The manufacture of tracked vehicles at M.N.H. in Hannover from 1939 to 1945

Written by Frank Köhler on 20 October 2011.

MNH's destroyed assembly hangar after Germany had surrendered

The manufacture of track vehicles at M.N.H. in Hanover from 1939 to 1945, post-War tank manufacture and testing by the British Army
The history of the development and manufacture of military tracked vehicles in Germany is closely linked to the major manufacturers of rail and heavy vehicles, weapons and steel. Generally speaking, the company which conducted the final assembly of a tank was usually referred to as its supplier. During war time, spare part suppliers varied according to the respective requirements and capabilities.

As of about 1940, the Hanover-based company MNH was among the important manufacturers of main battle tanks and their components; as opposed to most of the other companies, however, MNH did not have a strong tradition in the civil sector, which is why only few of the circle of interested people have heard of it.

In addition to well-known companies such as MAN, Daimler-Benz and Henschel, the list of manufacturers of the Panther – the production of which started in 1943 and which is widely regarded as the best medium main battle tank fielded in World War II – includes MNH. It is safe to say that MNH accounted for 30 % of the approx. 6,000 Panthers ever produced and more than 30 % of the approx. 400 tank destroyers Jagdpanther ("hunting panther"). It was the only company which, at times, produced Panthers and Jagdpanthers simultaneously. As most of the company's facilities for tank manufacture were deconstructed in 1946/47 by order of the Allies of World War II and the company ceased to exist, it is not possible to learn much about it in the relevant literature.

1. Notes on the company MNH and its formation
The documents of the U.S. Strategic Bombing Survey state that the company was founded in the spring of 1939. They mention an overall number of 8,000 to 10,000 employees, although 12,000 workers and forced workers are mentioned elsewhere. It may be deemed certain that MNH was comprised of three plants, was derived from the earlier companies Gebrueder Koerting ("Koerting Brothers") and "Eisenwerk Wuelfel" ("Iron Works Wuelfel") and was designed for the production of armaments from the very beginning.

The Reichsbetriebskartei Industrie (Reich industrial company index) as of May 31, 1944 listed the factory under "Maschfab Laatzen", and official company headquarters of "M.N.H. Maschinenfabrik Niedersachsen G.m.b.H" was located in Hanover-Wuelfel at Eichelkampstr. 4. The works Linden and Laatzen are mentioned as subsidiaries without separate addresses. According to this document, the company had already served the armaments sector since 1937 and had an overall number of 3,383 employees.

The premises of the Linden works in Badenstedter Strasse belonged to the predecessor of the machine construction company Koerting Hannover AG until it became insolvent in 1932.The insolvency creditor probably sold the premises to Eisenwerk Wuelfel in the course of the 30s. Eisenwerk Wuelfel most probably was the only shareholder in MNH.

The Laatzen works in Hildesheimer Strasse was a subsidiary plant belonging to Eisenwerk Wuelfel, and as of spring 1945 American forces and, later, British armed forces used it until the end of 1957. Afterwards, it belonged to Eisenwerk Wuelfel, just as it had before.

On April 9, 1945, the Linden works was occupied by the British Army. This tank assembly factory seems to have been the focus of interest of the British forces and was deconstructed in 1946/47. Only one building, probably the chassis assembly hangar which had hardly been damaged, was blasted in November 1947. Today, a plant by Mannesmann-Rexroth is located on this spot. The ground plan of several other buildings might still have been identical to numerous former factory hangars and residential buildings in 1993. Second and third sector companies were located in these buildings.

2. The works
The operating part having the most sinister history is the underground works in Ahlem. It was built in an asphalt adit system extending to the North and South of Harenberger Landstrasse and had the code name "Doebel" ("chub"). In Adit I (Ahlem I), the company Continental was ought to manufacture aircraft fuel tanks, technical aircraft hoses and other products, while MNH should manufacture final drives for the Panther in Adit II (Ahlem II).

