the task.
Application and Operations
Little thought was given to why helicopters might be desirable beyond the reduction in need for conventional landing surfaces, which were hardly significant for the airplanes of the time. This lack of pressing need explains why so few attempts at helicopter construction occurred in this early period as airplanes were far simpler in terms of mechanical complexity, stability, propulsion and control. However, World War I did see the first military requirements for rotorcraft appear as alternatives were sought for tethered military observation balloons.
Design and Manufacture
The primary form of innovation at this time was typically an individual inventor/entrepreneur operating with a small team of assistants and limited capitol. These individuals were often self-taught in aspects of aerodynamics and most progress was of an empirical (trial and error) nature.
However, World War I marked the beginning of governmental interest and support in rotary-wing technology and the first government sponsored projects began to appear. These were critical for establishing the model for providing the significant resources necessary to investigate the challenges of vertical flight and develop practical solutions.
- Cornu 1907 Helicopter
- Ellehammer 1912 Helicopter
- Petróczy-Karman-Zurovec PKZ-2
- Pescara 1S
- Berliner 1922 Helicopter
- de Bothezat 1922 Helicopter
- Paul Cornu
- Jens Ellehammer
- Maquis Raul Pateras Pescara
- Emil and Henry Berliner
- George de Bothezat