In 1945, there were several aircraft companies involved in helicopter design, test and production in America. The smallest and least well financed one had just been incorporated by 26-year-old Charles Kaman to pursue a synchropter design and flight control concept which featured a pair of intermeshing rotors with small sero-tabs attached to the blades to twist them in flight. This proved the Kaman to be much easier to control in a hover than a conventional helicopter and eliminated the need of a tail rotor. In 1949 the Navy became interested. The Navy ended up purchasing small trainers, observation and rescue helicopters and transport and utility helicopters for itself and the marines. These aircraft were operated into 1965 and the design was eventually developed into the turbine-powered H-43B/F Huskie used by the USAF in Vietnam.