M18 Hellcat

The M18 Hellcat (officially designated the 76 mm Gun Motor Carriage M18 or M18 GMC) was an American tank destroyer. It was the fastest U.S. armored fighting vehicle on the road. The speed was attained by keeping armor to a minimum, using the innovative Torqmatic automatic transmission, and by equipping the relatively light vehicle with the same main gun used on the much larger Sherman tank.

Development

In Dec 1941, the Ordnance Department issued a requirement for the design of a fast tank destroyer using a Christie suspension, a Wright-Continental R-975 radial aircraft engine, and a 37mm gun.

Two pilot vehicles were to be built. What became the M18 originated in Harley Earl's design studio, part of the Buick Motor Division of General Motors . Though it weighed about 20 tons, the Hellcat was capable of traveling 55 mph. Its power came from Wright R-975, a nine-cylinder, 350-to-400-horsepower radial aircraft engine, paired to a 900T Torqmatic automatic transmission. In early 1943, the gun was changed to a 76mm one.

Once developed, the Hellcat was tested at the General Motors Milford Proving Ground. Top speed testing was done on a paved, banked oval and ride quality tests were done over specially developed stretches of bumps. The M18 also required tests of its ability to ford six feet of water, climb small walls, and ram through structures. The M18 had thin armor, a good gun and excellent speed.

Combat History

M18s served in tank destroyer battalion supporting US Army infantry divisions in the latter stages of the war, notably in the Philippines and Okinawa

The M18 saw service primarily as the turretless M39 armored utility vehicle which was used as a prime mover, infantry carrier, and ammunition carrier. A number of variants were proposed including a mobile command post, howitzer variant, and flamethrower variant. The tank destroyer was also used as its original purpose intended

credits for the info - @Pz.Kpfw.VI Ausf. E#8008 from Defence Matrix Discord Server