JCh-5

No.5 Tank (JCh-5)
All five service variants of the JCh-5.
Type	main battle tank
Place of origin	Menghe
Service history
In service	1979-present
Used by	Menghean Army
Wars	Ummayan Civil War Innominadan Crisis
Production history
Designed	1975-1979
Manufacturer	Inmin-Chŏlgang-Nodongja Vehicle Plant
Produced	1979-2008
No. built	at least 24,000
Variants	JCh-5G, JCh-5N, JCh-5D, JCh-5R, JCh-5M, JCh-5/6
Specifications (JCh-5D)
Weight	45.5 metric tonnes
Length	9.64 m (inc. gun and fuel tanks) 6.41 m hull only
Width	3.64 m
Height	2.07 m to turret roof
Crew	3 (driver, gunner, commander)
Armor	welded steel plate "Second-generation ERA" (Menghean classification)
Main armament	125mm L/45 smoothbore gun
Secondary armament	12.7mm HMG (commander) 7.62mm GPMG (co-axial)
Engine	KV-12 diesel 708 kW (950 hp)
Power/weight	21.1 hp/tonne
Suspension	torsion-bar
Ground clearance	38 cm
Operational range	600 km (internal fuel), 800km (with external tanks)
Speed	60 km/h (road)

The JCh-5 (Menghean designation: 5호 전차 / 五號戰車, O-ho Jŏncha, meaning "Type 5 tank" or "No.5 tank") is a second-generation main battle tank introduced in the Democratic People's Republic of Menghe and inherited by the Socialist Republic of Menghe. Though initially based on the Letnian T-66, later variants diverged considerably from the original design, and the JCh-5 is regarded as a completely separate model of armored fighting vehicle. It is also considered Menghe’s first advanced MBT, and its general design philosophy – a three-man crew, a low profile, and a 125mm autoloading gun – would be followed by later Menghean tanks such as the JCh-6 and JCh-8.

T-66

Variants of the Letnian T-66, from which the JCh-5 was developed.

During the early 1960s, the main tank used by Socialist countries was the T-58, license-produced in Menghe as the JCh-3. With its dome turret and 100mm gun, it was fairly advanced at the time of its introduction, but two decades later its shortcomings were becoming apparent. This was especially true with regard to its main armament and its armor.

Beginning in the late 1950s, design teams in Letnia began work on a revolutionary new tank design which would represent the new generation after the T-58. In its final form, this tank carried a 125mm gun and was fairly well-protected, with rudimentary composite armor on the glacis plate and turret front. On top of this, it also had a lower overall profile, and a higher top speed, making it a true main battle tank rather than a medium or heavy tank. This balance of capabilities was achieved through the use of a carousel autoloader on the turret floor, which reduced the crew to three and allowed for a smaller protected volume. Speed was improved through a compact opposed-piston engine, which fit into an engine compartment smaller than that of the T-58.

These revolutionary advances, however, did come at a cost. Even in its early trials, the T-66 was found to be a notoriously unreliable tank, heavy on maintenance hours in the base and prone to breakdowns in the field. The autoloader frequently jammed on early models, and several crew members sustained injuries after their clothing was caught on the rotating carousel mechanism. The opposed-piston engine was another source of difficulty, in part because it was engineered to high specifications that Letnian factories and repair crews could not consistently meet. Other problems extended to the suspension, the fire-control system, and the turret hydraulics.

Export Restrictions

For these two reasons – the tank’s advanced character, and its disappointing performance – the Letnian government was reluctant to offer the T-66 for export, especially to its less developed allies. Rumors of the T-66's poor reliability also made Menghe reluctant to pursue an arms deal, leading instead to a focus on modernizing successive variants of the JCh-4.

By the mid-1970s, however, the lack of a second-generation main battle tank was becoming a major issue in the eyes of Menghe's generals. The T-66A, introduced in 1973, solved many of the early prototype’s reliability problems, leading the Soviet military to cautiously offer up the latest variant for export. At first this seemed to satisfy Menghe’s needs, but the country's High Command remained wary of the need for further simplification, as Menghe engineers and repair crews were even less skilled than their Letnian counterparts.

In 1975, representatives from the two countries reached a tentative agreement by which Menghe would license-produce a T-66 variant modified to its liking. Several members of the design team were temporarily transferred to the Inmin-Chŏlgang-Nodongja Vehicle Plant's design bureau, where they provided their foreign counterparts with blueprints and technical advice. The new program, approved in 1976, was designated JCh-5 and was primarily intended to further simplify the T-66A design to make it suitable for Menghe service.

