by Adrian-Liviu Dorofte

Fire protection under the three-pointed star: The history of Mercedes-Benz fire-fighting vehicles and their predecessors - PART III


Stuttgart, Germany, Jan 01, 2007

Mercedes-Benz fire-fighting vehicles of Daimler-Benz AG: 1926 - 1945

After the merger: fire-fighting chassis from Gaggenau

The hesitant attitude many fire brigades adopted vis-à-vis the technical innovations, which emerged in the commercial vehicle sector immediately after the First World War, and the difficult economic situation meant that many innovative features remained shelved in fully matured condition for quite some time, to be introduced only gradually from the late twenties. The merger of Daimler and Benz was therefore a good opportunity to launch a new, uniquely diversified range of the latest chassis for all purposes.

In 1927, the Gaggenau factory, now dedicated completely to the production of commercial vehicles including fire-fighting vehicles, started manufacturing the new Mercedes-Benz chassis series. These chassis initially carried designations like L2, “L” standing for ‘Lastwagen’ (truck) and the figure for a defined payload range (L1 = 1 – 1.5 tons, L2 = 3 – 3.5 tons, L5 = 5 tons). An “N” instead of the “L” designated low-frame chassis. These chassis were fitted with four- and six-cylinder engines with output ratings between 45 and 100 hp.

As diversification increased, more precise designations became necessary. From 1929, for instance, an offset low-frame chassis for a fire engine with 2.75 ton payload was designated LoS 2750; a corresponding turntable ladder chassis with 3.5 ton payload was named LoD 3500. The small “o” replaced the previous “N” for low-frame chassis which was above all known from the bus sector.

In combination with suitable engines, different “Benz-Gaggenau” pumps for a wide range of delivery rates were available. The capacity of the smallest pump, driven by a 55 hp six-cylinder engine, was soon raised from 1,000 to 1,200 liters per minute. The 70 hp engine driving the next-larger pump delivered first 1,500 and then 1,800 liters per minute. The top-of-the-range engine was a 100 hp unit which was capable of delivering 2,000 – 2,500 liters per minute up to a height of 80 meters. Powered by such an engine, a vehicle set up on a five-ton chassis for a gross vehicle weight of eleven tons reached a top speed of 50 kilometers per hour around 1930.

A large number of technical innovations were introduced in fire-fighting at the time, resulting in a diversification of the vehicle fleets. And time and again, chassis from Daimler-Benz were first choice when fire brigades opted for new vehicle models.

Lightweight design experiments in Frankfurt

It was commissioner Schänker of the Frankfurt fire brigade, who in 1928 performed the first, groundbreaking tests with lightweight designs. He had started out by converting an existing vehicle of the Frankfurt professional fire brigade and in 1930 had the superstructures for three new chassis completely made of light alloy. He had opted for the Mercedes-Benz Lo 2500 low-floor chassis complete with light-alloy engine hood and fenders. The vehicles created in this way were a fire engine, a carrier for a 24 meter long turntable ladder from Metz and a hose carrier.
Schänker’s efforts were prompted by the severe vibrations which were caused by heavy-duty fire-fighting vehicles with solid rubber tires at the time. The introduction of pneumatic tires meant that his positive approach took a back seat. He then proceeded to suggest that turntable ladders should be made of light alloy – something Messrs. Metz managed to achieve for the first time in 1932.

Dry agent tender in Frankfurt

At the same time, Schänker broke new ground by introducing dry agents in fire-fighting. In 1929, the Berlin-based company Total had used a Gaggenau chassis to set up a fire engine with a 500 kilogram container for its Totalit dry powder extinguishing agent. Six bottles containing 25 kilograms of carbon dioxide each provided the pressure required to throw the powder into the fire through 50 meter long hoses.
In the “Feuerschutz” (‘Fire Protection’) journal, in 1931, the commissioner of the Frankfurt fire brigade reported exhaustively on the experience he had gained with the “first large dry-agent fire extinguishing appliance in Germany.” In the same year, he ordered another vehicle, again on a Mercedes-Benz chassis, from Total. Schänker opted for just 250 kilograms of Totalit this time but had a Balcke high-pressure pump fitted on the vehicle, permitting the crew to change over to extinguishing water from the hydrant after the first attack using powder. The superstructures were largely made of light alloy.

