Most writers state that Sorikin failed to build a working (or complete) machine in St. Petersburg, mainly because of a low power engine. On the eve of WW1 Sorokin completed his (modified) helicopter design in his home place at Novgorod-Seversky (Ukraine) [Новгород–Северски] after a long development during 1911-1914. It is stated that the machine was tested and actually flew. The construction was based on the two rotors and a tractor propeller. There were rudders to steer the machine.
All Aero 