AC1 (Australian Cruiser 1)5:

Australian Sentinel

Australian Sentinel Mk I
Royal Armored Corps Tank Museum

With Japan becoming a threat in the Pacific and England occupied by Germany, the Australian Ministry of Munitions started to consider building their own tanks in early July 1940. In November the Australian General Staff developed the requirements for a tank. It was to have a 2-pdr (40 mm) gun and two 7.7 mm (0.303") machine guns.5 It was to use as many of the same components as the American M3 Light Tank.5 The engine was to be three Cadillac automobile engines joined together.5 Cast armor was also a requirement.5

The estimated 2,000 would be needed and first ones to be ready by July 1941 and 70 per month being produced. Advisors arrived from England and development started. Among the advisors was Colonel Watson who had studied the M3 medium who helped with the design.

A wooden prototype was built in early 1941 and in October the first hull had been cast. The first 3 pilot models were completed in January 1942, only 22 months after the original General Staff specifications.

The Chullona Tank Assembly Shops in New South Wales would produce the tanks. Production started in August 1942 with a total of 66 being built. A new factory was built, but with America able to supply enough tanks for Australia's use production ceased and the tank was used for training.

AC2:

Was another design that was dropped after truck components became unavailable from US.

AC3:

Had 25 pdr howitzer mounted in turret. This had a larger turret ring and turret. The hull MG was removed. The 3 engines were given a single crankcase. Prototypes appeared in early 1943. Never went into production.

AC4:

Was to have the 17 pdr gun in turret. However, none were available and 2 25 pdr guns were installed in the turret to simulate the recoil of the 17 pdr. Prototype was built in mid-1943. One of the prototypes had a torsion bar suspension.

Description

It was designed with a one piece hull and cast turret. It had rubber-block suspension with horizontal volute bogies similar to the French Hotchkiss.

The hull MG had a armored sleeve.

Usage

Used only for training.

    AC-1 AC-3 AC-4
Crew 51 Commander, driver, hull gunner, gunner, loader.2
52,3,4,5
Commander, driver, gunner, loader.2
52
 
Physical Characteristics        
Weight 62,720 lb, 62,732 lb
28 tons1
28,489 kg1
62,720 lb2,3,4,5
28,450 kg4,5
62,720 lb2  
Length w/gun 20' 9"1
6.4 m1
20' 9"2,3,4,5
6.325 m4,5
20' 9"2  
Length w/o gun        
Height 9' 1", 8' 5"1
2.59 m1
8' 4.75"4,5, 8' 5"2,3
2.56 m4,5
8' 5"2  
Width 8' 2", 8' 5", 9' 1"1
2.8 m1
9' 1"2,3,4,5
2.768 m4,5
9' 1"2  
Width over tracks        
Ground clearance 1' 3"      
Ground contact length        
Ground pressure        
Turret ring diameter        
Armament        
Main 40 mm (2 pdr)1 2 pdr. OQF2
2 pdr.3,4
25 pdr.2,4,5
25 pdr. howitzer3
17 pdr.3,4,5
Secondary        
MG 2: 7.62 mm MG1
7.7 mm, coaxial, hull
2: Vickers .303 cal MG2
2: Vickers MG3
2: 7.7 mm MG4
Vickers .303 cal MG2  
Side arms        
Quantity        
Main 130 1302    
Secondary        
MG 4,250 4,2502    
Side arms        
Armor Thickness (mm) 651 252, 652, 25 - 263, 25-655 25 - 654
252, 652
 
Hull Front, Upper        
Hull Front, Lower        
Hull Sides, Upper        
Hull Sides, Lower        
Hull Rear        
Hull Top        
Hull Bottom        
Turret Front        
Turret Sides        
Turret Rear        
Turret Top        
Engine (Make / Model) 3 x Cadillac1 3: Cadillac2,3,4,5 3: Cadillac2  
Bore / stroke        
Cooling        
Cylinders 81 x 31 V-82,3 V-82  
Capacity        
Net HP 1171 x 31 117 each2,3
3304,5
3972  
Power to weight ratio        
Compression ratio        
Transmission (Type)        
Steering        
Steering ratio        
Starter        
Electrical system        
Ignition        
Fuel (Type) Gasoline1 Gasoline2,4,5 Gasoline2  
Octane        
Quantity        
Road consumption        
Cross country consumption        
Performance        
Traverse   360°2 360°2  
Max speed 20 mph, 30 mph1
48 kph1
20 mph3, 30 mph2,4,5
48.2 kph4,5
30 mph2  
Cross country speed   20 mph2 20 mph2  
Road radius 200 miles, 198 miles1
319 km1
200 miles2,4,5
322 km4,5
229 miles2  
Cross country radius        
Turning radius        
Elevation limits        
Fording depth 3' 11.5" 4'2 4'2  
Trench crossing 8' 8'4,5, 9' 6"2
2.438 m4,5
9' 6"2  
Vertical obstacle   2'2 4'2  
Climbing ability        
Suspension (Type) Volute Scissors      
Wheels each side 6x2      
Return rollers each side 3      
Tracks (Type)        
Length        
Width 16.5" 16.5"2 16.5"2  
Diameter        
Number of links        
Pitch        
Tire tread        
Track centers/tread   7' 6.5"2 7' 6.5"2  
Production 1/42 - 7/43: 66 8/1942: 663    

Sources:

  1. The Encyclopedia of Tanks and Armored Fighting Vehicles - The Comprehensive Guide to Over 900 Armored Fighting Vehicles From 1915 to the Present Day, General Editor: Christopher F. Foss, 2002
  2. British and American Tanks of World War Two, The Complete Illustrated History of British, American, and Commonwealth Tanks 1933-1945, Peter Chamberlain and Chris Ellis, 1969
  3. Tanks of the World, 1915-1945, Peter Chamberlain, Chris Ellis, 1972
  4. The Encyclopedia of Weapons of World War II, Chris Bishop, 1998
  5. Tanks - Over 250 of the World's Tanks and Armored Fighting Vehicles, Chris Chant, 2004
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