Large-scale order from Lisbon

Daimler-Benz received another large-scale order in 1929. The Portuguese capital Lisbon ordered 26 fire-fighting vehicles and set great store by the largest possible water reservoirs, due to Lisbon’s topography and the resulting difficulties in obtaining water. This also applied to the nine mobile command and fire chief vehicles which were based on the elegant Nürburg sportscar. Each carried a 350 liter water tank, 100 meters of pressure hose and a Metz pump that delivered 600 liters of water per minute up to a height of 80 meters.

LoS 3500 and LoS 4000 low-frame chassis with 110 hp six-cylinder engines formed the backbones of the 17 fire engines. Each of these vehicles accommodated a crew of ten on transverse benches and carried an additional 400 liter water tank.

First German motorized fire engine with enclosed crew compartment

The winter of 1929 was unusually severe in Germany, with temperatures around minus 20°C, dropping to below minus 40°C in some areas. This meant a lot of work for the fire brigades. Water pipes froze and burst, and glowing stoves time and again set houses on fire. Illness and frostbite were the price paid by firefighters on assignments at extremely low temperatures and traveling under these conditions in vehicles that were still open.
The Berlin fire brigade was the first to react to this situation: its Zehlendorf branch took delivery of the first German motorized fire engine with enclosed crew compartment in 1930. The compartment, built by Messrs. Hermann Koebe from Luckenwalde on a Mercedes-Benz chassis, accommodated a crew of nine.

Inconceivable heights: the development of turntable ladders

Turntable ladder development during the decade between 1924 and 1934 could be described as almost breathtaking. In 1923, Metz had introduced the first turntable ladder which was powered by the vehicle engine, via a transmission power take-off; the following year, the company presented an all-steel latter set. In 1925, it reached new heights with a 36 meter wooden ladder set.

In Germany, six rated lengths of fire-fighting ladders – between 18 and 30 meters – had just been defined in norm DIN FEN 105 at the time. Ladders longer than 30 meters were therefore destined predominantly for export. Metz’s 36 meter ladder was shipped to Russia, another two 38 meter long ladders were exported to Vienna and Rio de Janeiro in subsequent years. In the early thirties, Metz established a new record with a 42 meter long ladder for Brussels – this was even extendable to 48 meters by an additional element. With its five-part ladder set made of riveted light-alloy profiles, Metz presented a new, future-oriented technology. The chassis for all of these turntable ladders came from the Gaggenau factory of Daimler-Benz.

Daimler-Benz’s strong orientation to the export market is revealed by a 1929 brochure in English, French and Spanish, offering among other things turntable ladders up to 36 meters high. As early as 1932, the company already advertised an all-new 45 meter long turntable ladder. In 1934, finally, a catalogue presenting the entire range of turntable ladders was jointly published by Daimler-Benz and Metz.

At the time, the LoD 2500 and LoD 2750 chassis with 65 hp engines served as the backbones for 18 – 24 meter long turntable ladders. For 26 – 40 meter long ladders, the LoD 3500 and LD 4000 chassis were used for which engines with output ratings between 65 and 110 hp were available. In theory, Daimler-Benz and Metz offered turntable ladders up to 50 meters long on the LD 5000 chassis even though the longest ladders actually produced until 1951 were “only” 46 meters long. Automatic tilt control, impact control and balance control were standard equipment on all ladders.

An unusual experiment by Metz

Turntable ladders may have impressed people greatly by their extension heights and technical refinements, but they were rarely used in real life. They rendered indispensable services in only about one in 40 assignments. At the same time, technical support services grew in importance. As long as road traffic was dominated by horse-drawn carriages, the service most frequently performed by the fire brigade was hoisting up horses which had collapsed in the street. With this in mind, the Berlin fire brigade equipped all its turntable ladders with crane devices for loads up to one ton between 1931 and 1933.

Metz opted for a different approach as early as 1930 in developing a unique telescopic mast system. Inside the mast, which could be extended to a length of 50 meters, a water pipe was laid that ended in a swivel-type pipe at the top of the mast. A centrifugal pump at the rear of the vehicle generated the necessary pressure. The telescopic mast also doubled as a crane which, at a reach of two meters, was able to lift four tons – and still as much as 900 kilograms at a reach of five meters. When equipped with a platform, the vehicle with telescopic mast, secured by two supporting jacks, could also be used for rescue operations.

