This vehicle was the only one of the series to enter production. On 27th July 1942 Hitler issued an order for the cancellation of the 5-ton Sd.Kfz.6 vehicle and for the turning over of production facilities for this vehicle to the output of the sWS. The sWS was a new, simplified, low-speed tractor designed primarily for use by infantry units as a supply vehicle in adverse conditions. The parent firm was Bussing NAG of Berlin Oberschönweide, and Ringhöfer-Tatra assisted in production. On 27th July 1942 the OKH presented WaPruf.6 with a requirement for 7,484 of these vehicles to be completed within the next two years. Production was scheduled to begin during the spring of 1943 with a monthly output of 150; but the first vehicles did not enter service until December 1943, when only five were completed. The firms assigned to producing these vehicles were Bussing NAG and Tatra in Czechoslovakia (the latter continuing production for some years after the war for the Czech Army). By September 1944 only 381 sWS had been delivered to the army, and total production by 1945 amounted to 1,000. The Tatra version employed the air-cooled Tatra 111 engine.
The vehicle had a greatly simplified suspension and dry-pin tracks. It was mainly intended as a supply vehicle, although versions existed which had heavy bows for canvas covers and could carry wounded men (four stretchers, six minor casualties and two orderlies). There was also a version with an armoured cab which, apart from its role as a normal tractor, was used as a platform for various weapons. It was originally intended that the sWS should replace the Maultier hybrid semitracks which had been produced as an expedient prior to its introduction; but as production never reached a satisfactory level, the Maultier remained in service for the remainder of the war.
The tractor was normally provided with an open lorry body. The engine was a 6·cylinder Maybach HL42 TRKMS, basically similar to and of the same rating as the engines used in the 1- and 3-ton tractors, and it had dry-sump forced lubrication, using a gear-type pump. The dry double-disc clutch, type PF220K, was the same as that used in the 1- and 3-ton tractors. The main gearbox, type Kb40D , gave four forward speeds and one reverse speed and was of sliding-mesh, non-synchromesh type. The auxiliary gearbox was connected to the main one by a short propeller shaft. Two ratios were provided. The vehicle had a conventional controlled differential. The steering brakes were mounted co-axially with the half-shafts and were pneumatically operated. Here the road brakes were not integral with the driving sprockets. The half-shafts drove the driving sprockets through final reduction gears secured to each of the main chassis members. The suspension consisted of five pairs of double overlapping bogies, there being three widely spaced and two narrowly spaced on each side. The bogies were mounted on taper roller-bearings on hubs carried on radius arms, each separately sprung by means of a torsion-bar. The arrangement of these differed from that on the older semi-tracked vehicles in that the radius arms on the two sides were directed in opposite senses, those on the left pointing forward and those on the right trailing. Further, each torsion·bar was arranged to be co-axial (whereas in the older semi-tracks they were slightly offset) and tracks of the same number of links were used on each side. The driving sprocket consisted of two truncated cones, united at the smaller ends and carrying toothed rings bolted to the two outer rims. The bogies consisted of pairs of identical shallow discs carrying solid rubber tyres at their peripheries and were bolted to the hubs. They were detachable without removing the hubs. The idlers consisted of spoked wheels, rubber blocks being secured round their peripheries by steel clamping rings that also acted as guides for the teeth of the tracks. The idlers were mounted on cranked axles and the usual track-tensioning device was used, comprising a nut and threaded rod device incorporating a shear-bolt. Each track consisted of fifty-five main links, each carrying two spuds and two guide teeth, and an equal number of intermediate links hinged together by track pins. The intermediate I inks were secured on the outer side by a head and on the inner side by a circlip and pin. The guide teeth ran between the widely-spaced bogies but outside the narrowly-spaced ones. The track width was 500mm (19.7in).
The front wheel steering was of the ZF Ross worm and- cam type, and it was connected with a pneumatic valve for operating the track brakes when the steering wheel had been turned through a certain angle. A new feature was a lever on the dashboard that enabled each track to be braked independently, allowing the vehicle to be driven on one track only in the event of one track slipping excessively or when removing tracks.
A winch was optional and would be incorporated only by special request. It was driven from the auxiliary gearbox through a propeller shaft and worm gear. The capacity of the winch was 5 tons.
The version with an armoured cab weighed 10.5-tons unladen and could carry up to 3 1/2 tons. The trailer load capacity was 8 tons. In this version the engine, radiator and driver's compartment were enclosed in light armour plate. This armour was joined by welding except that of the engine cover, which was bolted on. The armour varied from 15mm on the front to 8mm on the sides and roof. The body of the vehicle consisted of a flatbed covered with steel plates and fitted with hinged sides. A compartment of the same height as the sides extended across the rear of the body. A seat for a gun crew was located at the back of the cab and was protected by an extension of the side armour. A folding canvas top was provided. This armoured version was not fitted with a winch.
Manufacturer: Bussing-NAG, Ringhoffer-Tatra
Chassis Nos.: 150001-
825 produced from December 1943 to March 1945
Engine: Maybach HL42TRKMS
Gearbox: 2 x 4 forward, 2 x 1 reverse
Weight (tons): 13.5
Length (metres): 6.92
Width (metres): 2.5
Height (metres): 2.07
Speed (km/hr): 28
Range (km): 300