Reports emanating from Ukraine demonstrate the effectiveness of current 30mm canon systems against Russian APCs and the BMP-4 in particular. This puts a big question mark over the threat analysis conducted in the 1990s which saw a need for 40mm and the CT-40 canon in particular, to defeat the BMP-4. Has the decision by the US to go for 50mm in 2020 also been found wanting?
The Argument for 40mm
So how does CTA technology allow the CT40 cannon to perform above its competition? Due to the nature of telescoped ammunition, CTA ammunition has 30 percent more performance for the same volume of ammunition. This can be seen in a comparison of the size of the rounds: forty-millimeter CT ammunition is only the size of conventional thirty-millimeter ammunition while delivering performance on par with conventional forty-millimeter rounds. Talking in numbers, the forty-millimeter CT Armor Piercing round can pierce 150 millimetres of armor at 1.5 kilometers. This is sufficient performance to defeat any current BMP-series IFV and their upgrades. This is superior to the hundred-millimeter-plus RHA at one kilometer offered by the 30×173-millimeter rounds used by the latest versions of the U.S. Army’s thirty-millimeter Stryker. The airburst capability of the forty-millimeter CT rounds is also superior, more than doubling the affected area versus thirty-millimeter rounds. All of this comes in a package that is around the same size and bulk as the thirty-millimeter cannons.
The CT40 cannon can also hold more rounds in the ready position, around a hundred ready rounds compared to the twenty-four to twenty-five ready rounds that are possible with the Swedish forty-millimeter L/70 cannon on the CV9040, as reported by Jane’s. This is due to a novel rotating breech that is deployed on the CT40 cannon, as well as a linkless ammunition-feeding mechanism, made possible by the geometry of the CTA rounds.
The lack of take-up of 40mm as the calibre of choice was underlined in December 2021 when the US Army rejected a 40mm solution and went for the Northrop Grumman XM813 Bushmaster Chain Guns® .
Northrop Grumman XM813 Bushmaster 30/40
Northrop Grumman offered the UK an upgrade to the Bushmaster 30, the Super Forty which used the same systems as the 30mm upgraded to support a 40mm round. The UK MoD never considered this and decided to go sole source to CT-40 even though the Bushmaster Super Forty offered commonality to the 30mm, thus reducing costs and the logistics footprint.
The 30mm/40mm XM813 Bushmaster® Chain Gun® automatic cannon is a next generation weapon available, battle-proven and in use today. It continues the Bushmaster® tradition of excellence with its design simplicity, external power, positive round control, ease of maintenance, and constant velocity ammunition feed. The XM813 is also capable of firing the new programmable air burst munitions. What’s more, it incorporates all of the battle-proven features of the 25mm M242 Bushmaster® Cannon®, with significant system commonality for low-risk, proven performance.
Northrop Grumman Corporation (NYSE: NOC) was awarded a contract in 2020 from the U.S. Army for XM813 Bushmaster Chain Guns® as part of the Stryker Medium Caliber Weapon System 30mm Lethality Upgrade program. The base contract and first delivery order calls for 95 chain guns with initial deliveries beginning in early 2022.
The XM913 is an experimental American chain gun produced at Picatinny Arsenal. The cannon is a larger and more modern version of the 25 mm Bushmaster cannon. Although its shells, 50 x 228 mm, are twice the diameter of the 25mm M242 Bushmaster, the 50mm cannons is not much longer than the smaller weapon. The overall lengths of the 25mm cannon and 50mm cannon are 105.2 inches (267 cm) and 117.7 inches (299 cm), respectively; while the portion of the gun that intrudes into the turret are 30.0 inches (76 cm) and 40.1 inches (102 cm), respectively.
The XM813 is a 30x173mm caliber cannon and a derivative of the company’s Mk44 Bushmaster Chain Gun® integrated on air, land and naval platforms across the globe. The XM813 was initially fielded to meet the urgent operational need to ‘upgun’ the 2nd Cavalry Regiment’s Stryker fleet based in Germany to provide crews with increased capability to defend against emerging threats. The current contract will support enhancements to the XM813 and the integration of the chain guns into an additional U.S. Army Brigade Combat Team.
