Hughes/MD 500
Prior to the OH-6′s first flight, Hughes announced it was developing a civil version, to be marketed as the Hughes 500, available in basic five and seven seat configurations.[2] A utility version with a more powerful engine was offered as the 500U (later called the 500C).
The improved Hughes 500D became the primary model in 1976, with a more powerful engine, a T-tail, and new five-blade main rotor; a four-blade tail rotor was optional.[2] The 500D was replaced by the 500E from 1982 with a pointed nose and various interior improvements such as greater head and leg room. The 530F was a more powerful version of the 500E optimized for hot and high work.
McDonnell Douglas acquired Hughes Helicopters in January 1984, and from August 1985 the 500E and 530F were built as the MD 500E and MD 530F Lifter.[2] Following the 1997 Boeing/McDonnell Douglas merger, Boeing sold the former MD civil helicopter lines to MD Helicopters in early 1999.
Military variants are marketed under the MD 500 Defender name.
