H15G1B32 Ho-u

The H15G1B32 Ho-u ("downpour") is a type of multiple rocket launcher developed in Menghe. It was intended to replace the H12G2B40 Ubak in divisional rocket artillery battalions. Compared with its precursor, it has additional ammunition types, a longer range, and a faster reloading process, as well as moderately better protection. The launcher has 32 tubes in two individually loaded blocks of 16, and fires 150mm rockets containing submunitions similar to those in Menghean 150mm artillery shells. Its longest-range ammunition type has a range of 60 kilometers, with most common-use rockets in the 45-55 kilometer range.

Development

In 2007, the Menghean Ministry of National Defense launched the New Divisional Rocket Artillery program, seeking candidates for a H12G2B40 Ubak replacement. The requirements included compatibility with Buŏng-i smart anti-tank submunitions, a palletized rocket transport system to speed up reloading, the ability to load a pallet of rockets from the ground without the help of a transloader or crane lorry, and an increase in range to 50 kilometers or more. Use of the Samsan S915 chassis was also recommended, though not required. The MoND did not request a specific rocket caliber, as it had done in the past; rather, it invited designers to submit systems with different calibers and different numbers of tubes, with the goal of adequately balancing range, cost, and the total warhead mass carried on a single launcher.

The competing systems ranged in caliber from 15cm to 30cm; the latter would have been heavier than the H23G1B18 Pokpo used by corps-level rocket artillery brigades. Samsan Defense submitted a 20cm model which could carry 120 Chŏl-u submunitions per rocket by arranging them as if in a 203mm shell; but with only eighteen rockets per launcher, this system carried fewer Buŏng-i submunitions than smaller-caliber competitors.

This assessment shifted the competition in favor of Buksŏng, which had submitted a fairly conservative system with a 15cm caliber. Buksŏng then considered a number of different rocket arrangements before settling on the simple pair of 4×4 grids in the final production version, which offered the greatest firepower attainable within the launcher's weight and space limits.

The initial prototype, designated HB-15/32, had an open-topped launcher resembling the type used on the H12G2B40. It satisfied the self-reloading requirement with the help of a knuckleboom crane behind the cab, which could lift rocket pallets off the ground and lower them onto the launcher. When not in use, the articulated crane folded into place facing sideways. The rest of the vehicle was borrowed from the H12G4B80 Ichung Ubak, also a Buksŏng product. The MoND declared this prototype the winner of the New Divisional Rocket Artillery competition in 2010.

Rather than rush the prototype into service immediately, Buksŏng made several further refinements to the design, most notably by adding an entirely new launcher and loading system. The impetus for this decision remains unclear; initial explanations speculated that the MoND was dissatisfied with the initial prototype, but later reports suggest that engineers at Buksŏng independently pursued a new design despite complaints from the MoND that the existing version was adequate. The final version of the system, with its distinctive armored launcher and rectangular hoists, entered service in 2013, three years after the prototype's approval. Curiously, it was given the system iteration designation "G1," indicating that the preceding crane-loaded prototype either was not officially put into production or that the production version was given the same designation.

Design

The H15G1B32 is based on the Samsan S917, a variant of the Samsan S915 with a double-length cab featuring an extra row of seats. As on the H12G4B80 Ichung Ubak, the cab is armored against small-arms fire and medium-range shrapnel, though it can be defeated by 12.7mm HMG fire, close-range armor-piercing 7.5×54mm rounds, and shrapnel from nearby high-caliber artillery impacts. The frame around the launcher is armored to a similar level of protection on the sides, preventing stray shrapnel or bullets from detonating or disabling rockets. The 12.7mm HMG on the cab is also carried forward from the H12G4B80, and allows the crew to defend against special forces, light vehicles, and helicopters.

The launcher contains two pallets of 16 rockets each. These pallets are sealed at the factory and remain sealed until they are fired, keeping the rockets protected from the elements and greatly prolonging their shelf life while reducing peacetime maintenance requirements.

In addition to reducing maintenance needs, the palletized loading system also speeds up reloading: rather than manually ramming individual rockets into the rear of the launcher, as the Ubak and Ichung Ubak systems required, the crew only have to lift a single pallet onto the launcher. For this purpose, the launcher has two rectangular frames overhanging the front. To reload, the launch vehicle pulls up alongside a pair of rocket pallets, extends its stabilizing hydraulic braces, traverses the launcher to overhang the pallets, extends the loading frames to their full length, lifts each pallet in front of the launcher, rotates it to properly align with the empty space, and retracts it into place. The full process of moving into position, removing an empty pallet, loading a new one, and driving off takes approximately ten minutes, and can be completed with two crew members in the cab and five outside on the ground. Importantly, because the launcher has its own crane and a larger crew, the transloader vehicle does not have to be present during the reloading process: instead, the rocket transport unit can drop off pallets in the open at a predetermined loading site, then leave the area to pick up new pallets from a higher-level logistics unit. Alternatively, the launch vehicle can also pick up rocket pallets directly from a rocket transport lorry.

Each pallet contains rockets of a single type, though a single launch vehicle can carry pallets of two different types. Because the various rockets in the H15 family have different warhead masses and propellant volumes, they differ in ballistic characteristics, and the launch vehicle must adjust its elevation between firing different rocket types. To speed up this process, the vehicle's launch computer allows the crew to calculate and store a second firing solution ahead of time, calling it up immediately after the first barrage is launched.

Collectively, these features give the H15G1B32 a great deal of mobility and versatility. The vehicle can transition from a road march to a fire-ready state in 2 minutes if firing calculations are performed beforehand, and it can transition from a fire-ready state to a road march in 1 minute. All preparation, aiming, and firing operations can be performed from within the cab, though three crew members must exit to supervise the reloading process. Fast relocation and reloading allow the Ho-u system to evade enemy counter-battery fire or react quickly to requests for fire support.