Willys MB

Advances in early-20th century technology resulted in widespread mechanisation of the military during World War I. The United States Army deployed thousands of motor vehicles in that war, including some 12,800 Dodges,[21] and thousands of four-wheel drive trucks: Jeffery / Nash Quads, and trucks from the Four Wheel Drive Auto Company (FWD). General John Pershing viewed horses and mules as acceptable for the previous three U.S. wars, but in the new century, his cavalry forces had to move quicker, with more range and more personnel.[22]

Immediately after World War I, the use of motor vehicles in that war was considered only a prelude to much greater application in future armed conflicts. As early as 1919, the U.S. Army Quartermaster Corps recommended the acquisition of a new kind of military vehicle, ".. of light weight and compact size, with a low silhouette and high ground clearance, and possess the ability to carry weapons and men over all sorts of rough terrain." [23] The U.S. Army started looking for a small vehicle suited for reconnaissance and messaging, while at the same time searching for a light cross-country weapons carrier.[24]

At the same time, there was a drive for standardization. By the end of World War I, U.S. forces overseas had a total of 216 makes and models of motor vehicles to operate, both foreign and domestic, and no good supply system to keep them running.[18]

Various light motor vehicles were tested — at first motorcycles with and without sidecars, and some modified Ford Model Ts.[25][26] In the early 1930s, the U.S. Army experimented with a bantam weight "midget truck" for scouts and raiders. A 1,050 lb (480 kg), low-slung mini-car with a pick-up body, provided by American Austin,[27] was shown in a 1933 article in Popular Mechanics magazine.[28] One of the pictures showed that the vehicle was light enough to be man-handled — four soldiers could lift it from the ground entirely.

After 1935, when the U.S. Congress declared World War I vehicles obsolete, procurement for "remotorization of the Army" gained more traction.[29] In 1937 Marmon-Herrington presented five 4x4 Fords, and American Bantam (previously American Austin) once again contributed — delivering three Austin derived roadsters in 1938.[30][20]

Meanwhile, in Asia and the Pacific, Japan had already invaded Manchuria in 1931, and was warring with China from 1937. Its Imperial Army used a small, three-man crew, four-wheel drive car for reconnaissance and troop movements, the Kurogane Type 95, introduced in 1936.

By 1939 the U.S. Army began standardizing its general-purpose truck chassis types by payload rating, initially in five classes from ​¹⁄₂-ton to 7​¹⁄₂-ton, but in 1940 the categories were revised. For the first time, a quarter-ton truck chassis class was introduced, at the bottom of the range, and the ​¹⁄₂-ton category was supplanted by a ​³⁄₄-ton chassis.[31]

By the eve of World War II, the United States Department of War had determined it needed a ​¹⁄₄-ton, cross-country reconnaissance vehicle. Although ​¹⁄₂-ton four-by-fours had outperformed ​1 ¹⁄₂-ton 4x4 trucks during testing in 1938,[32] the half-ton 4x4 trucks – both from Marmon-Herrington Ford, and the 1940 Dodge VC series – still proved too large and heavy, and insufficiently agile off-road.[33][24] Anxious to have a quarter-ton truck in time for America's entry into World War II, the U.S. Army solicited proposals from domestic automobile manufacturers. Recognizing the need to create standard specifications, the Army formalized its requirements on 11 July 1940, and submitted them to 135 U.S. automotive manufacturers.

Bantam's first prototype – the BRC Pilot model ("Old Number One")

In the early 1930s, the Infantry Board at Fort Benning became interested in the British Army's use of the tiny Austin 7 car in a reconnaissance role, and they obtained a car from the American Austin company in Pennsylvania which built them under license. By 1938 American Austin had gone bankrupt and reorganized as American Bantam. They had loaned 3 cars to the Pennsylvania National Guard for trials during summer maneuvers. Bantam officials met with chiefs of Infantry and Cavalry and suggested a contract to further develop a military version of their car. A subcommittee of army officers and civilian engineers was tasked with created detailed specifications for the proposed vehicles. One of the first things they did was to visit the Bantam factory and look at their existing compact cars. By the end of June 1940 specifications had been drawn up[34]

The remainder of Bantam's 70 test units, usually called "BRC60", still had a round hood and grille, but square fenders. Shown is #7, nicknamed "Gramps", owned by the Smithsonian.[35]

By now the war was underway in Europe, so the Army's need was urgent and demanding. Bids were to be received by 22 July, a span of just eleven days. Manufacturers were given 49 days to submit their first prototype and 75 days for completion of 70 test vehicles. The Army's Ordnance Technical Committee specifications were equally stringent: the vehicle would be four-wheel drive, have a crew of three on a wheelbase of no more than 75 in (191 cm), later upped to 80 in (203 cm), and track no more than 47 in (119 cm). The diminutive dimensions were similar in size and weight to Bantam's compact truck and roadster models.[36] It was to feature a fold-down windshield, carry a 660 lb (299 kg) payload, and be powered by an engine capable of 85 lb⋅ft (115 N⋅m) of torque. The most daunting demand, however, was an empty weight of no more than 1,300 lb (590 kg).

Initially, only American Bantam and Willys-Overland entered the competition. Ford joined later.[37] Although Willys was the low bidder, Willys was penalized for requesting more time, and Bantam received the contract, as the only company committing to deliver a pilot model in 49 days and production examples in 75.

Conforming to specification, Bantam delivered the last eight test units with four-wheel steering.