A new type of vehicle: the emergency tender

However, such combined solutions did not prove to be convincing in the long term. As early as 1907, the Munich professional fire brigade started operating an electrically powered support vehicle on a Daimler chassis. In the late twenties, such vehicles became known as pioneer or rescue vehicles before they were generally referred to as emergency tenders. In 1931, the Munich fire brigade ordered such an emergency tender on a Daimler-Benz L2 chassis from Metz. A folding extension crane at the rear of the vehicle was capable of lifting a light car.

Until then, fire brigades had cleared obstacles of all kinds out of the way by means of a three-legged frame with tackle. Since mobile cranes were too expensive for many fire brigades, the principle of the emergency tender with folding extension crane was used more and more often. In 1936, Metz built such an emergency tender on a Daimler-Benz LS 3750 chassis with 100 hp engine; it had a capacity for lifting five tons. Inside the vehicle, there were seats for a crew of seven, and in fully laden condition, the vehicle weighed 8.9 tons. The crane, mounted separately from the body, was electrically driven by the vehicle engine via a 6.5 kilowatt DC generator. When not in use, it was folded away into a recess in the vehicle roof. Support legs at the rear ensured the required stability.
One size larger was the emergency tender built in 1938 for the Berlin fire brigade. Metz fitted a heavy-duty three-axle chassis, model L 8500 with 110 hp engine from Daimler-Benz, with a three-ton crane to create a vehicle for removing traffic obstacles after accidents or for setting up derailed streetcars. This vehicle continued doing service until the mid-sixties.

Fire-fighting vehicle fleet for Dresden

The commissioner of the Dresden fire brigade, Ortloph, decided in 1934 on a major acquisition that caused quite a stir. The necessary funds having been available since 1931 already, he placed an order worth 500,000 Reichsmark with Daimler-Benz acting as general contractor; the 18 fire-fighting vehicles this involved were completed in time to be displayed to an amazed public at the “German People’s Show for Fire Protection and Rescue Services” the following year. “Dresden’s fire brigade – the most modern in Europe” read a headline in the local newspaper.
Nine fire engines, six turntable ladders and three hose carriers were ordered by the Dresden fire brigade from Daimler-Benz. A number of companies were involved in providing the equipment and superstructures for the vehicles. The four-speed overdrive transmissions were supplied by Zahnradfabrik Friedrichshafen.

Superstructures were contributed by fire-fighting specialists E. C. Flader and Gustav Hornung & Co. The fire engines were equipped with front-mounted three-stage pumps by Amag-Hilpert, delivering 2,400 liters of water or 4,000 liters of foam per minute at six bar. Front-mounted pumps from the same manufacturer, with a capacity of delivering 1,000 liters of water or 1,500 liters of foam per minute at a pressure of nine bar, were installed in front of the radiators of the turntable ladder carriers. The 28 + 2 meter long all-steel turntable ladders themselves were supplied by Metz.
All vehicles were set up on identical Daimler-Benz low-floor chassis with a wheelbase of 4.6 meters and a load-bearing capacity of 5.8 tons. Where engines were concerned, however, Ortloph was not satisfied with the Daimler-Benz range. He selected eight-liter twelve-cylinder units from Maybach, which at the time had a remarkably high output of 150 hp. The Maybach engines were still gasoline-powered; no sooner than the following year, Daimler-Benz presented the six-cylinder OM 57 diesel engine – a unit that equally developed 150 hp but was considerably more compact.

The fire brigades’ first diesel engines

It would be difficult to name a company that has promoted the development of the diesel engine for commercial vehicles as intensively as Daimler-Benz. As early as 1924 both Benz-Gaggenau and Daimler-Marienfelde had displayed diesel-engined trucks at the Berlin Motor Show. Since the pre-chamber diesel engine from Benz appeared to be the more suitable version for the time being, it found its way under the hoods of Mercedes-Benz commercial vehicles built in Gaggenau from 1926. Around 1930, the majority of heavy-duty trucks in Germany was already powered by diesel engines – 90 percent of these came from Daimler-Benz.
The fire brigades, having had so many reservations against the gasoline engine at the beginning of the century, did not operate a single diesel engine at the time. Again, the firefighters had their doubts, fearing that too much time would be lost for pre-heating. Unlike haulage operators, however, they were not forced to keep fuel costs down – given the short distances they usually had to cover.

