KJJ-108 Typhoon

The Signus Systems KJJ-108 Typhoon (Zhenian: KJJ-108 태풍), commonly the KJJ-108 Typhoon Armored Fighting Vehicle (AFV), is a line of tracked developed in Zhenia. Developed for service in the Republic of Zhenia Defense Forces and as a replacement for existing tracked armored vehicles in service, it was developed into numerous variants, although the infantry fighting vehicle and armored personnel carrier variants are the most notable; the former was developed with the intent to defeat other infantry fighting vehicles and some tanks in mind, while the armored personnel carrier variant focused on personnel protection, survivability and networking more than its predecessors. As an infantry fighting vehicle, it is capable of transporting eight fully-armed infantrymen into battle, while the vehicle itself is normally operated by three crew members.

Development
Work on the KJJ-108 Typhoon initiated around the late 1990s, when the existing KJJ-80 Cyclone, although it had superb amphibious capability and was geared towards rapid, expeditionary warfare, was starting to become outdated. There were concerns regarding the survivability of the Z11, amid the development of infantry fighting vehicles and anti-vehicle weapons around the world; soon, it became clear that the KJJ-80 Cyclone, although a well-built platform aimed for fast-paced warfare often involving weapons of mass destruction, was not suitable and survivable in the battlefield of the 21st century.

With such circumstances in mind, proposals for what would eventually become the KJJ-108 Typhoon mainly focused on increasing survivability, even at the expense of amphibious capability; while the KJJ-80 Cyclone had for amphibious operations and had restricted its weight to under 25 tons, such design restrictions were removed when working on the new vehicle. While logistical restrictions - including its capability of being transported aboard the C-21 Cheonma - remained, selected proposals included a further emphasis on armor and survivability than overall mobility, allowing for the development of a platform that could serve a variety of tasks including, , and  roles.

The initial prototype vehicle, dubbed the Z21, was released in October 2006, its power pack issues, as well as the integration of into the logistics network, delayed its introduction into service to December 6, 2008, when it was finally given its designation code KJJ-108. Prior to its introduction to service, however, the vehicle underwent an array of testing in extreme conditions, including both cold and hot weather testing.

Layout
The KJJ-108 Typhoon, although following a similar general layout with existing infantry fighting vehicles, incorporates cutting-edge technologies developed after the KJJ-80, with a higher emphasis on modularity and survivability, evident with the existence of modular armor and the compartmentalization of the cabin with additional composite armor to ensure survivability. The vehicle is normally operated by three crew members - commander, gunner and driver - with the commander and gunner in the turret, while the driver is located on the frontal left side of the hull, just left of the power pack. Although the roles of three crew members is clearly distinguished, the commander can at times override controls over the turret (and in later variants, the vehicle itself) in emergency situations, theoretically allowing for the vehicle to be operated by only one or two crew member at times. More recent variants have even introduced unmanned turrets, effectively ensconcing all crew members within the well-protected hull, at the expense of its passenger capacity.

The basic chassis of the KJJ-108 line is designed with modularity in mind, allowing for one variant can be readily modified into another in a relatively short amount of time. The 3+8 crew capability allows for adequate space for other auxiliary equipment, such as command & communications consoles, 120 mm mortar systems, and the like. In its infantry fighting vehicle configuration, it is air transportable via tactical airlifters within service of the ROZDF.

Armament
Although a variety of armament options are available for other variants, the infantry fighting vehicle variant of the KJJ-108 Typhoon is equipped with a two-person turret, armed with a 40 mm capable of firing an array of rounds, including, high-explosive, smoke, multipurpose and air-burst rounds. With the main gun directly connected to the vehicle's fire control system and gun stabilizer, the vehicle is capable of engaging moving targets while the vehicle itself is on the move with a great degree of accuracy. Later upgrades have allowed for the gun to fire  (CTA) rounds, adding to the vehicle's adaptability to various combat situations.

The multipurpose munition, in particular, can be configured on site via the onboard fire control system into a variety of modes depending on the situation, including armor-piercing, fragmentation, air burst and proximity. Each round contains a programmable fuse system that receives on-site information from the fire control system, allowing for a greater diversity of targets it is capable of engaging.

