The M9 ACE ("Armored Combat Earthmover") is a frontline military-grade tracked bulldozer utilized by the United States Army. The system was developed to allow forces the ability to dig entrenchments for various artillery pieces while also fulfilling the roles of minefield breaching/clearance, trench crossing/filling, general bulldozing, grading, excavation, route-/area-proofing and pushing/towing of vehicles and/or obstacles. The M9 ACE entered service in 1986 and upgrade programs have kept the machine a viable battlefield piece for American forces. Despite it not being armed, the M9 series has seen its fair share of combat in other ways.
As designed, the M9 weighs in a 36,000lb and features single crew member. The vehicle showcases dimensions of 6.25 meters long, a width of 3.2 meters and a height of 2.7 meters. The crew sits protected under the armored hull superstructure allowing them to continue to operate even when under threat of direct fire from the enemy. Protection is adequate against small arms and fire and artillery spray. Vision ports allow for the necessary situational awareness and project direction. The vehicles configuration is conventional with a dozer blade set to the front of the hull and the crew compartment aft. Running gear includes a track-and-wheel arrangement featuring four road wheels to a hull side with the drive sprocket at rear. The vehicle can promote its own smokescreen through the bank of eight smoke grenade launchers fitted to the hull roof. The M9 line features an amphibious quality as well as an integrated Nuclear, Biological, Chemical (NBC) suite.
Power is served through a Cummins V903C 8-cylinder diesel-fueled engine outputting at 295 horsepower. This provides the vehicle with a top road speed of 30 miles per hour and an operational range out to 200 miles.
Key to the M9's success is its 8.7-cubic-yard "scraper bowl" and bulldozer blade. The hydro-pneumatic suspension allows the front of the vehicle to be raised, lowered or tilted to permit either dozing, excavating, rough grading or ditching functions. The system sports a 2-speed winch with a 25,000 pound pull capability. As the vehicle features no armament for self-defense, it is typically fielded along with other allied units such as Bradley Infantry Fighting Vehicles (IFVs).
With its introduction in the mid-to-late 1980s, the M9 ACE was featured by U.S. Army forces in the 1991 Persian Gulf War as Allied ground forces moved against Iraqi units in Kuwait. The vehicles played a critical role in removing road obstacles for the main ground force and in breaching prepared Iraqi Army fortifications. Combined with other elements for protection, M9's served dutifully in their role when dismantling the "Forth Largest Army in the World" at that time.
Due to the rather compact dimensions of the M9 ACE vehicle, it is easily transportable in the hold of a Lockheed C-130 "Hercules" transport as well as the larger Lockheed C-141 "Starlifter" and Lockheed C-5 "Galaxy" heavy lifters.
Approximately 448 M9 ACE vehicles were taken into the U.S. Army inventory by the end of 1992. There were plans for an unmanned, remote-controlled version as the "Standardized Robotic System" (SRS) vehicle through Omnitech Robotics International though this does not appear to have been furthered.