Bantam's chief engineer, Harold Crist, who had previously worked on the first Duesenberg, and been an engineer at Stutz Motor Company of Indianapolis for 18 years,[36][13] drafted freelance Detroit designer Karl Probst to collaborate. Probst turned down Bantam initially, but agreed to work without pay after an Army request and began work on 17 July 1940.[38]

Probst laid out full design drawings for the Bantam prototype, known as the Bantam Reconnaissance Car, or BRC, in just two days, and worked up a cost estimate the next day. Bantam's bid was submitted, complete with blueprints, on 22 July.[39] Bantam was struggling after bankruptcy trying to sell very small cars licensed from the British Austin Motor Company. But their design was able to leverage commercial off-the-shelf components as much as possible. Bantam adapted body stampings from its car line: the hood, cowl, dash, and curvy front fenders. As the Bantam engines only made 22 hp[40] the engine was chosen to be a 112 cu in (1.8 l) Continental four-cylinder engine making 45 horsepower and 86 lb⋅ft (117 N⋅m) of torque.[41] Custom four-wheel drive train components including the transfer case to send power to front and back axles were provided by Spicer which continues to make Jeep axles as Dana Incorporated. The axles were modified from units from the Studebaker Champion to four-wheel drive, the transmission was from Warner Gear.[42]

Using off-the-shelf automotive parts where possible had partly enabled drawing up the blueprints quickly. By working backward, Probst and Bantam's draftsmen converted what Crist and a few others had put together into drawings.[13] The hand-built prototype was then completed in Butler, Pennsylvania,[43] and driven to the Army vehicle test center at Camp Holabird, Maryland. It was delivered on 23 September 1940. The vehicle met all the Army's criteria except engine torque. The Bantam pilot (later also dubbed the "Blitz Buggy" or "Old Number One") presented Army officials with the first of what eventually evolved into the World War II U.S. military jeep.

Preproduction models — Bantam mk-2, Ford GP and Willys MA

Vigorous testing for Army proving — shown a Ford GP, 1941

Willys MA jeep at the Desert Training Center, Indio, California, June 1942

Allies hastily received interim models – the U.K.'s King George VI inspects a Bantam BRC40 (1942).

As Bantam did not have the production capacity or financial resources to deliver on the scale needed by the War Department, the other two bidders, Ford and Willys, were encouraged to complete their own pilot models for testing. The contract for the new reconnaissance car was to be determined by trials. As testing of the Bantam prototype took place from 27 September to 16 October, Ford and Willys technical representatives present at Holabird were given ample opportunity to study the vehicle's performance. In order to expedite production, the War Department forwarded the Bantam blueprints to Ford and Willys, claiming the government-owned the design. Bantam did not dispute this move due to its precarious finances.

Pilot models: Willys 'Quad' and Ford 'Pygmy'

Willys "Quad" pilot car initially copied Bantam's rounded grille and hood.

Ford's first test model, the "Pygmy", U.S. Veterans Memorial Museum.

By November 1940, Ford and Willys each submitted prototypes to compete with the Bantam in the Army's trials. The pilot models, the Willys "Quad" and the Ford "Pygmy", were similar and were joined in testing by Bantam's entry, now evolved into a Mark II called the "BRC 60".[nb 8][nb 9] By then the U.S. armed forces were under such pressure that all three cars were declared acceptable and orders for 1,500 units per company were given for field testing. At this time it was acknowledged the original weight limit (which even Bantam could not meet) was unrealistic, and it was raised to 2,160 lb (980 kg).

For pre-production runs, each vehicle received revisions and a new name. Bantam's became the "BRC 40". Production began on 31 March 1941, with a total of 2,605 built up to 6 December — the number ordered was raised because Britain and Russia already wanted more of them supplied under the Lend-Lease program.[45][46][35]

The BRC 40 was the lightest and most nimble of the three pre-standardized models, and the Army lauded its good suspension, brakes, and high fuel economy. However, as the company could not meet the Army's demand for 75 Jeeps a day, production contracts were also awarded to Willys and Ford.[15]

External images
Four-wheel steering Willys Quad prototype (archived)
Four-wheel steering Ford GP testing unit (archived)
Mechanical features of the new "Bug" explained in Popular Science, Oct 1941, p.54

After reducing the Quad's weight by 240 lb (109 kg), through many painstaking detail changes, Willys renamed their vehicle "MA", for "Military" model "A". Some 1,555 MAs were built, most of which went to the Soviet Union under Lend-Lease. Only 27 units are still known to exist.[35]

Ford's pre-production model went into production as the "GP", with "G" indicating a "Government" contract, and "P" chosen by Ford to designate a car with a wheelbase of 80 in (203 cm).[nb 10] With about 4,458 units built, the Ford GP became not only the most numerous of the pre-standardized jeeps[35] — it was also the first jeep fielded in some numbers to U.S. Army units. The Ford's overall design and quality of construction had advantages over the Bantam and Willys models, but the GP's engine, an adaptation of the Model N tractor engine, was underpowered and insufficiently reliable. Fifty units were built with four-wheel steering, of which four have survived.[35]

Eventually, virtually all of the Bantam- and Willys-built jeeps were provided to Britain and Russia, as well as most of the Ford GPs, leaving under 1,000 GPs for the home troops.[45]

By July 1941, the War Department desired to standardize and decided to select a single manufacturer to supply them with the next order for 16,000 vehicles. Willys won the contract mostly due to its much more powerful 60 HP engine (the "Go Devil"), which soldiers raved about, and its lower cost and silhouette. The design features in the Bantam and Ford entries which represented an improvement over Willys's design were then incorporated into the Willys car, moving it from an "A" designation to "B", thus the "MB" nomenclature. Most notable was a flat wide hood, adapted from Ford GP.

