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Nov 7, 2021, 19 tweets

United Defense Thunderbolt 120mm light tank technology demonstrator shown at AUSA 2003. Thunderbolt is a 120mm smoothbore-armed derivative of canceled M8 Armored Gun System. Initially, UDLP sees Thunderbolt as a cheaper alternative to the Mounted Combat System of the FCS program.

In August 2003, prior to mating with its intended hull, the Thunderbolt turret incorporating the XM291 gun and modified AGS autoloader was mounted on a old diesel-driven M8 hull and test fired at Camp Roberts, CA.

Thunderbolt's XM291 main gun is backed by an autoloader that handles standard 120mm tank rounds including HEAT and APFSDS. The autoloader handles 120mm rounds with combustible casings and rounds of varying weight distributions, and it can eject stubcases.

The autoloader is evolved from M8 AGS. The Thunderbolt autoloader magazine accommodates 15 ready rounds, but in later optimized version form UDLP increases the number to 18, and a firing rate of 10-12 rds/min to be sustained.

The Thunderbolt fire control system incorporates a Raytheon HIRE-II 2nd generation thermal imager (as also used aboard four modified version of M8 AGS for the Fort Knox Platform Performance Demonstration during late 1999 to early 2000).

The brand new designed Thunderbolt hull integrates a Hybrid Electric Drive (HED) that provides improved performance and fuel economy. The propulsion system utilizes generator, inverter and traction motor components that have performed well in testing on UDLP's TTD demonstrator.

The old steel tracks has been supplanted by a Soucy band rubber tracks. The advantages of band track include improved ride quality, longer life, and reduced noise and thermal signatures.

The Thunderbolt HED system involved two traction motors in the front of the hull, a John Deere 300hp turbocharged intercooled diesel engine in the left sponson and a 24 batteries based energy storage system in the right sponson.

The difference in engine power is made up when maximum power is required by drawing on the energy stored in a pack of 24 lead-acid 6TMF batteries. Thunderbolt's HED gives it an estimated 965km range on 757 liters of fuel, and a 6km silent running range (batteries only).

The revised propulsion arrangement also frees up space in the original engine compartment, which in the demonstrator has been converted to allow the vehicle to carry four dismounting troops or additional fuel and ammunition.

The baseline weight is put at approx 40,000 lb (18.7t), and approx 20t with Level 2 ballistic composite armor, which provides the turret with 30mm protection over its frontal arc and 14.5mm AP all round. Higher Level 3 protection is available depending on the battlefield threats.

In 2004, United Defense working with US Army ARDEC to test the Electrothermal-Chemical (ETC) technology on the Thunderbolt platform.

The gun fired by Thunderbolt was a modified 120mm XM291 gun, which has been provided with an Electro-Thermal Ignition Pulse Power Supply (ETIPPS) for plasma ignition of 120mm rounds. The vehicle was renamed Lightning Bolt after the addition of ETIPPS and other ETC components.

The US Army did not choose the Thunderbolt, but that has not prevented United Defense from seeking foreign buyers for the lightweight armored platform.

In 2004, at the request of the Singaporean defense ministry, United Defense had submitted a proposal for Thunderbolt based on ST Kinetics' Universal Combat Vehicle Platform (UCVP) chassis.

After this, BAE Systems unveiled AGS 120 light tank at Asian Aerospace 2006. AGS 120 is basically a Thunderbolt mounted on a standard M8 hull.

The AGS 120 is an advanced and deployable 120mm auto loading gun on a light tank chassis. It is designed for low velocity air drops from C-130 Hercules aircraft or similar and can be configured in a variety of modular passive armor protection levels.

Unfortunately, no matter it is Thunderbolt or AGS 120, they failed to find potential buyers.

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