The SdKfz 251 stands with the Panzer IV at the focal point of Wehrmacht armor. Its only rival for “best of its kind” was its US army counterpart. It was a bit of a military afterthought. German infantry had regularly ridden trucks to the combat zone during maneuvers since the Reichswehr years. In the early days of the armored force, motorcycles were so popular that five of the nine rifle companies in a panzer division’s rifle brigade rode them. Trucks and cycles, however, shared common problems: high vulnerability and limited off-road capacity. On the other hand, the panzers’ commitment to the principle of close tank-infantry cooperation was reinforced by the experiences of both sides in the Spanish Civil War, when tanks operating alone in broken or built-up terrain proved highly vulnerable to infantry who kept their heads. In a 1937 exercise, the modified civilian two-wheel-drive trucks assigned to the motorized infantry performed so badly that Guderian, still a mere colonel, directly challenged the armís commander in chief, Werner von Fritsch, to remedy the situation.
“Had my advice been followed, we would now have a real armored force” were bold words, often cited to prove Guderian’s professional conviction, his moral courage, and his arrogance, depending on the author’s perspective. In fact, exercises and maneuvers were historically regarded as high-stress situations where such outbursts were more or less predictable, and Fritsch had a known high tolerance for young enthusiasts. Guderian, moreover, was widely understood as Lutz’s protégé (an alternate German word is Protektionskind, “favorite child”). In short, he got away with it.
In concrete terms, Lutz and Guderian pressed for the development of an infantry-carrying vehicle with sufficient cross-country mobility to accompany tanks into action, and with enough armor and firepower to allow the crew to fight from it, if necessary. Such a vehicle had to meet two external requirements. It had to be cheap, and it could not interfere with tank production. That ruled out prima facie any kind of full-track design. Trucks were disqualified because any reasonably armored version would be heavy enough to overload suspensions and to lack off-road capacity. The answer came from the artillery—and indirectly from France.
Even before World War I, truck companies on both sides of the Atlantic had been experimenting with replacing rear wheels with some sort of track in order to lessen ground pressure and improve mobility in mud, snow, and sand. Most prominent in this effort was French engineer Adolphe Kegresse, whose successful conversion of some of Russian Tsar Nicholas’s autos inspired the Putilov armaments works to consider a project for military half-tracks. After the war the French firm of Citroën developed several civilian versions, staging well-publicized desert crossings in North Africa and central Asia and attracting the particular attention of a French army still engaged in Morocco and southern Algeria.
From the later 1920s, half-tracks made up a steadily increasing percentage of France’s military motor vehicles. Initially and primarily used as artillery and engineer vehicles, they found their way to the mounted troops as well. The French cavalry division as reorganized in 1932 had 150 armored versions as reconnaissance and combat vehicles. Another hundred, unarmored, carried the men and weapons of the battalion of Dragons portés (motorized dragoons) newly created for each mounted division.
With such an example so ready at hand, as early as 1926 the Reichswehr’s Weapons Office began preparing its own design for half-track tractors. Daimler-Benz began working on a production version in 1931; by 1936, a series of vehicles from one ton to eighteen tons were on the drawing boards or in the field, mostly as artillery tractors. That reflected, in passing, the artillerís continued reluctance to accept the urging of the Lutz/Guderian school and fully mechanize the panzer divisions’ fire support by developing self-propelled mounts. This was more than commitment to branch self-interest and a tradition of towing guns into battle. Tracked vehicles were still fragile relative to the weight and the recoil of even a light field piece like the standard 105mm howitzer. In addition to probable effects on accuracy, a breakdown took the gun out of action as well. Not until well into the Cold War would even the US army abandon towed guns as standard divisional-level weapons.
On the bright side from the panzers’ perspective, Hanomag’s three-ton tractor seemed well suited to carry a rifle squad. The armored chassis was provided by Büssing and the fit, if not perfect, was close enough for government work. At eight tons, with between 8 and 15mm of armor and mounts for two light machine guns, the 251 was tough and durable, eventually serving as the mount for a bewildering variety of weaponry. Tracks extending to nearly three-fourths of the chassis, plus a sophisticated steering system, compensated for an unpowered front axle and gave the vehicle better cross-country abilities than its US counterpart and eventual rival.
The technical hair in the soup of the 251 was its complexity. It may be argued as well that neither the infantry nor the panzers sufficiently internalized the need to emphasize rapid, large-scale production. The first A-model versions did not begin service trials until 1939, and there would never be enough of them to equip more than one battalion in all but a few favored panzer divisions.
Production delays bedeviled as well the 251’s smaller cousin. The SdKfz 250 developed out of a growing mid-1930s belief that reconnaissance was too vital an element of mobile war to be trusted to existing combinations of motorcycles and armored cars. At times it might be necessary to fight for information; at times it might be necessary to traverse rough ground to secure information. The solution was a half-sized half-track built on the chassis of the 1-ton artillery tractor. At 5.4 tons, with up to 14.5mm of armor, an open top, and a six-man crew, the 250 could move at almost 40 miles per hour, cover 300 miles on a single fueling, and, when necessary, put a few boots on the ground to search, destroy, and provide fire cover. It would not see service until 1940, but eventually it would prove almost as versatile a weapons platform as the 251.
There were four main model modifications (Ausführung A through D), which formed the basis for at least 22 variants. The initial idea was for a vehicle that could be used to transport a single squad of panzergrenadiers to the battlefield protected from enemy small arms fire, and with some protection from artillery fire. In addition, the standard mounting of at least one MG 34 or MG 42 machine gun allowed the vehicle to provide support by fire for the infantry squad once they had disembarked in battle.
Positive aspects of the open top included greater situational awareness and faster egress by the infantry, as well as the ability to throw grenades and fire over the top of the fighting compartment as necessary while remaining under good horizontal cover. The downside was a major vulnerability to all types of plunging fire; this included indirect fire from mortars and field artillery, as well as depressed-trajectory small arms fire from higher elevated positions, lobbed hand grenades, even Molotov's cocktails, and strafing by enemy aircraft.
The first two models were produced in small numbers from 1939. A and B models can be identified by the structure of the nose armor, which comprised two trapezoidal armor panels - the lower of which had a cooling hatch. The B model, which began production in 1940, eliminated the fighting compartment's side vision slits. The C model, which started production in mid-1940, featured a simplified hexagonal-shaped forward armored plate for the engine. Models A through C had rear doors that bulged out. The C model had a large production run, but was quite complex to build, involving many angled plates that gave reasonable protection from small arms fire. From early 1943, the D model was developed with the purpose of halving the number of angled body plates, simplifying the design and thus speeding up the production. D models can be easily recognized by their single piece sloping rear (with flat doors).
The standard personnel carrier version was equipped with a 7.92 mm MG 34 or MG 42 machine gun mounted at the front of the open compartment, above and behind the driver. A second machine gun could be mounted at the rear on an anti-aircraft mount.
When comparing the M3 with the German Sdkfz.251 halftrack, you will find both of similar size, speed and weight, but the M3 had over 20% more internal capacity due to its boxy hull shape. The 251 halftrack was more thickly armored, and the armor was angled to derive the best protection possible. But, due to the greater horsepower from the US vehicle's engine, and the powered front axle, the M3 was a greatly superior vehicle for cross-country travel. Unfortunately, both vehicles were lacking in over-head protection, a problem that plagued occupants throughout WWII.