The Schwere Geländegängiger Lastkraftwagen 4.5t Mercedes-Benz L4500A als FlaKwagen was a self-propelled anti-aircraft gun (SPAAG) used by the German military during World War II. It was built by converting a standard Mercedes-Benz L4500A heavy-duty truck into an anti-aircraft vehicle by mounting either a 2 cm, 3.7 cm, or even a 5 cm anti-aircraft gun on the truck’s bed. This was a cheap conversion of a standard heavy-duty truck produced by Mercedes-Benz that could guarantee an adequate defense to German columns. It showed its limits due to the partial armor that protected only the most sensible parts of the truck, exposing the crew during the fighting. Together with other wheeled SPAAGs, it was intended as a stopgap solution until properly designed anti-aircraft vehicles were developed.
History of the Project
The need for mobile anti-aircraft vehicles became evident with the development of aviation technology in the early 20th century. Initially, these vehicles were intended to engage enemy balloons, which were used for reconnaissance and artillery spotting.
As aircraft technology advanced and became more prominent in warfare, the role of mobile anti-aircraft vehicles evolved to include countering this new threat. The German Army, in particular, recognized the importance of anti-aircraft defenses and began producing a series of SPAAGs during the First World War.
These early SPAAGs were mounted on wheeled chassis and were often equipped with machine guns or small caliber artillery guns. They were relatively mobile and could quickly respond to enemy aircraft, making them a valuable asset on the battlefield. Their primary purpose was to protect vital industrial and military targets against enemy aircraft.
Despite being built on civilian truck chassis, SPAAGs offered greater mobility than towed anti-aircraft guns. As the war progressed, these vehicles were upgraded with additional equipment, such as range finders, searchlights, and acoustic detectors, which further improved their effectiveness against enemy aircraft. Interestingly, SPAAGs also proved to be effective against enemy tanks thanks to their mobility and firepower. This versatility made them a valuable asset on the battlefield, and they continue to be used in modern military conflicts.
After the First World War ended, Germany was prohibited from having certain military vehicles, including SPAAGs, by the Treaty of Versailles. This was done to limit Germany’s military capabilities and prevent another world war. In 1930, the German Army gradually started to rearm and also began to develop and build more armored vehicles. After the Nazis took over Germany in 1933, the Treaty of Versailles was completely disregarded.
With this general rearmament, the concept of SPAAG was brought up again. This time the Germans turned to their half-tracks as the main chassis. This came in the form of the Sd.Kfz.10/4 half-track armed with a 2 cm Flak 30 anti-aircraft gun. Such vehicles were allocated to more mobile formations, such as the Panzer divisions.
No particular attention was given to wheel-based SPAAGs. One of the first such vehicles was the small Kfz.4 Truppenluftschutzwagen (English: Air Defense Vehicle) introduced in 1938. It was a 4-wheeled cross-country personal carrier armed with a Zwillingslafette 36 (English: Dual Mount 36) and machine guns. The idea behind the Kfz.4 was to have a small reliable vehicle that could effectively defend itself and the troops against low-flying aircraft with its dual machine guns. However, these vehicles would only be produced in small numbers.
As the war progressed, the Luftwaffe had more difficulty providing sufficient protection for the ground forces. These, in turn, were forced to find alternative solutions. Half-track SPAAGs were mainly allocated for highly mobile formations, such as the Panzer divisions. Other military units had to use what was at hand. This led to the development and deployment of various anti-aircraft weapons on wheeled chassis, including trucks. One solution was to improvise by placing an anti-aircraft gun in the rear cargo bay of a truck. This was a simple and quick solution that could be implemented with whatever resources were available at the time. Such improvised vehicles were relatively common as they were cheap and easy to build. Their improvised nature and lack of armor limited their combat effectiveness. But, as often nothing better was available, these did the job to some extent.
As improvisations were not the proper solution, the Germans resolved to build more dedicated designs. These vehicles were more effective and reliable than improvised solutions. The armament consisted of either 2 cm or larger 3.7 cm anti-aircraft guns. In rarer cases, the much larger 5 cm anti-aircraft gun was used. They all shared a basic overall design, with a front armored cabin, central firing, and rear storage compartments. Sources do not go into detail about when these vehicles were constructed or their numbers. Given that the half-track SPAAGs received armored cabins after 1942, it would suggest that these too were built around the same time. Production numbers are unknown, but it is most likely that not many were built given the overall limitations of the wheeled chassis.
