The German 150 mm heavy s.F.H. 18 heavy howitzer left a mark on the history of artillery. Developed in secret, given a made up name, combining excessive weight with excellent ballistics and reliability, this gun was one of the main pillars of German artillery in WWII, and continues to fight to this day in the Syrian Civil War. How did its history begin?
According to the Treaty of Versailles, Germany could not have more than seven infantry and three cavalry divisions after March 31st, 1920. The total size of its military could not exceed 100,000 men, including officers and civilians. The total number of officers, including staff, could not exceed 4000 men. The General Staff was disbanded, and could not be restored in any form. Conscription was outlawed, and the army could only be staffed with volunteers.
A German parade in Warsaw, fall of 1939. A s.F.H. 18 on a horsedrawn carriage is seen. The carriage carrying the barrel is seen in the foreground, the carriage in the background is carrying the mount. The wheels are completely metallic.
Artillery was greatly limited. Each infantry division would have one artillery regiment of three squadrons of 12 guns each, two of which would have cannons, and only one would have howitzers. The caliber of the guns was limited, in addition to their number: the limit was 105 mm light howitzers.
The Germans were prohibited from developing any new types of armament, but work was secretly restarted outside of Germany. Heavy artillery was also forbidden, with one exception: the fortifications at Königsberg. It was permitted for a small number of heavy guns to be kept there, namely 150 mm model 1913 field howitzers (15 cm s.F.H. 13), one of the most common type of heavy weapons in the German Imperial Army.
Officially, 12 s.F.H. 13 howitzers were kept, with 400 rounds of ammunition each, but the Germans secretly kept more, including 210 mm mortars. This allowed for preparation of artillerymen and creation of a backbone of the future Wehrmacht heavy artillery force.
150 mm s.F.H. 13 and its crew.
An oversight commission was left in Germany to ensure that the treaty was followed, consisting of 337 officers and 654 soldiers. The commission prohibited the development of new weapons, and even closed Krupp's R&D branch, a leader in its field. The Germans restarted the work in, literally, the next town over. The commission left Germany on February 28th, 1927, after which there was no reason to hide.
Old howitzer, new tricks
According to the secret plan for reviving the German army, the amount of artillery would triple. Each regiment would grow into three, and new guns had to be developed, which met the requirements of the time. The old s.F.H. 13 was no longer suitable, and Krupp and Rheinmetall joined forces to develop a new heavy field howitzer, indexed s.F.H. 18 (schwere Feldhaubitze, heavy field howitzer) to maintain secrecy several months before the commission left. This kind of index would mislead any observer into thinking that the gun dated back to WWI, and was not a new development.
A design group that also worked on new artillery systems for the future Wehrmacht was given the task. Work took three years. By existing classifications, the s.F.H. 18 was a gun-howitzer. The barrel was designed by Krupp, and the mount by Rheinmetall. With a barrel length of 29.5 calibers, the muzzle velocity increased by almost 1.5 times, from 365 m/s to 520 m/s. The range increased from 8500 m to 13,300 m.
The s.F.H. 18 in combat position. Top: maximum gun elevation. Bottom: 0 degrees elevation.
The new mount, unlike old systems, had split trails and three resting points, approaching cruciform mounts in its characteristics. The mass of the s.F.H. 18 grew by almost 2.5 compared to the s.F.H. 13: from 2135 kg to 5512 kg, but the firing arc also grew, from 5 degrees to 60 degrees. The s.F.H. 18 mount could also be used for the 105 mm K18 gun (10 cm schwere Kanone 18).
The weight of 5.5 tons meant that the barrel and mount had to be transported separately. The heavy weight forced the designers to omit the gun shield. The gun was meant to fire from rear positions, and the need to fire directly would only arise in an emergency. In these cases, it was also permitted to fire with the trails joined, but the vertical and horizontal aiming angles were limited.
The gun crew consisted of 12 men. The gun could be towed by horses or artillery tractors. Sets of six horses were used to tow the gun. The horse transport was given a priority, since the army lacked suitable mechanized transport.
s.F.H. 18 prepared for transport by horse. Top: mount carriage. Bottom: barrel carriage. The wheels are fully metal, with iron rims.
The gun was disassembled for transport by horse, the weight of each carriage totalling up to 4 tons. The top speed when towed in this form was 8 kph. The s.F.H. 18 could also be towed by tractors at a top speed of up to 60 kph on a paved highway.
With the appearance of the Sd.Kfz. 7 halftrack in 1938, the gun could be towed without disassembly. The barrel was pulled back to travel position. The top towing speed was 40 kph. If the gun was transported separately, it took 5-7 minutes to bring it back to combat position, a complex process that required eight men. When transported in one piece, it only took 3-4 minutes.
1300 mm fully metallic wheels were used when the gun was towed by horse. When it was towed with a tractor, 1230 mm wheels with solid rubber rims were used.
s.F.H. 18 howitzer with a barrel pulled back into travel position. The gun is towed by a Sd.Kfz. 7 halftrack. The wheels have rubber rims.
The s.F.H. 18 entered mass production at Dusseldorf, at the Rheinmetall-Borsig factory in late 1933. Production continued until 1945. The barrels were supplied by Krupp, and later other companies: Speerwerke, MAN, Dorris-Fullner, and (after occupation of Czechoslovakia) Skoda.
