OH-6A Cayuse AH-6J Little Bird Defender 500

The Boeing (McDonnell Dougles) (formerly Hughes model 369) 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 (LOH program). The Hughes 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" would find targets by flying low, "trolling" for fire, and lead in a Cobra, or "Snake", to attack. The OH-6A could be armed with the M27 armament subsystem, the M134 six-barrel 7.62mm "minigun" or the M129 40mm grenade launcher on the XM8 armament subsystem.

Army Special Operations variants

Two special operations versions of the OH-6A are the "Little Bird" AH-6C armed variant, and the MH-6B transport/utility version, which can carry up to six personnel for quick insertion and extraction missions. A previous version, the EH-6B, was used for command, control and radio relay. The MH-6 Little Bird is the only light assault helicopter in the Army inventory. It provides assault helicopter support to special operations forces and can be armed with a combination of guns and folding fin aerial rockets. It has an unrefueled range of 250 nautical miles. The AH-6 Little Bird Gun, a light attack helicopter, has been tested and proven in combat. Armed with guns, Hellfire missiles, and 2.75-inch FFAR, it provides armed helicopter support to both ground and air special operations. The unrefueled range of the AH-6 is 250 nautical miles. These versions were all powered by a single Allison T-63 252 SHP engine.

Later versions are based on the successful Boeing (McDonnell Douglas) MD-500/MD-530 series helicopters. The latest versions of these aircraft, the AH-6J attack helicopter and MH-6J insertion and extraction transport, based on the MD-530F, feature a more powerful engine and improved avionics, including an embedded GPS/inertial navigation system and forward-looking infrared (FLIR). The AH-6J can be armed with two seven-tube 2.75 inch rocket launchers and two 7.62mm M134 "miniguns". The "Little Bird" can also be armed with .50 Cal. machine guns, MK19 40mm grenade machine gun, Hellfire missiles, and Air-to-Air Stinger (ATAS) missiles.

Defender 500

This foreign military sales helicopter is offered with either a four- or five-blade main rotor, depending on the model, with a weapons platform mounted on the lower rear body. This light utility commercial helicopter could seat five passengers in comfort, and is used mainly by the military, being very flexible and offering good all round capabilities. Other missions include: direct air support, antitank, reconnaissance, observation, and light utility. A single engine is mounted inside the body with air intakes on top of the cabin and a blackhole exhaust. The fuselage is teardrop-shaped a features a round, glassed-in cockpit and landing skids. External stores are mounted on weapons racks on each side of the fuselage. Each rack has one hardpoint. The tail fin is boomerang-shaped, swept-back, and tapered. The tail flats are back-tapered with small fins attached to the tips, with the flats high-mounted on the fin forming a T. The rotor is moutned on the lower left of the tail boom.

On 12 February 1998 the Boeing Company announced its intention to sell its commercial helicopter business. Boeing built commercial helicopters -- the MD 500 Series, MD 600, and MD Explorer -- in Mesa, Ariz., where it also produces the AH-64D Apache Longbow. As of early 1998 the facility employed 5,300, of which 350 were dedicated to the production of commercial helicopters. On 25 February 1998 Bell Helicopter Textron announced a plan to acquire the Boeing MD 500 and MD 600 series product lines, However, the transaction was dis-approved by competition authorities at the Federal Trade Commission (FTC) in June 1998. Subsequently, on 19 January 1999 McDonnell Douglas Helicopter Co., the indirect subsidiary of The Boeing Company, and MD Helicopters Holding, Inc., an indirect subsidiary of the Dutch company RDM Holding, Inc., signed an agreement on an asset purchase of Boeing's MD 500, MD 600N� and MD Explorer� series of light commercial helicopter product lines. Included in the product line are the MD 500E and MD 530F� single-engine helicopters with conventional tail rotors, the MD 520N� and MD 600N single-engine helicopters with Boeing's exclusive NOTAR� no tail rotor system for anti-torque and directional control, and the MD Explorer series of twin-engine, eight-place helicopters. RDM is a European-based industrial group with aerospace activities. The company designs and builds diesel-electric submarines and builds and repairs ships, manufactures and overhauls military vehicles, and produces defense and aerospace products, including landing gear and transmissions for aircraft and helicopters. It is a subcontractor to Boeing for landing gear and fuselage assemblies for Apache helicopters.

