15 cm sFH 18

The 15 cm schwere Feldhaubitze 18 or sFH 18 (German: "heavy field howitzer, model 18"), nicknamed ''Immergrün'' ("Evergreen"), was the basic German division-level heavy howitzer of 149mm during the Second World War, serving alongside the smaller but more numerous 10.5 cm leFH 18. Its mobility and firing range and the effectiveness of its 44 kilogram shell made it the most important weapon of all German infantry divisions. A total of 6,756 examples were produced.

It replaced the earlier, First World War-era design of the 15 cm sFH 13, which was judged by the Krupp-Rheinmetall designer team of the sFH 18 as completely inadequate. The sFH 18 was twice as heavy as its predecessor, had a muzzle velocity increase of forty percent, a maximum firing range 4.5 kilometers greater, and a new split-trail gun carriage that increased the firing traverse twelvefold. The secret development from 1926–1930 allowed German industry to deliver a trouble-free design at the beginning of German re-armament in 1933. It was the first artillery weapon equipped with rocket-assisted ammunition to increase range. The sFH 18 was also used in the self-propelled artillery piece ''schwere Panzerhaubitze'' 18/1 (more commonly known as '' Hummel'').

The sFH 18 was one of Germany's three main 15 cm calibre weapons, the others being the 15 cm Kanone 18, a corps-level heavy gun, and the 15 cm sIG 33, a short-barreled infantry gun.

Design and development

Development work on the sFH 18 began in 1926 and the gun was ready for production by 1933. The model year was an attempt at camouflage. The gun originated with a contest between Rheinmetall and Krupp, both of whom entered several designs that were all considered unsatisfactory for one reason or another. In the end the army decided the solution was to combine the best features of both designs, using the Rheinmetall gun on a Krupp carriage.sFH 18
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The carriage was a relatively standard split-trail design with box legs. Spades were carried on the sides of the legs that could be mounted onto the ends for added stability. The carriage also saw use on the 10 cm schwere Kanone 18 gun. As the howitzer was designed for horse towing, it used an unsprung axle and hard rubber tires. A two-wheel bogie was introduced to allow it to be towed, but the lack of suspension made it unsuitable for towing at high speed.

The only remarkable feature of the sFH 18 was that it was the first weapon to make use of rocket-assisted projectiles (RAP), which in theory would give the howitzer a range equal or superior to the 10 cm sK 18, replacing it and freeing up German production capacity for more important weapons; In practice, the RAP rounds were not entirely successful and were withdrawn from service shortly after being introduced in 1941. Army reports at the time "speak with awe of the voluminous and involved firing instructions that accompanied it," which did nothing to dispel the artillery crews suspicions that the RAP rounds were scarcely out of the experimental stage.

The gun was officially introduced into service on 23 May 1935,Haubitzen und Mörser
and by the outbreak of war the Wehrmacht had about 1,353 of these guns in service. Production continued throughout the war, reaching a peak of 2,295 guns in 1944. In 1944, the howitzer cost 40,400 RM, 9 months and 5,500 man-hours to make.

Variants

Several other versions of the basic 15 cm were produced:

*The 15 cm sFH 36 was a version with a greatly reduced weight that was an attempt to improve mobility, but as it used various light alloys to achieve this saving it was considered too costly to continue production.
*The 15 cm sFH 40 was another improved version, featuring a slightly longer barrel and a new carriage that was suitable for vehicle towing and allowed the barrel to have wider firing angles and thereby improve range up to 15,400 m. However this version was even heavier than the ''sFH 18'' (at ) and was found to be too difficult to use in the field.
*The 15 cm sFH 18/40 was created by fitting the barrel of the ''15 cm sFH 40'' to existing ''sFH 18'' carriages. Roughly 46 howitzers were created.
*A further modification was the 15 cm sFH 18/43, which changed to a split breech that allowed for the use of bagged charges instead of requiring the gunners to first put the charges into casings.
*Two further attempts to introduce a newer 15 cm piece followed, but neither the 15 cm sFH 43 or 15 cm sFH 44 progressed past the stage of wooden mock-ups.

Combat record

The first field combat for the 15 cm sFH 18 was with the Chinese National Revolutionary Army in the Second Sino-Japanese War. The Chinese planned on purchasing a total of 240 pieces but only 24 were delivered by 1937 due the lack of funds. The few 15 cm sFH 18 units the Chinese did have hopelessly outclassed their Japanese counterparts which were mainly the Type 38 15 cm howitzer and Type 4 15 cm howitzer, forcing the Japanese to introduce the Type 96 15 cm Howitzer. Some earlier pieces (about 24) of sFH18 in China were designed specially with a 32/L barrel, known as sFH18 32/L; the maximum range was increased to 15 km.

Against the Soviet Union, the sFH 18 lacked the range of the Red Army 152 mm ML-20 gun-howitzer, its maximum range of allowed it to fire counter-battery against the sFH 18 with a advantage. This led to numerous efforts to introduce new guns with even better performance than the ML-20, while various experiments were also carried out on the sFH 18 to improve its range. These led to the 15 cm sFH 18M version with a removable barrel liner and a muzzle brake that allowed a larger "special 7" or 8 charge to be used. The 18M increased range to , but it was found that the liners suffered increased wear and the recoil system could not handle the increased loads in spite of the brake. This led to the introduction of the 15 cm R. Gr. 19 FES ammunition, which used a rocket-assisted round that could reach and give it some level of parity with the ML-20.

Several countries continued fielding the sFH 18 after the war in large numbers including Czechoslovakia, Portugal and many South American and Central American countries. Finland bought 48 sFH 18 howitzers from Germany in 1940 and designated them 150 H/40. These guns were modernized in 1988 as the 152 H 88, and they were used by the Finnish Army until 2007.

Versions

*15 cm sFH 18 – standard version
*15 cm sFH 36 - lightened version
*15 cm sFH 18M – modification of sFH-18 with muzzle brake and replaceable barrel liner
*15 cm sFH 18/40 – sFH 40 barrels on sFH 18 carriages
*15 cm sFH 18/43 – a sFH 18 development to accept bag charge with sliding-block breech
*15 cm sFH 18/32L – Chinese (Republic of China) version with longer barrel and longer range of 15 km
*152 mm Howitzer M18/46 – Post-war Czechoslovak modification with a shorter barrel that was rebored to fire Soviet 152 mm ammunition, a straight topped gun shield and a double-baffle muzzle brake
* 152 H 88-40 – Finnish modernization with a lengthened 152-mm barrel and a muzzle brake

Operators

* – Post-war use
*
* − sFH 18M
* – Post-war use
*
* Republic of China − 24 sFH 18/32L purchased in 1937
* Czechoslovakia – Modified as the ''Howitzer M18/46''. Kept in reserve as late as 1976
* – 48 pieces, known as ''150 H/40''
*
* – Designated as the ''Obice 149/28''
* – Post-war use
* − Designated as ''Haub m/39''
* – sFH 18 and sFH 18M

See also

* 152 mm howitzer-gun M1937 (ML-20) – Soviet 152 mm howitzer
* BL 5.5 inch Medium Gun – British gun of similar size
*10 cm schwere Kanone 18

References

Citations

Bibliography

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External links

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{{Use dmy dates, date=June 2017

150 mm artillery
World War II field artillery
World War II artillery of Germany
World War II artillery of Italy
World War II weapons of China
Krupp
Rheinmetall
World War II howitzers
Military equipment introduced in the 1930s