15 cm sFH 18

15 cm schwere Feldhaubitze 18
Preserved sFH 18 howitzer at CFB Borden
Type	Howitzer
Place of origin	Germany
Service history
In service	1934–70
Used by	Germany Finland Republic of China
Wars	World War II Portuguese Colonial War Syrian Civil War
Production history
Designer	Krupp
Designed	1926–1933
Manufacturer	Krupp, Rheinmetall, Spreewerke, M.A.N. and Skoda
Unit cost	40,400 RM (1944)
Produced	1933–45
No. built	5403
Variants	sFH 18M
Specifications
Weight	Travel: 6,304 kg (13,898 lb) Combat: 5,512 kg (12,152 lb)
Length	7.849 m (25 ft 9.0 in)
Barrel length	4.440 m (14 ft 6.8 in) L/29.5
Width	2.225 m (7 ft 3.6 in)
Height	1.707 m (5 ft 7.2 in)
Shell	149 mm × 260 R (cased separate-loading ammunition)
Shell weight	43.52 kg (95.9 lb) (HE)
Caliber	149 mm (5.9 in)
Breech	horizontal sliding block
Recoil	hydropneumatic
Carriage	split trail
Elevation	0° to +45°
Traverse	60°
Rate of fire	4 rpm
Muzzle velocity	520 m/s (1,700 ft/s)
Maximum firing range	13,325 m (14,572 yd)
Sights	Model 1934 Sighting Mechanism

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 during the Second World War, serving alongside the smaller but more numerous 10.5 cm leFH 18. It was based on the earlier, First World War-era design of the 15 cm sFH 13, and while improved over that weapon, it was generally outdated compared to the weapons it faced. It was, however, 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.

Development work on the sFH 18 began in 1926 and was ready 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.

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 inability of heavy artillery like the sFH 18 to keep up with the fast-moving tank forces was one of the reasons that the Luftwaffe invested so heavily in dive bombing, in order to provide a sort of "flying artillery" for reducing strongpoints.