The Hughes/McDonnell-Douglas MD-500/530 series civil helicopter is a very popular version in the US & world helicopter market, well regarded as one of the best small size multi-purpose helicopter.
Soon the company provided the MD500/530 Defender series of military variations. The fuselage of the military variations are the same with the civilian ones, excpet the TOW Defender. The US Army named these variations OH-6 Cayuse, AH-6 and MH-6, nickname "Little Bird".
The MD-500M is called OH-6A, developed from civilian MD500 with engine power increased. The engine is the same to the civilian version and the total fuel are 227l.
This version was deployed in Apr,1968, and the users inclued Japan, Argentina, Bolivia, Denmark, Spain, Mexico and Philipin.
The Argentina RACA company and the Japan Kawasaki industry had the license to build this version, the serail are 369HM/OH-6J & 369D/OH-6D. The OH-6J had been taken down from the product line. The MD500 anti-submarine variation for Spain Navy can carry AN/ASQ-81 magnetism sensor on the right side, as well as two MK44 torpedo under the fuselage.
The control pannel of the sensor is on the center of the cockpit panel. The standard avionics of OH-6A are, AN/ARC-164 UHF radar, AN/ARC-115 UHF radar, AN/ARC-114 VHF radar, ARN-89 radio direstion finder set, APX-72 IFF, AN/ASN-43 gyro magnetic compass, ID-1315, C-6533/ARC interphone.
During the vietnam war, the OH-6 was widely used as an observation and cavalry platform. The OH-6 would find targets by flying low, right over the tree tops, and lead in AH-1 Cobras to attack them. The AH/MH-6 Little Bird has been based on both the Army OH-6A Cayuse and originally designed as a military scout. The AH-6 is an attack varient.
The MD500MD Defender is the multi purpose military variation. The fuselage & engine are the same with the MD500D. The difference are, self-pressrize fuel tanke and the air inlet strainer. The customer could also ask to add on the armor, blackhole infrared suppresser and hardpoints which can carry TOW and other weapons. MD500MD fits for the missions like training, control & command, light arming attack, anti-submarine, transportation & airborne supply. It can carry seven people including the pilot. The airborne rescue variation can take two pilots, two litters and two nurses. The Korean Aviation Company assembled this version with license.
The MD500MD reconnaissance Defender is a basic military variaion, too. The armament of it are 14 rounds of 2.75 inch rockets & a 7.62mm Minigun with 2000 rounds. Or one 40mm grenade launcher & a 7.62mm EX34 chain gun with 2000 rounds. The Kenya Army bought 15 MD500MD, Korea had 144.
The Hydra 70 rocket is a weapon derived from the 2.75 inch (70 mm) Mk 4/Mk 40 Folding-Fin Aerial Rocket developed by the United States Navy for use as a free-flight aerial rocket in the late 1940s.
The MD500MD TOW Defender keeps down the nose of the MD500, with a M65 TOW aiming system. Four TOW anti tank missles are fitted on the hardpoints on both sides. Inside the fuselage there are the aiming control system and handrail for the shooter, and control display for the pilot. The engine can be Allison 250-C20, 250-C20R or 250-C30. Israel Airforce had 30 MD500MDs, Kenya had 15 and Korea 50. The MD500MD/MMS TOW is based on MD version with an add on rotor mast aiming system.
The MD500MD anti-submarine Defender is the anti-submarine and search variation. The two-man helicopter has a search radar on the nose, AN/ASQ-81 towed Magnetic Anomaly Detection system (MAD)on the side. And other equipments are smoke launcher, winch system, emergency floating system, two Mk44/Mk46 torpedo. Special instruments include 15.24mm pose displayer & radar altimeter. The maxium takeoff weight of it is 1610kg. When proceeding the typical anti-submarine missions with 40~160km voyage, the MD500MD can remain in flight for 1 hour & 48 mins. Since May 1979, 12 of this variation were deployed in the Taiwan Navy.
MD500MD Defender II multi purpose variation`s development was begun in the summer of 1980. This type can use the standard 5 flaked rotor and the new 4 flaked Low Noise tail rotor, which runs 25% slower than the original 2 flaked tail rotor so that 47% noise cut down. The selectable equipments are rotor mast aiming system, two pods with 2 TOW missiles for each, Blackhole infrared suppresser, two pods with 2 Stinger missiles or other types of air-to-air missiles for each, FLIR system for pilot, AN/APR-39(V-1) radar warning system, fuel tank on hardpoints, advanced avionics and mission equipments.
MD500MG Defender has a 313kw Allison 250-C20B turboshaft engine and the rotor of the MD500E. Feb 1986, the MD company delivered 6 MD500MG to Columbia Airforce, and 22 to Philipin Airforce in Aug 1990. Jul 1985, a low price MG variation appeared, mainly do the job as security, border guarding, rescue, anti-drugs.
The Allison Model 250, now known as the Rolls-Royce M250, (US military designations T63 and T703) is a highly successful turboshaft engine family, originally developed by the Allison Engine Company in the early 1960s. The Model 250 has been produced by Rolls-Royce since it acquired Allison in 1995.
The cockpit of MG is very modern, decreasing the time pilot needs to make decision and proceed helicopter management so that the work is cut down. The intergrade cockpit has a compact multi function display which widened the view of the cockpit. The pilot can only used the joy stick to control the plane in all the flight time. A 79.5l fuselage inside fuel tank can be added.
MG would mainly be used to destroy the point target and tanks. The equipments are RAMS3000 intergrade control and display system for all weather & low altitude flight. The system fits the MIL-STD-1553B interface, made up of PIU, CDU, dual DTD connected with 1553B bus. The multi function display gets a high quality single color CRT. Pressing the function button on the display set pannel can proceed kinds of functions. The selectable equipments are TOW rotor mast aiming system, FLIR, radar warning system, IFF, laser range detector.
The weapons are TOW missile, two 7.62mm or one 12.7mm FN gun pod, one 70mm 7 rounds or 12 rounds pod. Four Sting missiles and a 7.62mm chain gun can be used, too. The MG can launch chaff and flare when needed.
The BGM-71 TOW is an anti-tank missile. "BGM" is a weapon classification that stands for "Multiple Environment (B), Surface-Attack (G), Missile (M)". "TOW" is an acronym that stands for "Tube-launched, Optically-tracked, Wire command data link, guided missile". The TOW was first produced in 1970 and is one of the two most widely used anti-tank guided missiles in the world.
The MD500 Nightfox was first shown in Jan 1986, designed for night reconnaissance and other purposes. The Nightfox has a FLIR, night vision goggles and the same weapons of MD500MG. Four Nightfox had deployed in Columbia Airforce. The Nightfox has two versions, 500MG Nightfox & 530MG Nightfox.
In US army, the MD500/530 are the H-6 series. The variations of H-6 series are AH-6C/EH-6B/MH-6B, based on OH-6A, with 252 SHP Allison T-63 engine. AH-6F/MH-6E, based on MD-500MG with 420 SHP Allison 250 C20 gas turbine. AH-6G/AH-6F/MH-6F, based on MD-530MG with 650 SHP Allison 250 C30 gas turbine.
The EH-6 was designed for command and control and radio relay, but all had retired now. The NOTAR (No Tail Rotor) system was once fitted on an EH-6 for testing, a jet spout was added in the tail to work as the tail rotor. But the performance is poor because requires more power from the engine. So the NOTAR is now only used in civilian versions.
The MD500E NOTAR helicopter.
Maximum speed: 152 knots (175 mph, 282 km/h)
Guns: Two M60 or M134 Minigun 7.62 mm machine guns; Two .50 cal (12.7 mm) MG pods