Prior references to this type of vehicle in Tactical and Technical Trends will
be found in No. 11, p. 27 and
No. 39, p. 34. Unlike the
semi-tracked vehicles, the German wheel-cum-track armored observation
vehicle Sd. Kfz.* 254, is designed to be driven either on the
track or on the four wheels.
a. Characteristics
The vehicle examined weighed 11,900 pounds. Its principle dimensions
and armor-plate thickness are:
Length | | 14 ft 10 in |
Width | | 7 ft 4 in |
Gage of track | | 4 ft 3 in |
Wheel base | | 7 ft 10 in |
Height on wheels | | 7 ft 7 in |
Height on tracks | | 7 ft 3 in |
Width of wheels | | 8 in |
Width of tracks | | 9 1/2 in |
Fording on wheels | | 2 ft 11 in |
Maximum gradient | | 37 degrees |
Ground clearance on wheels | | 9 1/2 in |
Ground clearance on tracks | | 1 foot |
Fuel consumption--roads on wheels | | 19.4 miles per gallon** |
Fuel consumption--cross-country on tracks | | 3.85 miles per gallon |
Radius of action--roads on wheels | | 310 miles |
Radius of action--cross-country on tracks | | 62 miles |
Fuel capacity | | 16 gallons |
Armor | | |
Front | | .394 in |
Sides | | .197 in |
Back | | .197 in |
Top | | .197 in |
b. Drive
The wheels can be raised for track drive and lowered for wheel drive. Although
the tracks use spring-suspension, the four wheels are suspended by two torsion bars.
To effect the change-over from tracks to wheels the vehicle must be stopped, and
a power take-off from the transmission engaged. This rotates a heavy disk
situated laterally across the vehicle with a pin set on either side of it diametrically
opposite, the pins being vertical to the surface of the disk. Connected to each of
these pins is an arm extending out through the side of the body of the vehicle, one
arm on each side. When the diameter between the pins is vertical, the arms are
withdrawn, and when the diameter is horizontal, the arms are extended sideways. The
rotation of the disk is controlled through the power take-off. On either side
of the vehicle extending from the front suspension unit to the rear axle is a torsion
bar, either of which is connected to one of the arms through a lever. The front
end of the torsion bar is connected to the front wheels. The rear end is connected
to the rear wheels, in either case by an arm solid with the torsion bar and
pivoted at the wheels. The front wheels are mounted on parallel arms, the upper
ones being connected to the torsion bar. Between the arms a hinged tie rod
operates, permitting the wheels to be turned by means of a conventional steering
wheel. The rear wheel assembly consists of a conventional differential and axles
which are solid, in that they may be raised and lowered as a whole. The arms
from the torsion bars are connected to the wheels through knuckle joints.
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If the torsion bar is rotated, the wheels will be raised off or lowered on
to the ground. To complete the picture, when the disk is in such a position that
the diameter between the pins is vertical, the arms are drawn inwards, the
torsion bars are rotated so as to raise the wheels. On rotating the disk by the
engine through the power take-off the arms extend sideways, rotate the torsion
bars and lower the wheels to the ground. Further turning, jacks up the vehicle on
the wheels, the tracks being raised off the ground. At this stage the diameter
between the pins on the disk is in the horizontal position.
The "Track Wheel" gear selection lever is then moved to the "Wheel" position
and the vehicle may be driven off.
c. Suspension
(1) On Tracks
There are 6 small hollow steel bogie wheels. The front and rear wheels
are mounted singly and each is sprung by a coil spring. The remaining four wheels
are in the form of two scissor articulated pairs sprung by coil springs. There
are four hull stub axles, the first carrying a single bogie wheel, the second and
third an articulated pair and the fourth again a single bogie wheel. There is also
a front sprocket, rear idler, and 4 hollow steel return rollers. A girder connects
the first three hull stub axles on the outside of the suspension assembly. The
track is rather light and is made up of links connected by unlubricated pins. There
are two bridges to each link, the bogie wheels running between them.
(2) On Wheels
The torsion bar used for raising and lowering the road wheels also provides
the method of springing them. The wheels are fitted with pneumatic tires.
d. Steering
On tracks steering is effected by controlling the differential by means of
two steering levers. On wheels, steering is effected by means of a normal steering
wheel.
*Sonder Kraftfahrzeug--special motor vehicle
**Using a 70 HP Diesel motor