YDH-23

YDH-23
File:Sunglin SL-6M Naval Strike color shaded.png Sŏngrim SL-6HG carrying two YDH-23 AShMs, a heavy strike payload
Type	anti-ship missile
Place of origin	Menghe
Service history
In service	1985-present
Used by	Menghean Navy
Production history
Designer	Chŏnggong design bureau
Designed	1977-1985
Produced	1985-present
Variants	YDH-23A, YDH-23B, YDH-23DJ
Specifications
Weight	3,450 kg
Length	8.18 meters
Diameter	58 cm
Wingspan	147 cm
Propellant	solid fuel
Operational range	~500 km (high trajectory) ~200 km (low trajectory)
Speed	Mach 3.3-4.0 (hi-alt cruise) Mach 5 (hi-alt terminal) Mach 2.2 (lo-alt)
Guidance system	Terminal Active radar with intertial guidance and satellite navigation for initial approach to target.
Steering system	aerodynamic surfaces
Launch platform	Sŏngrim_SL-6, Sŏngrim_SL-27, Sŏngrim_SL-8

The YDH-23 (Menghean: 유도탄,대함 "Yudotan, Daeham" lit. "Missile, Anti-Ship") is a long-range, air-launched anti-ship missile designed in the Democratic People's Republic of Menghe, predecessor state to today's Socialist Republic of Menghe, and used by the Menghean Navy. With a long range and a high top speed but an exposed flight path, it is meant to be used in massed attacks against enemy carrier battlegroups, though in theory it can also be used against large missile cruisers and modernized battleships, and against supply and transport convoys. A YDH-23DJ variant for attacking hardened land targets was introduced in 2008.

Development

Work on the YDH-23 began in the late 1970s, in response to a requirement from the Menghean People's Air Force for a standoff weapon which could be used against enemy carrier battlegroups. A successful prototype was accepted for service in 1985, but production ground to a halt in 1987 when the Menghean government seized power in the Decembrist Revolution. The Menghean Navy resumed production of the weapon in 1997.

Design

The YDH-23 is a solid-fueled, two-stage missile with a diameter of 58 centimeters. Its control surfaces are located on the tail and driven by mechanisms around the engine nozzle, but the guidance unit itself is forward of the fuel section, linked to the tail by a covered “spine” that runs along the top. Terminal guidance relies on active radar homing, with a secondary home-on-jam capability for increased resistance to certain countermeasures. En-route guidance is provided by a combination of Satellite Navigation and inertial guidance, and the missile can be datalinked back to the launch aircraft or a partnered “watcher” to allow course correction if the target fleet moves.

Sandwiched between the guidance unit and the solid fuel is a 750-kilogram conventional warhead. This warhead incorporates a pre-fragmented outer shell to increase damage to ship systems after impact, and the missile’s own weight and momentum causes extensive damage by itself. On the diving flight path (see below), the missile is programmed to detonate after a slightly longer delay, allowing it to penetrate into the depths of a large ship and explode near the keel, engines, or magazines to increase the risk of critical damage. A nuclear-armed anti-ship variant was proposed during the 1980s, as was a nuclear-armed land attack variant, but neither entered service prior to the new Menghean regime’s nuclear disarmament.

Flight Paths

On its typical anti-ship flight profile, the YDH-23 gradually climbs to an altitude of about 30,000 meters and cruises toward a target area set by inertial navigation, satellite navigation, or datalinked manned aircraft. At this stage of the flight course, it reaches a top speed of somewhere between Mach 3.3 and Mach 4, depending on the source. As the missile nears the enemy fleet and switches over to radar guidance, it climbs again to over 40,000 meters, then executes a maneuvering dive on the target. At this stage in the flight path, it nears Mach 5, making it extremely difficult to intercept. Maximum attainable range with this flight path is cited as 500-600 kilometers, allowing the launch aircraft to remain outside the range of ship-based SAMs and limiting exposure to patrolling fighters.

A problem with this high flight path, however, is that it exposes the missile to long-range surface-to-air missiles during its high-altitude approach. In order to mitigate this problem, the designers added a secondary “sea-skimming mode” in which the missile gradually descends to an altitude of 10 meters after launch. This means that against most surface warships, the missile will only cross the horizon at a distance of less than 30 kilometers. Higher air resistance at this altitude, however, means that the missile’s range is reduced to about 200 kilometers, and its terminal speed to a little over Mach 2.

KST-23

A land-attack variant, the KST-23, was introduced in 2008 in response to the perceived danger of war with Maverica or Firmador. Though it uses the same missile body, the KST-23 replaces the radar seeker and prefragmented warhead with a single 1000-kilogram ground-penetrating munition based on the KST-1000 bomb family but with higher-strength walls and a slightly reduced explosive content. The resulting weapon, designated YDH-23DJ (대지하엄폐호, Dae-Jihaŏmpyeho, anti-bunker), is a standoff ground penetrating munition for use against high-value hardened land targets such as command bunkers and missile silos. Using the same diving profile as the anti-ship variant, it can penetrate much deeper than a gravity bomb, but due to high costs and niche usefulness, relatively few were produced.

Variants

File:Majian MJ-23.png

Externals and Cross-Section of the YDH-23A and YDH-23DJ.

• YDH-23A: original production design accepted for service in 1985.
• YDH-23B: upgraded variant from 2009, with improved electronics. Can datalink with other missiles in transit to assign targets, and can perform evasive maneuvers while descending in the final attack.
• YDH-23DJ: bunker-buster variant with a 1000-kilogram penetrating warhead and SatNav guidance.

Operators

Menghe

See also

• YDH-28
• List of Menghean missiles