The decisive impetus was provided by the German Reich’s Aviation Ministry which – with a view to the international conflict already planned at the time – established in 1934 that fire-fighting vehicles should not be dependent on imported fuels and that diesel should therefore be preferred to gasoline engines, the diesel engine being better suited to running on replacement fuels. In the same year, the Mannheim fire brigade ordered a fire engine on an LoS 3500 chassis with 95 hp six-cylinder OM 67 diesel engine from Daimler-Benz and Metz. Another special feature of this vehicle, presented at the fire brigades’ convention in Erfurt the same year, was its equipment with Komet air foam pipes. Also in 1934 the professional fire brigade of Kassel took delivery of a complete fire-fighting combination with diesel engines. In this case, too, the fire engine, the hose carrier and the 26 meter long turntable ladder from Metz were set up on Mercedes-Benz chassis.

The following year, the Ministries of the Interior and Aviation jointly decreed that fire-fighting chassis with a load-bearing capacity upwards of three tons must in future be fitted with diesel engines exclusively. “Since reservations against the use of the diesel engine, founded on the special features of fire-fighting operations, no longer exist, ...” read the decree. Doubts had indeed been dispelled and diesel engines had proved themselves excellently, for instance in terms of their starting behavior at freezing temperatures.

Three orders from Nuremberg

One of the first fire brigades to change over completely to diesel engines as early as 1936 was the professional fire brigade of Nuremberg. It ordered three fire engines, a 30 meter long turntable ladder and a hose carrier from Metz and Daimler-Benz. The fire tenders were equipped with Amag-Hilpert pumps which delivered 1,500 liters per minute at eight bar.

Commissioned by the NSDAP, the Ministry of Aviation ordered three KL 46 turntable ladders for Nuremberg, Berlin and Hamburg in 1938. The only company capable of producing a 46 meter long ladder at the time was Metz. Magirus secured a fourth order for Munich for itself but was capable of supplying only a 45 meter ladder. The turntable ladders were mainly used for putting up garlands and flags for Nazi Party conventions.

As early a January 1, 1933, Metz had concluded a goodwill contract with Daimler-Benz, under which the two parties undertook to engage in exclusive cooperation. The KL 46 ladders were mounted on Mercedes-Benz LD 6500 chassis with a permissible gross weight of 14 tons; the six-cylinder diesel engines developed as much as 150 hp.
Metz received another special order for the Nazi Party conventions in Nuremberg in 1938. The combination of fire tender, carbon dioxide extinguisher, hose carrier and command vehicle became known as the March Field Vehicles. All four of them were set up on Mercedes-Benz chassis – the two tenders on LG 3000 three-axle chassis with two driven rear axles and 100 hp six-cylinder engines.

Forced into line, categorized and standardized

As early as late 1933 the National Socialists integrated all fire brigades in the Reich police forces, which put them under the command of the Minister of the Interior. The Ministry of Aviation was responsible for anti-aircraft defense, and this ministry started in 1934 ordering prototypes for standardized fire-fighting vehicles. Parallel to that, the committee for the standardization of fire-fighting equipment (FEN), founded in 1920, issued the first standards for fire-fighting vehicles.

In 1938, the Ministry of the Interior issued the German Reich Fire-fighting Law with the goal of standardizing and simplifying fire-fighting vehicles. The so-called Schell Plan in March 1939, limiting the number of commercial vehicle models, was followed one year later by a decree of the Ministry of the Interior ruling the types of vehicles to be used in fire-fighting vehicle production. The decree listed 23 types of vehicle, subdivided into three payload categories of 1.5, 3 and 4.5 tons.
Leading producers like Daimler-Benz, Klöckner-Humboldt-Deutz and Metz were now forced to cooperate. As a result of these developments, Daimler-Benz manufactured the Opel Blitz in Mannheim towards the end of the war – not that the company lacked suitable chassis of its own. Mercedes-Benz chassis were represented in all weight categories and served as backbones for virtually all standardized fire-fighting vehicles at the time.

However, the Aviation Ministry had used designations and abbreviations in 1934 which differed from those of the fire-fighting police in 1940. What’s more, the air force had given preference to other types of vehicle than the Ministry of the Interior. The Aviation Ministry, for instance, had specified 26 meter long turntable ladders whereas the 1940 norm provided for ladders in three different lengths: 17, 22 and 32 meters.

On April 30, 1943 new abbreviations came into force, replacing the previous designations and categorizing the different types of vehicle in accordance with a uniform principle. From then on, there were three weight categories for fire-fighting crew vehicles, pump water tenders, turntable ladders and hose carriers.

