Panzerkampfwagen IV with Hydrostatic Drive
Photo courtesy of George Bradford
Zahnradfabrig Augsburg built this particular Panzer IV. The
design had no gearbox, and was not a liquid drive. Rather the
"Thoma" drive allowed the primary Machbach HL 120 TRM engine to
power two high-performace oil pumps which in turn powered two oil
engines.
The results of the German tests on the vehicle were lost during the war.
After the war, the vehicle was taken to the Aberdeen Proving Grounds
to be tested by the U.S. Army (as they were working on their own
hydrostatic drive project). The vehicle remains at the Aberdeen
Proving ground today.
Photo courtesy of George Bradford