P150G5P Dŭngsu-po

The P150G5P Dŭngsu-po ("Wisteria gun") is a Menghean self-propelled howitzer developed as the successor to the P150G2P Songsu-po. It is part of the P150G5 artillery system, which also includes battery-level and battalion-level command and fire control vehicles. It is built on a utility chassis derived from the hull of the JCh-8 main battle tank, giving it a unique appearance, with the turret centered on the hull rather than offset toward the rear.

Development

Although the P150G2P Songsu-po and its P150G4P variant were generally well-liked by the Menghean Army, many leading engineers at the General-Directorate for Research and Development at the Menghean Ministry of National Defense expressed interest in a more capable self-propelled gun. Watching developments abroad, these engineers argued for the benefits of a fully automated ammunition handling system, as opposed to the semi-automatic system on the Songsu-po. A fully autoloaded turret, they concluded, would offer a higher rate of fire, allowing the vehicle to more effectively perform shoot-and-scoot fire missions. It would also reduce crewing requirements, and thus reduce the logistical footprint of artillery formations.

Engineers from the design bureau of the Chikai Heavy Machine Building Plant were especially active in promoting the design of a new self-propelled gun. Chikai had also entered a prototype in the Ministry of National Defense's 2003 SPG design trials, losing out to Samsan Defense, which produced the design that became the P150G2P. At that time, Chikai's use of the JCh-5 chassis had been one of the reasons for its loss; because of the small hull and confined turret ring, the 2003 prototype's ammunition capacity and rate of fire were both poor. By using an autoloading turret and a utility variant of the JCh-8 chassis, also a Chikai design, it would be possible to counteract both of these problems.

An evaluation of competing prototypes took place in 2015, under the oversight of the General-Directorate for Procurement. Samsan entered a comprehensive upgrade of the Songsu-po, with an all-new turret featuring a fully-automated ammunition handling system. This allowed a reduction in crew size to two individuals: the gunner and the commander. On paper, Samsan's option offered lower costs and better reliability, as well as a faster introduction timeline, as existing P150G4P production lines could be converted to the production of the new type. Yet Chikai's prototype was selected as the winner despite its greater mechanical complexity and longer timeline to introduction. The judgment ostensibly rested on the claim that the Chikai prototype would have greater mechanical commonality with JCh-8s elsewhere in Menghean combined-arms formations, and on its larger autoloader capacity and greater isolation of the crew. Yet rumors of bribery and favoritism swirled around the decision, and were confirmed in the late 2020s when opposition media gained access to classified records via a freedom of information request.

Design

Layout

The P150G5P self-propelled gun is built on a common utility chassis derived from the JCh-8 main battle tank. This means that it shares the powerplant, suspension, and tracks of the JCh-8, along with some other internal systems, allowing for more consolidated maintenance. The use of the JCh-8 chassis also dictates the unusual layout of the P150G5P, with the crew in the front of the hull, the turret and turret basket in the center, and the engine compartment in the rear.

The crew consists of a driver, a commander, and a gunner, all of whom sit in the front cab of the hull. This cab is separated from the rest of the hull by an armored bulkhead, which protects the crew against an ammunition cookoff and eliminates the need for CBRN filtration systems for the gun compartment. As on most other utility vehicles on the JCh-8 hull, the driver sits on the left side, the commander sits on the right, and the gunner sits in between, in a seat slightly offset to the rear. This arrangement allows for easy communication between the driver, the gunner, and the commander. The driver and commander are provided with periscopes, front vision hatches, and roof hatches, but the gunner must climb into another crew member's seat and out their hatch in order to exit the vehicle.

Armament

The vehicle's main armament is a 150mm L/56 howitzer, developed specifically for the Ministry of National Defense's P150G5P design requirement but originally tested on a P150G4P hull. Measuring a full 9.69 meters long when including the trunnion and the pepperpot muzzle brake, this weapon gives the P150G5P its unique long-nosed appearance and contributes to its impressive range. It can achieve a maximum range of 29 kilometers with a standard 150mm artillery round, 40 kilometers with a base bleed round, and 72 kilometers with a rocket-assisted guided projectile.

