Helicopter Engineering and Research Corporation JOV-3
Development began in 1946 with the Helicopter Engineering and Research Corporation headed by D.K. Jovanovich and F. Kozloski, where a small 2-seat prototype (N9000H) was built with the designation JOV-3. This aircraft, powered by a 125hp Lycoming O-290, was flown successfully in 1948. It had 3-blade rotors of 5.64m diameter, a gross weight of 618kg, a maximum speed of 161km/h and a range of 221km.
The JOV-3 Tandem rotor machine was powered by a 100hp Franklin engine. It had a neat fuselage of steel tube covered with aluminium and fabric, with a tricycle undercarriage and a forward cockpit for two occupants seated in tandem. The rear pylon allowed the rear rotor to turn on a higher plane than the forward rotor so that the arcs could overlap safely.
In 1949 Helicopter Division of McCulloch Motors Corporation appointed as chief designer D. K. Jovanovich, formerly of Helicopter Engineering and Research Corporation, who developed his JOV-3 as McCulloch MC-4 tandem rotor two-seat helicopter, first flown Los Angeles March 20,1951.