Development

JCh-5G

The initial JCh-5 closely resembled the T-66 series, but incorporated several major design differences. The largest of these was the replacement of the opposed-piston engine with a more conventional V-shaped layout. To make room for the larger powerplant, the rear chassis was extended slightly, with the treads rising to the toothed drivewheel at a lower angle. The JCh-5 also incorporated many of the minor simplifications applied to the T-66A and T-66B, which reduced reliability problems with the hydraulics, suspension, and autoloader. In other areas, however, the JCh-5G was something of a downgrade. It continued to use the old composite armor scheme, as that under development for the T-66V remained classified, and it also retained the outdated optics arrangement of the T-66A – which included a stereoscopic rangefinder and a rudimentary stabilization system.

Later upgrades

Disappointed at the shortcomings of the JCh-5G, Menghe engineers set out to improve the design even further, without adding too much to its unreliability. It was at this point in the design stage that the JCh-5 departed most radically from its Letnian origins.

Designated JCh-5N, the new tank entered limited service late in 1985. The most prominent change was an all-new welded turret, which incorporated a more advanced composite armor scheme over the frontal arc. This was armed with a new 125mm gun, which incorporated a better cooling sleeve and bore evacuator, firing tungsten APFSDS ammunition. The optics were also upgraded, addressing severe accuracy problems which the JCh-5G had encountered in combat trials. As with all T-66-derived variants, there were also minor fixes to minor hull systems, though not on as large a scale.

Due to its complexity and cost, the JCh-5N was not produced in the numbers Menghe’s military commanders desired, especially after economic decline at home cut into the availability of advanced military hardware. After the Decembrist Revolution, however, the new Socialist leadership decided to expand production, as the JCh-5N was the most advanced tank in its inventory.

In 1991, the Menghean Army introduced the JCh-5D, which added early-generation ERA bricks to the hull and turret as added protection against HEAT warheads. This variant also had the capability to fire anti-tank guided missiles through the gun barrel, which had been a feature in Letnia since the T-66B. The type of missile fired, YDCh-14, had a range of 4,000 kilometers and employed SACLOS guidance.

JCh-5R followed this trend in 2002, adding what Menghean sources refer to as a "second-generation ERA" system capable of inducing shear forces on APFSDS ammunition. It also improved the fire-control system for standard ammunition, including the addition of a more sophisticated wind and temperature sensor and more capable passive night vision sights for the gunner and commander. In the most substantial change to the design, it even incorporated a more powerful diesel engine, with an output of 950 shaft horsepower.

Together, these two variants (-D and -R) account for most JCh-5 tanks in Menghean service.

JCh-5M

Designed in 2010, the JCh-5M applied successful features of the JCh-6D to the JCh-5 chassis. It was designed as a "bolt-on" upgrade, which could easily be retrofitted to existing units without restarting JCh-5 production. Most of the changes related to the fire-control system: a muzzle reference device was installed atop the barrel, and new visual-wavelength and infrared sights were installed in place of the old ones. This change also enabled the removal of the active IR spotlight on the turret face, and allowed ERA panels to be extended over the area it had covered.

Contrary to initial expectations, JCh-5M did not incorporate "third-generation ERA" of the type used on the JCh-6D. Instead, it relied on the "second-generation" panels used on the JCh-5R, which were lighter, more reliable, and easier to manufacture.

The JCh-5M also incorporated a new storage system on the turret rear. Sometimes mistaken for a bustle autoloader of the type used on the JCh-5/6, this is actually a replacement for external storage bins, and cannot be accessed from inside the vehicle. The central-rear bin is used to hold spare 125mm shells and propellant charges, eliminating the loose ammunition stowage within the crew compartment which had contributed to catastrophic detonations on penetrated vehicles during the Ummayan Civil War. Live-fire tests against JCh-5N and JCh-5M hulls at full ammunition loads have confirmed that the latter are considerably less prone to catastrophic detonations, but can still cook off if the carousel autoloader itself is hit.

