This vehicle was a familiar sight, widely associated with the German infantry during all of World War Two. It began simply as an armored version of the Sd.Kfz.11 half-tracked artillery tractor. The half-track was one of the several solutions given to the problem of low off-road capabilities of trucks and associated “special purpose vehicles” (Sonderkraftfahrzeug). The Sd.Kfz.11 was designed in 1938 by Hanomag and was the prime mover for the 105 mm (4.13 in) LeFH howitzer and 37 mm (1.46 in) Flak 43, and 9000 units were built until 1945.
Because the Sd.Kfz.251 was produced by the same manufacturer as the Sd.Kfz.11, the natural choice was to use the HL kl.5 chassis as a base on which a stronger framework, supporting the armored panels, was constructed. After a few sketches, the sloped armor that characterized the type was taken from the previous 7.5 cm Selbstfahrlafette L40 prototype made by Hansa-Lloyd (1937). This was a risky choice in terms of efficient storage and production ease, but the idea behind was straightforward. The slope meant that any bullet or shrapnel had to travel through more of the plate, while keeping the weight low. The Ausf.A (Ausführung A or “A-version”) was the first of the Mittlerer Gepanzerter Mannschaftskraftwagen. It appeared in mid-1939 and was first allocated to the Panzergrenadiers attached to the 1st Panzer Division (stationed at Weimar, during the spring of 1939), the best equipped German unit at the outbreak of the Polish campaign. Production figure estimates for 1939 are only 232, and production was assumed by Hanomag in Hanover, Büssing-NAG of Berlin Oberschoeneweide, Weserhuette of Bad Oeynhause, Wumag of Goerlitz, and F. Schichau of Elbing. The Ausf.B appeared in 1940and was similar in all aspects but the relocated radio antenna (from the step to the rear fighting compartment), and the removal of the rear vision sights, for production ease. By the end of 1940, only 337 more would be delivered. An estimated 500 took part in the French campaign. That's all I know, but I'm still learning more about this vehicle.
