Mortars

A CV90 equipped with the Mjölner mortar system to provide indirect fire at a battalion level. (Photo: BAE Systems Hägglunds)

Room for improvement?

Mortars offer clear advantages to the modern warfighter with their flexibility and low maintenance costs. Can these venerable weapon systems be significantly developed any further though?

Flavia Camargos Pereira

Mortars were first used in conflicts in the 15th century. Since then, they have played a relevant role in many battles, including in both World Wars. Although they have a long history, these systems are still a necessary capability for modern armies.

Mortars can be used in different types of missions, including fire support of infantry, mechanised units and SF, attrition of disembarked infantry, border patrol and convoy protection as well as mountain and COIN operations. They can also neutralise light armoured vehicles, buildings and structures and hostile emplacements as well as provide illumination or obscuration of the battlefield.

Game changer

John Spencer, chair of urban warfare studies at the Modern War Institute at West Point, explained that the basic ability to launch an explosive over a wall, building, hill or other obstacle remains important for armed forces. ‘It really changes the game. You can catch someone that is in an unprotected position, which it is really important to do until today,’ he claimed.

Speaking off the record, a defence analyst from Brazil pointed out that the main advantage of mortars is their flexibility. He explained that they are extremely simple and robust weapons. ‘It is very difficult to identify the firing positions of mortars. In addition, because they are lightweight, they can change positions very easily,’ he highlighted.

He further added that they are much cheaper than other weapons and, due to the fact that managing these systems does not require much technical knowledge, they need only a minimum of training.

 

🜂 British soldiers train with the 81mm mortar system. (Photo: UK MoD)

 

Spencer, meanwhile, stressed that over the past 20-30 years there have been many upgrades in these systems that have enhanced their range and made mortars lighter, more mobile and more accurate. ‘Because of this evolution, the person who is firing the weapon can be behind protection, miles away, and hitting the enemy with precision,’ he noted.

Spencer added that the use of GPS is among the major improvements made to the accuracy of mortars. In his opinion, it demands fewer rounds to adjust the system and hit the target.

Technical feats

The defence industry has been working on using new components and materials and adding new technologies into mortar systems. Spanish company EXPAL, for instance, has developed a new mortar bomb cartridge to reduce blast pressures inside the barrel and increase range.

A spokesperson for the company explained that, in order to improve accuracy, the traditional sight unit was replaced by EXPAL’s eCOMPAX, which has GPS, north finding and topographic location.

In addition, ruggedisation of the bipod and base plate was enhanced to ensure stability during firing. The manufacturer also added into the ground mortars fire control and C2 systems that allow corrections for meteorological conditions, propellant temperature and the bomb’s muzzle velocity.

‘We constantly rethink and optimise our mortar systems, offering to fulfil the requirements of the current battlefield in indirect fire support missions. These continuous improvements are focused on increasing accuracy, interoperability, reliability and manoeuvrability,’ the spokesperson said.

French company Thales is developing new types of munitions, adapted to evolving threats, for its 120mm rifled mortar systems. These include laser and global navigation satellite system (GNSS)-guided rounds with longer range (up to 17km). These have metric precision and enable closer fire support and reduce collateral damage.

Also, the company is working on insensitive munitions that offer more safety for the crew on the battlefield, optimise ballistics and ensure accuracy.

 

🜂 EXPAL has enhanced the ruggedisation of the bipod and base plate of its ground mortars to increase stability. (Photo: EXPAL)

 

‘Thales’ rifled mortars are also compatible with smooth ammunition used by some countries in order to enable interoperability with nations that are not using Thales’ rifled mortar ammunition,’ the company’s spokesperson noted.

Austria-based Hirtenberger Defence Systems has created an asymmetrical bipod that carries shock absorber, barrel clamp and elevating, traverse and cross levelling gear. The base plate is drop-forged and made of a high-strength aluminium alloy with reinforcing ribs. Its design combines low weight with high stability, allowing to withstand impact stresses.

These new capabilities are drawing the attention of armies from different parts of the world. Some countries are increasing efforts to acquire or develop new systems and technologies. For example, the FY2020 budget of the Japan Ground Self-Defense Force included funding for 60mm and 120mm mortars.

Also, in April this year, the Swiss Federal Department of Defence, Civil Protection and Sport reported that the Federal Office for Defence Procurement had completed testing of the 120mm Mortar 16.

The British Army, meanwhile, released in June initial procurement documentation to purchase instrumentation systems to integrate its 81mm L16 mortars into its Tactical Engagement Simulation System training environment, and in July, the Brazilian Army announced the delivery of the first units of an 81mm system. These mortars were developed by the service itself and manufactured at Rio de Janeiro Military Arsenal.

Mobile mortars

In Spencer’s opinion, attaching a mortar to a vehicle is among the main improvements introduced into these systems. He claimed that it enhances the readiness of armies: ‘A mortar vehicle or a mortar carrier uses the vehicles as space plate, which brings stability to fire. It also improves the mobility of these systems.’

In terms of precision, he stressed that onboard mortars can use vehicles’ systems to support aiming. ‘We have computers integrated with the vehicle that takes some of the human errors out of the mortar systems,’ Spencer pointed out.

EXPAL’s onboard mortars have integrated fire control, aiming control and C2 systems. They are also equipped with precision mechanics, GNSS positioning and an integrated inertial navigation unit sensor. ‘It will automatically process own geographical, meteorological and ammo data while receiving information from observers, command posts and other units,’ the EXPAL spokesperson pointed out.