The jeep, once it entered mass production, introduced several new automotive technologies. Having four-wheel drive for the first time introduced the need for a transfer case, and the use of constant-velocity joints on the driven front wheels and axle, to a regular production car-sized vehicle.[47]

By October 1941, it became clear that Willys-Overland could not keep up with production demand, and Ford was contracted to build jeeps as well, using Willys blueprints, drawings, specifications, and patents, including the Willys engine.[48] The Ford car was then designated "GPW", with the "W" referring to the "Willys" licensed design and engine. During World War II, Willys produced 363,000 Jeeps and Ford some 280,000. Some 50,000 were exported to the U.S.S.R. under the Lend-Lease program.[8] For Bantam, jeep production stopped, Bantam received no further orders from the U.S. government and instead made two-wheel jeep trailers. This continued until the company was taken over in 1956.[49]

Standard 1944 cabin and engine

Three pedals and three sticks – for shifting gears, engaging front- / four-wheel drive, and high or low gearing

Willys "Go Devil" engine

Ford built jeeps with functionally interchangeable parts and components, in part facilitated by using components from common sources: frames from Midland Steel, wheels from Kelsey-Hayes, and axles and transfer-cases from Spicer.[48] However, there were many minor differences; the most well known: the Ford chassis had an inverted U-shaped front cross member instead of a tubular bar, and a Ford script letter "F" was stamped onto many small parts. Many body detail differences remained for as long as January 1944, when a composite body, fabricated by American Central, was adopted by both Ford and Willys. It integrated features of both designs.[35] Through the chaotic circumstances of war, sometimes peculiar deviations from regular mass-production came off the assembly line, that are now prized by collectors. For instance: the earliest Ford GPWs had a Willys design frame, and in late-1943, some GPWs came with an unmodified Willys body; and in 1945 Willys produced some MBs with a deep mud exhaust system, vacuum windshield wipers, and a Jeep CJ-style parking brake.[50]

On 7 April 1942, U.S. patent 2278450 for the WW II jeep, titled "Military vehicle body" was awarded to the U.S. Army, which had applied for it, listing Colonel Byron Q. Jones as the inventor on the patent, though he had performed no work on the design of the vehicle.[51] Filed on 8 October 1941, stating in the application that "The invention described herein, if patented, may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon",[52] the patent relates to a "small car vehicle body having convertible features whereby it is rendered particularly desirable for military purposes" and describes the purpose of the vehicle as being to create the automobile equivalent of a Swiss Army knife:

"One of the principal objects of the invention is to provide a convertible small car body so arranged that a single vehicle may be interchangeably used as a cargo truck, personnel carrier, emergency ambulance, field beds, radio car, trench mortar unit, mobile anti-aircraft machine gun unit, or for other purposes."[52]

Ford GPA amphibious jeep

A further roughly 13,000 amphibious jeeps were built by Ford under the name GPA (nicknamed "Seep" for "Sea Jeep"). Inspired by the larger DUKW, the vehicle was produced too quickly and proved to be too heavy, too unwieldy, and with insufficient freeboard. In spite of participating successfully in the Sicily landings in July 1943, most GPAs were routed to the U.S.S.R. under the Lend-Lease program. The Soviets were sufficiently pleased with its ability to cross rivers to develop their own version of it after the war, the GAZ-46 MAV.

The World War II jeep with Bantam trailer, Potsdam, Germany

Contrary to the larger Dodge WC series, the Willys and Ford jeeps were all the same from factory, and specialization happened only through standardized accessories, field kits, and local modifications. Frequently made additions to the standard jeeps were to fit weaponry, communications equipment, medical gear, wire cutters, or rudimentary armor.

Some 150,000 ​¹⁄₄-ton trailers were made by over ten different companies, specifically built to be towed by the jeep – most of them by Bantam and Willys. These doubled the jeeps nominal payload. They were hardly modified after the war, and versions of them remained in use for jeeps, into the 1990s.

Willys jeep interior with radio

The jeep's primary command and reconnaissance roles of course necessitated fitting many kinds of tactical communication equipment. The first standard production fitting was for the SCR-193 radio, placed on either side in the rear of a jeep, on top of the rear wheel well. For proper reception, this included radio interference suppression shielding, so indicated by a suffix 'S' on the jeep's hood registration number. In 1943/1944, the Army shifted to FM radios, and new fittings were developed for those. At least fourteen Signal Corps Radio set fittings were standardized, including for the SCR-187, SCR-284, SCR-499, SCR-506, SCR-508, SCR-510, SCR-522, SCR-528, SCR-542, SCR-608, SCR-610, SCR-619, SCR-628, SCR-694, SCR-808, SCR-828, and VRC-l.[53]

British SAS jeep, armed with Vickers gun for driver and twin Vickers for co-driver

Two of the original uses of the ​¹⁄₄-ton truck were reconnaissance, and the support of infantry with machine-guns. These roles led to the desire to mount automatic rifles, to be fired from the jeep. To mount either a .30-caliber or .50-cal. machine gun, the M31 pedestal, a tubular pedestal with bracing in three directions, was developed. This was the most common factory jeep machine-gun mount during the war, with 31,653 produced. It was followed by the improved M31C in March 1945, but this came too late for much combat in World War II. Besides these, units often created their own pedestal mounts in the field, or adapted other pedestal mounts as available. Additionally, in 1943 the M48 bracket mount was standardized, to attach the .30-cal. machine gun or .30-cal. Browning Automatic Rifle in front of the passenger seat. Like with the pedestals, troops improvised many gun-holding brackets in the field.[53] Troops frequently preferred a .30 cal machine gun on a pivot, to fire from the front passenger seat.

Aside from actual fielding intentions, the jeep was widely used for various weapons mounts trials during World War II, simply because the jeep was a handy platform to test all kinds of ring mounts, multiple gun mounts, as well as different weapons. The widespread adoption of the jeep in other armies also meant many different armaments. The most rigorous efforts were by the British. Perhaps the most well-known are the jeeps modified by the SAS for the 1942 desert raids in Egypt. These had several armaments, commonly using twin Vickers K machine guns on the passenger side. These also served as a pattern for the later British airborne jeeps, armed with single Vickers K guns.

