The 10.5 cm leFH 18/4 self-propelled gun on the Lorraine 37L French tractor chassis, here the Baukommando Becker version, source: Flickr.com, with permission of the publishing user, edited

Origins of the Vehicle

By the turn of 1941–42 it had become definitively clear to the Germans that they had underestimated the Soviet army. The German Ordnance Office was therefore working feverishly on a whole range of projects aimed at getting as many new and more effective weapons as possible to front-line units as quickly as could be managed — weapons that would help establish superiority over the adversary. One distinct area of focus was the search for anti-tank weapons capable of dealing with the unexpectedly advanced Soviet tanks, the T-34 and the KV-2. The primary means of destroying them was to be the new 75 mm Pak 40 gun developed by Rheinmetall. In order to maximise the effectiveness of its deployment, the army was also calling for a self-propelled version — but where to quickly find a suitable chassis without eating into their own tank production?

One option under consideration was mounting the gun on the chassis of one of the fully tracked vehicles the Germans had captured during the earlier campaigns in Western Europe, which were therefore available essentially immediately and at no cost. It was while these options were being discussed at the Ordnance Office that one name came up — a name that promised the practical experience needed. That name was Alfred Becker: a qualified engineer and artillery battery commander in the 227th Infantry Division, then fighting in northern Russia. Alfred Becker had, together with his unit's soldiers, built by their own efforts during the second half of 1940 twelve 105 mm leFH 16 self-propelled howitzers on the chassis of captured British Vickers Mk. VI tanks. When his division was sent to the Eastern Front in September 1941, Becker's creations had the opportunity to prove their worth — and it turned out that, given what they had cost to produce, they were remarkably effective fighting machines. So effective, in fact, that word of it reached Berlin.

Ordnance Office representatives therefore approached Becker, recalled him from the front and brought him together with engineers from the firm Alkett to jointly design the conversion of the ex-French Lorraine 37L cargo tractor into a tank destroyer armed with the Pak 40. Whether it was part of the army's brief or not is not entirely clear from the sources, but in addition to the tank destroyer, Becker also prepared two further proposals: for fitting the Lorraine chassis with a light 105 mm howitzer (either the leFH 16 or leFH 18) and with a heavy 150 mm sFH 13 howitzer. In May 1942, no fewer than three different possibilities for using the French chassis could therefore be presented to the Führer — and Hitler liked all of them! When informed that at least 160 serviceable Lorraine 37L tractors were available in German army vehicle depots (the so-called Heeres-Kraftfahrpark, or H.K.P.) in Paris and in Bielitz in Poland, he decided that 60 of them were to be converted into tank destroyers, 40 into 150 mm self-propelled howitzers, and the remaining 60 into carriers for the 105 mm howitzer. We can say straight away, however, that the number of light self-propelled howitzers actually built on this chassis fell well short of this original plan.

10.5 cm leFH 18/4 auf Geschützwagen Lorraine Schlepper (f) — here specifically the Alkett-built version
source: Flickr.com, with permission of the publishing user, edited

Series Production

The first 12 leFH 18 self-propelled howitzers on the Lorraine tractor chassis were built to Becker's design by the firm Alkett, either in September or November 1942. By that time Alfred Becker was no longer working at Alkett. On behalf of the Ministry of Armaments he had relocated to France to head the so-called Baukommando Becker (sometimes also referred to as Baustab Becker) and organise the conversion of further usable captured equipment into fighting vehicles for the German Wehrmacht. It was in the workshops of Becker's Baukommando that a further 24 self-propelled guns of this type were built by September 1943, in two production batches of 12 each. The total production thus came to 36 vehicles — though they were not identical machines. Vehicles from each production batch differed slightly from one another, so photographs reveal, for example, three different configurations of the fighting compartment armour (see photo HERE). According to some authors, only 24 vehicles of this type were built — 12 by Alkett and 12 by the Baukommando.

Vehicle Description

The French Lorraine 37L tractor (referred to by the Germans as the Lorraine Schlepper) had its engine located in the centre of the hull, with the rear reserved for the cargo compartment. For conversion into a self-propelled gun this was an ideal arrangement, since the rear section could be converted into a fighting compartment with relative ease — and that is exactly what happened. The front section of the hull was left essentially unchanged, with only the hot-air exhaust vents for the engine cooling air being moved from the roof to the sides, where louvred openings were cut into the armour for them. The running gear consisted on each side of six road wheels fitted with solid rubber tyres and suspended in pairs by leaf springs. At the front was the drive sprocket and at the rear the idler wheel. The tracks were only 22 cm wide.

