The first helicopter patent granted by the British Patent Office related to an aircraft with two contra-rotating co-axial two-bladed rotors mounted on a vertical shaft. The patentee was Henry Bright.

This configuration has been adopted by numerous twentieth-century workers: Berliner, von Karman, Asboth, D'Ascanio, and also by several recent makers, including Bendix, Breguet, Gyrodyne, Kamov, Lualdi-Tassotti, etc.

P.Lambermont "Helicopters and Autogyros of the World", 1958

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