The XM813’s versatility allows for the incorporation of future advancements, including the ability to fire Northrop Grumman’s advanced ammunition types which will ultimately include proximity fuzed and guided munitions. Currently, the XM813 is capable of firing Northrop Grumman’s MK310 Programmable Air Bursting Munition (PABM) with air-burst, point-detonate and point-detonate with delay fuze settings to defeat a variety of targets. The chain gun production will occur at Northrop Grumman’s Mesa, Arizona facility.
Turrets and Turret Technology
There are now a plethora of turrets and turret technology on the market as was visible at Eurosatory this year. Technology enhancements and new displays are being offered by such companies as Curtiss-Wright, Moog, IEE, KME and Oxley.
Boxer APC With Rheinmetall LANCE 30mm two-man turret
The Boxer armoured transport vehicle is being produced under a bi-national programme. At Eurosatory 2014, Rheinmetall presented for the first time the Boxer IFV (Infantry Fighting Vehicle) variant, this equipped with the Rheinmetall LANCE 30mm two-man turret. Combining the Boxer inherent high level of protection and the unique mobility with the latest turret technology, the IFV variant presents state-of-the-art capabilities to face current requirements. The Boxer IFV variant, equipped with the LANCE turret system is completely in line with the modular Boxer philosophy as the LANCE turret itself features a new modular design. It thereby ensures maximum flexibility and an optimized capability for further upgrades for changing requirements. Also the protection of the turret is adaptable for a wide range of missions and to face different threats.
Cockerill® 3000 Series
Based on an unprecedented modular concept, the Cockerill® 3000 Series is a single platform enabling guns of different calibers and their corresponding technological modules to be integrated onto the same turret: automatic 25 mm, 30 mm, 30/40 mm, 35 mm and 50 mm caliber guns, along with direct fire guns of 90 and 105 mm, which are also able to fire anti-tank missiles.
Modularity and flexibility
Rapid interchangeability of crews and weapons, unique operational capacity, a very high level of common configuration… all of these qualities enable our modular Series 3000 Cockerill® turrets to cover all missions and objectives on the battlefield: from engaging fighting tanks, bunkers or helicopters, to intervening in combats known as asymmetrical, not forgetting urban conflicts. Modularity and common configuration are two unique characteristics which significantly optimize both total cost of ownership and the operational flexibility of our systems.
These systems in particular benefit from Agueris® solutions, unique to John Cockerill Defense simulation solutions. These enable precise and high quality training, both in virtual immersed cockpits and in on-board simulators.
These Cockerill® 3000 Series benefit in particular from the simulation solutions of John Cockerill Defense supplied under the Agueris® brand. These enable training and practice on both virtual immersive cockpits and embedded simulators.
KONGSBERG PROTECTOR RT60
PROTECTOR RT60 is designed for optimizing lethality and protection on fighting vehicles.
The PROTECTOR family includes three Remote Turret (RT) variants, the RT20, RT40 and RT60. The systems can be tailored to meet customer-specific requirements, – including key elements like protection level, sensor performance and whether operated by a single or multiple operators. Despite their differences all variants share great commonality in terms of system components and fire control architecture – the latter allowing all to be wirelessly operated when integrated on an unmanned vehicle.
Like all systems in the PROTECTOR family, the Remote Turrets benefit from KONGSBERG’s 20+ years’ experience as the world’s leading provider of remote weapon systems.
The RT60 is the Infantry Fighting Vehicle (IFV) variant in the PROTECTOR family. The system is designed for optimizing lethality and protection on fighting vehicles and can be fitted with elements like an ATMG launcher, Commanders Independent Weapon Station, Laser Warning System, Active Protection System etc. The RT60 shares great commonality with the technology in both the RT20 and RT40 variants.
