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.
MD500MD “陶”“防御者”保留了最初MD500的机头，机头装有M65“陶”瞄准具。装有4枚“ 陶 ”式反坦克空地导弹。机内为射手设有瞄准控制装置和扶手，以及驾驶员用的操纵指示器。可装艾利逊公司250-C20，250-C20R或250-C30发动机。以色列空军购买30架，肯尼亚购买15架，韩国购买50架。MD500MD/MMS“陶”反坦克型在MD型的基础上，加装了旋翼轴瞄准具。
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反潜“防御者”是反潜与水面搜索型。载两名机组人员，机头上设有搜索雷达、AN/ASQ-81拖曳式磁异探测器、烟雾弹发射器、拉降装置、应急漂浮装置、两枚Mk44或Mk46寻的鱼雷。磁异探测设备的控制盒安装在仪表板和中央操纵台上。特殊仪表有一个15.24厘米的姿态指示器和雷达高度表。最大起飞重量为1610千克。在执行典型反潜任务、航程为40～160千米时，能在空中停留1小时48分钟。1979年5月开始交付给中国台湾海军12架。
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.
MD500MD“防御者”Ⅱ多任务型。1980年夏开始研制。该型装有标准的5片桨叶旋翼，也可选装4片桨叶的“ 低噪音 ”尾桨，其转速比标准的两片桨叶尾桨慢25%。据说噪声可减少47%。选装设备包括：旋翼轴瞄准具、装4枚“陶”式反坦克导弹的2个双联吊舱、“黑洞”红外抑制器、装两枚“毒刺”或其它空-空导弹的吊舱、飞行员用前视红外夜视系统、直升机被雷达制导的武器跟踪时会报警的AN/APR-39(V-1)设备、副油箱和先进的航空电子设备与任务设备组件。旋翼轴瞄准具可将视频信号输给飞行员的电视显示器。旋翼轴瞄准具备激光测距仪。为了不被敌人发现，“防御者”Ⅱ直升机可借助旋翼轴瞄准具在树木或地形后面进行隐蔽悬停，而且还能观察战场远处的情况。只要稍作改装，就可安装为OH-6A研制的标准轻型航空电子设备。
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.
MD500MG “防御者”研制始于1982年末，原休斯直升机公司根据武装直升机驾驶员的反馈，以民用型MD530F的机体和动力装置为基础研制MD530MG“防御者”。该型装有一台313千瓦(426轴马力)艾利逊公司250-C20B涡轮轴发动机。1986年2月，麦克唐纳?道格拉斯公司向哥伦比亚空军交付了6架，1990年8月交付给菲律宾空军22架。1985年7月推出一种便宜的准军用MG“防御者”型，主要用于治安、边境巡逻、救援、反毒品。
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.
驾驶舱非常先进，缩短了驾驶员作关键性决定和直升机管理任务所需的时间，减轻了工作负荷。综合驾驶舱装有一个紧凑的多功能显示器，扩大了座舱的视野。飞行员在整个飞行时间内都可以握杆操纵对直升机实施操纵。可选装一个79.5升的内部辅助油箱。
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.
MD530MG主要用于攻击点目标和反坦克。设备有用于全天候和贴地飞行的RAMS3000综合控制与显示系统。这种系统可以与MIL-STD-1553B接口匹配，由处理机接口装置(PIU)、控制显示装置(CDU)和双套与1553B数据总线联接的数据传输装置(DTD)构成。多功能显示器有一个高分辨率单色阴极射线管。使用控制显示装置键盘上的专用键能完成各种功能。选装的航空电子设备包括：“陶”式导弹旋翼轴瞄准系统、前视红外装置、雷达告警接收机、敌我识别器和激光测距仪。
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.
武器包括“陶”式反坦克导弹，装两挺7.62毫米或一挺12.7毫米机枪的FN武器吊舱和70毫米火箭的7管或12管发射巢。还可以用4枚“毒刺”空空导弹和一挺7.62毫米链式自动机枪。MG型可使用金属箔条和红外诱饵曳光弹。
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.
MD500 “ 夜狐 ”(Nightfox) 1986年1月推出，用于夜间侦察和其它军事用途。该型装有前视红外热成象设备和夜视镜，武器与MD530MG的相同。交付4架MD500MG“夜狐”给哥伦比亚空军。“夜狐”分500MG“夜狐”和530MG“夜狐”两种型式。
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.
美陆军内的MD500/530系列命名为H-6系列。H-6系列的改型还包括AH-6C/EH-6B/MH-6B，由OH-6A发展而来，采用252马力阿里迅T-63发动机。AH-6F/MH-6E由MD-500MG和420马力阿里迅250-C20发动机发展而来。AH-6G/AH-6F/MH-6F，同样以MD-530MG为基础，使用650马力阿里迅250-C30发动机。
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.
EH-6 是H-6系列中指挥控制和通信中继型号，但目前已退役。EH-6曾一度采用无尾桨系统，尾桨被一个尾部喷口取代。但由于无尾桨系统要耗费更多的发动机功率，性能表现不好。因此无尾桨系统后来仅为民用型号采用。
The MD500E NOTAR helicopter. MD500E 无尾桨直升机。