But it is important to note that even such vehicles were far from perfect. Despite the attempts to improve their performance, they were in essence still improvisations, albeit to a slightly lesser degree. Designing a dedicated wheel-based SPAAG would have taken too much time and resources.
The SPAAG on Mercedes-Benz L4500A chassis received the official name of Schwere Geländegängiger Lastkraftwagen 4.5t Mercedes-Benz L4500A als FlaKwagen (English: Heavy Off-Road Truck 4.5t Mercedes-Benz L4500A as Anti-Aircraft Gun Truck). Für (English: for) and the designation of the main armament – für 3.7 cm FlaK 37, für 5 cm FlaK 41 and für 2 cm FlaKvierling 38 – were added.
The generic Heer designation of this type of SPAAG was Mittlerer FlaK Kraftwagen (English: Medium Anti-Aircraft Motor Vehicle) with Kraftfahrzeug or Kfz. (English: Motor Vehicle) code number 410. The Mittler designation refers to the anti-aircraft gun designation, not the load capacity of the vehicle’s chassis.
The Kfz.410 was also split in three other designations: Kfz.410/1, Kfz.410/2, and Kfz.410/3, even if it is not clear if the sub-designations referred to the chassis used or main armament installed on the truck chassis.
Another slightly shorter official designation that was used was Schwerer Geländegängiger Lastkraftwagen 4,5t für FlaK (Selbstfahrlafette) (English: Heavy Off-Road Truck 4,5t for Anti-Aircraft Gun [Self-Propelled Gun Carriage]).
Chassis and Frame
The 4.5 tonnes Mercedes-Benz L4500 was a heavy-duty truck that was developed as a larger version of the L3000 medium truck. It entered production in 1939 at the Mercedes-Benz plant of Gaggenau, in south-west Germany. Between the months of September and October 1944, two Allied bombings raids on the city destroyed the Mercedes-Benz plant, forcing it to restart production at the Saurer plant in Vienna until the end of the war. Today, the Mercedes-Benz L4500 is a rare and highly sought-after collector’s item, with a number of examples preserved in museums and private collections around the world.
|Empty weight||5.250 tonnes||5.717 tonnes|
|Payload capacity||5,150 tonnes||4.685 tonnes|
This was an uncommon capacity for the period and permitted the Mercedes-Benz truck to transport, for example, a Panzer I in its cargo bay. The towing capacity is not specified, but it was able to tow an 8.8 cm FlaK anti-aircraft gun or a tank transporter trailer.
All three variants of the truck shared the same frame and bodywork but differed in the suspensions used. The Mercedes-Benz L4500S and L4500A were equipped with leaf spring suspension on both front and rear axles, while the Mercedes-Benz L4500R had, on the rear axles, Panzer II light tank suspension and tracks.
During its service history, some modifications were made to the chassis to speed up production output and lower the overall cost of the vehicle.
In 1943, a new type of cab substituted the original civil cab. The new Einheitsfahrerhaus (English: Standard Cabins) was a box-shaped pressed-wood cab developed to fit on various German and Italian trucks and half-track chassis. Another modification, which appeared in late 1944, when production switched to Saurer, was a different and shorter bumper, simplified fenders, and lastly different headlights.
|Mercedes-Benz L4500 heavy-duty truck production 1939 – 1945|
Of the 6,402 Mercedes-Benz L4500S produced, 2,021 were converted into firefighter trucks and 1,214 were equipped with gasifier engines. Of the 2,711 Mercedes-Benz L4500A, 308 were converted into off-road firefighting trucks. The total number of Mercedes-Benz L4500A trucks converted in SPAAGs is unknown.
The civilian variants were standard cargo trucks with wooden cargo bays. A bus version called O4500 was produced only in 1943-1944, and a firefighting truck, called LF25, was also built.
Engine and Suspension
The Mercedes-Benz L 4500 engine was the diesel 4-stroke, inline 6-cylinder Mercedes-Benz OM 67/4 water cooled, 7,274 cm3, delivering 112 hp at 2,250 rpm. This powerful engine was of the precombustion chamber injected type with Over Head Valves (OHV).
The diesel engine, mounted in front of the cab, was coupled with a single disc dry clutch and 5 gears and one reverse manual gearbox with reductors. The maximum speed was 66 km/h on-road.
The fuel capacity was 140 liters in a single tank placed under the cab. The truck had a fuel consumption of 25 liters per hour on-road, which meant that the truck had an on-road range of about 500 km.