The PROTECTOR Remote Turret
The PROTECTOR Remote Turret provides highly accurate firepower. It is remotely controlled and operated from a protected position inside the vehicle compartment, – enhancing crew safety. The turret can be accessed and reloaded from under armour and the linkless ammunition handling system provides superior reliability compared to link fed systems. The remote turret eliminates the need for a basket taking up space inside the vehicle, – facilitating more space to transport troops or mission essential equipment, and reduces weight for better mobility.
Fire Control Capabilities
The Remote Turrets include a combat proven fire control system based on fielded PROTECTOR weapon systems. The system automatically performs ballistic computations compensating for the lead angle, cant, tilt and vehicle motion, making targeting easier in the most challenging scenarios. The network-based fire control architecture enables wireless operation of the system – relevant for unmanned/robotic vehicles.
Through the KONGSBERG Integrated Combat Solution (ICS) the turret gains access to a number of enhanced lethality features like automated precision Hunter-Killer and target sharing between vehicles.
Rheinmetall’s family of medium calibre cannons
Rheinmetall Defence’s portfolio of medium-calibre automatic cannons is based on the products of two highly regarded companies: Oerlikon and Mauser. Rheinmetall continues to build on their legacy, developing and manufacturing automatic cannons featuring exceptional firepower, precision and reliability. Rheinmetall is proud to present its current family of medium-calibre cannons in the 20 mm to 35 mm calibre range.
Designed to retain their firepower, precision and reliability even under extreme environmental conditions, they have excellent mass-to-performance ratios, compact designs, long service lives and reduced recoil forces – to name just a few of the factors that make our cannons the ideal solution for ground, naval and air applications. They are designed with the user in mind. For example, service members can fieldstrip them without special tools, while the Group’s replacement part packages reflect our extensive in-service experience.
25 mm x 137 KBA
The KBA is used for ground-based air defence, naval surface combatant and armoured fighting vehicle applications. It features a high rate of fire and an instantaneous ammunition selection between two belts, and can fire the whole range of full and subcalibre 25 mm x 137 ammunition. With more than five thousand cannons delivered, the KBA is combat proven and is currently in service with numerous nations.
30 mm x 173 KCA
Combining high firepower and low weight, the KCA cannon is a gas-operated system with a linked feed system. It is qualified for installation in aircraft, and can also be used in ground-based air defence systems (e.g. with airburst ammunition)
30 mm x 173 MK30-2/ABM
The optimum combination of a high rate of fire and state-of-the-art ammunition technology makes the MK30-2/ABM an uncompromising, highly reliable weapon system. With a maximum effective range of 3,000 metres, the MK30-2/ABM is extremely effective against land, air and sea targets. The MK30-2/ABM is the main armament of the new German Puma infantry fighting vehicle.
30 mm x 173 / 35 mm x 228 WOTAN30 / WOTAN35
The WOTAN30 is an externally driven, medium-calibre automatic cannon with a rate of fire of 200 rds/min. Easy to handle and highly reliable, the WOTAN30 can neutralize a wide variety of targets, making it the perfect choice for arming modern IFVs and other combat vehicles. The WOTAN35 is the latest member of the new WOTAN family and, due to its larger calibre, delivers longer range and deeper penetration than 30 mm cannons
35 mm x 228 KDG
The KDG revolver cannon is a gas operated cannon with a linkless feed system. It combines a high firepower with precise accuracy. The cannon is completely remote-controlled, the integrated fibre-optical sensor system supports the fully digital control of the cannon. The KDG cannon is mainly used with the Rheinmetall AHEAD ammunition giving the user outstanding performance on a wide range of targets. It is fully qualified according to STANAG 4516 and has redundant safety circuits. The maintenance of the cannon is simple and the KDG has undergone extensive qualifications and complete life cycle firing tests.
Evotex turrets emerge from the shadows.
Although having supplied numerous South African defence companies with design and manufacturing solutions in the weapons systems area for many years, Pretoria-based Evotex is a first-time exhibitor at the Africa Aerospace and Defence (AAD) 2022 exhibition this week.
