Vehicles - The Lightweight

Background to the Lightweights

Some 30 years ago the average helicopter could not lift a couple of 1/4 ton vehicles. The Americans came up with the "Mighty Mite" manufactured by American Motors from April 1960 to January 1963. The US started development in 1950 with a design by Ben F Gregory. The US Marines tested twelve prototypes in the early 1950's. The wheelbase was only 64" and weight 1496 lbs., with an air cooled engine and 3 speed high/low range transmission and positive 4x4 at all times. AMC acquired exclusive rights to manufacture in Nov 1954, but it still took 6 years to start quantity production. In the end nearly 4000 vehicles were delivered to the US Marines. Known as the Truck 1/4 Ton 4x4 Utility Lightweight M422 and M422 A1 (suffix letter is a modified version) the production model differed in many respects from the prototypes, i.e. 4x4 could be disengaged, engine (still air-cooled) etc.

Meanwhile the British also wanted a lightweight 4x4, at first testing their 1/4 Ton minus body by parachute etc. The end result with the Champs was a big "splat". During 1959/60 BMC introduced the Mini Moke. Some were tested by the MoD who were not happy with the design as it did not meet their requirements. The Moke was 4x2; a 4x4 twin engine version was produced for evaluation in 1962, but was again no good for the MoD. During 1966 the Austin Ant 4x4 was produced to tempt the MoD. However in 1967, British Leyland amalgamated and Austin's 4x4 were finished. The Austin Gypsy ceased production in 1968. Rover's 4x4 remained the only vehicle in it's class left in production at that time. Land Rover, which supplied the standard 1/4 Ton 4x4 to the MoD, was developing their Lightweight during 1966/67. It was based on the standard 88" wheelbase chassis and engine etc. The MoD approved this as it was aimed at a "General Staff requirement for an airportable helicopter vehicle that could carry a useful payload and be capable of towing light support weapons" (official text).

The standard 88" was not suitable for the role because it was too wide and heavy to be stored in military aircraft of the time. Land Rover made a totally new body making it possible to remove the rear top half of the load bed, tailgate, doors, windscreen and top bulkhead, and bumper. 6.00X16 tyres were even fitted to save weight along with the oil cooler disappearing on very early vehicles. The axles were modified with different halfshafts to keep flush with the overall width; (this feature disappeared on later SIII vehicles, as it was no longer necessary). However when production started 6.50x16 tyres were fitted as standard. The Wessex helicopter could lift a stripped down Lightweight, the rest of the vehicle coming later. One prototype 20 BT 91 was tested during "Operation Wagon Trail" in 1967 (see Vanderveens "Cross-Country Cars since 1945"), looking at the photo, this vehicle seems to have a higher bonnet or lower headlights than the production vehicles. Other "Test vehicles"(?) were VXC 702F, CXC 212G (Chassis 2360001 in the Dunsfold collection) and NXC 25H (FFR with headlights in wings).

Official titles and codes of Lightweights Series IIA
Truck, Utility, General Service, 1/2 Ton, 4x4, Rover Mk 1. Codes 1620-0772 (for RHD) and1620-5772 (for LHD)

Truck, Utility, General Service, FFR, 1/2 Ton 4x4 Rover Mk 1. Codes 1625-0772 (for RHD) and 1625-5772 (for LHD)

Note; Payload increase to 1/2 Ton compared to 1/4 Ton for other 88" 4x4 in use. This description means there were two Mk 1's, this may be useful to know so you don't confuse it with Truck Utility 1/4 Ton 4x4 GS Rover Mk 1 80" WB (1948/51).