The vehicle was equipped with a ZF Typ 721 steering system that assisted the driver in turning the steering wheel and a peculiar brake system: a hydraulic system for the front drum brakes and a pneumatic system for the rear drum brakes (and the trailer brakes). Although all wheels were equipped with drum brakes, the parking brake blocked only the rear axle (and the trailer brakes). The vehicle was equipped with 10.5-20″ tires with twin wheels on the rear axle.
The Mercedes-Benz L4500A had an off-road gear, which permitted the driver to switch on the front-wheel-drive. With this off-road gear, the performance of the truck was diminished, with a maximum speed decreased to 43 km/h, while the payload capacity was reduced to 4.085 tonnes.
|Mercedes-Benz L4500A Specifications|
|Length||7. 86 m|
|Ground Clearance||34 cm|
|Water Depth||80 cm|
|Turning Radius||19.3 m|
|Payload With Off-road Gear||4.085 tonnes|
|Total Weight Permitted by Law||10.400 tonnes|
|Total Weight With Off-road Gear||9.800 tonnes|
The Geländegängiger Lastkraftwagen 4.5t Mercedes-Benz L4500A, due its crucial role and vulnerability on the frontline, was equipped with armored plates to protect part of the crew from light arms fire.
The great payload capacity of this massive German truck allowed the bolting of armored plates on the cab without overstressing the chassis. The Germans called the armored structure Behilf Panzerung (English: Auxiliary Armor).
The engine compartment was protected on the front by an armored plate-shaped V fixed on the bumper on the lower part, and by means of a long rod on the upper part.
The armored cab was composed of armored plates revered on an internal structure and shared similar shapes to the armored cabs of other German vehicles, such as the 8.8 cm FlaK 18 (Selbstfahrlafette) auf Schwere Zugkraftwagen 12t (Sd.Kfz.8) nicknamed “Bunkerflak”, the Sd.Kfz.7/2 anti-aircraft armored half-track, and the similar Büssing-NAG 4500A anti-aircraft armored truck.
On the front armored plate of the cab, there were two slits protected by the armored glass, while on the side hatches, there were two sliding slots. A fifth slit was placed on the rear of the armored cab to connect the crew inside the cab with the other soldiers on the platform. For self-defense, ventilation and observation, there were two hatches on the armored roof from which the commander and driver could check the area around or defend the vehicle with personal weapons. The commander had a split hatch with parts fixed on the sides, while the driver’s hatch, albeit of the same dimension, had a single part openable to the front.
The armored cab’s plate thickness is not specified in official documentation, but it probably ranged between 10 mm to 14.5 mm, similar to other German armored cabs. This thickness was barely enough to protect the occupants of the cab from light arms fire and artillery splinters. This level of protection did not even protect the vehicle from enemy air strikes, the most likely opponent to defend against.
The crew in the rear platform, apart from the protection given by the armored cab and gun shield (8 mm to 10 mm thick), was severely exposed.
During production, some parts were simplified in the hope of speeding up the assembly and to decrease costs. The slots protected by armored glass were substituted with bigger ones without armored glass and with armored ports. The side slots were replaced with sliding slots of bigger dimensions. The bench on the rear was removed and the cab was shortly elongated. Also, the radiator’s plate was replaced with a longer one.
Behind the armored cab, a new firing platform made of iron sheets was fixed on the truck chassis. The platform was equipped with foldable sides made with robust wire mesh. When in firing position, the sides were folded horizontally to permit a 360° traverse of the anti-aircraft gun and increase the floorspace for the gun’s operators. Right behind the armored cab was the padded bench for the gunner and loaders. In the middle of the platform was the main armament.
At the rear, a stowage box was placed, the top of which could open. It was used to transport ammunition for the anti-aircraft gun, toolboxes, and other parts. Over the rear stowage box was a backrest to allow it to be used as a bench for other crew members.
In later vehicles, the stowage box on the rear was removed and replaced with a bench, while the front bench was removed too. This gave more space for the crew but reduced the possibility of transporting other equipment.
A total of four jacks were added, two for each side of the firing platform, and used to increase the stability of the vehicle while firing. These jacks were not introduced on the half-tracked SPAAGs because of the sturdier chassis and bigger contact area of the tracks, which gave more stability than wheels. During serial production, the four jacks were first simplified to save on raw materials and then reduced to one for each side. The new jack model was composed of a telescopic rod with a foot placed on the front of the firing platform. Sapper tools were placed on the platform’s foldable sides while, under the platform, on each side, was a 20-liter fuel can support.