For the purpose of construction, internees from different camps were moved there. The premises and the barracks which already existed there were in such a bad condition that large parts of the "Ahlem Concentration Camp" still had to be built by 100 internees before the work in the adits began in late November 1944. Some of the approx. 200 internees who were deployed to Ahlem to do extremely hard work there were malnourished and exhausted to such an extent that they were no longer able to do the factory work at Conti, which was easy by comparison, to the satisfaction of the company. It is uncertain whether production ever started. It seems to be clear, however, that machines were assembled by concentration camp internees in the MNH adit.

The smallest one of the three plants was the one in Laatzen which was most probably the Maschinenfabrik Laatzen (Maschfab. Laatzen) mentioned above. It is said to have produced continuous tracks, chassis components and guide rollers for the Panther tank and delivered them to the assembly plant in Linden. Additionally, gun barrels were reportedly produced there. It is also possible that aircraft components for the Junkers Ju 87 and Junkers Ju 88 were produced here.

At the Wuelfel works ("Eisenwerke Wuelfel") with about 4,000 workers, gearwheels and gear box housings for various tank manufacturers and for the captive Linden works were produced. It was bombed on September 22, 1943 and on March 28, 1945. Both attacks were severe, but it was still possible to supply the Linden plant with components after the first attack. During the second attack the energy supply was destroyed which ended production for good. The Linden works was the main one: Here, the tanks were assembled, tank components were processed and 4,000 to 6,000 people were supposedly employed, only 600 of whom are said to have been Germans. The foreign workers were mainly of Russian and French nationality and the Russian forced workers were the largest group among them. During an interrogation after Germany had surrendered, the senior engineer who had been responsible for production and development stated that 80 to 100 vehicles per month had been produced by 2,500 to 3,000 workers. During the first targeted bomb attack on March 14, 1945, the gas pipes were damaged and the energy supply was interrupted for two days. Two less severe attacks on March 17 and 25 did not cause much damage, but the attack on March 28 mentioned above interrupted the energy supply for a long time and destroyed the buildings which had been spared up to then. After that, production almost entirely came to a standstill.

3. Production at the Linden works
The production of military vehicles is said to have begun as early as in June/July 1939 with the production of semi-tracked IFVs and armoured reconnaissance vehicles. MNH was a major supplier of the chassis for the medium armoured fighting vehicle (Sd.Kfz.251) from the spring of 1941 to October 1944. From January to December 1942, MNH also conducted the final assembly of this vehicle type. The number of 138 chassis produced in 1942 (including final assembly) and 808 chassis produced in the following two years (1943 and 1944) may be deemed verified. It may well be possible that there is a link to the company Hanomag which also produced the medium armoured fighting vehicle and chassis for it. Hanomag is mentioned at least once in connection with the production of the Kampfpanzerwagen II (Armoured Fighting Vehicle II), and a former employee of Hanomag mentions it in connection with the assembly of Panthers.

An eye-witness who was once employed at the Linden works reports that the manufacture of the medium armoured fighting vehicle (SdKfz) in cooperation with Hanomag was started in 1941. He also recounts that in 1940 test assemblies of 8x8 heavy armoured reconnaissance vehicles have taken place in collaboration with the company Buessing-NAG. However, he adds, they were shelved after initial difficulties. He is the only eye witness whom the author of this article has met to this day, and he also reports that the manufacture of the light 1 ton ZgKw (armoured towing motor vehicle; SdKfz 10) "ran at full speed" in 1940 and that, parallel to that, PzKpfw III (armoured fighting vehicle III), PzKpfw IV (armoured fighting vehicle IV) and StG III (assault gun III) were produced in mid-1941 at one assembly line, at least until he was called up in 1942. The simultaneous manufacture of three tank types by means of assembly-line work and the wide range of products described to the author of this article suggest that the company which had been founded only a short time earlier was extremely flexible and efficient.

