Neubaufahrzeug (Nb.Fz.) was an early German multi-turreted heavy tank design developed covertly starting in 1932 by Rheinmetall and Krupp to modernize the earlier Großtraktor concept. Heavily influenced by international multi-turreted designs of the era like the British Vickers Mark III, the tank featured a main turret armed with both a 7.5 cm KwK and a coaxial 3.7 cm gun, complemented by two auxiliary machine gun turrets positioned diagonally at the front and rear. Only five prototypes were built between 1933 and 1936—two mild-steel test platforms by Rheinmetall powered by BMW aircraft engines and three armored combat prototypes by Krupp featuring Maybach HL engines. Although deemed too complex, large, and costly for mass production, the project provided crucial technical insight, layout concepts, and turret engineering that directly influenced the development of Germany’s primary wartime medium tank, the Panzer IV.