Jeep with rear baggage rack (Netherlands, 1944) — note spare wheel moved to the rear right side.

Ambulance jeeps often had racks for two litter patients front and back.

Many field kits originated as locally made modifications and additions, for which standard kits were later produced by both the U.S. and Britain. Frequently used examples were rear baggage racks, ambulance litters and frames to transport lying wounded on jeeps, and wire cutters. Soldiers frequently ran into (literally) wires — either inadvertently, inconveniently strung communication wires, or deliberately placed by the enemy, to injure or kill motorcycle and vehicle personnel. The typical countermeasure was to mount a tall vertical steel bar to the front bumper, that would either cut offending strings, or deflect them over the heads of the jeep crew. This was first used in Tunisia, 1943, but became frequent in Italy (1943–1945), and especially necessary in France (1944).[54]

More specific kits were created to enhance off-roading and mechanical capabilities, dealing with extreme climates, and technical support applications, like laying communication cables, or a field arc welder kit.[55]

WV-6 snorkel kit for deep water fording – from TM9-2853 (1945)

Many solutions made the jeep run on rails, popular in the Pacific theater with U.S., Britain, and Commonwealth troops, especially in Burma. A-frames on the front bumper enabled two jeeps to tow heavy trailers (for 2​¹⁄₂‑ton trucks) in tandem. For desert cooling, radiator surge tanks were used in North Africa in 1942. Equally, there were winterization kits, even snowplows, and the jeep's go-anywhere capability was further aided with deep water fording kits, tire air compressors, and a winch option. For communications, jeeps were modified with rear ditch plows and cable laying reels, such as the RL-31 reel unit.[54]

To disembark jeeps in amphibious landings, in 1943 a deep water fording kit for the jeep was produced. This enabled jeeps to be driven off landing craft like the LCM (Landing Craft Mechanized), wading into relatively deep water, without flooding the engine or short-circuiting the electrical system. After several interim kits were issued, the U.S. Army standardized the universal WV-6 kit (later G9-5700769) which served all WWII ​¹⁄₄‑ton to 2​¹⁄₂‑ton trucks. The kit contained flexible hoses for both the exhaust and the air intake, as well as proper waterproofing equipment. Westinghouse developed a T1 air compressor, to be used in conjunction with special tires, to deflate the tires off-road, in soft mud or snow, and be able to pressurize them again after. It could be fitted under a maintenance work order, from October 1944. There was even a small capstan winch field kit made for the jeep, driven off the motor, for self-extracting, or pulling other jeeps trapped in mud or snow.[54] The winch was very small, and made hand-cranking of the jeep impossible. The latter two gadgets remained very rare.

Willys developed a winterization kit for very cold climates. This included a cold-starting stove, crankcase ventilator, primer, hood insulation blanket, radiator blanket, a body enclosure kit, defroster/de-icer, and snow chains. These kits were however frequently unavailable, so units took their own measures in the field, particularly improvising various body enclosures, to protect the crew from extreme weather. In addition, two companies fabricated snow-plows for the jeep. Geldhill Road Machinery Company made the 7T1NE plow, an angled single blade, while the JV5.5E was a V-shape design. The Wausau Iron Works built two similar designs, designated as the J and JB snowplows. Neither of these seem to have been commonly issued in combat. Photos of snowplows in use in the European theater mostly show improvised plows, likely adaptations of snowplows locally found at hand.[54]

Although no other light jeeps were taken into production, it was not for lack of trying. Both key military men, who had been championing the development of military vehicle concepts they had formulated for years – sometimes already since World War One – had led to conclusions about the logic of military mechanization, as well as automakers large and small, who now saw that in wartime, all of a sudden there were budgets available to work with. Of course, this was primarily true for the firms involved so far.

After losing out on mass-production of the four-wheel drive ​¹⁄₄-ton, Bantam built the Army one 4x2 quarter‑ton chassis in 1942, but to no further consequence.[56]

One of thirty-six Crosley CT-3 'Pup' extra-light, 4WD mini-jeep prototypes

After the initial design specification of a maximum 1,275 lb (578 kg) weight had been raised to almost double that in production, to achieve the necessary ruggedness on the main ​¹⁄₄‑ton, the Army still wanted a truly lightweight model for airborne missions, and use in the jungles of the Pacific theaters. In 1942 and '43, at least five companies proposed designs: Crosley, Chevrolet, Ford, Willys, and Kaiser. The Crosley CT-3 "Pup" prototypes were superlight, one- or two-passenger, but still four-wheel-drive buggies, that were transportable and air-droppable from a C-47 Skytrain. Six of the 2-cylinder, 13hp, 1,125-pound (510 kg) Pups were deployed overseas after undergoing tests at Fort Benning, Georgia, but the project was discontinued due to several weak components. Seven of 36 Pups built are known to survive.[57][58]

Preparing for the July 1943 Sicily campaign: a jeep is loaded onto an American Waco CG-4A glider plane.

Most of the competitors' models were more similar to standard jeeps, just lighter and smaller. Willys managed to reduce the weight on their 'MB-L' (MB Lightweight) to some 1,570 lb (710 kg) in 1943; and Army engineers were impressed by the Chevrolet and its advanced features: a single center spar frame, and an integrated gearbox and transfer case.[59] Kaiser created six 1,300–1,400-pound (590–640 kg) prototypes with a 42hp engine, but including some unfavorable design trade-offs.