The armoured fighting vehicle III is said to have been added to the range of MNH from late 1940 to January 1943. Two former directors of the company say that the month of July in 1943 marked the end of Panzer III production at MNH. The Panther was produced from the end of January/beginning of February 1943 onwards. Over the course of 1943, a number of 445, in 1944 a number of 1,232 and in January and February 1945 not less than 161 vehicles were delivered.

In my opinion, however, it is verified that vehicles were still completed in the days just before April 9, 1945, even if only in small quantities. With respect to the period after the last and most severe bomb attack on the works on March 28, 1945, two of the former directors say: "Since machine work was no longer possible, only a few tanks which had already almost been completely manufactured were manually completed". The pictures which were taken by British military personnel shortly after the end of the war and show the chassis assembly hall support this statement; they mainly show the tank assembly lines, on which partly assembled chassis of the Panther and Jagdpanther can be seen, and give an insight into the chassis manufacture as well as the chaotic production conditions at the end of the war. By the way, the hall does not give such a destroyed impression as one would expect after having read the American report. The pictures accompanying this report only show several other, severely damaged or levelled halls.

The tank bodies (hull and turret bodies) delivered by various manufacturers were mechanically finalized for assembly at the plant. Additionally, the final assembly and testing of various finished or manufactured components was conducted here. For example, a 2-hour noise and heat development test is said to have been carried out for the control gears (with additional load) and the final drives manufactured in-house (without additional load). It is said that the engines were delivered by Auto-Union (Siegmar works) and allegedly the engines were not modified prior to their installation, apart from carburettor settings during running-in. According to the responsible senior engineer, the "standard Wehrmacht transport fuel" was used during running-in which consisted of 25 % of petrol, 30 % of benzene and 45 % of alcohol, no tetraethyl lead added, and had an octane number of 70. He says that no problems occurred during operation, in fact, engine performance was rather higher. (Note: This seems to be credible as it was also possible to additionally inject a methanol water mixture (MW 50) into fighter jets for short-term performance increases.) The two men estimated that the service live of the engines was 2,000 hours. Motor problems did not occur according to them.

The boring and drilling machines were connected to each other by means of tracks embedded in the floor. In this way, the chassis to be processed did not have to be lifted and it was possible to simply push them onward, which was beneficial for the workflow. Valuable tool machinery was protected against the effect of highly-explosive bombs by means of bricks loosely piled up to a medium height, as was common practice.

According to available pictures, the assembly of chassis took place on three short parallel assembly lines towards the end of the war. The change of the original process with only one single long assembly line which moved back and forth and thus brought along disruptions of the workflow might have been caused by the start of the manufacture of the Jagdpanther at the end of 1944. Available pictures, taken after Germany had surrendered, suggest that a "one-type-only" construction, i.e. the manufacture of Panthers OR Jagdpanthers on these three assembly lines, was possibly envisaged.

The chassis transport along the assembly line was conducted by pulleys which, by means of guide rollers, were driven by the crane systems. The cassis were moved on tracked transport wagons. A British report describes the system of quality assurance as very effective and helpful due to the optimized manufacturing conditions at MNH. It says that only 6 Wehrmacht quality assurance representatives were employed in assembly (3 during the day and 3 during the night) who were responsible for intermediate acceptance tests during the manufacture as well as for the acceptance of the finished products. The effective and profound intermediate and final tests are said to have been conducted by about 60 internal quality assurance representatives at the works. It is interesting that the tests during manufacture and the setting of the entire turret and weapon system, however, were mainly conducted by the Wehrmacht quality assurance representatives.
For the tested parts and/or supplier parts, the works had locked deposits to which the employees did not have access. Generally, the parts which had been properly accepted and "certified" (by Wehrmacht quality assurance representatives) were not subjected to any further incoming-goods tests apart from tests for transport damage.

