YDCh-73
| YDCh-73 | |
|---|---|
 YDCh-73G in tank-round form (middle) and with cross-section (bottom). At top is a unitary 125mm APFSDS round for scale. | |
| Type | gun-launched anti-tank guided missile |
| Place of origin |  Menghe |
| Service history | |
| In service | 2016-present |
| Used by | Menghe |
| Production history | |
| Designer | Samsan Defense Group |
| Designed | 2010-2015 |
| Manufacturer | Samsan |
| Produced | 2016-present |
| Specifications | |
| Weight | 14 kilograms |
| Length | 91 cm |
| Diameter | 125 mm |
| Wingspan | 39 cm |
| Propellant | solid fuel rocket |
Operational range | 5,000 meters |
Guidance system | IIR with manual initial stage |
Steering system | aerodynamic surfaces |
The YDCh-73 (Formal designation: 73식 대전차 유도탄 / 七三式對戰車誘導彈, chil-sam-sik daejŏncha yudotan, "Type 73 anti-tank missile;" Short designation 유대차-73 Yudaecha-chilsam "YDCh-73") is a 125mm gun-launched anti-tank guided missile developed in Menghe for the JCh-6 and JCh-8 main battle tanks.
Developed by Samsan, the YDCh-73 draws on experience gained from the YDCh-72, and uses the same guidance and trajectory modes. In non-line-of-sight mode, it can be fired over an obstacle, with the operator acquiring a target after launch using the video feed from the missile's infrared imaging camera, and then handing the missile over to autonomous terminal top-attack guidance. Unlike the YDCh-73, it uses a high-frequency datalink rather than a fiber-optic cable.
Development
From the mid-1980s onward, the Menghean Army had followed a practice of equipping high-priority tank units, such as those in Kimsŏng divisions, with gun-launched anti-tank missiles. The first in this series, the YDCh-13, was a licensed copy of the Letnian 9K112 Kobra, while the second, the YDCh-19, was domestically developed using components from the YDCh-18. Both were designed to be broken up for storage in 125mm tank autoloaders, and both used SACLOS beam-riding guidance.
By the mid-2000s, when the YDCh-19 was new in production, it was already becoming apparent that beam-riding ATGMs were less effective against the newest armor threats in Maverica and the Able Vigil Accords. Even with a precursor charge, the YDCh-19 was judged inadequate against improving composite armor schemes, and diameter constraints prevented the improvement of the HEAT charge. These weapons also required continuous line-of-sight to the target, and while a JCh-6D was able to demonstrate YDCh-19 guidance on the move using its new stabilizer, accuracy nevertheless suffers when not stationary.
In 2009, the MoND issued a design requirement for a 125mm gun-launched ATGM which would impact targets on their roof armor. Two design bureaus took up the offer. Hanbyŏl, the Menghean Army's organic design arsenal, developed a beam-riding ATGM which followed an overflight path, much like the YDCh-70, detonating a downward-facing shaped charge as it passed over the target. As the YDCh-19 was spin-stabilized, this required an all-new missile body. Samsan Defense, a wing of the Samsan Group, took a more ambitious approach, drawing on the ongoing project that would become the YDCh-72. In addition to the required top-attack function, their concept demonstrated non-line-of-sight and fire-and-forget capabilities. Both projects proceeded in tandem until 2011, when the YDCh-72 proved itself in trials, at which point Hanbyŏl's project was shelved and further resources directed to Samsan. The Samsan prototype proved itself in trials in 2015, and the following year it entered service under the official designation YDCh-73.
Design
The YDCh-73 is conceptually similar to the YDCh-72, with the same guidance options. In non-line-of-sight mode, the tank gunner slews the turret in the direction of the target, fires the missile, and selects a target in flight using the video feed from the missile's IR-spectrum camera, handing control over to the missile for terminal homing. In fire-and-forget mode, the gunner points the barrel directly at the target, allowing acquisition through the missile camera, then fires, with subsequent homing fully autonomous. By default, the YDCh-73 follows a top-attack trajectory, diving on the target to penetrate its thinner roof armor.
Among the differences with the YDCh-72 is that the -73 lacks a trailing fiber optic cable, and instead relays video information and control commands via a radio datalink. This decision was made to eliminate the bulky fiber optic spool at the rear, a necessary choice given the limited length available in the autoloader, and to avoid the problem of how to eject the trailing end of the cable from the barrel after firing. In theory, the datalink is more reliable when firing over foliage, but it may also be more vulnerable to jamming.
When stored in the tank, the YDCh-73 is handled similar to any other unitary round. It is loaded into the turret bustle autoloader by hand between engagements, and automatically selected and rammed on gunner input. The main difference is that the YDCh-73 requires a protective cap over the node to avoid damage to the camera cover in autoloader operation; the autoloader pauses before ramming to allow the gunner to manually remove this cover. The YDCh-73 "round" also comes with a stub-shaped booster module around the base, with enough propellant to throw the missile clear of the barrel before its own rocket motor kicks in.
Like the YDCh-72, the YDCh-73 has some functionality against helicopters and slow, low-flying drones, which are also IR-contrast targets. To engage them effectively, the tank gunner must select the direct-attack (non-top-attack) mode.
Operational service
Because it entered production in 2016, the YDCh-73 did not see combat in the Innominadan Crisis, and it has yet to see combat anywhere else. A high production cost has also slowed its deployment, with the YDCh-19 still making up a large majority of the GLATGMs in the Menghean Army's arsenal. Other factors hindering the YDCh-73's deployment include the need for a dedicated datalink antenna on the tank, as opposed to a drop-in laser rangefinder replacement on the -19, and concerns over the risk of friendly fire from NLOS missile launches, which has also prompted doctrinal revision studies surrounding the YDCh-72.
Menghe has also been slow to approve the YDCh-73 for export abroad, at least as of 2019. This may be related to concerns about the sensitivity of its technology, which is mainly domestically developed. Defense analysts have also noted that at present the YDCh-73 is only compatible with the JCh-8 and late-model versions of the JCh-6, neither of which have been exported. Datalink refits to existing vehicles may be negotiated in the future, but backwards compatibility with the JCh-5 is not possible, as the missile cannot be broken in two for storage in the latter tank's autoloader.