Ray Russell, the creator of the Gadabout, was thinking outside of the traditional design box in 1945. He took several pumps directly connected to the engine crankshaft and forced oil at high pressures through pipes to "motors" located at the wheels. The hydraulic pressure turns the wheels and drives the car. Among the advantages claimed for this new drive system were flexibility of operation, and weight savings of up to 800 lb. compared to conventional cars.
Full hydraulic drive should not be confused with the hydraulic coupling used on many cars built since the late thirties. In these, the fluid coupling is a link between the engine and the drive shaft. It still requires a geared transmission, either manual or automatic, a drive shaft, and a rear axle. The Gadabout simplified this system by applying the hydraulic pressure directly to the wheels.
The idea of a full hydraulic drive was not new, in 1945. Past endeavors to develop the principle however, had never passed the experimental stage. Detroit engineer and industrial designer, Ray Russell, took the principle of a pump and remote motors from experimental models to the road.
With three pumps of different capacity connected to the engine shaft, seven forward and reverse speeds are possible. By engaging four pumps, 15 different speeds or ratios could be obtained. All pumps would turn with the engine. Only those required to operate in the hydraulic system were cut into the system by their feed valves. A pump that is temporarily cut out of the system by closure of this intake valve absorbed negligible power and therefore was not a drag on the engine. The basic valve actions and pipe circuits required to control the hydraulic system were not complicated.
The directional movement of the car was controlled by a four-way valve. The valve determined the direction of the oil flowing in the wheel-motor circuit. It disconnected the engine and wheels as desired. By reversing the flow of oil through the wheel-motors, a powerful braking action was available to supplement the action of conventional brakes.
In test runs Russell's model is said to have displayed smooth, silent acceleration. With up to 1,000 lb. per inch pressure available in the hydraulic system, plenty of power could be delivered at the wheels. Good heat dissipation due excess heating of the hydraulic system was avoided.
Simplicity of operation was the one feature that Russell believed would win public acceptance of his hydraulic drive. The only pedals on the floor board were for accelerator and brake. A single valve changed the direction of oil flow and replace the conventional reverse gear system. Other valves, possibly automatically controlled, selected the pumps used changing the ratio between engine and wheels, and then speed.
The experimental Gadabout's steel tube framing and piping system would have allowed for almost any body configuration. As no straight line was required for the drive train, there would have been few restrictions on body design and passenger compartment layout.
While the Gadabout never became a commercial reality for car buyers, Russell's success was noticed by the automotive industry. His services were retained by the Ford Motor Company where he reportedly supervised Ford's hydraulic-drive research.
Source by George Kynman