From motorized extinguisher to fire-fighting crew vehicle

In 1934, the Aviation Ministry had specified three fire tenders: in the category up to 1.5 ton payload, a fire tender trailer was to be attached to a crew carrier; this combination (KzS 8) was not successful and therefore later replaced by a fire tender (KS 8) which in police terminology was known as a light fire-fighting crew vehicle (LLG) and was given the acronym LF 8 in 1943. Daimler-Benz produced 3,800 vehicles of this type until the end of the war, the majority of them with 60 hp six-cylinder M 159 gasoline engines. The pump delivered 1.500 liters of water per minute. Chassis of the Mercedes-Benz L 1500 and L 1500 S type were manufactured in Untertürkheim, parts of the superstructures in the Sindelfingen plant (1941-44).

The heavy-duty fire-fighting crew vehicle (SLG) with three ton payload was the successor to the KS 15 fire tender and later received the acronym LF 15. Its MB L 3000 S chassis came from Mannheim and Gaggenau. Its four-cylinder OM 65/4 diesel engine developed 75 hp. Daimler-Benz produced the fire-fighting equipment for the LF 8 and LF 15 vehicles itself – in Sindelfingen. The pump had a capacity of 2,000 liters per minute and the water jet reached heights of 80 meters at a pressure of eight bar. The vehicle carried a 400 liter water tank for the first attack. In the Daimler-Benz plants, 1,775 three-ton fire-fighting vehicles of this type were manufactured until the end of the war.

With 9,300 units, light and heavy-duty fire-fighting crew vehicles (LF 8 and LF 15) represented the lion’s share among the total fire-fighting vehicle fleet of 16,000 produced until 1945. Even though the Aviation Ministry and the police showed their preference for the Opel Blitz, some 60 percent of these vehicles came from Daimler-Benz.

Of the KS 25 tender for a payload of 4.5 tons, later known as the large fire-fighting crew vehicle (GLG) and finally as the LF 25, only 3,700 units were built. Of this total, 2,066 came from Mannheim and Gaggenau. Initially, Daimler-Benz also used the MB L 3750 chassis with 100 hp diesel engine, later to change exclusively to the L 4500 S chassis with 112 hp six-cylinder OM 67/4 diesel engine. The pump on this vehicle delivered 2,500 liters of water per minute up to a height of 80 meters. The vehicle itself was equipped with a 1,500 liter tank, and its superstructures were supplied by external fire-fighting equipment specialists.

Turntable ladders

Some 700 turntable ladders were built in Germany between 1936 and 1945. Whereas the Aviation Ministry initially preferred 26 meter long ladders (KL 26), the fire-fighting police specified lengths of 17 meters (LDL), 22 meters (SDL) and 32 meters (GDL) in 1940. At a later stage, all four lengths were included in the standards with acronyms DL 17 – 32.

In setting up turntable ladder vehicles, Daimler-Benz cooperated with Metz. The light LD 17 turntable ladders were mounted on L 1500 chassis with 45 or 60 hp gasoline engines. Initially, the L 3000 S chassis with 80 hp diesel engine served as a backbone for DL 22 ladders and the L 3750 chassis with 100 hp engine for 26 meter long ladders. At a later stage, the L 4500 S chassis with 112 hp engine was added to the range.

Hose carriers and pump water tenders

Back in 1934, the Aviation Ministry had specified a hose carrier in the category up to 4.5 tons. At a later stage, this vehicle was given the designation GSK (large hose carrier) and finally S 4.5. As in the case of turntable ladders, Daimler-Benz initially used the L 3750 chassis with 80 hp engine for hose carriers and later on the L 4500 S chassis with the 112 hp six-cylinder OM 67/4 diesel engine. The large hose carrier was manned by a team of two and carried a total of 98 hoses with a combined length of 1,860 meters as well as extinguishing foam equipment.
From 1940 there was also a heavy-duty hose carrier (SSK, later renamed S 3) in the three-ton payload class. Daimler-Benz produced this type of vehicle with Metz superstructure on the L 3000 S chassis. The latter’s six-cylinder diesel engine developed 80 hp from a displacement of 4.9 liters.

The L 4500 S chassis also formed the backbone for some 110 units of the TLF 25 pump water tender produced during the last years of the war. These vehicles had become necessary to fight the fires caused by air raids in German cities.

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Anonymous said...

I am very interested in how the derrick on the emergency tender (L3750) folds away into the roof. Are there other photos or diagrams by any chance?

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