YDH-29 Chŏngryong

YDH-29 "Chŏngryong"
Comparison of the YDH-29G and N
Type	Supersonic anti-ship missile
Place of origin	Menghe
Service history
In service	2012-present
Production history
Manufacturer	Buksŏng Industries Group
Specifications
Weight	1,900 kg (without booster)
Length	6.14 m (without booster)
Diameter	48 cm
Warhead	220 kg warhead
Detonation mechanism	Contact fuse
Engine	quad ramjet, liquid fuel solid-fuel booster (YDH-29N)
Wingspan	132 cm
Operational range	250-450 km (depending on launch profile)
Flight altitude	40 km (high altitude) 5 m (sea skimming)
Speed	Mach 2-3
Guidance system	inertial guidance, terminal active radar homing with infrared imaging backup
Launch platform	Songrim SR-8 Daesŭngri DS-9

The YDH-29 Chŏngryong ("Blue Dragon") is a Menghean supersonic anti-ship missile. It is designed to be launched from fixed-wing aircraft, surface warships, and land-based vehicles. It has a programmable launch profile, and can follow a high-altitude cruising approach for maximum speed and range, or a low-altitude sea skimming approach for minimum detectability.

Development

The YDH-29 was developed as a successor to the YDH-25, Menghe's license-produced version of the Letnian P-270 Moskit. It branched off of a development effort for an extended-range version of the YDH-25, but resulted in an entirely new missile design with a smaller configuration. The design may also derive some features from the smaller Kh-31 anti-radiation missile, also licensed by Menghe. One of the design requirements of the new missile was that it be light enough to be carried on the under-wing and centerline hardpoints of the Songrim SR-8 heavy multirole fighter. These hardpoints are rated at 2050 kilograms, and with its adapter pylon included, the YDH-29G falls just within this limit.

The missile was designed by the Buksŏng Industries Group, a major Menghean defense contractor which also produced the YDH-26. In some respects, Buksŏng treated it as a competitor to the YDH-27, developed by Institute 57 of the Navy's in-house design system. The YDH-27 has comparable performance in its high-altitude mode and is 25% lighter, but lacks a sea-skimming flight mode and cannot be launched from surface craft.

Description

The YDH-29 has a similar body structure to the P-270 and Kh-31, with four ramjet intakes arranged in a square around a single cone-nosed missile body. It can be easily distinguished from either of those missiles by the fact that the air intakes are squared off rather than circular or semicircular. With a mass of 1900 kilograms, it is roughly four times heavier than the YDH-26 and 33% heavier than the YDH-27, but still less than half the weight of the YDH-25.

Like several contemporary Menghean anti-ship missiles, the YDH-29 has a dual-mode seeker. The main guidance system, located in the nose, uses active radar homing with a secondary home-on-jam capability. This is complemented by an imaging infrared seeker slung below the missile body between the lower two intakes. The infrared guidance system has a shorter range, but it can be used to improve resistance to jamming and countermeasures by cross-referencing radar contacts with infrared imagery in multiple spectra.

The warhead of the YDH-29 has a total mass of only 220 kilograms, of which roughly half is explosive mass. It reportedly uses a number of explosively formed penetrators to maximize the distribution of damage throughout a ship after impact. Even with this structure, however, the warhead is less than one-third the mass of the warhead on the YDH-28, which also features an explosively formed penetrator design. One possibility is that YDH-29 missiles would be used in the first wave of an attack to damage enemy escort ships, and slower YDH-28 missiles would form the bulk of the second strike to sink damaged escorts and high-value targets.

The YDH-29 may incorporate a similar networking system used on the YDH-28, though it is also possible that this system was removed to save weight.

Flight profiles

The performance of the YDH-29 depends on the flight profile programmed into the missile at launch. Because the air is thinner at higher altitudes, an all-high approach maximizes range and speed, and allows the missile to use its existing momentum to reach speeds close to Mach 4 in its final descent toward the target. This flight profile, however, leaves the missile exposed to enemy radar systems, providing advance warning of an attack and permitting interception by long-range surface-to-air missiles.

The missile can also follow a sea skimming trajectory, cruising at an altitude of 25 meters for most of the approach and dropping to 5 meters once a radar return appears on its targeting radar. This method reduces speed and range, but also conceals the missile by hiding it behind the radar horizon. Against a Sieuxerrian destroyer with a 30-meter radar mast, the missile only crosses the radar horizon at a range of 30 kilometers, leaving under 40 seconds of reaction time with a Mach 2.4 approach speed. During this approach, the missile can perform 10g evasive maneuvers to reduce its probability of interception.

On a Hi-Lo trajectory, the missile follows a high-altitude trajectory for the initial approach, but descends to sea-skimming level once it comes within 100 kilometers of the target area. This provides some measure of protection from anti-air defenses on the final approach, but it still provides the targeted formation with some advance warning of an incoming missile attack.

All-High Profile

• Range:
  • 450 km (air launch)
  • 400 km (surface launch)
• Speed:
  • Mach 3+ (cruise)
  • Mach 4 (at target)

Hi-Lo Profile

• Range:
  • 350 km (air launch)
  • 300 km (surface launch)
• Speed:
  • Mach 3+ (cruise)
  • Mach 2.4 (at target)

All-Low Profile

• Range:
  • 250 km
• Speed:
  • Mach 2.4

Variants

YDH-29G

The air-launched version of the missile. Its most readily distinguishing feature is the lack of a solid-fuel booster. Its wings are also non-folding, as it is carried below the aircraft rather than inside a container.

YDH-29N

The surface-launched version of the missile, launched from warships and land vehicles. It has a 1.4-meter solid-fuel booster section which propels the missile out of the launch box and accelerates it until the ramjet engine can sustain itself.

YDH-29D

Extended-range version which made its first appearance in 2018. It has a lengthened fuselage with additional fuel space, resulting in a claimed range increase of roughly 50% (600km in hi-hi mode, 400km in hi-lo mode). Because it is too long to be fired from existing box launchers for the YDH-29N, and too heavy to be carried by Menghean multirole combat aircraft, it is probably only compatible with the Yŏng'an Y-4 bomber.

See also

• YDH-23
• YDH-25
• YDH-27
• MM80