Development and History of the International No.1
In 1952 the Government of the time decided it was time to replace much of the equipment that the Army was using as much of it was of WWII vintage. This was no minor undertaking, and the Army Design Establishment (ADE) played a major role. In 1952 and 1953 ADE was in discussion with a number of truck manufacturers. The government wanted as much local content in the vehicle as possible, and the International Harvester Company of Australia (IHC) was certainly willing to do the job. International mostly put together imported trucks and American model numbers in a number of configurations, but nothing quite like what the army was after.
It was army practice to downrate off road vehicles payload by up to 50% from what their on road payload would be. So what would be an army 3 tonner for off road, would normally be a 5 tonner in civilian life. The vehicle had to be 4x4 with a single track on 12.00 x 20 tires. In order to maximise space it was to be in a cab over configuration like the Ford/Chevrolet Blitz. This also improved the turning circle as well as approach and departure angles. A forward sloping, and opening windscreen was another requirement placed by the Army. Soldiers both retired and serving at the time were also asked by the R&D department of the company, what they wanted from their Army trucks.
The cab over was the first problem for IHC. The closest that they has was the semi cab over AR and AS models, but these vehicle lacked the foward sloping windscreen. Three prototypes were completed by late 1953. IHC had built their own crude box shaped cab. The vehicle had obvious influences in the Blitz as well as the Bedford QL and RL series vehicles. Research and Development bought a Chev Blitz from a disposal auction and sent it to the carpentry department for the initial cab prototype. The Carpenter's brief was to "fit this Blitz cab to this chassis". These prototype cabs were designed to fit on a modified version of the bonneted AS model trick chassis, with the steering box altered and the gear lever arrangement altered. This imported chassis was channel section but tapered off at each end.
The Australian No.1, Mk.1 and Mk.2
The first of three prototypes were completed in 1955 and delivered to the ADE, however it was only of a 4x2 configuration because the driven front axle was not yet ready. This vehicle had a 12' wheelbase, and was 21' overall with a 3 ton payload. It rode on the 12.00x20 bar tread tires and had an enlarged version of the locally built 6 cylinder petrol engine which was now 282 cubic inches.
The Army tested the vehicle to it's limits (and in some cases beyond them) at the ADE proving ground at Monageeta as well as a number of locations around Australia. It was tested in all kinds of weather and conditions, and in general the Army was very happy with them. The only change of any note appears to be to the gear change arrangement. One was even sent to Antarctica for a time.
In late 1956 the Army finally placed an order for 100 of the 3 ton vehicles with the idea being that the vehicles would be given more testing and real world use before further orders were placed. It seems that somewhere around 1960 the Army tried to standardise some of it's equipment with the US, rather than British military, so the type subsequently became known as the 2.5 ton truck. Deliveries began in 1959.
The Mk.2 was the first development of the Mk.1. It retained the metal bonnet of the Mk.1 but was fitted with a Olding - Garwood 20,000 lb winch mounted behind the transfer case. The winch could be fed out the front or rear of the vehicle for recovery purposes. A number of Mk.1 and 2 vehicles have had their designations changed as winches were added or removed to vehicles during their service life.
It is believed that a government department purchased some Mk.1/Mk.2 vehicles, but the number is unknown, and if it is part of the order of 100 vehicles.
Full Production of the Mk.3 and Mk.4
On the 16/12/1962 the Australian Army placed it's first large scale order for 600 Mk.3 Models. The Mk.3 retained the stronger chassis and centrally mounted winch of the Mk.2, but had a revised cabin. The corners were more rounded and a larger fiberglass bonnet was fitted. Initially fiberglass front mudguards were fitted and had an integral step, but they were replaced later in production with metal units. Inside the cab a new dashboard was fitted and the wiper motors were moved to the top of the windscreen. In september 1963 second order of 650 vehicles was placed by the Australian Army. (Ref, Mike Cecil, AWM)
The Mk.4 appeared in the form of an order for 610 more vehicles for the Army. The cab was similar to that of the Mk.3, but the fiberglass bonnet was replaced with flat metal unit, a change that was carried over to the Civilian versions of the ACCO. A twin circuit braking system was also introduced to reduce the chances of total brake failure.
A 6x6 Model, F1, F2 and F5
6x6 prototypes had been constructed and trialed as early as 1958 in an effort to produce a larger version of the ACCO. In the end 390 of the 6x6 Mk.5 version of the ACCO were ordered in 1966. Essentially the 6x6 was a Mk.4 with a longer, reinforced chassis, and an extra axle. The tray was also moved rearwards to make space for storage boxes behind the cab to be fitted. The heavier 6x6 vehicle required more power than it's smaller counterpart and one prototype was built with a V8 engine. However for production the army settles on a twin carbureted version of hte existing engine and a heavier 5 speed transmission was used.
The 6x6 was produced in several configurations, A standard General Service type (F1), a recovery vehicle / Wrecker(F5) or as an aluminium bodied tipper (F2). It is also a misconception that teh 6x6 Model was called the Mk.5. In army service it was never refered to as such as the F1, F2 and F5 models all had major differences and were essentially different vehicles on a similar platform.
The 6x6 was an incredibly capible vehicle off road, with a ground clearance of 330mm, and approach angle of 45 degrees and a departure angle of 40 degrees. It could climb a 33 degree gradient fully loaded, and ford water 1 meter unprepared, or 1.8 meters with preperation. The final 6x6 ACCO's were delivered to thye army in 1973 and were widely used in vietnam. Because of their simplicity, and ease of repair these vehicles were keenly sought after by private concerns when the army disposed of their fleet.
In the 70's there was a proposal to refurbish the 6x6 ACCO's by converting them to Diesel and adding full power brakes and power steering. Probably with a IH or Perkind engine fitted. However the army did not proceed with this and the fleet was eventually replaced with Unimogs.
A number of variants appeard to have been created in small numbers, from a Garbage compactor to a cement mixer, water tankers and evenm a semi trailer tractor.
It's not knowm how many of these vehicles were made by international, and how many were created by RAEME, but if you know anything, feel free to let REMLR know..
Certainly it appears that the NZ army used some International No.1 Trucks. It's not known precisely how many, or if they were built new, or sold to NZ second hand as some of our Series 2 Land Rovers were. Until such time as we get some chassis numbers or documents we won't know for sure.