The Boeing (McDonnell Douglas, formerly Hughes) OH-6A was designed for use as a military scout during the Vietnam war to meet the U.S. Army's need for an extremely maneuverable light observation helicopter (under the 1963 LOH program). The Army initially ordered 1,438 Hughes Model 369s, designated by the Army as the OH-6A Cayuse helicopters, fielded in Vietnam in early 1968. The OH-6A was used for command and control, observation, target acquisition, and reconnaissance, organic to division, brigade, and battalion size units. The four-passenger teardrop shaped "Flying egg" (six-passenger with rear seats folded-down) was a small, light, sturdy, maneuverable helicopter, with very low drag.
The OH-6A Cayuse was quite effective when teamed with the AH-1G Cobra attack helicopter as part of what were known as "Pink Teams". The OH-6A "Loach" (for "LOH") would find targets by flying low, "trolling for fire", then marking the target with colored smoke to lead in a Cobra, or "Snake", to attack. The Cayuse could absorb an extensive amount of small arms fire and still bring the crew home safely. The OH-6A could be armed with the M27 armament subsystem, the port-side mounting M134 six-barrel 7.62mm "Minigun" or a 40mm grenade launcher on the XM8 armament subsystem. In addition, an M60D 7.62mm machine gun could be mounted in the rear starboard door opening.
The OH-6A replaced the Korean era OH-13 Sioux and OH-23 Raven light observation helicopters. The Hughes Model 500M international military version was sold in ten countries and built under license in Italy and Japan.
The OH-6A Cayuse had a single articulated four-bladed main rotor and a metal two-bladed tail rotor. Two Special Operations versions of the OH-6A are the Hughes Model 500C AH-6C "Little Bird" armed variant, and the MH-6B transport/utility version. These advanced versions feature a quieter five-bladed main rotor, minimal-cavitation tail rotor, and a distinctive T-shaped tail.
U.S. Army OH-6 Cayuse Light Observation Helicopter
U.S. Navy TH-6B Training Helicopter, a Navy derivative of the MD-369H. The TH-6B program consists of six McDonnell Douglas TH-6B aircraft used at the USN Test Pilot School. The TH-6B is powered by the 420 shp Allison T63-A-720 turboshaft engine.