YDH-28

YDH-28
File:Majian MJ-28.png YDH-28A and YDH-28Ch, the most common variants
Type	Anti-Ship Missile
Place of origin	Menghe
Service history
In service	2002-present
Used by	Menghe Qusayn
Production history
Designer	Chŏnggong design bureau
Designed	1995-1999
Unit cost	$450,000
Produced	2002-present
Variants	YDH-28G, YDH-28N, YDH-28GJS, YDH-28NJS
Specifications
Weight	540 kg (YDH-28GJS) 450 kg (YDH-28G)
Length	3.93 m (YDH-28GJS) 3.32 m (YDH-28G)
Diameter	35 cm
Engine	Turbofan
Wingspan	1.14 meters
Propellant	kerosene
Operational range	110 kilometers
Flight altitude	15 meters mid-course 2 meters terminal
Boost time	solid-fuel booster
Speed	Mach 0.8
Guidance system	Active radar (with IIR secondary in MJ-28Ch and BCh)
Steering system	aerodynamic surfaces
Launch platform	GHZ-28, GHZ-36, Daesŭngri DS-12, Sŏngrim SL-6, Sŏngrim SL-8

The YDH-28 (Menghean: 유도탄,대함 "Yudotan, Daeham" lit. "Missile, Anti-Ship") is a subsonic Anti-Ship Missile designed and built in the Socialist Republic of Menghe. Armed with a 130-kilogram warhead, it is primarily intended for use against frigate-sized ships with a displacement of 5,000 tonnes or less, but can also be used as a disabling weapon against larger targets such as cruisers, carriers, and troop transports. It is a universal weapon, and can be launched from surface warships, coastal vehicles, and helicopters, depending on the variant. Due to its limited weight, low range, and relatively light warhead, it is mainly used as a short-range or secondary weapon to supplement heavier anti-ship missiles in Menghean service.

Design

The subsonic YDH-28 follows a conventional cruciform wing design, with fixed stabilizers mounted halfway down the missile's length and similarly shaped steering fins mounted at the rear. An intake for the turbofan is slung underneath the missile's body. Prior to launch, these fins are folded against the missile's body, allowing it to be stored in more compact launch containers; these fins automatically spring open shortly after launch.

The YDH-28 is relatively small, and weighs only 550 kilograms (with booster), allowing it to be carried by smaller launch platforms. Its size also makes it harder to detect on a warship's radar, and makes it an efficient weapon against smaller warships that might not merit the use of a heavier anti-ship missile.

Variants ending in "JS" (증속 / 增速, Jŭngsok, roughly "Booster") have their launch initiated by a solid-fuel booster, which drops off once its fuel is expended. After this, the missile's flight is sustained by a turbofan engine, which draws in air from an intake under the missile's body. During the early stages of its flight path, the missile autonomously guides itself toward the target through the use of an inertial navigation system, maintaining its altitude at 15 meters through the use of a radio altimeter. This system has a terrain-following capability, allowing the missile to approach its target over land obstacles when launched over land by an aircraft or coastal battery. "G" based variants approach the target directly along a straight line, though "N" based variants can be programmed to follow a pseudo-random curving or zig-zag trajectory to evade CIWS and other countermeasures.

When the missile's inertial navigation system indicates that the missile is 30 kilometers away from its target coordinates, the missile activates its active radar seeker and performs a brief "pop-up" altitude change to confirm the target's location. Once the target's new coordinates have been found, the missile drops to a "sea-skimming" altitude of 2 meters and makes its final approach. The "N" based variants feature an imaging-infrared seeker, slung below the missile body in a special pod, which serves as a backup for targeting and increases the missile's resistance to a warship's ECM systems. The warhead, weighing 130 kilograms, consists of RDX surrounded by a steel fragmentation tube and can be augmented by the presence of unburnt fuel inside the missile.

Due to its small size and relative simplicity, the YDH-28 is considered one of the most cost-efficient missiles in service in Septentrion. This is especially true of the basic "G" variants, which lack imaging-infrared secondaries or programmable course-change systems. It is also designed for easy storage and maintenance, and can be stored fully-fueled for a period of up to 15 years.

Coastal defense version

File:YDH 28 Battery.png

Components and organization of a YDH-28 coastal defense battery.

In 2005, as part of the country's pivot to defensive warfare, the Coastal Defense Forces of the Menghean Army placed a request for a self-propelled, land-based launcher for the YDH-28 missile. The resulting system, which was publicly displayed in 2008 and bears the designation JYDH-28 (Jaju-Yudotan Dae-Ham, Self-Propelled Missile, Anti-Ship), consists of eight vehicles:

• 1x JYDH-28JS (Jungdae Salyŏngcha), Company/battery command vehicle with radio and wire connections. Crew of five.
• 1x JYDH-28SR (Susaek Reida), search radar vehicle with an elevating mast to detect ships within horizon range. Crew of three.
• 3x JYDH-28BG (Balsagi), launcher vehicle with eight missiles. Crew of four.
• 3x JYDH-28JCh (Jaejangjŏn-Cha), reload vehicle with eight missile boxes and a crane. Crew of two.

Variants

• YDH-28G: basic variant with solid-fuel booster, launched from stationary or slow-moving firing platforms.
• YDH-28GJS: fixed-wing-launch variant, lacking a booster.
• YDH-28N: upgraded booster variant, with imaging-infrared reference seeker and more course-change programs.
• YDH-28NJS: fixed-wing-launch variant of the MJ-28Ch.
• YDH-28D: universal missile with an extended range of up to 300 kilometers; still in development.

See also

• YDH-23
• List of Menghean missiles