The MD Helicopters MD 500 series is an American family of light utility civilian and military helicopters. The MD 500 was developed from the Hughes 500, a civilian version of the US Army's OH-6A Cayuse/Loach. The series currently includes the MD 500E, MD 520N, and MD 530F.
MD Helicopters MD 500
A Hughes 500C (Model 369HS)
A Hughes 500D
A NOTAR MD 520N
The Hughes OH-6 Cayuse is a single-engine light helicopter designed and produced by the American aerospace company Hughes Helicopters. Its formal name is derived from the Cayuse people, while its "Loach" nickname is derived from Light Observation Helicopter (LOH) program under which it was procured, and likely the word "chopper", a common nickname for helicopters.
Hughes OH-6 Cayuse
OH-6 helicopter in flight
A OH-6A in Vietnam, May 1970
An OH-6A and two AH-1G Cobra helicopters flying a reconnaissance mission near Phuoc Vinh, circa 1970