Nazi Germany (1942) SPG – 705 built

The German self-propelled howitzers

The full designation of this self-propelled artillery gun was Panzerfeldhaubitze 18M auf Geschützwagen III/IV (Sf) Hummel, Sd.Kfz. 165.The German word ‘Hummel’ means bumblebee. This armored fighting vehicle had a nasty sting. There were two main types of self-propelled guns in the German Army during WW2. One was fitted with an anti-tank gun and the other with an artillery howitzer, like the Hummel. A vehicle fitted with an artillery field howitzer was called a ‘Geschüetzwagen’, which is literally translated as a ‘gun vehicle’. The letters ‘Sf’ stand for ‘Selbstfahrlafette’ – self-propelled carriage. ‘Panzerfeldhaubitze’ means armoured field howitzer.

Self-propelled artillery guns were developed to enable fast moving attacks to have artillery support that could keep up with the speed of advancing Panzer Divisions. They could use direct fire mode at targets they could see or, more commonly, use indirect fire at targets plotted on a map.

They were not designed to be in the front line or engage in combat with tanks. They were motorized artillery guns that could fire high explosive HE shells over the heads of friendly troops. Most targets would have been given to the crew as map grid references by forward observation officers or infantry units under attack.

Quite often, the gun crews could not see where their shells landed, as the target was so far away. They would have to rely on the forward observer to tell them if adjustments had to be made.



Early production Hummel. Notice the wire rack covering the open fighting compartment.

The open-topped back design of these self-propelled guns had a number of advantages. The elevated commander’s position when standing in the crew compartment, behind the protective armored shield, meant that he had a good view on all sides. If there was the threat of enemy small arms fire, then the crew could use a twin lens range finder telescope that could peak over the top of the armored casement.

There was enough room for the crew to be transported towards the battlefield whilst protected from small arms fire and shell shrapnel. The vehicle had good mobility and could follow the infantry almost anywhere. The gun was quicker to get ready for action and fire on targets than towed artillery guns.

Putting the 15cm s.FH 18/1 howitzer on top of a tank chassis was a more efficient use of manpower from the traditional form of German artillery battery transportation. Even in WW2, horse power was still widely used although tracked vehicles were also employed when available. Each field gun would require a six-horse team to pull the gun and limber. The ammunition, supplies and kit would be kept in the limber, which was a very large box on a pair of wheels with seats on the top. Three men would ride on the left hand horse of each pair to control them. The remaining six men of the gun crew would ride on top of the limber. Only a relative few were towed by the 3 ton halftracks.

Production

A total of 705 Hummel 15cm self-propelled artillery guns were built by the end of the Second World War in 1945 and 157 Hummel ammunition carriers were also produced.

The Hummel was designed in 1942. The prototype featured a very large muzzle brake, but this was not used on the production models. The contract was awarded to Alkett and Deutsche Eisenwerke in Duisberg was contracted as the assembly firm. The first five production series Hummels were completed in February 1943 and entered service in March 1943. They were sent immediately to the Eastern Front to provide artillery support for the Panzer Divisions.

The initial contract for 500 (including the ammunition carrying Munitionsträger version) was completed in January 1944. The new improved version of the Hummel appeared in early 1944. A total of 705 Hummels were reported as completed by the end of March 1945.



Late production Hummel 15cm self-propelled artillery gun. Notice that the raised armoured driver’s compartment now covers the width of the vehicle to give the radio operator and driver more room.

The powerful 15cm sFH 18 L/30 heavy field howitzer was mounted on a specially designed Alkett/Rheinmetall-Borsig lengthened German tank chassis called the Geschützwagen III/IV. Components were adopted from both the Panzer III and Panzer IV tank chassis. The more robust final drive wheels, front drive wheels and steering units plus the Zahnradfabrik SSG 77 transmission gearbox were adopted from the Panzer III Ausf.J. The Maybach HL 120 TRM engine with its cooling system, the suspension, and idler with track tension adjustment were adopted from the Panzer IV.

The engine was moved from the rear of the tank to the centre of the vehicle to make room for the gun and the armored fighting compartment at the back of the SPG. The Geschützwagen III/IV hull was also used for mounting the 88cm anti-tank gun. This self-propelled gun (SPG) was called the Nashorn. Unlike the Nashorn’s armor piercing rounds, the Hummel’s 15cm HE high explosive shells came in two parts. The explosive shell was loaded first, followed by the variable charge canister. This meant that the Hummel could only carry 18 rounds of HE.

When not in use the Hummel’s 15cm howitzer was locked in place by a large ‘A’ frame travel-lock bracket that was mounted on the front hull glacis armoured plate. This stopped the gun moving up and down too violently when the vehicle was travelling across rough undulating ground.