The vehicles were equipped with Notek night lights placed near the front armored plate that protected the radiator.
There was a compartment in the rear stowage box of the platform for an unknown but limited number of round clips or magazines.
Crews regularly transported spare ammunition on one-axle standard military trailers. The most common ones were the Sonderanhänger 56 or Sd.Ah.56 (English: Special Trailer 56) for 2 cm FlaK ammunition, the Sonderanhänger 57 or Sd.Ah.57 (English: Special Trailer 57) for 3.7 cm FlaK automatic cannon rounds or the multiuse Sonderanhänger 51 Sd.Ah.51 that could be loaded both with 3.7 cm FlaK 36/37 or 2 cm FlaKvierling 38 ammunitions. The trailer also transported the gun’s spare optics, spare parts, and other tools.
2 cm Flakvierling 38
The 2 cm Flakvierling 38 was a common anti-aircraft gun of the Second World War. It was designed by Mauser-Werke to replace the older 2 cm Flak 30 and was introduced in May 1940. Its effective firing range was between 2 to 2.2 km, while the maximum horizontal range was 5,782 m. The maximum rate of fire was 1,680 to 1,920 rpm, but 700-800 rpm was a more appropriate operational rate of fire. The elevation was –10° to +100°.
The gun was placed on a triangular-shaped platform with three supporting legs. For transportation, this platform was connected to a two-wheel bogie. To hold the gun in place, three stabilizer connectors for the 2 cm Flakvierling 38 legs were added on top of the vehicle’s rear positioned platform.
3.7 cm FlaK 36 and 37
The 3.7 cm FlaK 36 was intended to replace the inadequate 3.7 cm Flak 18. It could engage enemy air targets up to 4.8 km. The firing rate was 160 rounds per minute but 80 rpm was a more practical fire rate. The elevation was –8° to +85°. It was generally an effective design that had improved firepower over the weaker 2 cm rounds. Unfortunately for the Germans, they never produced enough of them. The Flak 37 version received some improvements, such as a better gun sight but, in general, these two were almost identical.
The 3.7 cm FlaK 36/37 used a similar triangular-shaped platform, with three supporting legs, albeit somewhat larger. Early 3.7 cm Flak 18 used much complicated two two-wheel bogie. Later models would use only a single two-wheel bogie. The installation process of these two guns on the Mercedes-Benz’s rear-positioned platform would be the same as on the 2 cm gun.
On some trucks armed with 3.7 cm automatic cannons, other ammunition racks were placed under the firing platform, behind the rear axle. Each rack could be loaded with three iron crates for 2 8-round clips each, for a total of 96 rounds.
5 cm FlaK 41
The 5 cm Flak 41 was Krupp’s response to the request made by the German Army for an anti-aircraft gun to fill the gap between the 3.7 cm and 8.8 cm anti-aircraft guns. In 1935, Rheinmetall was tasked with developing such an anti-aircraft gun. A few years later, in 1939, Krupp was also contacted for the same purpose, but its design would be rejected. Rheinmetall 5 cm anti-aircraft gun was deemed a better design and it would be accepted for service in November 1940.
The gun was placed on a triangular-shaped platform, equipped with two side folding outriggers to provide better stability during firing. For transportation, this platform was connected to two two-wheel bogies, which were then moved either by a heavy-duty truck or a half-track.
This gun was gas operated and equipped with a vertical sliding breech. With a muzzle velocity of 840 m/s, it had a maximum firing range of up to 9 km, while the more practical range was 5.6 km. The horizontal firing range was 12.4 km. It had a full traverse of 360° with an elevation of –10° to +90°. The total weight of the gun was 3.1 tonnes.
It could fire a few different rounds. The standard high-explosive round had two different settings. It could be timed to explode after 5 to 8 seconds or longer, at 14 to 18 seconds, depending on the combat need. In addition, this round was also provided with a tracer that burned for up to 10 seconds. It could also fire an armor-piercing round (basically a modified 5 cm PaK 38 round) and a training round. The practical firing rate was 130 rounds.
While issued early in the war, these guns proved disappointing. They were unstable during firing, slow in tracing enemy aircraft, and due to their large size, difficult to conceal and move. After some 200 (precise numbers differ greatly between sources, from 80 to 200) guns were built, the production was canceled. Despite their limited production numbers, these guns saw combat in their original configuration but also in some self-propelled versions.
