Abstract: A novel method and device for self-contained inertial vehicular propulsion using the combined effort of linear and rotational kinetic energy. The propulsion device containing pairs of flywheels with parallel axial orientation, opposite rotation and opposite alternate cyclic linear movement in the direction of vehicular travel. Kinetic energy is supplied to the flywheels with integral motor-generators means while at the same time the motor-generator means is connected to a rotational-to-reciprocal transmission means causing the alternating cyclic movement of the flywheels and supplying kinetic energy output for the propulsion of the vehicle. The formulation of the rotational-to-reciprocating transmission means allows an accumulation of kinetic energy into the motor-generator means rotational kinetic energy without causing a negative reaction force, due to the governing effect of the flywheels linear inertia in a governing negative feedback loop.