YDCh-70
| YDCh-70 | |
|---|---|
 YDCh-70G with cross-section (middle) and launch tube (bottom). | |
| Type | Anti-tank guided missile |
| Place of origin |  Menghe |
| Service history | |
| In service | 2008-present |
| Used by | Menghe |
| Production history | |
| Designer | Hanbyŏl Missile Design Bureau |
| Variants | YDCh-72G, YDCh-72N |
| Specifications (YDCh-70G) | |
| Weight | 24.8 kilograms |
| Length | 1.34 meters |
| Diameter | 152 mm |
| Wingspan | 58 cm (fins extended) |
| Propellant | solid fuel rocket |
Operational range | 6 kilometers |
Guidance system | SACLOS beam-riding |
Steering system | aerodynamic surfaces |
The YDCh-70 (Formal designation: 70식 대전차 유도탄 / 七〇式對戰車誘導彈, chil-lyŏng-sik daejŏncha yudotan, "Type 70 anti-tank missile;" Short designation 유대차-70 Yudaecha-chillyŏng "YDCh-70") is a type of anti-tank guided missile developed in Menghe during the early 2000s. Though it uses conventional beam-riding SACLOS guidance, it defeats armored targets with a unique overflight mode, firing two downward-facing shaped charges as it passes above a vehicle to penetrate the thinner roof armor. At the time of its introduction it was the only ATGM in Septentrion to use such a warhead, and its exact operation was kept a closely guarded secret until 2014.
Development
Little is known about the development of the YDCh-70, which first appeared in July 2009 at a military parade celebrating the 45th anniversary of Menghe's victory in the War of Liberation. Pressure for its development likely escalated after the Ummayan Civil War, where combat experience revealed doubts about the YDCh-18's ability to penetrate the frontal armor of the latest Tyrannian and Sieuxerrian-made MBTs. The same conflict spurred work on new top-attack ATGMs, like the YDCh-72, and improved ammunition for the JCh-6 MBT. At the same time, the short span of time between 2005 and 2009 suggests that some basic work on the YDCh-70 had already been conducted before then, possibly as an alternative to the YDCh-18. It is known that development work was led by the Hanbyŏl Design Bureau, the Menghean Army's in-house weapons development agency, which is better known for license-produced weapons.
Work on the YDCh-70 proceeded under intense secrecy, as Menghean military officials were not keen on divulging its ingenious method for defeating armor. Even after it was unveiled in 2009, very little official information about it was published, and only images of the sealed launch tubes were available. Most state sources referred to it as an upgraded version of the YDCh-18 with improved range and penetration." At one point a penetration figure of 2,200 mm began to circulate, likely a misinterpretation of the claim that it could defeat tanks with 2,000mm RHAe frontal armor, as such a figure is theoretically improbable for a 150mm copper-lined shaped charge.
Photos of partially disassembled YDCh-70 missiles were first leaked to the media in 2014, most of them taken by insurgents and government soldiers in Innominada following the Menghean invasion in September of that year. Menghean authorities initially attempted to censor leaked information, but in 2015 acknowledged the leaked photos as accurate, and published more detailed information on the YDCh-70 and its capabilities. By that time, it was already being supplanted by more advanced weapons, such as the YDCh-72.
Design
The YDCh-70G missile is 134 cm long and 152mm in diameter (fins closed), with a blunt nose and a slightly tapered tail. It has cruciform wings about halfway down its length, and cruciform steering surfaces just ahead of the rear taper, with the former offset 45 degrees from the latter. A booster rocket in the tail provides initial thrust, but the sustainer motor is located in the middle of the fuselage, with one vent on each side. The missile body is of all-metal construction and the entire projectile (without tube) weighs 24.8 kilograms.
Missile guidance is beam-riding, semi-active command to line of sight. The launch platform aims eight collimated laser beams onto the target, with a narrow conical overlap between them, and a rear-facing sensor on the base of the missile keeps it within the laser overlap zone. An internal gyroscope keeps the missile upright throughout its entire flight path, in contrast to the YDCh-18, which is spin-stabilized.
