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Currently, ST Engineering Land Systems is finalising the development of the BRONCO 3 vehicle. For the end of a test campaign lasting several weeks, ST Engineering invited interested parties from Europe, America and Asia, as well as international specialised journalists, to Ivalo/Finland – 300 km north of the Arctic Circle – to present and demonstrate the performance of the vehicle under Arctic conditions.

The BRONCO 3 can cross rough terrain with low bearing capacity without preparation thanks to its particularly low ground pressure (0.3 bar) at 16 tonnes combat weight and its unusual articulated steering. The vehicle can transition from soft to swampy ground to water without external support. Propelled by tracks, the fully amphibious vehicle can swim at speeds of up to 5 km/h. On firm ground, the vehicle – powered by a Mercedes-MTU TD 106 diesel engine (Euro 3) – reaches a top speed of 65 km/h. The vehicles of the BRONCO family are steered by an articulated joint connecting the two bodies of the vehicle. The four tracks are all driven at different speeds during steering

Development in the BRONCO Family

The development of the BRONCO 3 was based on lessons learned in missions with its predecessors, including the BRONCO 2, which the British Army deployed to Afghanistan as WARTHOG. The central development goal was to reduce its empty weight by two tonnes while maintaining its protection level by optimising the structure and using lighter components. Buoyancy was not to be impaired by the payload of four tonnes. On land, it should be possible to increase the payload by two tonnes (combat weight 18 tonnes) in a system-compatible manner. A new stowage concept and not placing the seats above the tracks improved the ballistic protection against mines/IEDs while providing more space for the crew. The front body of the latest BRONCO version has an interior volume of 5.9 m³ and the rear body 7.9 m³, with an interior height of 1.25 m, which allows for more efficient crew operation. In the passenger transport version, the BRONCO 3 offers space for five (front) or eight (rear) soldiers; the rear seats are attached to the side wall and fitted with footrests to protect against blast.

The articulated coupling is the one of the basic features of BRONCO 3 (Photo: Heiming)

For protection against mines, the underbody of both vehicle bodies is a continuous, V-shaped armour steel plate. The rear car has a ground clearance of about 1 metre. The cabin walls are made of armoured steel to protect against ballistic threats. The basic protection is level 2a/2b according to STANAG 4569 and can be increased to level 3 (ballistic only) when required, at the expense of available payload. For self-protection, a remote-controlled weapon station can be integrated on the roof with a heavy (12.7mm calibre) machine gun about which ST Engineering has not given further specifications.

The running gear uses a Soucy Composite Rubber Track (CRT). Standard width is 0.6 m, but wider tracks of 0.65 m or 0.7 m can be mounted in order to maintain the low ground pressure when increasing the overall weight. The 0.65 m track has different track profiles to increase climbing ability, for example, in mountainous areas. Depending on the driving style and ground conditions, the tracks achieve a mileage in the order of 6,000 km, and changing them requires maintenance personnel and special equipment.

In order to be able to operate the electronic equipment required in modern warfare, for example, for observation, reconnaissance, command and control and communication, a generator supplies 550 A at 24 V; the vehicle concept envisages the integration of an additional power generator (Auxiliary Power Unit, APU). Power and data are distributed via an open electrical architecture that is compatible with the Generic Vehicle Architecture (GVA). The standard BRONCO 3 is equipped with a front and rear camera system that supports the driver in driving the vehicle and provides the entire crew with information on the situation in the immediate vicinity of the vehicle.

The BRONCO 3’s modular design provides a high level of flexibility,
facilitating quick and easy mission module switching. (Graphics: ST Engineering)

A special feature of the rear body is the consistent division into chassis and mission structure; this allows the rear body to be equipped for other missions in a short time via quick connectors. Next to the standard cabin for passenger transport, which features mounting rails to rapidly change devices depending on the mission, ST Engineering also offers an open box and a flatbed for logistics transport. ST Engineering has developed numerous other variants with special equipment for reconnaissance, combat (with increased protection, a weapon station and extended range), indirect fire, medical evacuation and treatment, as well as recovery and repair.

The BRONCO DAWN is a highly mobile mortar system; the front body features a radar for reconnaissance, target tracking and identification friend-or-foe (IFF), a shot detector, a remote-controlled 12.7mm weapon station and the rear body an automatic 120mm mortar. The system can detect slow-flying objects with a low radar cross-section, such as unmanned aerial systems, gliders and helicopters and engage them with the weapon station.

The Arctic tests in Ivalo are at the end of the company’s trials; final tests in hot weather will follow. From ST Engineering’s point of view, the BRONCO 3 is ready for series production. Production can start at short notice, with a rate of eight vehicles per month. If required, the rate can be doubled in two-shift operation.

The Next Step

The next development step has been initiated and has reached the prototype stage; ST Engineering has introduced a patented diesel-electric hybrid drive for autonomous operation of the rear body.

The rear body is fitted with batteries in the chassis and an engine/generator (MoGen), which is driven through the articulated joint in (coupled) normal operation and charges the batteries with a portion of the power of the main engine in the front body. In this operating mode, the steering takes place unchanged via the articulated joint with the tracks running at the same speed. For silent driving, the main engine can be switched off and – due to the CRT being quiet anyway – the BRONCO 3 can approach its position almost silently with the electric drive.

Hybrid drive is provided by a combustion engine in the front body and a motor/generator with batteries in the rear body.

The electric drive in the rear body also allows it to be operated autonomously (Manned–Unmanned Teaming, MUT). For this purpose, the two bodies need to be disconnected, which takes a few seconds. New steering gears in both cars enable power transmission between the inner and outer tracks for regenerative steering, so that the rear body can be positioned by remote control alone via an autonomous set to bring sensors or weapons into position without endangering the crew. The energy supply will allow a range of up to 20 km depending on battery size.


ST Engineering sees opportunities to market the new BRONCO 3 to armed forces; the company had invited specialist personnel to the demonstration. However, sales opportunities are also seen in nations which want to replace the BV206, introduced decades ago with the same vehicle concept. Experiences gained in disaster operations – such as the snow disaster in Germany in early 2019 – show that the built-in protection can also reduce the risk of falling trees or debris. For this reason, civilian disaster prevention officers are also part of the target group. Japan, for example, uses the EXTREM V – the commercial variant of BRONCO – for this purpose.

To date, ST Engineering has sold around 1,200 BRONCOs in over 20 versions; the new BRONCO 3 offers the opportunity to increase sales further.

Gerhard Heiming