A final interesting feature of the JCh-5M is its MChGJ-0800 short-range radio antenna, also adopted after successful tests on the JCh-6D. This uses a frequency in the C band, between 4 and 8 GHz. The frequency is not high enough to suffer severe problems with atmospheric attenuation in rain, but is still limited to line-of-sight communication, as its waves do not experience surface diffraction. This makes it a highly secure band, unable to be intercepted by enemy units outside line-of-sight and nearly impervious to jamming. As on the JCh-6D, this system would be used for close-range communication between tanks in a Company under conditions of intense electronic warfare, effectively a replacement for semaphore flags carried by the tank commander.

JCh-5/6

An interesting evolution of the JCh-5 series was the cancelled program later designated JCh-5/6. It began in 1996, not long after the Menghean government issued a design requirement for a new main battle tank capable of firing more effective single-piece 125mm APFSDS ammunition. The main design team responded with Project 805, which would become the JCh-6. A secondary design team, however, produced an alternative design, which was intended to take the place of Project 805 if it fell short of expectations.

Project 804

This alternative program, designated Project 804, was intended to meet the design requirements while continuing to use the same base chassis as the JCh-5 series. The turret face, as well as the glacis plate and hull sides, carried the same "second-generation ERA" used by the contemporary JCh-5R. On the rear of this turret was a prominent bustle with a cycling-belt autoloader carrying 18 main gun rounds. The bustle itself was thinly armored, with protection only against shrapnel and ammunition of less than 12.7mm caliber, but in the event of a more serious penetration its upper panel would blow off to relieve the pressure. Additional main gun ammunition was stored on the turret floor in place of the carousel autoloader, which was removed, and loose ammunition was no longer stored in the hull itself. In the hull rear, a more powerful engine allowed for a higher power-to-weight ratio, increasing road speed and offroad handling.

Three prototypes were built for testing in 1998, and they performed adequately in demonstration trials, meeting nearly all of the government's design requirements except below-ERA armor protection on the hull. They were surpassed, however, by the Project 805 competitor, which exceeded its targets in all areas. Project 805 was then accepted for service as the JCh-6, while Project 804 was shelved and its prototypes moved into storage.

Project 814

Interest in the notion of a bustle-armed JCh-5 returned in 2010, after High Command decided to prioritize new-build production of the JCh-6 over the JCh-5 variant. The Marine Infantry force in particular expressed its interest in such a vehicle, which would be lighter than the JCh-6 and therefore more suitable to amphibious transport. At High Command’s approval, the original team was reassembled under an arms subsidiary of Samsan Heavy Industries and instructed to revisit the concept in line with the Marine Infantry’s requirements.

Although the Project 804 prototypes provided some initial conceptual guidance for the new design, the resulting Project 814 proposal amounted to a new design. The design team built an all-new hexagonal turret with lighter but more efficient composite armor of the type used on the JCh-6R, with a lightly armored bustle similar to that of Project 804 protruding from the rear. In addition to allowing for the storage of longer APFSDS ammunition carried by the JCh-6, the autoloader could also handle the YDCh-73, which was introduced to limited service in late 2016. To compensate for the thinner base armor, the designers added a standoff hard-kill active protection system, the first of its kind carried by a Menghean main battle tank. The engine was also improved yet again, to a 12-cylinder diesel with an output of 1020 hp but the same overall dimensions to allow refitting into the same engine compartment, to maintain the same power-to-weight ratio as the JCh-5R despite the added weight. After several years of testing, the vehicle was approved for service in 2013, with the Marine Infantry placing an order for 250 vehicles.

Owing to its conceptual resemblance to the SuChong-6, and to clarify confusion over compatibility with full-length APFSDS ammunition, the new tank was designated the JCh-5/6 in service. The same designation is sometimes retroactively applied to the Project 804 prototype, resulting in some confusion over the origin of the term. Although marketed as an all-service vehicle, in Menghean service it is only used by the Tank Battalions of the Marine Infantry.

Service

At least 24,000 JCh-5 tanks of all variants were produced during the vehicle's production run, which lasted from 1978 to 2008. The majority of these vehicles were completed between 1990 and 2008, and are of the D, R, or M variants. As of 2015, all JCh-5N tanks have been refitted to at least R standard, and all JCh-5Gs have been either scrapped or sent to early training units. The JCh-5 was the most advanced type of Menghean main battle tank from 1994 until 2005, when the newly introduced JCh-6 entered service. As of 2016, the JCh-6 has replaced the JCh-5 in nearly all active units, though the latter still forms the backbone of Class 2 units in the Mobilization Reserves.