VARIANTS

OH-6A/Cayuse: Developed initially by the Hughes Aircraft company (later McDonnell Douglas Helicopter Company) in the mid-1960s for the US Army. Fitted with 1x 253-shp Allison T63-A-5A turboshaft, 4 bladed main rotor, and an offset �V� tail.
Hughes 500M: Military export version of OH-6 in mid-1970s with upgraded 278-shp Allison 250-C18 turboshaft engine, �V� tail. A recontoured nose allowed for greater leg and head room. Modifications were also made to the rotor assembly by way of a five blade main rotor which increased stability.
MD-500MD/Scout and TOW Defender: Improved military version of the model 500 with 5 main rotor blades, 375-shp Allison 250-C20B turboshaft engine, and T-tail.
MD-500E/MD-500MG/Defender II: Had a more elongated nose for streamlining, and an optional 4x blade tail rotor for reduced acoustic signatures. Possible mast-mounted sight.
OH-6A/MD-530F Super Cayuse/Lifter: Upgraded engine to a 425-shp Allison 250- C30 turboshaft, and avionics in 1988 for the US Army.
MD-530MG/Defender: Has a mast-mounted sight, and incorporated upgrades of all previous variants.
AH/MH-6J: US Army Special Operations variant derived from the MD-530MG.

Specifications Variants in �( )�
Country of Origin	USA
Builder	McDONNELL DOUGLAS
Role	ASW, scout, antitank, multimission
Similar Aircraft	BO 105, Alouette II
Blades	Main rotor: 4 or 5 (see VARIANTS) Tail rotor: 2 or 4 (see VARIANTS)
Rotor diameter	26 ft, 4 in (8 m)
Length	Length (rotors turning): 9.4 m (500), 9.8 m (530) Length (fuselage): 7.6 m (500), 7.3 m (530)
Height	2.6 m (500), 3.4 m (530 over mast-mounted sight)
Width	1.9 m
Rotor Diameter	Main Rotor Diameter: 8.0 (500), 8.3 (530) Tail Rotor Diameter: 1.4
Cargo Compartment Dimensions	Floor Length: 2.4 m Width: 1.3 m Height: 1.5 m
Weight	Maximum Gross: 1,361 kg (500), 1,610 kg (530) Normal Takeoff: 1,090 kg Empty: 896 kg
Engine	see VARIANTS
Fuel	Internal: 240 liters Internal Aux Tank: 80 liters
Speed	Maximum (level): 241 km/h (500), 282 km/h (530) Cruise: 221 km/h (500), 250 km/h (530)
Range	Normal Load (est.): 485 km (500), km 430 (530)
Ceiling	Service: 4,635 m (500), 4,875 m (530) Hover (out of ground effect): 1,830 m (500), 3,660 m (530) Hover (in ground effect): 2,590 m (500), 4,360 m (530)
Vertical Climb Rate	8.4 m/s (500), 10.5 m/s (530)
Standard Payload	Internal load: INA External load: 550 kg Transports 2 or 3 troops or cargo internally, or 6 on external platforms in lieu of weapons.
Armament	2 - M134 7.62-mm 6x barrel, Gatling type twin MG pods 2 - M260 2.75-in Hydra 70 rocket pods (7 or 12 each) 2 - .50 cal MG pods 2 - M75 40-mm grenade launchers 2 - MK19 40-mm grenade launcher 2 - TOW missile pods (2 each) 2 - Hellfire ATGM 2 - Stinger AAM Most Probable Armament MD-500MD/Scout Defender: Fitted with guns, rockets, grenade launchers, or a combination on 2x fuselage hardpoints. MD-500MD/TOW Defender: Twin TOW missile pods on 2x fuselage hardpoints; mounts missile sight in lower-left front windshield.
Survivability	Some models have radar warning receivers. Chaff and flare systems available. Infrared signature suppressors can be mounted on engine exhausts.
AVIONICS	The MD-500 allows for the mounting of a stabilized, direct-view optical sight in the windshield. Options exist to fit a mast-mounted, multiple field of view optical sight, a target tracker, a laser rangefinder, thermal imager, a 16x FLIR for night navigation and targeting, and autopilot. Optional avionics include GPS, ILS and full instrument weather conditions packages. The more advanced variants are fully capable of performing all missions under any conditions.
Crew	1 or 2 (pilots)
Cost
User Countries	At least 22 countries -- Argentina, Bahrain, Bolivia, Colombia, Costa Rica, Denmark, Dominican Republic, El Salvador, Honduras, Indonesia, Iraq, Israel, Jordan, Kenya, North Korea, South Korea, Spain, Taiwan, USA Some 200 McDonnell Douglas 500-MD helicopters were produced under license by Korean Air between 1976 and 1984. At least fifty of these helicopters were equipped with TOW antitank weapons. The remainder were used as transports and for other support missions. North Korea acquired at least 60 Defender 500 helicopters during the mid- 1980s, reportedly through US dealers.