thunder and steel







Other Tanks


Local Pattern Carriers




Post War Armoured Cars

Other Armoured Cars


M1A1 Abrams

LP Armoured Cars



sentinel model


Even though the production had been canceled experimentation continued. A up gunned version mounting a 25 pdr in place of the 2 pdr was contemplated. The AC III as it became known had considerable modifications from the AC 1. A larger turret although the turret ring remained the same size. The engine installation was redesign with a common crack case for the three Cadillac engines, this also gave extra room for larger fuel tanks. The hull was redesigned allowing the bow machine gun to be eliminated to give more ammunition stowage, this also reduced the crew to four. The AC III was due to begin manufacture in May 1943. The name "Thunderbolt" was associated with this vehicle. It was built on the prototype numbered E2. The one vehicle built was hull number 8066, with around 80 hulls and turrets being cast for the AC3 before the project was shut down. In 1963 this vehicle was installed as a memorial on Mount Pleasant at the Royal Military College. It was dedicated by Lieutenant General Sir John Northcott. The AC3 was only there for 20 years when it was moved again, this time to The Australian War Memorial, Canberra were it resides today.

17pdr upgrade.

Trials were also started to mount the 17 pdr in the Sentinel. The Sentinel trials to test the turret ring started about January 1943. The Firefly was made possible by the Australian development of a recoil system by the firm of Charles Ruwolt. On arrival in Britain A.R. Code was asked by the Ministry of supply weather it was true that the Australians had succeeded in mounting a 17pdr gun in a turret approximately the size of that of a Sherman tank. His reply was that it was not only true, but that he could show them photos and drawings. His answer was that it had been done by the Australians. To test the turret ring which was increased in size to 70 inches and to see if it could withstand the pressure of a 17 pdr being fired a twin coaxial 25 pdr mount was added to the turret of the Sentinel prototype number E1(which can be identified by having a hull made from 5 cast pieces) with the turret ring increased to 64 inches. The firing of this combination together would give 20% greater recoil than the 17 pdr. This was done using a lanyard from a safe distance. There was no adverse affect to the vehicle from the firing of this combination. The designation of this vehicle is said to be AC IV. A stowage capacity of 50-60 rounds was recommended.

Other experiments.

One Sentinel hull was also modified to test out torsion bar suspension. In a attempt to provide a better ride and more stable platform for the up gunned variants. Though complete and run there was no time to incorporate this modification on production models before the cancellation of the tank. I do not know of the results of this trial.