• 1. Pre-assembly of engines, final drives and guide rollers
• 2. Mechanical section
• 3. Mechanical processing of turret and hull chassis
• 4. 8 spindle drilling machine for the completion of the chassis bores
• 5. Column drilling machine for drilling into the turret body
• 6. Mechanical completion of the hull body
• 7. Two spindle drilling machines for drilling the bores required for installation of the final drives and the swinging arm of the guide wheel
• 8. Portal lathes for processing the turret ring seat
• 9. Radial drilling machines with prolonged side arms for drilling bores with smaller diameters
• 10. Chassis assembly line
• 11. Assembly platforms
• 12. Assembly lines for the assembly of 10 vehicles each

After Germany had surrendered, 9 Panthers and 12 Jagdpanthers were assembled from remaining parts within nine months from August 1945 to the spring of 1946. Since parts of the main MNH factory had been severely damaged by bomb attacks, the existing vehicles which had already partly been assembled were taken to the Laatzen works which showed less damage. The completion was managed by Captain Hadlow of the 823 Armoured Troops Workshop, a workshop unit for armoured vehicles, which was probably accommodated in the Laatzen works. Hadlow received the order via the headquarters of the British Army of the Rhine to complete as many vehicles as possible. They supposedly all received a front metal plate which said that the assembly of the vehicle had been completed by the REME (Royal Electrical and Mechanical Engineers, the British Overhaul Corps). The Panther which today is in the possession of the Scientific Collection of Defence Engineering Specimens (WTS), for example, originally bore a plate with the inscription: BUILT IN 823 ARMD TROOPS WKSP, REME, NO. 6, BOAR, 1945. The vehicles were test-driven in the heath lands north of Hannover by British personnel, but it is said that they were tested in accordance with the German requirements. Available pictures show that some vehicles were not completed – for example, one Jagdpanther does not have a main weapon system and several hatch covers are missing.

Solid evidence proving that vehicles were also assembled in England could not yet be found. The then-head of the subject area of wheeled and tracked vehicles of the Scientific Collection of Defence Engineering Specimens reported to the author of this article that British partners had declared on the occasion of the Panther hand-over that two thirds of this vehicle had been completed and the final assembly had taken place in England.

At least one vehicle, however, is said to have been assembled in order to have a new vehicle available for the planned comparative testing with the "Black Prince" and the "Centurion". Two Panthers, two Jagdpanthers and a Bergepanther (armoured recovery vehicle) were ought to be subjected to all acceptance inspections for new British armoured fighting vehicles at the British Fighting Vehicle Proving Establishment in Chertsey, Surrey, in 1948 under the supervision of the Fighting Vehicle Design Establishment. However, means were cut first and the programme was finally cancelled. The vehicles (from Hannover) are said to have been almost as good as new with the exception of the Bergepanther with its 600 km in operation.

The testing of the vehicles in England is said to have been "disappointing". Apart from spare engines, no spare parts were available. There were difficulties with the steering and engine fires occurred; the necessary spare parts were obtained by cannibalisation of other vehicles.

A German prisoner of war had to enlighten the British testing team about the correct operation of the vehicles. He reported to the British that, according to his experience, Panther crews had been advised not to use the superimposed steering system and, instead, the steering brake right away as the clutches were too weak for the superimposed steering system. Using the steering brake required immediate pulling of the lever beyond the steering radius area. It is commonly known that the passenger-car type simple-disk dry clutches were too weakly set to function as radius steering clutches and, in case of heavy strain, hit their limit of performance quickly; this is also confirmed by experience with the vehicles which are part of the Scientific Collection of Defence Engineering Specimens. In this context, page 48 of the Panther handbook for Panther crews, published on July 1, 1944 by the inspector general of the tank troops, states: "...Also remember that it is not right and proper to torture the steering brake whenever one thinks it is necessary; this will break the engine quickly; those who do this have no sense of tanks at all!"

