viking pioneered important innovations over the v-2. one of the most significant for rocketry was the use of a gimbaled thrust chamber which could be swiveled from side to side on two axes for pitch and yaw control, dispensing with the inefficient and somewhat fragile graphite vanes in the engine exhaust used by the v-2. the rotation of the engine on the gimbals was controlled by gyroscopic inertial reference; this type of guidance system was invented by robert goddard, who had partial success with it before world war ii intervened. roll control was by use of the turbopump exhaust to power rcs jets on the fins. compressed gas jets stabilized the vehicle after the main power cutoff. similar devices are now extensively used in large, steerable rockets and in space vehicles. another improvement was that initially the alcohol tank, and later the lox tank also, were built integral with the outer skin, saving weight. the structure was also largely aluminum, as opposed to steel used in the v-2, thus shedding more weight.