Hull armour was thickest at the front at 12 mm, with 9 mm on the sides and only 6 mm on the floor and roof. The original French Delahaye 135 engine was of course also retained — a six-cylinder petrol unit with a displacement of 3.556 litres producing 70 horsepower — as was the original five-speed gearbox. The fighting compartment, formed at the rear of the vehicle, was enclosed by a tall protective shield welded and riveted from flat 10 mm plates. Armour of this thickness was insufficient even against armour-piercing rifle or machine gun rounds, offering protection only against ball ammunition and light shell fragments. Heavier armour was prevented by the chassis's limited load capacity. The original French Lorraine 37L tractor weighed 6.05 tonnes and could carry up to 810 kg of cargo in its load compartment. Its chassis was therefore rated for approximately 6.86 tonnes of direct load — yet the self-propelled gun weighed 7.7 tonnes. Remarkably, this does not appear to have had any adverse effect on driving performance, at least on paper. The vehicle's maximum speed remained the same as the original tractor's: 35 km/h.

10.5 cm leFH 18/4 auf Geschützwagen Lorraine Schlepper (f) with the unusual additional shield above the engine compartment, source: Flickr.com, with permission of the publishing user, edited

The self-propelled gun received the somewhat unwieldy official designation 10.5 cm leFH 18/4 auf Geschützwagen Lorraine Schlepper (f) (though other designations are also encountered). Sources unfortunately cannot quite agree on the size of the crew. According to some there were 5 men aboard: driver, commander, gunner and two loaders; according to others only 4: driver, commander, gunner and one loader. It is quite possible that there were indeed only four men, but that the driver left his station in the hull when preparing to fire and moved into the fighting compartment, where he temporarily served as a second loader. Within the context of German self-propelled guns this would not have been unusual at all, and would explain the supposed "fifth" crew member. It is also worth noting that the commander was simultaneously responsible for operating the Fu.Spr.Gr. radio set.

The fighting compartment was open at the top — completely standard practice for German self-propelled guns of this era. An open roof allowed far better observation and ventilation, and given the vehicle's intended role it represented no serious safety weakness. Self-propelled guns were not designed for direct contact with the enemy. They were to stay several kilometres behind the front-line units and fire over their heads at an enemy they would usually never even see.

The 10.5 cm leFH 18/4 Howitzer

The vehicle's main armament was the already repeatedly mentioned 105 mm leFH 18 light howitzer — or more precisely its leFH 18/4 variant, modified specifically for installation in this vehicle. The howitzer used separate-loading ammunition, meaning the shell was rammed first followed by the propellant cartridge. The range could be regulated by varying the propellant charge — that is, the number of powder bags inserted into the cartridge. On the standard towed leFH 18, six charge sizes were available. It is quite possible, however, that on the self-propelled variant the use of the heaviest charge was prohibited — which would not have been unusual. To reduce the weapon's recoil (and thereby the stress on the chassis during firing), the howitzer barrel was fitted with a muzzle brake. Photographs show it in two different configurations. Only 20 rounds of ammunition could be stowed on board. The self-propelled gun had no secondary weapon built in "under armour." Crews most likely carried a loose machine gun and submachine guns for close-range defence, firing over the top of the fighting compartment's walls.

10.5 cm leFH 18/4 auf Geschützwagen Lorraine Schlepper (f) firing — note the folded-down rear stabiliser spade for better vehicle stability, source: Flickr.com, with permission of the publishing user, edited

Although it may not be immediately obvious, the gun was in fact positioned above approximately the rear third of the chassis, significantly shifting the vehicle's centre of gravity toward the rear. To reduce the stress on the rear of the running gear and to improve overall stability, a folding stabiliser spade was therefore fitted beneath the overhanging rear section of the fighting compartment. During travel it was raised against the rear armour plate; before firing it was lowered to the ground. As for the combat deployment, only the fate of 24 vehicles is known — those assigned to Panzer Artillerie Regiment 155 of the 21st Panzer Division. In June 1944 all of them were committed against the Allies following the Normandy landings. Their numbers gradually dwindled, and the last were lost in the Falaise Pocket in August 1944.

As an aside, photographs exist that show at least one example of the 10.5 cm leFH 18/40 auf Geschützwagen Lorraine Schlepper with an interesting modification that no published source mentions. Above the hull roof, directly in front of the fighting compartment, an additional raised hood of some kind appeared. Since the engine air intake louvres were located in precisely this area, it is possible that this was a "shield" intended to protect the engine compartment — perhaps against shell splinters, or possibly against rainwater. Whether it was an experimental installation on just one vehicle or whether more vehicles were modified in this way is unfortunately unknown. A photograph of this modified self-propelled gun can be viewed HERE.

Technical Data

ARTICLE
CONTENTS:

ORIGINS OF THE VEHICLE

PRODUCTION

VEHICLE DESCRIPTION

ARMAMENT

TECHNICAL DATA