On early versions of the Hummel, the front top of the hull had sloping armor with a raised armored compartment for the driver on the left of the vehicle. The front hull superstructure and driver’s armoured compartment were redesigned in early 1944 and enlarged, covering the whole width of the vehicle. The radio operator and driver now had more space to work in.

The exhaust system was also changed on the later model. It was moved from the original location below the rear double doors. The exhaust mufflers were dropped and the end of the exhaust pipes were cut at a slant away from the tracts to avoid stirring up additional dust.

The Geschützwagen III/IV tank chassis did not have a hull mounted machine gun. Crews were issued with a single MG34 or MG42 machine gun, carried inside the fighting compartment, for self defence.

The Hummel was designed to be operated by a crew of six: commander, driver and four gunners. They were protected by an enclosed high silhouette armored fighting compartment. Although it was open topped, the crew were issued with a thick canvas tarpaulin covers that could be used in bad weather.

In front of the driver a metal wire grid was fixed into position to aid the driver manoeuvring the vehicle in the correct fire position. Some early versions of the Hummel had a metal pole and wire mesh roof framework fitted above the fighting compartment of the vehicle. These were designed to prevent grenades and mines being thrown into the vehicle as it moved through towns and cities.



Early version Hummel fitted with wire mesh top screen to prevent grenades and mines from being thrown into the fighting compartment. Notice the large exhaust muffler/silencer box under the rear hatches. It was removed on the later version.

A metal louvered cover ventilated the engine, but many later versions were fitted with an angled shield that opened upward.

Three aiming stake poles were carried in brackets below the rear door. The gunner would use a large ZE 34 sight. The top lens aperture would point to the rear of the vehicle. The gunner uses this aperture of the sight to locate the aiming sticks that a member of the crew had pounded into the ground at the rear at a known bearing from the vehicle, having used a compass (compasses did not work inside a metal vehicle in 1943). By lining up the red and white fire aiming stake, subtracting 180 degrees, he would be able to work out the correct bearing the gun barrel is pointing towards.

The upper fighting compartment superstructure walls were constructed using 10 mm (0.39 in) thick E11 chrome-silicon armor plates hardened to 153 kg/mm2 for protection against shell fragments. The 30 mm (1.18 in) thick front hull was made using face-hardened FA32 armour plates. The rest of the hull was made out of cheaper rolled SM-Stahl (carbon steel) that was hardened to 75-90 kg/mm2. It took 20 mm (0.78 in) thick plates of SM-Stahl to provide equivalent protection against penetration by SmK (7.92 mm AP bullets) as 14.5 mm (0.57 in) of E11 armour plate.

The early Hummel SPGs used the standard 1943 38cm wide SK18 track that had three smooth metal pads visible on the front face of the track. In winter some vehicles were fitted with track width extenders called Winterketten (winter track). These triangular pieces of metal were bolted on to the outer edge of the track to extend the width of the track and help the vehicle move across snow and mud by spreading the load over a larger area. They were problematic: they fractured and often fell off. In 1944, vehicles started to be fitted with the wider Ostketten (east track) to cope with the conditions found on the Eastern Front. The Winterketten extensions made the SK18 tank track 55cm wide. The one-piece Ostketten was 56cm wide and did not have bits falling off it.

Operational service

The German Army Wehrmacht and SS Panzer Divisions each had their own heavy self-propelled artillery battery as part of their Artillery Regiment battalion. Each battery normally consisted of six Hummels supplied by one Munitionstrager Hummel armored ammunition carrier.

In March 1943, the first batch of eight Hummel SPGs entered service followed by another 46 in April. A few months later they saw their first action during Operation Zitadelle (Citadel) in July 1943 on the Eastern Front. They were used by Panzer-Artillerie regiments on the Eastern Front until the end of the war. A small number were captured by the Soviet Red Army and used against Axis forces in Hungary. Hummels were used in Greece, Italy and North West Europe in 1944.

The authorised establishment of the Panzer Artillery Regiment of the Heer Panzer Division that took part in the Battle of the Bulge, Ardennes Offensive in December 1944 had three Abteilungs (battalions). The second and third battalion comprised of towed 10.5cm, 15cm and 17 cm Howitzers but the first battalion was equipped with artillery self-propelled guns.