Starting with January 1st, 1934, when a new type of artillery regiment was formed. A fourth squadron, reserved for heavy artillery, was added. The long period of secret development, trials, and improvements did not go to waste: the army received an effective gun almost immediately, nearly free from "growing pains".
Modernization, successful and otherwise
The heavy weight of the gun forced the army to demand a modernization of the gun. From 1935 to 1939, a lightened variant of the howitzer was developed by Krupp and Rheinmetall, equipped with a lighter 23 caliber barrel. This variant received the title 15 cm schwere Feldhaubitze 36 (s.F.H. 36).
Moving the howitzer from travel to combat mode: removing the tail of the mount from the limber.
The barrel of the s.F.H. 36 was 99 cm shorter than of the s.F.H. 18, but the range also dropped by 825 meters, to 12,500 m. A muzzle brake was used to reduce the recoil length. Aluminium was introduced into the design of the mount. The mass in travel position was reduced by 2.23 tons, to 59.6% of the weight of its predecessor. This meant that the gun could be towed by one tractor or a six-horse cart. Production of the s.F.H. 36 began in 1939, but, due to a shortage of aluminium, it ceased in 1941. Very few guns of this type were produced.
Krupp and Rheinmetall received another order in 1938, for a gun with superior characteristics to the s.F.H. 18 and s.F.H. 36. This gun would have a barrel that was three calibers (45 cm) longer than on the s.F.H. 18, but also it would have a muzzle brake. The mass was 100 kg higher in combat position. The gun could fire at at elevation of up to 70 degrees, and the maximum range was 15,600 m. Further improvements included a pneumatic recoil brake, variable recoil length, and increased chamber volume: significant improvements to the s.F.H. 18 without radical modifications. The gun was ready by 1942, but war introduced its corrections: the need to change production, issues with raw materials, and the need to increase production volumes meant that this design was dead on arrival.
s.F.H. 36 howitzer from Die Wehrtechnische Studiensammlung im BAAINBw.
There was another modification of the s.F.H. 18, called s.F.H. 42 or s.F.H. 18/43 in various sources. Some sources claim that the s.F.H. 42 is a renamed s.F.H. 18/40, others consider it a separate variant. This gun was built in very small numbers, and was equipped with a sliding semiautomatic breech, self-obturation, and a chamber that did not require a steel casing. The propellant was loaded into the weapon directly.
In 1942-43, further work by Krupp, Rheinmetall, and Skoda involved using three-trail or cruciform mounts. These mounts allowed for 360 degree fire at elevations of up to 70 degrees, and allowed a range of up to 18 km, while weighing less than the existing mount in both travel and combat positions. However, none of these creations moved past wooden models.
Hummel self propelled gun. The muzzle brake of the s.F.H. 18 is clearly visible.
The last noticeable modernization of the s.F.H. 18 was the attempt to install a muzzle brake in 1942, which reduced the load on the mount while firing, but it is not known whether or not this modification was widespread. Chamber liners were also introduced. Now, one could fire without worrying about wear from using the maximum charge. The barrel did not have to be entirely replaced, and the liners could be swapped even in battlefield conditions. The modernized gun was indexed s.F.H. 18M. The Panzerfeldhaubitze 18M auf Geschützwagen III/IV (Sf) Hummel, Sd.Kfz. 165, or Hummel, famously used this weapon.
In the hands of victors
After the war, Skoda modernized the s.F.H. 18 to match the needs of the Czechoslovak army, and modified the gun to work with Soviet ammunition. The gun was renamed 152 mm houfnice vz. 18/47. A new barrel with a muzzle brake was installed on the s.F.H. 18 mount. This modification served until the late 1980s, and a number of these howitzers were used for installation into the vz. 77 DANA (Samohybná Kanónová Houfnice vzor 77) self propelled howitzer.
Czechoslovak 152 mm houfnice vz. 18/47, Lešany military museum.
During WWII, the Red Army captured several s.F.H. 18, and the GAU performed trials. The results of the trials highlighted the following elements as deserving of attention:
- The method of attaching recoil mechanism shields to the breech.
- The method of attaching a hydraulic recoil mechanism inside a pneumatic one.
- The lower mount design.
- The suspension design.
- The elevation mechanism flywheel, located on one of the trails.
However, the overall conclusions were negative:
"The gun is insufficiently simple, due to complex mechanisms, difficulty in finishing some parts, and many riveted connections. This makes it unsuitable for mass production. However, it is incorrect to call it complex from a production standpoint."
Shells and casings of the s.F.H. 18.
Tactical-technical characteristics of the s.F.H. 18 howitzer:
GAU data | German data | |
Caliber | 149 mm | 149 mm |
Barrel length | 30 calibers | 30 calibers |
Maximum range | 13,325 m | 13,325 m |
Minimum range | 4000 m | - |
Muzzle velocity | 210-520 m/s | 520 m/s |
Vertical firing arc | 0–45° | 0–45° |
Horizontal firing arc | 60° | 60° |
Number of variable charges | 8 | 8 |
Mass in combat position, without trails | 5180 kg | 5512 kg |
Mass of the mount carriage | 4000 kg | - |
Mass of the barrel carriage | 4095 kg | - |
Rate of fire | 6 RPM | 4 RPM |