Vought-Sikorsky VS-300 - Design and Development

Design and Development

Igor Sikorsky's quest for a practical helicopter began in 1938, when as the Engineering Manager of the Vought-Sikorsky Division of United Aircraft Corporation, he was able to convince the directors of United Aircraft that his years of study and research into rotary-wing flight problems would lead to a breakthrough. His first experimental machine, the VS-300 was test flown by Sikorsky on 14 September 1939 but had to be tethered by cables due to its inherent instability. In developing the concept of rotary-wing flight, Sikorsky was the first to introduce a single engine to power both the main and tail rotor systems. The only previous successful attempt at a single-lift rotor helicopter, the Yuriev-Cheremukhin TsAGI-1EA in 1931 in the Soviet Union, used a pair of uprated, Russian-built Gnome Monosoupape rotary engines of 120 hp each for its power. For later flights of his VS-300, Sikorsky also added a vertical aerofoil surface to the end of the tail to assist anti-torque but this was later removed when it proved to be ineffective.

The cyclic control was found to be difficult to perfect, and led to Sikorsky locking the cyclic and adding two smaller vertical-axis lifting rotors to either side aft of the tail boom. By varying pitch of these rotors simultaneously, fore and aft control was provided. Roll control was provided by differential pitching of the blades. In this setup, it was found that the VS-300 couldn't fly forward easily and Sikorsky joked about turning the pilot's seat around.