M151 1/4-ton 4x4 utility truck

M151 Truck, Utility, 1/4-Ton, 4×4
Overview
Manufacturer Ford, Kaiser, AM General
Production > 100,000 (1959–1982)
Body and chassis
Class 1/4 ton truck/personnel transport, four wheel drive
Layout Front engine, 4WD
Related M422 "Mighty Mite" contemporary
Powertrain
Engine inline 4-cyl., 141.5 cu in (2.319 L)
71 hp (53 kW) at 4,000 rpm / 128 ft·lbf (174 N·m) at 1,800 rpm
Transmission 4-speed + reverse manual transmission
single-speed, part-time transfer case
Dimensions
Wheelbase 85 in (2,160 mm)
Length 133 in (3,380 mm)
Width 64 in (1,630 mm)
Height 71 in (1,800 mm) with top up
reducible to 53 in (1,350 mm)
Curb weight 2,400 lb (1,100 kg)
Chronology
Predecessor Willys M38A1
Successor AM General HMMWV

The Truck, Utility, 1/4-Ton, 4×4, M151 (M151) was the successor to the Korean War M38 and M38A1 jeep Light Utility Vehicles. Commonly referred to as a "jeep" or "quarter-ton", it was produced from 1959 through 1982 and served in the Vietnam War. The M151 had a monocoque design making it roomier than previous jeep designs, and incorporated an independent suspension with coil springs. It has since been replaced by the larger AM General HMMWV in most utility roles in frontline use. With some M151A2 units still in U.S. military service in 1999, the M151 series achieved a longer run of service than that of the WW2 MB/GPW, M38, and M38A1 series combined.

History

In 1951 Ford Motor Company was awarded the contract to design a 1/4 ton 4×4 truck to replace the M38 and M38A1 model jeeps. The M151 was developed to specifications and guidance of the U.S. Army's Ordnance Tank Automotive Command. Design started in 1951 and testing and prototyping lasted through most of the fifties. Although the M151 was developed and initially produced by Ford, production contracts for the M151A2 were later also awarded to Kaiser and AM General Corp, a subsidiary of AMC.

Design

Improvements

M151A2 with top up and closed

Although the M151 mostly retained the same basic layout and dimensions of its predecessors, it was for all intents and purposes a completely new design. Unlike previous jeep designs, whose structure consisted of a steel tub bolted onto a separate steel frame, the M151 utilized a integrated frame design, which integrated the box frame rails into the sheet-steel body-structure. Eliminating the separate frame gave the M151 slightly more ground clearance, while at the same time lowering the center of gravity. This process slightly enlarged the vehicle, making it roomier than previous jeep designs, while retaining the same light weight.

Front has grille with horizontal slats

Another area improved upon in the M151 was the suspension. Dispensing with the rigid live axles in the front and rear that all previous military jeeps used (a layout still used on modern day Jeeps, such as the Jeep CJ and Wrangler), the M151 was instead equipped with independent suspension and coil springs. This made it capable of high-speed, cross-country travel, while boasting high maneuverability and agility. The new suspension also had the added benefit of providing a more comfortable ride.

Due to copyright and trademark issues, the M151 did not feature Jeep's distinctive seven vertical slot grille, instead, a horizontal grille was used.

Problems

Unlike other military transports, such as the WWII and Korean War Jeeps and Dodge and Chevrolet transport trucks, the M151 was never widely released into the civilian market. This was partly because it did not meet federal highway safety standards for civilian vehicles, and because of a series of early rollover accidents. While these were often blamed on the independent suspension (which played no small part), they were also due to driver errors, with operators unprepared for the increased performance compared to the Jeeps which it replaced. The swing axle rear suspension design was prone to radical camber changes when subjected to abrupt shifts in lateral loads, resulting in catastrophic oversteer, which often led in turn to a vehicle rollover. Sudden and excessive steering input, as commonly found in a high-speed emergency avoidance maneuvers, was a recipe for disaster, as was heavy braking mid-turn. The vehicle's tendency to lose control was reduced when there was weight in the rear, so drivers would often place an ammunition box filled with sand under the rear seat when no other load was being carried. The box could simply be emptied or abandoned when the extra weight was not needed. Recoilless rifle carrier models were especially prone to rollover accidents due to their stiffer rear springs and were typically subjected to severe speed restrictions any time the gun was not aboard.

The handling issues were eventually resolved by a redesign of the rear suspension, introduced in the M151A2 model. However, due to liability concerns, the U.S. Department of Defense deemed all M151 series vehicles "unsafe for public highway use", limiting their public use. Continuing problems with vehicle roll-overs into the 1980s led the US military to retrofit many M151 series vehicles with the "Roll over protection structure" (ROPS), a roll cage intended to protect both front and rear seat passengers.

Service

Soldiers of the 82nd Airborne Division in a heavily loaded M151 during Operation Urgent Fury

First put into service in Vietnam, the M151 played an active part in American military operations well into the 1980s, when it was phased out in favor of the HMMWV. Despite its official replacement, the M151 had some distinct advantages over its much larger and heavier successor, like being small enough to fit inside a CH-53 heavy transport helicopter. This flexibility was one of the reasons the U.S. Marine Corps deployed M151 Fast Attack Vehicle (FAV) variants up until 1999, in theatres such as Kosovo. It currently serves in U.S. special forces units as a FAV.

Various models of the M-151 have seen successful military service in 15 different NATO countries and M151s were sold to many countries, including Canada, Denmark, the United Kingdom and non-NATO countries like Egypt, Lebanon, Israel, the Philippines, and Pakistan. Currently, the M151 is used by over 100 countries worldwide.

Post-military use

In the late 1980s the M151s began being phased out of service in favour of the HMMWV. A few (perhaps 1,000) were sold via Government Surplus auctions, and those that were not sold via Foreign Military Sales (FMS) overseas were cut into four pieces and scrapped. However some individuals were able to buy these "quartered" M151s and simply weld the four sections back together, and rebuilt them into drivable condition. Some vehicles sold in the United States were simply cut in half, some of which were simply welded back together and driven. Additionally, beginning in the late 1990s a few companies dealing in Military surplus items bought M151s from some of the foreign governments that received the vehicles via FMS for reconditioning and further sales.

American Growler

A Growler Light Strike Vehicle for the U.S. Marine Corps in December 2005, with a towed mortar.

American Growler designs and sells a line of Light Utility Vehicles based on the M151 drivetrain. The Light Strike Vehicle is intended to replace Fast Attack Vehicle variants of the M151, and is reduced in size to fit into the V-22 Osprey tiltrotor transport. Although originally intended to utilize the M151 drivetrain, the final result is an all new design and contains no M151 parts or design elements.

Variants

TOW missile being fired from M151A2.

Users

Group of three American soldiers, their M151, and two West German Bundesgrenzschutz officers, 1979.
Saudi Arabia used M151s in the Persian Gulf War.

Asterisk indicates not listed in Annex C Appendix II of US Army Technical Manual of Foreign Military Sales. TM 9-2320-356-BD "Battlefield Damage Assessment and Repair, Washington, D.C. 18 December 1987"[2]

See also

References

  1. ↑ "M151A2 FAV", GlobalSecurity
  2. ↑ http://imfmotorpool.com/063247.PDF
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