Des weiteren würden die Motorbrände durch Überlaufen der Vergaser ausgelöst, im Betrieb zu erkennen an lang herausschießenden Flammen bei weissglühenden Auspuffrohren. In diesem Fall sei ein Brand bei Nachzündungen beim Abstellen des Motors ziemlich wahrscheinlich. Daher hätten es die Fahrer in diesen Fällen vorgezogen, den Motor durch "Abwürgen" abzustellen.
Die von Anfang an bekannten Probleme mit Motorbränden durch überlaufenden Kraftstoff scheinen also, trotz aller durchgeführten Detailverbesserungen, bis zum Ende der Fertigung des Panthers ein Thema gewesen zu sein.

Furthermore, the engine fires were supposedly caused if the carburettor overflowed, recognisable during operation by large spouting flames and white-hot exhaust pipes at the same time. In this case an afterflame was quite possible when the engine was turned off. Thus, the drivers allegedly preferred stalling the engine in such cases. It seems, thus, that – despite all the improvement of details – the problematic engine fires due to spilling fuel, which had been an issue from the beginning, were a source of difficulties right through to the end of Panther manufacture. During further testing, drives on the street at maximum speed for determining fuel consumption were cancelled for safety reasons due to the "unpredictable" steering; the same is true for a 25-mile cross-country drive at a safe maximum speed for testing the cooling appliance and fuel consumption. When one of the vehicles was stopped at a steep slope with a grade of 22 %, its brakes malfunctioned and the engine and the running gear were damaged when the vehicle rolled back down; afterwards no vehicle was operational anymore and the tests had to be ceased on February 11, 1948. The fact that the correct adjustment of the steering was very important is explained on page 44 of the Panther handbook: "…If every horse pulls to a different direction (note: in case of a coach-and-four), the steering will cause difficulties. In case of 700 horses (note: the Panther's 700 hp), this can become extremely dangerous: The Panther will run randomly if its steering is badly adjusted…"; in a politically-bias way typical for that time, the text continues by describing a "lord" sitting on a "donkey", not being able to move forward because he is "too stupid" to steer such a "stubborn" beast; the text warns: "If you do not set the additional brake correctly, the Panther will be stubborn, too." If no original maintenance guidelines, preferably in a translated version, were available during testing in England and the unusual, not self-explanatory adjustments were possibly done inaccurately or not at all, severe problems during driving were inevitable. This also corresponds to the experience the Scientific Collection of Defence Engineering Specimens has had with this type of tank for years.

Not only the Panther but also the Jagdpanther of the Bovington Camp Tank Museum, is from the post-war series. The remains of another Jagdpanther were found on a training ground in Surrey, England. From this vehicle in combination with pieces of another one, a vehicle was built which was as good as new and is privately owned by a person in England. A third Panther of type G has survived; it is privately-owned, too. Generally, however, it may be assumed that most of these vehicles came to their end as hard targets on training grounds in England or Germany.

The captured Bergepanther (armoured recovery vehicle), which was also submitted to intense testing, seems to have been more satisfactory. Among other tasks, it had to pull a "Centurion" out of the mud and was referred to as "useful". Only the cable winch of this tank survived because it had served the testing centre well for decades. The Bovington Tank Museum was as kind as to donate the cable winch to the Scientific Collection of Defence Engineering Specimens in exchange and so it significantly adds to the Bergepanther of the Scientific Collection of Defence Engineering Specimens.

References:
English translation of the article by Frank Köhler: Die Fertigung von Kettenfahrzeugen bei der Firma M.N.H. in Hannover von 1939 – 1945", die Nachkriegs-Panzerfertigung und Erprobung durch die Britische Armee (The manufacture of track vehicles at M.N.H. in Hannover from 1939 to 1945 – post-War tank manufacture and testing by the British Army), Koblenz, 2007.

Updated contribution from the magazine WTS-Info, Issue 12, Koblenz, 1994.

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