- Yes
- No
Hello, and welcome to the suggestion for the Chieftain Mark 11! This is the last variant of the Chieftain in British Army service, taking the upgrades and Stillbrew armor added to later Marks of the Chieftain, and adding TOGS, or Thermal Observation and Gunnery System. This is a generation 1 thermal sight for the gunner, allowing increased levels of target acquisition. While this would be the primary attraction in War Thunder, I’d also suggest the Mark 11 receive the L23A1 round and be foldered with the Mark 10, leaving the Mark 11 as an optional upgrade and lineup filler.
History
A Chieftain Mark 2 from the 17th/21st Lancers, 1960s.
When the Chieftain was accepted for service in the 1960s, it was equipped with a combined white light and infrared searchlight. While it did work, this system proved to be unpopular, especially for the illuminating tank during night time. Developers of the tank explored potentially superior options, including image intensification. The Barr & Stroud firm based out of Glasgow had created a demonstrator thermal imaging device mounted on the new No.21 cupola, named ‘Tombola.’ This would be used on the FV4211, and later offered for use on a potential German/UK design. Tombola was flawed from the start though, requiring the No.21 cupola to be locked to the turret, meaning traverse couldn’t be employed, negating the advantages of power operation. This was due to the fact that no slip rings were available to transmit power to Tombola. While Tombola ultimately wasn’t successful, it was the first thermal imager fitted to a British tank, and the team at Barr & Stroud weren’t ready to give up.
In the late 1970s, Barr & Stroud had begun work on TOGS, or Thermal Observation and Gunnery Sight. This was a first generation thermal imager, able to detect targets even through adverse conditions such as mist or smoke. It was comprised of two principal elements, the Thermal Surveillance System (TSS), and Gunnery Sighting System (GSS). TSS was the actual thermal imaging equipment of TOGS, picking out objects radiating heat, and through a computer integrating data from multiple sources, transfers the image to GSS, turning what would otherwise be a thermal camera into a gunsight.
The experimental Chieftain with a modified searchlight to house the TOGS, 1981.
While it was suggested that a TOGS demonstrator be mounted on Chieftain, there was much resistance, both from the Ministry of Defence and the team working on the replacement for Chieftain, MBT-80. The MoD thought it would be impractical, while the team at the Military Vehicles and Engineering Establishment (MVEE), or Chertsey, didn’t want the project to belittle its work on MBT-80. Therefore, Barr & Stroud would have to make TOGS a private venture, but wanted to have the support of Operational Requirements (OR) staff and the Director of the Royal Armoured Corps (DRAC) if they could prove that thermal imaging on tanks could work. A trial was therefore organized, to be hosted by retired Major Bagnall-Wild, intended to prove that thermal imaging could work on tanks, especially Chieftain. Demonstrator thermal equipment fitted to a Chieftain was able to clearly see targets up to 2.5 km away After much back and forth between the MoD and the supporters of using thermal imaging, Barr & Stroud were ultimately awarded a contract for TOGS.
In order to establish the best way of employing TOGS, several large scale trials were carried out, including one named Exercise Dragon’s Eye. Author Rob Griffin was part of this, attached to the Royal Scots Dragoon Guards, stating that the aim of the exercise was to film and record crews carrying out textbook fire orders using thermal imaging. To this end, a thermal imaging camera was mounted on the barrel, just behind the fume extractor. Part of these trials were to establish the optimal location for the thermal imager head would be, as well as the compressor to cool the air required for it to work. By the end of Dragon’s Eye, author Rob Griffin felt that they had achieved something that would be of real value in the future.
A Chieftain Mark 11 of the 4th Royal Tank Regiment at the conclusion of the final exercise conducted by the Chieftain MBT with the British Army, Salisbury Plain, June 1995.
Initially, an early version of TOGS was mounted in the searchlight on four Chieftains for trials. At this time, the Chieftain was undergoing upgrades, notably with the addition of Stillbrew armor to the turret. This coincided with the solution for mounting TOGS, in a ‘barbette’ on the loader’s side of the turret. While it was lower in profile, it was much longer due to the cooling unit behind the imager, resulting in additional mounting pads being welded to the turret. Internally, fitting TOGS required 16 new boxes and 30 new cables, with additional modifications done to the ammunition stowage and radio equipment. With the additional Stillbrew armor and TOGS, the smoke dischargers, turret lifting eyes and a fire extinguisher were relocated, along with minor modifications to the engine decks. The additional weight of the modifications was 450kg for TOGS and 2,000kg for the Stillbrew armour. These modifications were done at the Royal Engeering and Mechanical Engineers’ (REME) 23 Base Workshop and 38 Central Workshop.
This culminated in what would be the final Chieftain variant, the Mark 11. It took work done over the past decade and essentially finalized the Chieftain in British Army service. The effort in putting TOGS into service wasn’t for naught either, as the Chieftain’s successor, Challenger 1, used TOGS as well, entering service in 1983 and famously being used in Operation Desert Storm. As for the Chieftain, it had its last hurrah with the Mark 11 until 1995, when it exited service with the British Army.
A Challenger 1, the squadron leader of D Sqn, 7th Armoured Brigade, Royal Scots Dragoon Guards, moves into a base camp during Operation Desert Storm, February 28th, 1991.
Specifications
- Crew: 4
- Mass: 57 t
- Length: 10.7 m
- Width: 3.6 m
- Height: 2.9 m
- Main armament: 120 mm L11A5 rifled gun
- Main armament elevation: -10°/20°
- Secondary armament: 7.62 mm L8A1 coaxial machine gun & L37A1 commander’s machine gun
- Engine: 737 hp Leyland L60 Mark 14A diesel engine
- Maximum speed: 48 km/h
- Maximum range: 500 km
- Ground clearance: 0.56 m
Sources
- Suttie, W. (2022). Chobham Armour: Cold War British Armoured Vehicle Development. Osprey Publishing.
- Dunstan, S. (2020). British Battle Tanks: Post-War Tanks 1946-2016. Osprey Publishing.
- Griffin, R. (2001). Chieftain. The Crowood Press UK.
- Schulze, C. (2020). FV4201 Chieftain Britain’s Cold War Main Battle Tank. Tankograd Publishing.
- Chieftain - The Tank Museum
- A look around inside a Chieftain Mk 11 (Rest in peace, TankNutDave)