Willys eventually produced even more radical designs. The Willys WAC (Willys Air Cooled) had three seats, built around a centrally mounted 24hp Harley Davidson engine, weighed only 1,050 lb (480 kg), but was noisy and not user-friendly. Still, it showed promise, and was further developed, eventually resulting in the Willys JBC, or 'Jungle Burden Carrier'. By early 1945 this had turned into a mere 561 lb (254 kg) motorized wheeled load-carrying platform, with a single seat, that preceded the 1950s Willys M274 'Mechanical Mule'.[59]

In Britain, Nuffield Mechanizations and Aero cut down a Willys MB in length and width, and stripped it for minimum weight, to serve airborne forces. The Airborne Forces Development Centre in Wiltshire oversaw an entire modification program for jeeps in airborne units, involving many modifications to reduce both weight and or size, including to wedge them into Horsa gliders, for operation Market Garden.

Jeep with a 37mm cannon and a belt-fed, water-cooled, rapid-fire Browning machine gun in U.S. 3rd Infantry, Newfoundland, 1942

Besides towing 37mm antitank guns, it was also tested directly mounted on the quarter‑tons. In early 1941, the US Army's Tank Destroyer Command was urgently looking to make their antitank guns more mobile, to better serve their tactical doctrine. One of the first prototypes, the T2 37mm Gun Motor Carriage (GMC), mounted a standard 37mm gun and gun shield on a Bantam BRC-40, aiming forward over the hood. Seven of these were built and tested, starting in May 1941, but were found awkward. So instead, eleven T2E1 GMC units aimed the 37mm gun rearwards for trials. Shooting rearwards had advantages, but this configuration also proved difficult to man and operate the gun. The units were all dismantled to regular jeeps. In 1942, the larger ​³⁄₄‑ton Dodge WC-52 was converted and standardized as the M6 Gun Motor Carriage, with a rear-aiming 37mm M3 gun, but these also worked poorly in the field, and most were built back to regular WC-52 trucks. Further designs were tried with stretched 6-wheel jeeps, but by 1943, the 37mm guns had become largely ineffective against German tanks.

Late in the war, in 1945, the first large-caliber recoilless rifles became available, and the first jeep-mounted tests were performed, but they only came to fruition after World War II. One rare exception was Operation Varsity, for which two 75-mm. recoilless rifles were issued to the 17th U.S. Airborne Division, that could be mounted on their jeeps, proving useful in anti-tank fights.[60]

The jeep being too light to mount substantial guns, it was more suited later in the war, as a platform for rocket artillery, that didn't have the enormous recoil as conventional tube artillery. The California Institute of Technology developed two different 4.5in jeep-based rocket launcher systems for the U.S. Navy. Several other initiatives all used 4.5in rockets and tubes. Testing was also done by both U.S. Army and Marine Corps, but none of the jeep-mounted rocket launchers were built in any significant number, because it was more efficient to use larger trucks that could carry more rockets. The Soviet Red Army deployed twelve units fitted with 12-rail M8, 82mm rocket launchers in the bed of a jeep, from December 1944 in the Carpathian Mountains.[61]

Willys T14, rearwards firing 37mm Gun Motor Carriage (GMC) – the first 6x6 "Super-Jeep"

Willys MT-TUG, ​³⁄₄-ton 6×6 Tractor / "Super-Jeep" — picture from TM10-1513 manual supplement

Willys MLW-2 pickup, ​¹⁄₂-ton, 4x4, 'Light Jungle' prototype initially rode on 36 inch (91 cm) wheels and tires, and had a whole new rear, with a tailgate.

To extend the jeep's luggage space, the simplest, and frequently used method was the addition of a rear baggage rack. In exceptional cases, units would actually stretch both body and frame of a jeep, to give it more passenger and luggage space, but for this usage, a Dodge WC model was available in many cases. Nevertheless, building stretched, 6x6 jeeps with ​³⁄₄‑ton cross-country payload, was explored with much interest. As early as July 1941, after the unsuccessful testing with the T2 and T2E1 37mm antitank guns mounted on Bantam jeeps, the U.S. Quartermaster Corps (QMC) thought to lengthen ​¹⁄₄‑ton jeeps into 6WD for specialized roles, including the 37mm gun. Willys was contracted that month for both a T13 and a T14 Gun Motor Carriage, based on the Willys MA – one firing forward, and one rearwards, like the earlier Bantams. In reality, two models of rearward firing T14 were built, based on Willys MBs, one slat grille in late 1941, and one or more stamped grilles, by January 1942.[62] Although the Willys T14 was actually found to be the best of several 37mm tank destroyers tested by the U.S. Army, the Tank Destroyer Battalion had by that time standardized the Dodge ​³⁄₄‑ton M6 GMC.

Nevertheless, the QMC and Willys kept developing the ​³⁄₄‑ton 6x6, in various versions, as the "Super-Jeep". By March 1942, the T14 GMC was revised as a cargo / prime mover, named Willys 'MT-TUG', that could compete in some roles with the ​³⁄₄‑ton Dodges. The Army tested these in various configurations, up to a 1-ton rated version, as a light, multi-purpose tractor truck, cargo, or personnel carrier. For the Army Air Force / (US)AAF, several MT-Tug units were built with a fifth-wheel coupling on the cargo floor, for various Fruehauf trailers, and loaded with sandbags on the cargo bed, even as aircraft tugs. The Marine Corps also wanted a beefier truck, using standard jeep components, with higher fixed side body structure, as a personnel or mortar squad carrier, or an 'MT-CA' field ambulance.