From photographic evidence, it is possible to confirm that at least four 5 cm FlaK 41 were installed on Schwere Geländegängiger Lastkraftwagen 4.5t chassis. At least one was mounted on a Schwere Geländegängiger Lastkraftwagen 4.5t Mercedes-Benz L4500A als FlaKwagen, two were mounted on unarmored Mercedes-Benz L4500A chassis, and the fourth one was installed on an unarmored Schwere Geländegängiger Lastkraftwagen 4.5t Büssing-NAG 4500A als FlaKwagen.
The driver was placed in the left side of the armored cab, while the commander sat on the right side. Behind the cab was a padded bench on which the gunner and one or two loaders sat. It was not unusual for crews to number up to 7 soldiers, with 4 loaders and ammunition carriers for the gun.
Only the commander and driver were protected from enemy light arms fire by the armored cab, while the rest of the crew sat outside without any protection, even against bad weather.
During the production of SPAAGs on Mercedes-Benz trucks, there were small series built using unarmored vehicles.
The first one appeared to be produced in late 1942 according to the presence of some vehicles in North Africa, under the Deutsche Afrika Korp control.
This was a really rudimentary conversion probably produced in limited numbers, possibly for testing. This version was equipped with the original metal cab and without jacks. The precision of the main gun was badly influenced by the bad stability of the wheeled platform, so the crews tried to solve the problem using jacks to raise the chassis from the ground and sandbags stacked around the wheels when in battery position.
This peculiar version also sported different ammunition racks and crew benches on the firing platform. The folding sides were made of iron sheets instead of serial production wire meshes.
Another version that appeared later in the war was an unarmored Mercedes-Benz L4500A with an open-topped cab, foldable windshield, and early production firing platform with 4 jacks and wire mesh foldable sides.
Photographic evidence confirms the production of at least 2 unarmored vehicles with open-topped cabs armed with the rare 5 cm FlaK 41. The unarmed version of the Geländegängiger Lastkraftwagen 4.5t on Mercedes-Benz L4500A was produced in limited numbers, which perhaps stopped after these 2 prototypes. These vehicles seem to have remained in Germany to train recruits and defend the homeland.
This last unarmored version illustrates how desperate the German situation was at the end of the war. The unarmored Geländegängiger Lastkraftwagen 4.5t could only be operated in a relatively safe environment, safe from any ground attacks, artillery. Apart from the thin and small gun shield, the crew was completely exposed to artillery splinters and light arms fire. This unarmored solution, therefore, suggests that it was designed for training FlaK recruits as a cheaper and lighter version of the SPAAG.
Unfortunately, information about the combat use of these vehicles is quite difficult to find. They are often just barely mentioned in the sources. They surely saw combat use given the existence of many surviving photographs. Given the Luftwaffe’s inability to provide air defense and the general lack of half-track SPAAGs, these would be used to fill the gap.
These vehicles were part of a series of stopgap solutions that the German military developed during the war to counter Allied air superiority. This SPAAG based on a truck chassis was sort of a mix-bag. On one side, they provided increased mobility for the anti-aircraft guns. This helped to greatly increase the combat effectiveness of these units. The partial armor that protected only the most sensitive parts of the truck meant that the crew was exposed during combat. They also lacked proper mobility when driving off-road. It was ultimately a temporary solution to a growing problem that required more advanced and specialized anti-aircraft vehicles.
Schwere Geländegängiger Lastkraftwagen 4.5t Mercedes-Benz L4500A als FlaKwagen Specification
|Crew||4-5 (driver, commander, gunner and 1 or 2 loaders)|
|Engine||Mercedes-Benz OM 67 diesel engine delivering 112 hp at 2,250 rpm, 140 liter fuel tank|
|Range||~ 500 km|
|Armament||3.7 cm FlaK 37
5 cm FlaK 41
2 cm FlaKvierling 38
|Armor||8 mm to 14.5 mm|
Mercedes-Benz L4500S original brochure
P. Chamberlain and H. Doyle (1978) Encyclopedia of German Tanks of World War Two – Revised Edition, Arms and Armor press.
Walter J. Spielberger (1982). Gepard The History of German Anti-Aircraft tanks, Bernard & Graefe
Ian V. Hogg (1975) German Artillery of World War Two, Purnell Book Services Ltd.
11 Panzerwrecks Normandy 2
W. Muller Die Geschützte, Ortungs und Feuerleitgeräte Der schweren Flak, Dörfler Zeitgeschichte