The AMC M422 'Mighty Mite', or G-843 by its supply catalogue designation , is an extra lightweight ¼-ton 4x4 tactical truck, designed for the United States Marine Corps, to be suitable for helicopter airlift and manhandling. It is also noted for its exceptionally short length, and resulting very tight turning circle, while still highway approved for a top speed of (U.S. military), and capable of according to AMC.
During World War Two, many prototypes were already developed for a ton jeep, that was still significantly lighter and more compact than the U.S. Army's lightest, all-terrain, all-purpose vehicle at the time, the Willys ton jeep. They were intended for transport in small (glider) aircraft and such, but none went into full production. However, after the war, a self-taught engineer, pilot, and auto racer, Ben F. Gregory conceived a mini-jeep design and built a successful prototype, later named the 'MM-100'.
During the 1950s, it was further developed by the Mid-America Research Corporation (MARCO), including four of the former American Bantam engineers who designed and built the ton jeep's first prototypes; together with American Motors Corporation. It was intended to be liftable, underslung the strongest helicopters of the era, the Sikorski H-19 being the benchmark, but development and certification of the M422 took through 1959, and when the M422 debuted, it coincided with the adoption of helicopters like the Bell UH-1 “Huey” with much more carrying capacity, and except for parachute airdrops, the vehicle quickly became obsolete. From 1959 to 1962, just under 4,000 of the M422 Mighty Mites were built by American Motors for the U.S. Marines.
History
The Mighty Mite was first conceived in 1946–47, by self-taught engineer, pilot, and auto racer from Missouri, Ben F. Gregory. Gregory designed several front-wheel drive cars after World War I but was unsuccessful in marketing them, so he turned to commercial aviation, but a crash in 1942 ended his flying career. Recovering from serious injuries, he became an aircraft inspector. After the end of World War II, Gregory found new investors and turned again to front-drive cars, this time culminating in a fully driveable prototype—an innovative 1947 rear-engined, front-drive compact car, the Gregory Sedan. No carmaker was interested in his car, but he was inspired to use some of its design features, such as leading- and trailing-arms suspension, in a more modern four-wheel drive off-road vehicle, or jeep, and he found additional investors willing to fund a prototype.
One investor arranged a 1951 demonstration for the United States Marine Corps (USMC) Equipment Board, that went so well that the investors quickly formed the Mid-America Research Corporation (MARCO), to fully develop the vehicle for military or commercial markets. That same year, MARCO presented it as the MARCO MM-100, making it the first clean-sheet ton jeep to be designed for the U.S. military after World War II. The USMC executed a contract for ten test vehicles in August of 1951, the vehicles were delivered in December of 1952, and the USMC immediately began the test program. For further development, the company decided to hire Harold Crist, American Bantam's original chief engineer on designing the first ton jeep. Joining on 1 January 1953 as project manager, Crist brought with him three of the main men who had worked on the original Bantam jeep: Chet Hempfling, Ralph Turner, and Frank McMillan, so from then the team included four of the original WW II Bantam jeep's engineers. But Gregory, in turn, was eventually forced out of the company.
The MM-100 used a , flat-four engine from the "S" version of the Porsche 356, but this choice proved problematic, as using a foreign-built engine would violate regulations requiring U.S.-built equipment in U.S. military vehicles. Attempts were made to substitute the Lycoming O-145, an American aircraft engine, but it was deemed too expensive and difficult to adapt to a ground vehicle. A solution presented itself when MARCO discovered that American Motors Corporation (AMC) was developing a lightweight, air-cooled , V4 engine for a proposed economy car to be sold under AMC's Nash Motors brand. AMC quickly took a strong interest in the MM-100 because it needed a new product to keep a former Hudson commercial vehicle plant operating, and by 1954, AMC had completely taken over the project.