The Willys MT models had the same ​³⁄₄‑ton rating as the new for 1942 Dodge WC models, but weighed only 3,100 lb (1,400 kg), with a 300 miles (480 km) range, and a top speed of 55 miles per hour (89 km/h). Willys pointed out that every 6x6 'Super Jeep' would save 2,000 lb (910 kg) of steel for their construction, as well as 40% in fuel usage, compared to the Dodge trucks.[63] Moreover, it comprised 65% unaltered standard jeep components, and many of the other parts were also just modified standard jeep parts. By January 1943, the Willys MT-TUG was further evaluated by the Army Transport Command at Camp Gordon Johnston, FL. It was positively reviewed there for its effortless operation in deep sand. Although the Willys ​³⁄₄‑ton's performance was even called 'exemplary' by some,[64] the U.S. Army nevertheless abandoned the Willys MT in favor of the already produced ​³⁄₄‑ton and 1​¹⁄₂‑ton trucks, because the Willys was 'surplus to requirements'.

Fifteen 6x6 Willys MT(-Tug)s alone were built as "Truck, ​³⁄₄-ton, 6×6, Tractor", under Ordnance production contract W‑303‑ORD‑4623, production order T6620,[62][65][66] and even a maintenance supplement for the "6x6 Willys MB‑Tug" was printed with the 1943 TM10‑1513 technical manual. Including miscelaneous test units, a total of 24 units are believed to have been built, with six known survivors.[63]

An even smaller number of ​¹⁄₂‑ton jeeps with a slightly stretched wheelbase were built as the Willys MLW(-1) through MLW-4 "Jungle Jeep". LW  stood for Long(er) Wheelbase, to accommodate significantly larger wheels and 7.50-20 tires with a tractor-like profile, with the objective to serve in the jungles of the Pacific theater, after a September 1943 request from the South West Pacific for a truck with payload and mobility over mud and swamps of jungle terrain, superior to that of the regular jeep.[67][nb 11]

Several tracked jeep prototypes were built, because of such a need in Alaska and Canada. After America had entered the war, a Japanese attack on the Aleutians made the Alaskan military base there suddenly a zone of great military importance. The snow-rich circumstances created a need for tracked, jeep-like, all-purpose vehicles, and the Canadian Bombardier company created the T29 jeep half-track out of one of the existing 6−6 Willys MT chassis. Due to Willys' workload, International Harvester helped assemble a further five T29E1 prototypes. Under the steering front wheels, skis could also be mounted.[68] An Aberdeen test report critiqued that the T-29E1 was difficult to steer, as the tracks could not be controlled independently, and that prolonged use caused excessive track component wear. The only known surviving half-track WWII jeep is named Willys T28 'Penguin'. Further (fully) tracked "jeeps" were also armored, and developed for, and by Canada — see section 'Armored jeeps'.

America experimented with armoring jeeps for reconnaissance (reenactment car).

Many jeeps received added armor in the field, especially in Europe in 1944–1945. Frequently, a rear slanting armor plate was added in front of the grille, and replacing the windshield, as well as the sides, in place of where doors would be. The upper, biggest part was typically made of a single, large, 5/16th inch steel plate, folded in three, with two different sight openings in the front.

The T24 Scout Car was built on a 6x6 Willys MT "Super-Jeep" chassis.

One blitz buggy each month is our commitment [between 1939 and 1945], Archives of Ontario poster collection (I0016089)

Since reconnaissance was one of the jeep's primary purposes, there was a demand for some armor from the start of production. Starting April 1942, the second T14 GMC 6x6 Willys MT-Tug chassis was converted to the T24 Scout Car. Though performing well in trials, the T24 was abandoned in the autumn in favor of the M8 & M20 Light Armored Car. Concurrently, the Ordnance Corps was pushed to work on a lightly armored reconnaissance design, based on the standard Willys 4x4 jeep. Different armor configurations were tested on the T25 through T25E3 prototypes respectively. For all 4x4 armored jeeps, the significant weight increase reduced their payload, and adversely affected their mobility.

Canada went another step beyond, and created two small series of light, tracked, armed, armored vehicles using largely Jeep automotive components. In late 1942, the Canadian Department of National Defence (DND)’s Directorate of Vehicles and Artillery (DVA) began work at No.1 Proving Ground in Ottawa on a small tracked vehicle successively named: 'Bantam Armoured Tracked Vehicle', the 'Light Recce Tank', and finally: the 'Tracked Jeep', or Willys TJ. Main roles included: intercommunication (running messages over contested ground), armored reconnaissance, and engaging unarmored enemy troops in airborne and combined operations.[69] Willys and Marmon-Herrington were contracted for five more prototypes, Willys for power train components, and M.H. for hulls and running gear. The Tracked Jeep showed excellent cross-country performance over all terrain types, especially soft mud. Its up-hill mobility was deemed superior to all other light tracked utility vehicles, while its amphibious capability was adequate, despite its low freeboard.[69] There were however serious shortcomings with the running-gear and tracks. Work to fix this delayed testing until late 1944, and British insights demanded such fundamental changes, that a mk.2 version was developed, of which another six units were fabricated, and not ready until after the war had ended. The problems with tracks and running gear were still not sorted out, and development halted. America had observed the Canadian effort, but saw no advantages, compared to the M29 'Weasel' Tracked Cargo Carrier.

Canadian "Willys Tracked Jeep" (TJ) Mk.1 — Museum unit, information sign and interior

With maximum armor of 12mm (​¹⁄₂-inch), this measured 283 cm (111 in) long, 169.5 cm (67 in) wide, by 127.5 cm (50 in) high,[70] and aimed at top speeds of 56 km/h (35 mph) on land and 8 km/h (5 mph) in the water.

Hafner Rotabuggy in flight

The most extreme concept tried was to turn the jeep into a rotor kite (or gyrokite), similar to an autogyro – the Hafner Rotabuggy (officially Malcolm Rotaplane). Designed by Raoul Hafner in 1942, and sponsored by the Airborne Forces Experimental Establishment (AFEE), after their Rotachute enjoyed some success, a passive rotor assembly was added over the jeep cabin, along with a lightweight tail, for stabilization. This jeep could be towed into the air by a transport or bomber tug. The Rotabuggy would then be towed to the drop zone as a rotary-wing glider. It took until autumn 1944 to achieve a decent test flight, and other military gliders, particularly the Waco Hadrian and Airspeed Horsa) made the Rotabuggy superfluous. Incidentally, it was first named the "Blitz Buggy", but that was soon dropped for "Rotabuggy".