Description

Based on the Rover 10, which it replaced in GS and FFR, its main difference was the body. It fulfilled the same role as the Rover 8 and 10, but could be reduced in weight and bulk quickly, resulting in a stark but useful air transportable vehicle. The following could be removed for air lifting: doors, tailgate and upper body panels, hood and sticks, rear seats, spare wheel and windscreen. The main production change was the moving of the headlights to the wings. If one studied the weights it can be seen how useful in the late 1960's the vehicle was, even if the actual weight loss was quite small. Later larger helicopters made the Lightweight obsolete in its original role. The RAF and Royal Navy/Royal Marines also used the Lightweight. The Royal Marines adapted theirs for beach landing with waterproofed electrics and air intake and exhaust via snorkels. An impressive sight to watch, a head emerges first from the sea followed by the rest of the vehicle.

Amphibious Lightweights

The Royal Marines and certain Army units developed a way of wading ashore from landing craft in depths up to 5 feet (1.5M). This was achieved with special water proofing conversion kits comprising of:

  • elastic waterproof covers
  • PVC bags
  • rubber bungs
  • battery vent covers
  • rubber non return valves, etc.

Also used were various types of sealant and other proprietary (ie Scotch) materials, such as inhibitors for starter motors and industrial joint sealant for flexible seals. To enable use either as a normal road vehicle, or in the wading role, the kit is applied in various stages. Land Rovers were fitted with most of the kit at stage 1, which involved fitting the majority of the kit, at which there were no limitations on vehicle use. This would take at least 14 hours to do. Stage 2 took a further hour and involved checking all previous work carried out, making sure the fuel tanks were full, and minor greasing of components, fitting a towrope, and ensuring all kit was packed in PVC bags and stowed away. This would take place just before embarkation. Stage 3 involved checking the above, fitting tailboard stays to ensure quick flooding of the vehicle, and final finishing of sealing and greasing of some items.

Once the Land Rover left the Landing Craft, it was driven at a fast idling speed to prevent stalling in low gear and four wheel drive, without changing gear. The Royal Marines use a facility in Devon called, Amphibious Trails and Training Unit Royal Marines (ATTURM) to train personnel in this role. One way of telling if this modification has been done is to look for a large plugged hole on the left hand side of the bulkhead, below the heater motor. This is where the carb air breather pipe (Q-hose) ran up to the windscreen. The Dutch Army used the Lightweight with diesels as standard and a belt and braces system of fuses for the electrics. The rear light clusters were also different for the Dutch, looking more like add on trailer board lights.

Weights L/wt GS L/wt FFR Rover 10 GS Rover 10 FFR
Unladen 3210 lbs. 3330 lbs. 3364 lbs. 3748 lbs.

Laden 4453 lbs. 4553 lbs. 4460 lbs. 4776 lbs.
Stripped U/L 2660 lbs. 2810 lbs. with 5 gallons fuel no spare wheel
Stripped U/L 3596 lbs. 3596 lbs.
The FFR is fitted with a quickly demountable modular radio kit.

A 110" wheelbase with a 2.995cc 6-cylinder engine was also tested although quantity production did not occur. It is thought that 2 or 3 were built in 1965 and possibly 1966. VXF 100F survives in the Dunsfold collection. The SIII was introduced in October 1971. It was mechanically similar to the SIIA. What was new, was a new all syncromesh gearbox, servo assisted brakes (not early CL), full width fascia styling (i.e. a dash in front of the driver) and a lot more plastic. The SIII Lightweight kept the old style dash! The Rover Mk1 was the SIIa Lightweight, i.e. SIIA gearbox, headlights in grill panel (at least on early vehicles). This made it very hard to tell late SIIA vehicles from early SIII vehicles. The MoD classed the SIII vehicles as:

Truck, Utility, General Service, 1/2 Ton, 4x4, Rover Series 3. Code was 1620-0778 (RHD) and 1620-5778 (LHD).
Truck, Utility FFR (Fitted for Radio) 1/2 Ton 4x4, Rover Series 3. Code was 1625-0778 (RHD) and 1625-5778 (LHD)

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If you can add to or amend the facts presented in this feature, please contact me and I will gladly do so. My thanks to John Mastrangelo for supplying the above info and to those club members whose vehicles are shown.