American-built tanks ever saw service in the Great War, but big
efforts were made in the USA to develop these new types of vehicles
- quite apart from the British and French designs the Americans
themselves were using on the Western Front. The first tank built in
the USA was the so called Holt Gas-Electric, an effort by the
Tractor Co. of Peoria, Illinois.
the French S:t Chamond, it had a combined petrol-electric propulsion.
Hence the name: gas (i.e. petrol) electric. A Holt 90 h.p.
4-cylinder motor produced power for a G.E.C.
generator, which in it’s turn provided current to drive two
electric motors, one motor for each track. (The electrical
units were built and supplied by the General Electric Co.)
Special attention was paid
to ventilation and engine cooling, using a forced water cooling
system with a radiator placed immediately above the generator. Air
was drawn in through a louvre above the engine and foul air was
emitted through big louvres in the left hull rear.
rear drive sprockets were driven from these electric motors by a
worm gear to a roller pinion which meshed with the sprocket.
Steering was achieved mainly by varying the
current to the respective electric motors. When sharp turns was
needed this could be effected by braking the drive shaft on the side
of the turn. Track and suspension was of the standard Holt type with
two sprung bogies, each with six rollers, on each side, covered with
light steel plates.
engine, generator, and drive units were all at the rear of the
vehicle leaving the roomy box-like fighting compartment free for the
armament. (The exit and entry door was also placed at the rear.) The
main armament was a 75mm Vickers mountain howitzer, which was placed
low down in the V-shaped nose. The secondary armament consisted of
two Browning 0.30in machine guns in sponsons on each side. The tank
was to be serviced by a crew of six men.
a prototype was built of the Holt Gas-Electric Tank, and work on the
vehicle was abandoned after tests. One of the problems with the tank
was it’s weight: because of the rather complex propulsion and
transmission systems this had been pushed up to some 25 tons, which
in its turn lowered the speed to some 9 km/h.
in favour of a design with all-round tracks. One can also
surmise from the design, that trench crossing would have been tricky
with this machine, because the Holt type suspension was used as is.