Over the first decades of the twentieth century, dozens of pioneers attempted vertical flight. Some saw the weaknesses of airplane flight in requiring dedicated landing areas, while others viewed rotorcraft as a way of distinguishing themselves as designers. By the standards of true flight – sustained, stable and controllable over ranges of speed and altitude – these machines were not successful. Yet, they demonstrated the potential feasibility of vertical flight and gave a second generation of engineers and designers hope so that in the 1920s, rotary wing pioneers could make critical strides in rotor design, propulsion, control and stability, soon ushering in an era of practical rotorcraft.
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