The company has also created a recoil absorption system that stabilises the mortar in the fire and transmits the remaining energy to the ground through the vehicle with additional stabilisers deployment needed. ‘Lightweight 4×4 tactical high-mobility platforms are more suitable for medium 81mm mortars, and medium or heavyweight 6×6 or higher platforms can withstand better 120mm heavy mortars,’ the spokesperson highlighted.

Due to the capacities of these systems, many countries are currently increasing their ground vehicle fleets with mortar variants. The French MoD confirmed that the MEPAC (Mounted Front-Line Support Mortar) vehicle is one of the army’s priorities. This will be equipped with the Thales 120mm Rifled Recoiled Mounted Mortar (2R2M).

A company spokesperson stressed that it is a highly mobile platform with shoot-and-scoot capability, automated functions and high levels of protection for the crew.

 

🜂 The Brazilian Army plans to add mortar capability to the Guarani vehicle. (Photo: Iveco Brazil)

 

Meanwhile, the Brazilian Army is developing alongside Iveco the Medium Mortar Armoured Combat Vehicle to equip its infantry and cavalry units. This platform will be a variant of the Guarani family and will operate a 120mm system. The service released its operational requirements in 2019 and stated that the vehicle should provide an automatic elevation and positioning system.

The Swedish Defence Materiel Administration will receive 40 CV90 twin 120mm Mjölner vehicles from BAE Systems Hägglunds this year. These will fire 120mm high-explosive, smoke, illuminating conventional mortar bombs and m/94 STRIX guided projectiles. Interior features of this variant include an inertial navigation unit, communications equipment and, eventually, a battle management system and new radio.

A spokesperson for BAE Systems Hägglunds claimed that the Mjölner mortar system is designed for indirect fire support on a battalion level and executes its firing orders fast and efficiently with high precision. It is also well fitted to operate within its firing range of 500m out to 9km.

‘The obvious advantage is that the Mjölner system is confined to the turret, thereby it can be fitted to a wide range of vehicles,’ the spokesperson noted. He also pointed out that this system is easy to use and provides robustness and reliability. ‘This will really matter in situations where parts of your battalion rely on quick and accurate indirect fire support,’ they said.

Appealing prospects

Both ground and onboard mortar systems have the 120mm as the most requested calibre. EXPAL confirmed that the company has detected an increase in 120mm mortar orders. ‘We think the different land forces are always looking for the balance among range, effects and mobility. In the case of ground mortars, 120mm effects and range are bigger than lower calibres,’ the EXPAL spokesperson claimed.

For Thales, the use of 120mm systems is a general trend in the defence market due to the fact that modern armies seek mobile weapon systems with longer range, higher efficiency and accuracy.

According to the BAE Systems spokesperson, one of the advantages of the calibre is the vast range of NATO-qualified ammunition that is available on the market: ‘The 120mm mortars are widely used and have a great effect downrange.’

Spencer believes the popularity of this calibre comes from its lethal power in parallel with its mobility. ‘The 120 is a very attractive capability to get to your infantry in warfare because it is going to move around very fast. Also, it provides a big pain, and militaries always want to increase their lethality,’ he pointed out.

The Brazilian analyst agreed that its greater destructive capacity is a reason to procure the 120mm system. He added that countries seek to ready for any type of conflict, including for the traditional battlefield, in which the mortar is a necessary capability. ‘The Western armies’ concern about the growing possibility of a conventional war (tensions with China and Russia) may justify this interest in the 120mm,’ he emphasised.

Things to come

Although these systems have evolved significantly over the past few decades, there is still room for improvement, which is why industry continues to work on new solutions.

The EXPAL spokesperson explained that the company’s R&D lines will focus on reducing weight and increasing range through more resistant barrels and more powerful propellants.

In order to improve accuracy, EXPAL intends to work on better sensors and control systems to shoot on mobile targets as well as to enhance the ammunition effects (such as providing better fragmentation) and to upgrade smoke covers. Additionally, the OEM seeks to improve the safety of the ammunition and weapons of the ground and onboard mortar systems.

 

🜂 Thales is developing new types of munitions for its 120mm mortar system. (Photo: Thales)

 

Concerning ammunition, the spokesperson explained that EXPAL will work on insensitive explosives, safer fuzes for better handling, a warhead disable-after-shoot mechanism and protective measures against sabotage or mishandling.

Regarding the weapons, the focus will be on ‘safety sensors to avoid collisions with crew or entrapment and to increase remote control on mortar systems to get the crew out of the battlefield’, the spokesperson noted. In terms of onboard mortar systems, the company wants to have better recoil absorption subsystems and install heavy mortars on lighter vehicles.

They also pointed out that EXPAL intends to add more digitalisation into these systems and better integrate fire control and C2, speeding up orders and battlefield information.

Thales plans to focus on the modernisation and automatisation of towed mortars for the needs of expeditionary airborne operations. Additionally, the company seeks to work on the generalisation of mobile mounted mortars, attaching them on different platforms (heavy, medium and light), including 4×4 vehicles.

The company believes that mortars can also be improved in terms of mobility, protection, range, firepower, reactivity and anti-battery protection.

The Thales spokesperson claimed that future upgrades will enhance precision and add more technology into these systems. ‘They will continue evolving because it is really important to make them cheaper. If we improve the accuracy, we will need fewer mortars.’

The Brazilian analyst agreed that precision and the addition of new capacities into these systems will increase in the future. ‘The use of technology for command and control will bring greater speed and accuracy in indirect fire weapons,’ he pointed out.

He also claimed that there is room for improvement in mobility, and armies can be expected to use more mounted mortars in the future.