B1 ter

B1 ter
Name	B1 ter
Type	Armored vehicle
Origin	France
In service	1939–1940
Manufacturer	AMX
Crew	4–6
Length	6.5 m
Width	3.2 m
Height	2.9 m
Weight	32 t
Armour	40–60 mm
Primary armament	75 mm gun
Secondary armament	2 × 8 mm machine guns
Engine	Rolls-Royce Meteor V12
Power	450 hp
Speed	28 km/h

B1 ter The B1 ter was a French heavy tank concept developed in the interwar period and early World War II era, intended as an evolution of the series that included the Char B1 and Char B1 bis. It occupied a role alongside contemporaries such as the Char D2, Renault FT, Somua S35, and Hotchkiss H35, aiming to combine heavy armor and a powerful 75 mm gun with improved mobility. The design process involved collaboration between firms and institutions including GIAT Industries, Saint-Chamond, Atelier de la Dyle, and governmental bodies like the Direction des Fabrications d'Armements.

Design and Development

The B1 ter concept emerged from studies by designers influenced by earlier projects such as the Char B1 program overseen by engineers at FAMH and production planning linked to factories at Bordeaux, Brest, and Lyon. Debates in the Chambre des députés and among members of the École Polytechnique–trained technical corps shaped priorities, with input from officers of the Service Historique de l'Armée de Terre and testers from the Centre d'études d'actions techniques.

Designers sought lessons from tests on vehicles like the Char B1 bis, trials at the Centre d'expériences de Gâvres, and combat outcomes seen in clashes such as the Battle of Hannut and the Battle of Belgium. Influences included foreign developments studied by French military attachés in Berlin, Milan, and London, with comparisons to the Panzer IV, T-34, and A9 (tank) shaping armor and armament choices. Industrial constraints involving firms like Renault, Forges et Chantiers de la Méditerranée, and Société des Forges affected production feasibility and timetables presented to the Ministry of Armaments.

Technical Description

The B1 ter's hull layout built on the lineage of earlier French heavy tanks such as the Char B1 bis and the AMX 38, featuring a cast and welded hull with distinct crew stations for a commander, driver, radio operator, and gunner. The turret mounted a 75 mm gun influenced by designs like the SA 34 and complemented by machine guns akin to those on the Renault R35. Suspension borrowed elements from designs tested alongside the Somua S40 and components manufactured at Nexter Systems predecessors.

Powerplant choices reflected contemporary engines used in vehicles such as the Char G1 proposals and the AMX 40, with options including the Rolls-Royce Meteor derivative and French-produced engines by Hispano-Suiza and Société Lorraine-Dietrich. Transmission and drivetrain drew on experience from workshops at Bourges and Versailles with gearboxes related to those trialed in the AMC 35. Armor scheme referenced ballistic data from trials at the Institut de la Sûreté and riveted versus cast debates mirroring those surrounding the Char 2C.

Operational History

Although the B1 ter did not reach mass production, prototypes and mock-ups influenced doctrine and deployment planning alongside units equipped with the Char B1 bis, Somua S35, and Renault R35 during mobilization in 1939–1940. Lessons from early engagements such as the Battle of France, including operations by the 2e Division Cuirassée and coordination with the Armée de l'Air and Royal Air Force, informed tactical revisions.

Field reports compared the envisioned B1 ter capabilities with enemy vehicles like the Panzerbefehlswagen III, Panzerkampfwagen IV, and StuG III, and with Allied developments represented by the Matilda II and Churchill tank. Logistical discussions during the campaign referenced rail movements at stations like Gare de l'Est and supply hubs in Calais and Le Havre, while capture and study of prototypes by German units drew interest from organizations such as the Heer and research centers in Kassel.

Variants and Modifications

Planned variants paralleled conversion programs seen in contemporaries: command versions similar to adaptations on the Panzer III Ausf. F and recovery versions analogous to ARV prototypes. Proposed modifications included alternate turret layouts inspired by the AMX 13 oscillating concepts, diesel engine installations as tested on Somua S35 derivatives, and trench-crossing devices akin to those fitted to Char 2C experiments.

Specialist proposals referenced collaboration with firms like Berliet and Latil for prime mover conversions, radio suites comparable to sets used by the Luftwaffe on armored cars, and flotation kits echoing developments in Amiens amphibious trials. Armor upgrades considered face-hardened plates from suppliers who worked on the Bofors projects and sloped armor geometries examined in Minsk-era Soviet designs.

Users and Deployment

No nation fielded the B1 ter in large numbers; primary operators remained French planning staffs within the Ministry of War and unit cadres in the 2e Division Légère Mécanique planning tables. Observers from foreign militaries including personnel from Britain's Department of Tank Design, the Soviet Union's GABTU, and delegations from Italy's Regio Esercito reviewed mock-ups and documentation during interwar exchanges.

Captured prototypes and documentation were inspected by German technical missions linked to the Heereswaffenamt and prototypes shipped to facilities in Freiberg for study. Post-campaign influence appeared in design references within programs run by firms such as Krupp and later projects at Nexter, echoing aspects in Cold War tanks like the AMX 30.

Performance and Evaluation

Contemporary evaluations, drawing on trials at establishments like the Centre d'Essais de Matériels and comparative tests against vehicles such as the Panzer IV Ausf. D and T-26, suggested the B1 ter would have offered improved frontal protection and firepower relative to the Renault R35 and Hotchkiss H35, while still facing challenges in strategic mobility compared to the Char D1 and Somua S35. Engineering assessments referenced reliability records from Atelier de Construction de Levallois and endurance runs near Fontenay-le-Comte.

Analysts from institutions including the Académie des Sciences and staff colleges like the École de Guerre debated trade-offs between armor, weight, and logistics, noting parallels with later doctrines examined during studies on the NATO tank requirements and lessons incorporated into the Char Leclerc program.

Category:Tanks of France