On display at Air Force Base (AFB) Waterkloof is the company’s flagship Thebe (‘Spear’) dual-axis gyro-stabilised remote controlled weapon station. According to Gert Rossouw, chief executive, Thebe can be fired from land vehicles or patrol boats on static or mobile platforms.
The compact turret weighs 175 kg, which makes well suited for even a fairly light vehicle or boat platform. It traverses through 360°, with elevation from -20° to +55°.
Grenade launcher solution.
Also on display is the Vikela, a 40 mm multi-barrel grenade launcher system designated RMB-40. Like the Thebe system, it is a dual-axis remote control weapon. The Vikela system at AAD 2022 is the six-shot variant, with Evotex also offering it in a three-shot variant. The RMB-40 can fire low, medium and high velocity rounds, as well as less lethal grenades and is designed to fire single shots or bursts.
Grenades are chambered into the barrel and can be reloaded in seconds.
Evotex offers an optical payload and sensor pack for its weapon systems configured to client requirements. In the case of the RMB-40, the optical pack operates independently from the turret due to the higher launch angle required for grenades. While the Vikela system can be fired from land vehicles and patrol boats, it is also suitable for mounting on a drone. (Source: https://www.defenceweb.co.za/)
Anecdotally, the cost of the new 40mm ammunition is said to be ‘eye watering’, reliability and supportability have also yet to be determined in service.
Why has the UK and France persisted with this approach when there are many more conventional options like Super 40, for example?
Quite simply, it is one of space, although additional armour piercing performance is always a good thing. Modern vehicles need modern electronics, and contrary to popular belief, modern electronics, at least in combat vehicles, are not getting any smaller. Modern vehicles also need modern people, and modern people are larger and wear combat body armour, we also can no longer insist armoured vehicle crew are small in stature. All this places a premium on internal turret volume, so anything that reduces the volume of one of the main turret components simply means more room for ammunition, electronics and ergonomics i.e., a good thing.
The other issue facing potential CT-40 customers is the concern of re-supply on the battlefield. One only has to remember that poignant piece in ‘Patton’ where he tours the battlefield after his tanks have been wiped out after they ran out of fuel and ammunition. Logistic re-supply issues were in the forefront of planners minds in Afghanistan and Iraq. If the collation forces could have a limited range of calibres and makes, then resupply became an easier and thus quicker task.
This feature outlines many more advanced and better value turret systems and canons which have ammunition commonality on the battlefield that allows good resupply procedures but also a commonality of technologies and displays.
In conclusion, CT-40 does not offer the overmatch capability claimed by CTAI when compared with new and advanced 30mm rounds on the market or new 50mm ammunition under development in the USA.
In addition, the cost of buying and crucially supporting a CT-40 is prohibitive given that there is a limited number of users where increments and updates can be easily accommodated and paid for. The lack of uptake for CT-40 and 40mm ammunition is a clear indication that 40mm is a calibre which does not suit the requirements of today’s armies.
Clearly the Ukraine conflict has shown that 30mm is suitable for deployment on the 21st Century battlefield to defeat current threats. The way ahead should be developing advanced 30mm rounds giving better accuracy and penetration for lightweight APCs and vehicles, leaving the 50mm and upward category to the heavier class of vehicles.
Understanding the Complexity of Turret Systems
By Christian Kopp, Curtiss-Wright Defense Solutions
From the outside, the turret system on a ground vehicle may appear a straightforward mechanism: The turret resides on the top of the vehicle, and rotates as needed, while raising and lowering the gun barrel when required. Hidden from view, though, is a highly precise and complex system that integrates several key mechanical and computational subsystems that are either supplied by the platform’s manufacturer or from a number of different, highly specialized vendors. What drives the rotational movement of the turret is the turret aiming and stabilization drive system (for an example, see Curtiss-Wright’s Turret Drive Stabilization System [TDSS]). Other key elements of a turret system include the sighting system and the fire control system. All of these subsystems must be integrated together so that the information from the sighting system, which locates the target of interest, can be used to accurately position the turret via the stabilization drive system, thus enabling the firing system to engage the target. All of these functions must occur as close to real-time as possible, with great precision, often while the vehicle is moving at full speed over rugged terrain.