Other contemporaneous jeeps

World War II soldiers called the half-ton 1940 / 1941 Dodge Reconnaissance / Weapon Carriers "Jeeps" before the Willys MB.

The compact Ford GTB / G-622 1​¹⁄₂-ton 4x4 truck, introduced in late 1942, was still typically nicknamed 'Burma jeep'.[71]

According to some sources, the word "jeep" was used as early as World War I, both as U.S. Army slang for new, uninitiated recruits or other new personnel who still had to prove their mettle. It was also used by mechanics, to refer to any new prototypes or untested vehicles.[3][72] Later, in mid-March 1936, a character called Eugene the Jeep was created in E. C. Segar's Popeye cartoons.[5] Eugene the Jeep was Popeye's "jungle pet" and was small, able to walk through walls and move between dimensions, and could go anywhere and solve seemingly impossible problems.[73][74] The Eugene cartoon character brought new meaning to the Jeep name, diverging from the initial, somewhat pejorative meaning of the term, instead changing the slang to mean a capable person or thing.[75]

Eugene the Jeep's go-anywhere ability resulted in various industrial and four-wheel drive vehicles getting nicknamed "Jeep" in the late-1930s. Around 1940, converted 4WD Minneapolis-Moline tractors, supplied to the U.S. Army as prime movers, were called "jeeps",[76][77][nb 12] and Halliburton used the name for an electric logging device,[3][78] or for a custom built four wheel drive exploration/survey vehicle.[75] A small, anti-submarine, escort aircraft carrier was called a "jeep carrier" in the U.S. Navy in WWII,[79][80] and also several aircraft – prototypes for both Kellett autogyros, and for the Boeing B-17 Flying Fortress,[75][81] as well as the 1941 Curtiss-Wright AT-9 were called "jeeps". Additionally, in 1936/1937, Canadian soldiers had received a ​¹⁄₂-ton Marmon-Herrington half-track, and called it a "Jeep" (with a capital 'J').[82]

All three light U.S. 4x4 trucks, nicknamed 'jeeps' in World War II: a Willys MA ​¹⁄₄‑ton, and Dodge WC ​³⁄₄‑ton and ​¹⁄₂‑ton (L to R).

By 1940–1942, soldiers generally used "jeep" for half-ton or three-quarter-ton Dodge Command Reconnaissance cars, with the three-quarter-ton Command Cars sometimes called "beeps" (for "big Jeeps"), while the quarter-ton cars were called "peeps", "son of jeep", "baby jeep", or "quads" or "bantams".[3][77][78] A seven page article in Popular Science (Oct 1941) headlined introducing the quarter-ton as "Leaping Lena", and called it a buggy, or just a bug.[47] Originally, "peep" seemed a fitting name, because the quarter-ton was considered primarily a reconnaissance (peeping) car.[78]

The early-1940s terminology situation is summed up in the definition given in Words of the Fighting Forces by Clinton A. Sanders, a dictionary of military slang, published in 1942, in the Pentagon library: "Jeep: A four-wheel drive car of one-half to one-and-one-half-ton capacity for reconnaissance or other army duty. A term applied to the bantam-cars, and occasionally to other motor vehicles (U.S.A.) in the Air Corps, the Link Trainer; in the armored forces, the ​¹⁄₂ ton command car. Also referred to as 'any small plane, helicopter, or gadget'". "Jeep" could still mean various things, including light wheeled utility vehicles other than the jeep.

In the first years of the war, this usage of the term 'jeep' logically meshes with the ratios of U.S. light wheeled military trucks production. In 1940, the U.S. government took delivery of 8,058 light trucks – 6,583 of which were ​¹⁄₂-tons, 4x4, Dodge G-505 VC- and WC-models (82%).[83] The ​¹⁄₄-ton jeep was yet to be designed. The half-tons provoked two insights: the military wanted many more of them, but also needed another vehicle – even smaller, lighter, and more agile. In 1941, Dodge ramped up the ​¹⁄₂-ton WC-series, delivering some 60,000 units, compared to some 15,000 quarter-tons, almost all still pre-production units, built by three different manufacturers. Even in 1942, when production of the standardized ​¹⁄₄-ton jeep really got up to speed, it didn't catch up to the WC-series' numbers — the 170,000 jeeps built still only amounted to half of the total 356,000 light trucks the Army had received by end of that year. It took until early 1943 for the Ford and Willys jeeps to outnumber the ​¹⁄₂-ton and ​³⁄₄-ton Dodge WC models in service.[84]

One of the most frequently given explanations is that the designation "GP" was slurred into the word "Jeep", in the same way that the contemporary HMMWV (for "High-Mobility Multi-purpose Wheeled Vehicle") has become known as the 'Humvee' — either from the initial Ford model "GP" – or from the military 'G.P.', for "General Purpose" (vehicle).

Although prior existence of the term "jeep" dismisses this as an etymology in the strict sense, it may well have contributed to the marriage of the term with the WWII quarter-ton truck.

