Rijdendkalk 500
| Rijdendkalk 500 | |
|---|---|
| Overview | |
| Type | Prototype truck |
| Manufacturer | Schroeter Traktoren |
| Production | 1922–1925 (10 prototypes) |
| Powertrain | |
| Engine | 8.75 L ST-Motorwerkmerg-5A21 I5 (petrol) |
| Transmission | 4-speed manual |
Rijdendkalk 500 was a Dutch heavy truck developed in prototype form by Schroeter Traktoren. The model was introduced in 1922.[1] Five RK500-T Transport prototypes and five RK500-B Bos prototypes were built between 1922 and 1925. The Transport was intended for agricultural freight, while the Bos was designed to recover forestry machinery and tow trailers.
Design
[edit | edit source]Schroeter used the ST-Motorwerkmerg-5A21 petrol engine, which had first appeared in the company's M.Beschiet.I armoured vehicle in 1921. The naturally aspirated inline-five had a 120 mm bore and 155 mm stroke, giving a calculated displacement of 8.765 litres. It used a 5.0:1 compression ratio and pushrod-operated overhead valves, with a carburettor supplying the fuel-air mixture. An engine-driven centrifugal pump circulated coolant through a radiator with a mechanical fan. The engine had full-pressure wet-sump lubrication for its main and connecting-rod bearings.
A 12-volt battery supplied the coil-and-distributor ignition and a foot-operated electric starter engaging the flywheel ring gear. An engine-driven dynamo recharged the battery. Both Rijdendkalk variants used a mechanically operated dry single-plate clutch ahead of a four-speed manual gearbox. Universal-jointed propeller shafts carried power to bevel-and-spur double-reduction final drives.
Variants
[edit | edit source]The RK500-T Transport had a forward cab and an enclosed rectangular cargo body intended to carry agricultural supplies and farm equipment, including bagged produce. It used smaller front wheels and larger rear wheels, with drive and steering provided by a single rear axle.
The RK500-B Bos was built for direct-pull recovery of immobilised forestry machinery. A heavy rear towing coupling and recovery shackles allowed it to pull machinery or haul trailers without a powered winch. Unlike the Transport, the Bos had two rear steering axles, while its front wheels were unpowered. The first rear axle steered continuously and was normally driven. The driver could engage steering on the second axle separately from its drive.
For additional traction, a mechanical selector engaged the second rear drive axle through a positive coupling in a frame-mounted power-distribution unit. Separate jointed propeller shafts served each axle, without an interaxle differential. A selectable low-range gearbox was fitted for heavy pulling. The rear axles shared a coupled cantilever leaf-spring suspension and were equipped with mechanically operated internal-expanding drum brakes, supplemented by a separate parking brake. All main wheels used wide solid-rubber tyres. Two small free-rolling wheels beneath the centre of the chassis helped the Bos clear obstacles when it became grounded. It carried additional fuel tanks compared with the Transport.