The complexity of the turret system makes the quality of the engineering behind the gun turret drive stabilization system essential since it must have the capability to precisely position the heavy armored turret and keep the ground vehicle’s weapon precisely aligned on the target while under conditions of great shock and vibration, all while the platform travels at high speed. Because the subsystem components are often provided by a variety of different suppliers, the linkage, or interfaces, between these critical components are very important for the optimal, efficient performance of the overall turret system. During the vehicle design stage, how these subsystems communicate and interact must be defined in the interface documents. For example, these documents will define the interfaces for the turret aiming and stabilization drive system’s mechanical and electrical components, while also defining where the boxes that house these functions will be located within the turret’s limited interior space. The system’s electrical interfaces, such as the bus systems and latencies, must be clearly defined down to the lowest level.
Adding to these design issues is the constant drive from system designers to provide smaller and lighter solutions so that new capabilities can be introduced into an already space-limited platform. At the same time, these solutions must be extremely rugged and robust. To say the least, these sets of goals are often at odds with each other. These issues are only exacerbated when the turret drive stabilization system is a bespoke solution. The use of modular open systems approach (MOSA) designs reduces both the complexity and costs of these solutions.
Complex, precise systems such as those used in a turret drive system require robust control loop systems. One major challenge facing turret system designers is to ensure the signal quality of the various subsystems, especially when the subsystems are sourced from multiple vendors. For example, if one of the subsystems creates signal noises on an electrical bus, the improper signal values can interfere with the control loops of another subsystem. These problems are typically discovered during the confirmation process of a new ground vehicle. In theory it is possible that low quality signals from any subsystem can or will be amplified by the control loops, and the turret drive system motors will translate this noise into unwanted movement.
It’s critical to ensure that no subsystem negatively affects the performance of another. While project documentation will specify electrical signal range, it doesn’t typically specify signal quality. There is an inherent assumption that the signal quality from one vendor will be appropriate and not interfere with another subsystem. That means that integration problems of this type aren’t typically discovered until the platform is tested in a system integration laboratory. Subsystem suppliers need to be forthcoming in characterizing and providing accurate information about their own solution’s electrical characteristics to the platform manufacturer and other contributing vendors. This will ensure that all suppliers are informed what types of noise, if any, will be introduced into the platform and the system.
Another important step for turret system programs is for the platform manufacturer to involve all subsystem suppliers in the design process at the very beginning of the project. Subsystem suppliers should also be involved during the first joint test of a new turret. Simulation and testing should also take place at the earliest possible stages of design and development. Unfortunately, simulation remains a theoretical mode and requires a perfect model of each component in order to produce accurate identification of the source of any unwanted signal noise.
Another critical phase of turret design takes place when the turret is “married” to the vehicle, enabling the first real-world tests of the platform to commence. It’s at this point that additional complexities will come into play as numerous unique characteristics of the vehicle emerge, such as those related to its behavior while moving, or the vehicle’s unique vibration performance, which differs greatly on wheeled and tracked vehicles. The functional safety of the system is another area of complexity and must be guaranteed in accordance with standards such as DIN EN 61508, for example.
Finally, the commissioning process remains the most important step, as it is during this stage when all the subsystems are actually working together, so faults can be discovered and troubleshooting can take place to isolate any system or subsystems causing a problem. For example, it is at this phase that Curtiss-Wright’s embedded TDSS software suite is fine-tuned and configured to the overall system via parameter settings. Because of its importance, the commissioning process should happen as early as possible.
So, the next time you see a turret, it’s worth thinking “beneath the armor” to consider the amount of precision engineering and complexity involved in moving, controlling and firing the weapon. What looks simple on the outside requires close cooperation between the platform integrator and multiple suppliers, each needing to share accurate information and working together to ensure that the whole solution is greater than the sum of the subsystems. Our warfighters depend on it.