In 1960, the U.S. Army issued a specification for a four- or five-seat light single-engine turbine observation helicopter. The helicopter was to use the new Allison (now Rolls-Royce) 250 engine. Hughes (now MD Helicopters) won the competition with the Model 369 and received an order from the Army for 1,000 aircraft. An integral part of the development process was that commercial certification was obtained in tandem with meeting the U.S. Army requirements. The first military deliveries occurred about 1966 and full-scale production of the commercial model, called the Hughes 500, started in 1968. The first improvements to this popular helicopter (the 500C and 500D) focused on improving performance and increasing the takeoff gross weight. The next improvement, in 1983, involved a significant redesign of the cabin. The nose was restyled, yielding more legroom and better visibility for the occupants of the front seats, the bulkhead behind the front seat was lowered for improved visibility from the back seat and the head- and legroom in the back was increased. More soundproofing was added to the interior and a quiet tail rotor design become optional. This model is referred to as the 500E.
Immediately after the introduction of the 500E, McDonnell Douglas acquired Hughes helicopters and redesignated the Model 500 as the MD 500. When Boeing acquired McDonnell Douglas, it spun off the commercial helicopter group to MD Helicopters, Inc. This organization retained the MD 500 designation.
The MD 500E is a light single-engine turbine helicopter. It uses the same five-bladed, fully articulated rotor with medal blades and Rolls-Royce 250-C20B engine as the 500D. However, the higher power Rolls-Royce 250-C20R is available as an option on the MD500ER. A four-bladed tail rotor with metal blades provides directional control. A quieter asymmetric four-bladed tail rotor is available as an option. As with the 500D, a horizontal T-tail assists with pitch control. The fuselage has conventional aluminum construction, but is distinguished from its predecessors by its more pointed nose. The cabin has three seats in front and two seats in the rear. The engine and transmission are mounted on a diagonal behind and below the main rotor head. This yields a very narrow “doghouse” on top of the cabin and makes for excellent maintenance accessibility. It also results in a characteristic bulge that separates the left and right rear seats. A skid landing gear is used for the sake of simplicity.
Development of the 500E was launched in 1981, the first flight took place in 1982, and certification was obtained later that year. Deliveries started the same year and the 500E is currently in production.