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ETO Ordonance Technical Intelligence Report no. 175 10 March 1945

Subject: German Heavy Semi-Tracked Military Tractor, S.W.S.

Observations by: Lt. J.F. Eppes, Ord. Tech. Intell. Team No. 3

1 General:

German heavy semi-tracked military tractors, "Schwerer Wehrmachtschlepper", have been examined in the area of THIRD U.S. Army. This vehicle is similar in construction to the standard semi-tracked prime movers, the principal difference being the use of a steel track of the design used on German tanks.
The S.W.S. is highly maneuverable. lts high ground clearance and good traction combine to make it an excellent mud vehicle.


The following data was taken from the plate on the dashboard:

Chassis No.150636
Body No.3636
Motor No.524875
Horsepower100 at 3000 r.p.m.
Piston displacement4198 c.c. (256.3 cu. in.)
Weight empty9500 kgs. (20,900 Ibs.)
Payload4000 kgs. (8,800 Ibs.)
Axle load2000 kgs. (4,400 Ibs.)
Track load11,500 kgs. (25,300 Ibs.)
Trailer load8,000 kgs. (17,600 Ibs.)
Radio suppressiongroup II


The engine is the Maybach HL 42, 6 cylinder, water-cooled, gasoline engine, with pushrod operated overhead valves. The two carburetors are of Solex manufacture, type JFF 30. Ignition is by Bosch magneto mounted at the rear of the engine. The fuel tank is mounted at the rear of the chassis.


An instrument panel on the dashboard carries:
Oil pressure gauge (Gearbox)
Oil pressure gauge (Engine)
Water temperature gauge


From the engine the drive is taken through a dry plate clutch to a gearbox with four forward speeds and one reverse. The gearbox is manufactured by Zahnrad Fabrik - Friedrichshafen and its type is "K 40 D". There is, in addition, a high-low ratio box alongside the main gearbox.


Steering is by the steering wheel through a worm for the front wheels and in some cases aided by a controlled differential system for the tracks. The steering linkage to the front wheels is coupled to the track steering brakes, though under normal driving conditions the vehicle is steered only by use of the steering wheel. In difficult terrain, steering by the tracks iridependently may be effected by means of a rontrol switch on the dashboard to the left of the steering column. The steering and tracks brakes are operated hydraulically with air assistance. The steering linkage for the front wheels is shown in photo #3.


Suspension of the front axle is by a transverse, semi-elliptic spring anchored at the center. The front wheels are of the pressed steel, flat rim type. The tires are manufactured by "DEKA" and are size 270 x 20. They are held on the wheels by split locking rings. The spare wheel is carried mounted on the back of the cab.


a. Tracks: The tracks are of skeleton type with chevroned soles and are believed to be cast of manganese steel. Each link consists of two members, a plain shoe and a shoe with a double guide horn. The linkage is made with a single headed pin retained by a sleeve and cotter pin (photos #3 and #4). The width of the shoe is 19 inches. Track adjustment is by draw bolt fastened to the idler mounting.
b. Bogie wheels: There are five double bogie wheels on each side. They are interleaved; the first, third and fifth wheels being widely spaced and the second and fourth closely spaced (Photo #2). The bogie wheels are pressed steel with rubber tires (Photo #4). Overall diameter is 31 l/2inches. The bogie wheels are sprung on torsion bars which are mounted side by side.
c. Sprockets: The pitch diameter of the driving sprocket is 2'5 1/2". The sprocket is of fabricated construction having 12 teeth, with a pitch of 7 l /4", and six spokes.
d. Idlers: The idlers are of cast construction. Their overall diameter is 29 1/2 inches. Rubber tires, which are fitted in four segments, are bolted to the rim of each wheel.


The body of the vehicle is fastened to the longitudinal frame members. It is built of l 1/2" tongued and grooved board, amply braced with steel strips. The sides and tail gate are hinged along the lower edges. Metal supports are fitted at front and rear for a canvas cover (Photo #2). The cab is spacious and is open at the top and sides. A canvas hood is fitted. This may be folded back when desired. The windshield is hinged to fold forward (Photo #1)


Overall length 21 ft. O in.
Overall width 8 ft. l l /4 in.
Overall height 8 ft. 10 in.
Length of body 13 ft. 4 in.
Width of body 7 ft. 11 in.
Height of body sides l ft. 10 1/2 in.
Height from ground to top of body sides 5 ft. 81/2 in.
Tread of front wheels 7 ft. O in.
Track centers 6 ft. 3 in.
Center of front bogie wheel to center of rear bogie wheel6 ft. 8 3/4 in.
Center of sprocket above ground 2 ft. l /2 in.
Ground clearance l ft. 8 in.

For the chief ordnance Officier:

H.N. Toftoy
Col. Ord. Dept.

Heavy semi-tracked tractor, S.W.S. Note front suspension and shock absorbers, and canvas cover for driver's cab.

Right rear view showing track suspension. Note fuel tank filer pipe below tailgate, hinged sides, supports for cover over body, and spare tire mounting.

Front susspention and steering linkage, track and interleaving bogies.

Drive sprocket and bogie wheels

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