The turret bustle of the P150G5P contains 56 rounds of 150mm ammunition and a corresponding number of charges. The shells and charges are held in two separate belt assemblies, with the shells stacked two deep and the charges stacked ten deep. When a given round type is selected, the upper belt rotates to align the next round of that type with the basket assembly and ram it forward, and the lower belt rotates to ram forward the appropriate number of modular charges. The basket assembly then pivots down to align with the breech of the elevated gun, at which point an attached chain device rams the projectile, followed by the charges, into the breech.

The entire loading process takes 7-8 seconds, depending on the elevation of the gun, if the next round is indexed properly. This allows the P150G5P to sustain a rate of fire of 8 rounds per minute until the barrel overheats, usually 2-3 minutes according to training documents. Though the Songsu-po also has a maximum rate of fire of 8 rounds per minute on paper, it can only sustain this rate for three rounds, while advertising brochures for the Dŭngsu-po claim that it can sustain its peak rate of fire for 20 rounds. The crew of a Dŭngsu-po SPG would exploit this rate of fire in shoot-and-scoot missions, firing a concentrated barrage from a prepared location and then letting the barrel cool while the vehicle moves to a new position.

Because the ammunition handling system is entirely automated, there is no need for separate crew members serving as loaders. The turret is, however, accessible through two large hatches, one on either side. These allow crew members and other personnel to enter the turret to perform maintenance checks, clear faulty ammunition, and conduct basic repairs. In the event that the autoloader is not functional, it is possible for two personnel from the battery's ammunition transport unit to enter the turret, raise the loading basket out of the way of the breech, manually load shells and charges into the breech, and manually control the gun's elevation and the turret's traverse, though the gunner would still have to pass training and elevation commands from the crew compartment. This manual-firing configuration has been tested in field trials, and was apparently intended as insurance against the autoloader's uncertain reliability, but there are only a few recorded instances in which it was used during the Second Pan-Septentrion War, in all three cases because a unit of Dŭngsu-po artillerypieces was attacked while in depot.

Two gutter-like loading trays on the rear of the turret allow personnel to feed more shells and charges into the turret bustle. The gunner can lower these automatically using controls in the front cab, or other personnel can climb onto the engine deck and fold them down manually. The left tray has a chain rammer which pushes projectiles up to a small folding section, which tips down and feeds them into an empty space in the autoloader assembly. The right tray does the same for ammunition charges. Both trays are offset sufficiently far back that the turret can traverse through 360 degrees with both trays extended. Normally, an ammunition transport lorry attached to the artillery battery will park behind the P150G5P and dismount its crew, with one loader at the base of each loading tray and two more carrying rounds and charges back and forth between the two vehicles. Unlike the P150G4 system, there is, as of 2022, no armored resupply vehicle for the P150G5P.

Defensive armament consists of a single 12.7mm GCh-75Ch heavy machine gun in a remote weapon station on the roof of the turret. This weapon is operated remotely by the vehicle commander and feeds from a 200-round ammunition box. It can be used to fend off infantry, light vehicles, helicopters, and low-flying unmanned aerial vehicles. In addition, the turret has direct-fire visual and infrared sights which allow the gunner to engage heavier targets with the 150mm gun. A 150mm high-explosive anti-tank shell exists for self-defense work, and as of 2020, work was reportedly underway on a high-velocity 150mm APFSDS round, though there are no confirmed reports that this round was employed during the Second Pan-Septentrion War.

Production

The first operational P150G5P vehicles were delivered to front-line units in 2019. Their production required the construction of a new assembly hall at the Chikai Heavy Machine Building Plant in Jinjŏng, Menghe, though this construction project was expedited by the simultaneous construction of Assembly Hall 4, which allowed some combination of construction resources. During this time, the Northwestern Armored Vehicle Plant in Ryŏju continued manufacturing the P150G4P, only partially slowing production after Hall 5 of the Chikai Heavy Machine Building Plant came online. To critics of the P150G5P program, this confirmed two prior suspicions: first, that Chikai had oversold its ability to reach the required production numbers at an acceptable cost, and second, that the Menghean MoND regarded the P150G4P as adequate up to the early 2020s.

See also

• O9 Komainu