1.Abteilung

Stabskompanie (HQ company)

1.Batterien (6x Wespe 10.5cm Artillery SPG)

2.Batterien (6x Wespe 10.5cm Artillery SPG)

3.Batterien (6x Hummel 15cm Artillery SPG)



Late version Hummel on the Eastern Front painted with white-wash. The white paint has been rubbed away to expose the German Army black and white identification cross. Notice that there is no rear exhaust muffler/silencer box on the late version Hummel. The gun crewman outside the Hummel is carrying the shorter propellant canisters. It fired two-part ammunition. The HE shell went in the breach first, followed by the propellant canister.

Munitionsträger Hummel

The self-propelled artillery units that operated Hummels needed to be supplied with ammunition regularly. As each vehicle could only carry 18 rounds, they soon depleted their stock of shells.

The gun crew working the Hummel’s 15cm howitzer were protected by the vehicle’s armor plate from small arms fire and high explosive shell shrapnel fragments. Soft skinned lorries carrying ammunition near the frontline were liable to explode in that hostile environment.

The artillery regiments of the Wehrmacht used standard production Hummels, that did not have a gun and were fitted with a 10 mm (0.39 in) armor plate over the gun mount, to carry ammunition. These were called Munitionsträger Hummel. 157 armoured ammunition carriers based on the Hummel Geschützwagen III/IV hybrid tank chassis were constructed.

A flat 9.5mm (3/8th inch) armor plate was bolted to the fighting compartment front to replace the normal gun shield. The cargo space inside the armored compartment was 15 cubic meters (530 cubic feet).

Ammunition was delivered to the working Hummel battery in wicker tube shaped shipping containers, each containing one 42.9-kilogram (94.6-pound) high explosive projectiles. Artillerymen referred to the containers as a Koffer (suitcase). The separate charge cartridges arrived in wooden boxes.

The 15 cm s.FH 18/1 gun

The abbreviation 15 cm s.FH 18 used in the German Army designation of this artillery gun is short for 15 cm schwere Feldhaubitze 18. It was a heavy (schwere) field howitzer (Feldhaubitze). It was towed by horses and used by the German Army in World War II. When they were available, half-tracks were also used to tow these artillery pieces.

In the 1935s the longer barrelled 15 cm sFH 18 heavy field howitzer was introduced, replacing the WW1 15cm s.FH 13. It could deliver 150mm high explosives HE shells at a longer distance.

The gun was designed by Krupp and manufactured at the Krupp factory and also the factories of Rheinmetall. Over 5,000 of these guns were produced from 1933 to 1945. The recoil brake recuperator was positioned below and above the gun barrel to provide maximum possible stability for all gun elevations firing normal charges. A recuperator on an artillery gun is a device employing springs or pneumatic power to return a gun to the firing position after firing.

The HE high explosive shell weighed around 43.5 kg (96 lbs) and was loaded in two parts. This is known as a ‘separate loading’ round. First the explosive projectile shell was put into the gun breach and then the separate charge canister was rammed in behind it. It could also fire smoke rounds and AP armor piercing shells, though they were only effective at short ranges and used for self defence in an emergency.

The gunner had seven different strengths of charge canisters to choose from depending how far away the target was. The gun had a maximum firing range of 13.25 km 13,250m (8.23 miles 14,490 yards) when charge No.7 was used. It had a muzzle velocity of 495 m/s (1,620 ft/s) and a good gun crew could fire four rounds per minute.

Identification

One of the easiest ways of telling the difference between an early and late production Hummel when studying a photograph is to look at the upper front superstructure on the tank chassis. If you can see a separate armored raised box on the left of the vehicle, where the driver would sit, then this is an early production vehicle. If there is a raised box that covers the whole width of the vehicle than this is a late production version.

If you cannot see the front of the vehicle look for a large exhaust muffler/silencer box under the two small hinged doors at the rear of the vehicle. If you see one then you are looking at an early production vehicle. It was dropped from the late production models and two replacement spare bogie wheel holders were put in its place.

It is easy to tell the difference between a 15cm Hummel and 8.8cm Nashorn self-propelled artillery gun even though they both used the same Geschützwagen III/IV tank chassis. The 15cm howitzer used in the Hummel was not fitted with a muzzle brake on the end of the gun barrel. The Nashorn’s 8.8cm gun always had a muzzle brake fitted.



The early production Hummel is on the left with the large exhaust muffler/silencer box affixed under the rear doors and a late version is on the right.

2nd SS Panzer Division ‘Das Reich’ 1944

SS Panzer-Artillerie-Regiment 2

1st Battery 12x 17cm K18 Howitzer

2nd Battery 6x 15cm Hummel SPG

3rd Battery 12x 15cm Howitzer

4th Battery 12x 10.5cm Nashorn SPG

5th Battery 12x 10.5cm Howitzer

40x Motorcycle troops