In addition to the 40 mm gun, the turret is equipped with the Eagle's Nest 12.7 mm and a 7.62 mm coaxial machine gun as its secondary armament: unlike its predecessors and other vehicles, it was equipped with the 12.7 mm RWS since its introduction to service, minimizing the need for the vehicle-operating crew to exit the vehicle. A separate compartment towards the rear of the turret contains a total of four launchers, augmenting its anti-tank capabilities.

Protection
The basic armor of the KJJ-108 provides all-round protection against 14.5 mm AP rounds, while armor protection over the frontal arc is said to be capable of protecting the vehicle against 30 mm APFSDS munitions (30 x 165 mm). The top of the vehicle is capable of withstanding 155 mm artillery shells exploding as close as 8 meters. While the exact composition of the KJJ-108's is yet classified, it is said to consist of fiberglass and ceramic sandwiched between layers of reinforced steel, minimizing excessive weight normally resulting from heavy armor. Additional armor on the sides is also normally applied in most variants to counter tandem warheads and anti-tank guided missiles, while the crew compartment is additionally lined with a Spall liner to increase crew survivability against anti-personnel munitions and shrapnel. can also be optionally applied to parts of the vehicle for protection against.

The KJJ-108 is equipped with a (CBRN) filtration system, including a positive pressurization system and an airtight hull, to ensure survivability in such conditions, while it also employs features to reduce its heat and infrared signatures, thus countering counter thermal imaging and infrared cameras. The V-hull shape of the chassis allows for higher survivability against mines and improvised explosive devices (IED) as well. Even when the vehicle is hit, the vehicle's soft-sealing fuel tank can, to an extent, absorb the impact of a penetrating projectile.

The vehicle relies on an array of soft- and hard-kill defense systems to bolster its survivability. The vehicle's combat system, using millimeter-band radar systems and 360-degree threat monitoring systems providing real-time coverage around the vehicle, warning the crew of any incoming threat and immediately engaging with smoke grenades to blind the enemy from optical, thermal and infrared signatures. Like most Zhenian modern combat vehicles, it is also equipped with the Cheongan Active Protection System, which constitutes the hard-kill component of the vehicle's defense system. Similar to the same system found on the KZJ-96 Chungmu, it works in tandem with the vehicle's onboard combat system to detect and acquire incoming threats and fire interceptor grenades to intercept the incoming missile directly.

Mobility
All variants of the KJJ-108 Typhoon is powered by a single EDE-09X diesel-electric engine, an improved lighter derivative of the EDE-100X diesel-electric engine on the KZJ-96 Chungmu. Delivering up to 900 hp, the engine is equipped with a turbocharger, allowing a maximum speed of around 70 km/h and a range of around 700 kilometers with internal fuel. The vehicle's transmission system works in tandem with the torsion bar suspension system to reduce its noise signatures in certain speeds, ultimately increasing its survivability in contested environments. Its ground clearance has also been raised compared to its predecessors, allowing for higher mobility against rough terrain and increasing survivability against (IED) and land mines. Due to increased weight, it cannot travel into water that is deeper than the chassis without external assistance, unlike its predecessors.

The suspension system on the KJJ-108 Typhoon is automated by the vehicle's onboard operation system (TOOS), which analyzes the vehicle's impetus and nearby terrain to adjust the chassis and keep the vehicle stable. A semi-active in-arm suspension unit, similar to those used in later variants of the KZJ-96 Chungmu, have been implemented into the torsion bar system of the KJJ-108 chassis, allowing for more detailed control over the chassis: however, unlike the KZJ-96, it cannot control its posture to such degree of diversity as the KZJ-96.

Although not yet introduced to service, Signus Systems plans to implement a or even an all-electric power train in the mid-2020s to further reduce noise signatures and increase energy efficiency considerably. While the hybrid-electric version would sport a battery pack and a modified version of the EDE-09X, the EDE-09X-H, an all-electric version would entirely replace the vehicle's fuel tank with a modular, replaceable battery system and the diesel-electric engine with a series of electric motors linked to the suspension system. Although there have been concerns over logistics and cost regarding such upgrades, there have been claims that they are already being experimented in ROZDF facilities in Heuksu Province.

Operators
Republic of Zhenia Defense Forces
 * Republic of Zhenia Army
 * Republic of Zhenia Marine Corps