The first version, based on the Ford "GP" model code, was already given in an article in the San Francisco Call-Bulletin in late 1941,[85] and is to an extent plausible, because the pre-standardized Ford GP was the first of the ​¹⁄₄-ton jeeps to reach GIs by the hundreds, starting from early 1941. So it is possible "GP" could have evolved into "Geep" and then "jeep".[41]

The latter 'GP'-based explanation (from the term "general purpose"), though this does appear in the TM9-803 Manual (page 10),[1] and the car is designated a "GP" in the TM9-2800 Manual — these were published in late 1943 and early 1944, and their influence on the jeep's name is dubious. One reason being: the jeep wasn't the only of the Quartermaster Corps' "general purpose" vehicles – so if this was the source, people would have nicknamed others "geeps" or "jeeps" as well,[86] as they did before.
More influential perhaps, was the 1943 short propaganda / documentary film The Autobiography of a 'Jeep', by the U.S. Office of War Information, in which the jeep itself literally propagates this origin story of its nickname.[87]

Willys wartime ad promoting the Jeeps' contribution to the war effort – in particular used by the Seabees[nb 13]

Joe Frazer, Willys-Overland President from 1939 to 1944, claimed to have coined the word jeep by slurring the initials G.P.,[81] possibly related to Willys-Overland's 1946 copyright claim to the Jeep name. However, the company handling Willys' public relations in 1944 wrote that the jeep name probably came from the fact that the vehicle made quite an impression on soldiers at the time, so much so that they informally named it after the go-anywhere Eugene the Jeep.[85]

In early 1941, when the test cars went by names like BRC / "Blitz-Buggy", Ford Pygmy and such, Willys-Overland staged a press event in Washington, D.C., a publicity stunt and Senate photo opportunity demonstrating the car's off-road capability by driving it up and down the U.S. Capitol steps. Irving "Red" Hausmann, a test driver on the Willys development team who had accompanied the car for its testing at Camp Holabird, had heard soldiers there referring to it as a jeep. He was enlisted to go to the event and give a demonstration ride to a group of dignitaries, including Katherine Hillyer, a reporter for the Washington Daily News. When asked what it was, Hausmann said "it's a Jeep". Hausmann preferred "Jeep", to distinguish the Willys rig from the other funny-named quarter-tons at Camp Holabird.[77] Hillyer's syndicated article appeared in the newspaper on 20 February 1941, with a photo showing a jeep going up the Capitol steps and a caption including the term "jeep". This is believed to be the most likely origin of the term being fixed in public awareness. Even though Hausmann did not create or invent the word "Jeep", he likely contributed to its mainstream media usage indicating the quarter-ton vehicle.

In 1941, Willys publicly showed off their MA's off-road capabilities, like by stair-climbing on Capitol Hill

Part of Katherine Hillyer's February 1941 article. The caption: "LAWMAKERS TAKE A RIDE – With Senator Meade of New York at the wheel and Representative Thomas of New Jersey beside him, one of the Army's new scout cars, known as "jeeps" or "quads" climbs up the Capitol steps in a demonstration yesterday. Soldiers in the rear seat for gunners were unperturbed."

It is plausible that the origin was mixed and converged on "jeep" from multiple directions. Ford Motor Company pushed its Ford GP hard, to get the military contract, putting the term "GP" into use. Military officers and G.I.s involved in the procurement and testing of the car may have called it jeep from the WWI slang. Civilian contractors, engineers, and testers may have related it to Popeye's "Eugene the Jeep" character. People may have heard the same name from different directions, and as one person heard it from another, put their own understanding and explanation on it.[89] Overwhelming presence of the nickname 'jeep' in the public's opinion was probably the deciding factor.[75]

From 1941 on, a "constant flow of press and film publicity",[18] as well as Willys advertising as of 1942, proclaiming it had created and perfected the jeep, cemented the name "Jeep" in the civilian public's mind,[78][17] even when "peep" was still used at many army camps,[18] and President Roosevelt spoke of the vital role the "peep" had to play in defending the shores of Fort Story, Virginia (04-1942).

One other particularly influential article may have been the January 1942 full review of the military's new wonder buggy in Scientific American, reprinted as "Meet the Jeep" in Reader's Digest, the best-selling consumer magazine of the day.[90] Author Jo Chamberlin was duly impressed by the "midget combat car" and wrote:
"Our Army's youngest, smallest toughest baby has a dozen pet names such as jeep, peep, blitz-buggy, leaping Lena, panzer-killer. The names are all affectionate, for the jeep has made good. Only a year old, it stole the show in Louisiana. Now the Army plans to have 75,000 of them." In a prescient footnote, Chamberlin wrote: "Some army men call the bantam a "peep", reserving "jeep" for the larger command car in which the brass hats ride. However, the term 'jeep' (born of GP, an auto manufacturing classification) is used by newspapers and most soldiers, and apparently will stick'".[91][92]

Jeepney

When American troops began to leave the Philippines at the end of World War II, hundreds of surplus jeeps were sold or given to local Filipinos. The Filipinos stripped down the jeeps to accommodate several passengers, added metal roofs for shade, and decorated the vehicles with vibrant colors and bright chrome hood ornaments.

The jeepney rapidly emerged as a popular and creative way to re-establish inexpensive public transportation, which had been virtually destroyed during World War II. Recognizing the widespread use of these vehicles, the Philippine government began to place restrictions on their use. Drivers now must have specialized licenses, regular routes, and reasonably fixed fares.

Starting in 1950, a Jeep-engined utility vehicle was produced by Autoar in Argentina. Starting from 1951, a new sedan was introduced using the same 2199 cc Jeep engine and manual transmission. It was fitted with overdrive to compensate for the Jeep's low axle ratio. In 1952, a new overhead valve 3-litre six-cylinder was announced, but was probably never built. At that time, Piero Dusio returned to Italy. In the 1950s, production was sporadic, and models built included a station wagon with a Jeep-type 1901 cc engine.

Inspired by the U.S. Army Willys MB, Jeep produced about 1000 Willys editions of the 2004 Wrangler TJ, and hoped to sell twice that number for the 2005 model year.[109]