| Model 500 History|
The Model 500 series - a derivative of the OH-6A military helicopter - was
originally built by Hughes Helicopters in Culver City CA. In 1984, Hughes
Helicopters (originally owned by the legendary Howard Hughes, who developed and built the OH-6) was
bought out by McDonnell Douglas. The company was renamed McDonnell Douglas
Helicopter Company, moving to Mesa, Arizona.
Boeing and McDonnell Douglas merged in
1997, and in 1999 Boeing sold off the MD commercial helicopter line to MD
Helicopters Inc., a European subsidiary of RDM Holding, Inc. The company was recently sold to
the investment firm Patriarch Partners, which continues to
manufacture the aircraft in Mesa. The MD 520N is a Model 500 aircraft with a
NOTAR (No Tail Rotor) circulation control system replacing
the tail rotor. The MD 600N is a stretch version of the 520N, adding a center row of
passenger seats and a 6th rotor blade. The MD 900 was an entirely new design, first introduced in the 1990s.