I'm trying to learn what I can about the AbramsX project and the upgrade packages for the M1A2 variant. It sounds like AbramsX is cancelled and the army will upgrade the fleet to an M1E3 package. This seems to include a hybrid powertrain, a bunch of mission specific stuff, and new standards compliant software and hardware. The AbramsX was said to feature 50% reduced fuel consumption, which I believe is based on the ACE engine (advanced combat engine). Cummins has been developing a 1000hp opposed piston engine for DARPA that I believe is the ACE engine, intended for the AbramsX. I have some confidence in the above information. Speculation follows. The Abrams tank is 60 tons and has a 1500hp engine. A 1000hp engine would make more sense in a 30~40ton tank. The army has been playing with lighter designs for quite some time, as they are easier to air lift to the battlefield. On the other hand, drone tanks are just around the corner so perhaps the army has cancelled the AbramsX and even the ACE program to be replaced by something radically different. I know they want to make more use of hybrid powertrains to enable periods of quiet operation. Does anyone have any insight into this?