By
Kurt Laughlin
One
of the most frequent questions appearing on tank modeling newsgroups
is "What tracks should I use for a
?" Generally
people rely on period photographs (always a good idea) but other
information indicates that the answer is not nearly as clean as
the surviving photographs might indicate.
Wartime
Tracks
The
pre-war tanks of the US Army were designed to use a track block
consisting of steel tubes vulcanized into a symmetrical rubber block.
This minimized wear on the tank running gear and road surfaces,
reduced noise, and allowed for the track blocks to be flipped after
one side had worn. Although these reversible rubber blocks were
adequate for good ground, they suffered in soft terrain. The official
solution was to install steel grousers over the end connectors on
every four to seven blocks that would act as paddles in the soft
mud. Unfortunately running the tank with grousers installed on hard
ground reduced track and suspension life and made steering more
difficult. The time involved in mounting and dismounting the grousers
made switching to match the terrain impractical. As an alternate
the Ordnance department developed rubber chevron tracks which gave
good performance and life in both hard and soft ground.
With
the approach of war the Army sought to reduce the use of strategic
materials such as rubber. Because tracks accounted for something
like 10-15% of the Army's total rubber allotment, Ordnance began
developing an all-steel track block. Initially these steel blocks
had relatively shallow integral grousers because deep grousers were
too hard on the suspensions and increased rolling resistance. Although
these designs had long life, their traction was poor and the steel
wore out suspensions easily. As a compromise rubber-backed steel
tracks of various grouser designs were eventually developed combining
the conservation and wear properties of steel tracks with the suspension-saving
features of rubber.
The
track situation was never settled during the war, with numerous
combinations of grouser styles and fabrication methods in development.
The desires of the using arms also changed with the season and terrain,
such that in December 1943 Army Service Forces essentially threw
up its hands and authorized the production of both steel and rubber
tracks and in April 1944 allowed the issue of whatever tracks the
theater commanders thought best for the current or expected conditions.
A series
of meetings in the fall of 1942 assigned preferences for light and
medium tank tracks, "based entirely upon functioning"
and without "consideration of ease of manufacture or availability
of materials." The tracks used by Fifth Army were ranked by
the Ordnance Technical Committee thusly:
Light:
T16 (1), T36E6 (2)
Medium: T49 (2), T48 (3), T51 (4), T54E1 (5)
Curiously,
the preferred medium tank track, the T56E1, seems to have been little
used by US forces while quite common on Allied vehicles. Equally
as strange was the decision to restrict light tank rubber chevron
track to stateside usage while medium tanks used them wordlwide.
Tracks for Light Tanks
Tracks for Medium Tanks
The Fifth Army Report
Conclusion and References
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