Currently on leave, which means I have time to do the one thing I can’t. Explore the concept of Heavy Utility vehicles beyond the limits of the game. But how does one do it? I sure as hell can’t present any ingame content, as I am sure you’ll know that a man’s truck simply isn’t possible to make in game as there are no bodies suitable to pass for one (except maybe the cabover vans), dual rear wheels are not possible, and so is a Diesel engine with cylinder sizes far exceeding what is possible with the engine designer.
Bear with me this one is going to be text heavy. A short history of IMPs heavy trucks until 1978. Why 1978? Because 1978 was the year heavy utility vehicles were moved to the Monolith brand and because IMP was quite experimental until then which resulted in countless weird, wonderful and world moving innovations and Concepts.
IMP was created in 1913 by a former DMG (a predecessor of Daimler Benz) engineer as a third party constructor and manufacturer of internal combustion engines for a variety of purposes. Being based in Düsseldorf, North Rhine-Westphalia, first successes were found in repairing and building marine engines. In 1915 IMP absorbed the local truck manufacturer Nahber-Friedemann-Werke*, gaining access to their production facilities. The escalating great war nearby resulted in high production numbers of the unchanged Nahber-Friedemann until 1918. During 1919 work on modernizing the outdated trucks with new frames and IMP designed engines. The 1921 IMP La3t 45 was therefore the first true IMP truck, with a 3 ton payload and a 50hp 4.5L engine. A 5 ton version with a 5.2L engine followed in 1923. That year however french troops invaded the area and seized the nearby coal mines, causing the german government to literally print money which resulted in a hyperinflation of the Reichsmark currency. IMP however managed to survive the chaos and continued to expand, culminating in a 7-ton truck with a 9L six-cylinder petrol engine in 1929.
In the meantime highly efficient high-speed Diesel engines began to pop up all over the place and IMP had their own ready in 1932, a 9.4L six-cylinder with pre-chamber injection and 85hp. Smaller 6.9L and 5.5L diesel engines appeared in 1933, just as a historical change of leadership would change germany forever. Not bothered by politics (yet), the Diesel engines proved so successful that gasoline engines were phased out by the end of the decade. Other innovations were the introduction of four-wheel drive in 1935 for construction and mining companies (later found to be useful in the rasputiza of the russian wilderness) and the flagship 10-ton WK series in 1937 with an overhead-cam, 190hp 13.8L Inline 8 Diesel with an optional Roots-type supercharger.
The remilitarization of Germany was highly beneficial for IMP, who had become the country’s second largest manufacturer of trucks by 1938, and even attempted to break into the passenger car market with the highly advanced L8 and L12 in 1937. Of course come the outbreak of WW2 all production was military-only, making extensive use of forced labour by POWs and Concentration camp prisoners. IMPs leadership, while officially aligned with the regime, believed that a high quality of the product could only be achieved by a healthy workforce, and at least tried to ensure human working conditions for everyone without raising attention. At last an in-house coup in 1943 ousted the old leadership and working conditions took a drastic turn for the worse. Coincidentally so did the quality of the finished trucks. In the later stages of the war the main Factory was a popular travel destination for allied bombers. By May 8th 1945, production had all but stopped.
Shortly after, now under british rule and with the pre-1943 leadership reinstated, production recommenced with heavy damages to the facility and severe shortage of raw materials. Down to two models, the 1 1/2 ton VK and the 3-ton NK, IMPs trucks were a valuable asset for rebuilding the country. 1947 saw the introduction of the 5- and 7-ton RK series with new OHV Inline 6 or Inline 8 engines and up to 140hp. The RK was a massive success that was also exported globally and even received a redesign in 1955.
From leftover US trucks IMP managed to secure and dissect a number of GM Diesel two-stroke engines. An IMP reverse engineered 4-71 engine was introduced in 1949. From that point on all existing Diesel engines were quickly replaced by two-stroke Uniflow engines ranging from a 3.0L Inline four to a 10L Inline 8 with over 250hp. Two stroke Diesels would become a mainstay of IMPs trucks until changing customer demands spelled an end to them in 1969, with the last one commercially sold in 1964. From then on IMP would reintroduce an all new line of direct injection four-stroke Diesels with optional Turbocharging.
During all this IMP had cooperated with the competitor Büssing to develop an underfloor engined cab over truck like this example:
The idea behind the underfloor engine was quite ingenious, the engine tiled 90° and mounted far behind the cab removed the heat and most of the noise being emitted into the cabin by a traditional standing engine (especially advantageous for IMPs legendarily noisy two-strokes!), it allowed for a more spacious cab with a flat floor and low entry sills, and removed the need for a tilting mechanism of the cab as the engine was perfectly acessible for maintenance work. Finally the considerably lowered center of gravity resulted in excellent road holding. It also allowed for this:
Büssing Supercargo, a mid 1960s prototype using the flat engine concept to its full advantage and use the entire length of the truck as cargo area. I’ve seen this thing in person last year, odd-looking to say the least, lower than most cars and probably an absolute monster on the racetrack.
However the mid-engine design was unsuitable for all-wheel drive and other trucks designed for off-road usage, as the engine and its accessories were totally unprotected against dirt, weather, salt and other evil stuff you don’t want on your engine, it was also not possible to use this design for articulated semi-trailer trucks due to the short length of the traction engine. The IMP underfloor engine was therefore only available on rigid long-wheelbase lorries, which made it unfeasible for mass production. It was in production from 1959 to 1964, when a new range of conventional COEs was launched with the new four stroke engines.
*Nahber-Friedemann-Werke is a fictional company made up to expand the lore, any similarities to existing companies are unintentional
Conclusion of Part I. Part II to follow, going a bit more in-depth on the four-stroke 400D15 engines and the S64 and S76 heavy Cabovers that carried them and made IMP the true King of the Road. In the meantime I’ll also be swinging my artistic sword to give you even more reading pleasure with Illustrations and technical information.