The YDCh-70G's most ingenious feature is its warhead. This consists of two 135mm downward-facing shaped charges. Rather than impacting directly over the target, the missile flies 1-2 meters above the line-of-sight path between the launcher and target. A laser profiling sensor in the nose, which arms when nearing the target's range, triggers the warheads when the missile passes over the enemy vehicle. The relatively shallow shaped charges likely have relatively little armor penetration - independent estimates put it at close to 400mm RHAe - but this is adequate to defeat the roof armor on all known MBTs, and it also improves after-armor effects. The two shaped charges are each angled about 10 degrees off the missile's centerline, spacing their impact points by about 30-70 cm, depending on overflight height; this increases the probability that one charge will impact a critical component of the tank.
The missile flies at a speed of 340 meters per second, and can reach its maximum range of 6 kilometers in 17.6 seconds. It lacks a trailing wire, and can thus maintain higher speeds with no risk of snagging, but it is also more vulnerable to jamming. As with any SACLOS system, it requires constant line-of-sight between the launcher and the missile, and maximizes accuracy when the launcher is kept stationary. These faults somewhat counteract its advantages, yet while the YDCh-72 overcomes them with "true" fire-and-forget capability, the YDCh-70 remains in production as of 2019 because of its lower cost and adequate anti-armor performance.
YDCh-70N
The YDCh-70N is a variant of the YDCh-70 optimized for destroying structures such as bunkers, buildings, and caves. It uses a thermobaric warhead, with an 85mm HEAT precursor charge in front to knock holes in brick or concrete barriers. This also gives it some capability against light armored vehicles, such as APCs and older IFVs. Guidance for the two missiles is identical, and they are compatible with the same launchers.
Launch platforms
SYB-70
This is the designation applied to the portable tube launcher for the YDCh-70. It consists of a mounting unit for the launch tube, an optical sight with laser designator, a control unit, and a tripod. It can be broken up into separate loads and carried by a crew of as few as three: one carrying the optical unit and mount, one carrying the tripod, and one carrying two reload tubes. In light infantry units, a crew of four may be used instead, with the fourth crew member carrying two additional reload tubes. Otherwise, the launch team stays close to its host vehicle and stores additional reload tubes there.
Y70B1
This was the first launch vehicle for the YDCh-70. It consists of a Donghae D1728N 4×4 light utility vehicle with a ring mount for a single YB70 launch tube. Four reload tubes are stored in the vehicle. The Y70B1 has a crew of three, consisting of a driver, a commander, and a gunner, who also reloads the mount on the turret ring. The Y70B1 is fast and lightweight, able to reach speeds of 120 kilometers per hour on a paved road. It is entirely unprotected, however, leaving the crew exposed to the elements and to enemy fire. It also has limited offroad mobility. It was mainly intended as an interim solution until the introduction of newer anti-tank vehicles.
Y70B2
This tank destroyer, introduced in 2010, uses the hull of the Chŏnsŏ J107 4×4 armored car. With a top road speed of 110 kilometers per hour, it is only slightly slower than the Y70B1, and it is fully amphibious. It also protects the crew against small-arms fire, CBR contaminants, and shrapnel, though at the cost of having a higher and more noticeable profile. Like its predecessor, it has a crew of three: a driver, a commander seated in the front right seat, and a gunner seated under the turret.
The missile turret has four tubes and is controlled by the gunner from a non-rotating seat inside the hull. Up to eight more reloads can be stored inside the hull on racks on either side. To reload the launcher, the crew must open the rear doors and pass individual launch tubes to a crew member standing on a rail on the side of the hull, a time-consuming process which can only be performed outside of battle. With four tubes on the launcher, however, the Y70B2 has nearly as many ready missiles as the Y70B1 has total missiles.
Chŏnsŏ initially hoped to secure a large contract for the Y70B2, making it a 1-to-1 replacement for regimental tank destroyers based on the JJCh-1. In the end, however, the Menghean Army retained YDCh-17-armed tank destroyers at the divisional level and adopted the Y48G1 and later G2 as its new regimental tank destroyer systems.
Y70B3
A version of the Y70B2 for the Menghean Marine Infantry. It uses the Chŏnsŏ J109 chassis, which is largely identical to the J103 but has redesigned wheel wells and an improved propeller system for better seaworthiness. In terms of its combat capabilities and crew requirements, it is identical to the Y70B2.