ENGINE
SERVICE HISTORY
The 76mm GMC M18 was powered by a Continental R-975-C2 nine-cylinder air-cooled radial 400hp engine. The Wright R-975 Whirlwind engine was originally designed by the Wright Aeronautical division of Curtiss-Wright as an aircraft engine. In 1939 the US Army chose Continental Motors to build a version of the R-975 engine under licence that could power armoured fighting vehicles. They would manufacture over 53,000 R-975 engines. The light armour of the M18 enabled the engine to provide enough power to give a maximum road speed of 80km/h (50mph).
In May 1944, five M18s were shipped to Italy. The evaluation reports stated it was excellent in a reconnaissance role due to its speed but it was not as good as the M10 in a tankdestroying role, mainly because of the lack of internal space in the turret which hindered operating the gun. The 603rd, 704th and 705th Tank Destroyer Battalions, who were part of George Patton’s Third Army, were equipped with M18s and took part in Operation Cobra in Normandy; as the war progressed more M18-equipped TD Battalions arrived in Europe. Only one of these battalions was deployed to the Pacific. The high tank-kill-to-loss ratio obtained by the M18 crews has been attributed to their training and dedication rather than the abilities of the M18. Post-war, the M18 saw service in various armies around the world.