The Panzer III Ausf.D was the last version of the experimental series developed starting from the Ausf.A. It incorporated a number of improvements, of which the most obvious was the redesign of the rear engine compartment and introduction of a slightly modified 8-wheel suspension. It was also different from the previous version by being built in somewhat larger (but still limited) numbers. The Panzer III Ausf.D also had the longest service life, soldiering on to 1941 and possibly even after that
Daimler-Benz, which was responsible for the construction of the Panzer III Ausf.A, was contacted by Waffen Prüfwesen 6 (Wa Prw 6 – the automotive design office of the German Army) to produce an additional number of experimental chassis to test new types of suspensions and other elements that could be further improved (like the commander’s cupola, engine compartment interior, etcetera). To fulfill the production orders, Daimler-Benz built the Versuchs-Fahrgestell (experimental chassis) Z.W.3 (Zugführerwagen platoon commander’s vehicle), which would lead to the Panzer III Ausf.B. The Z.W.4 would be used as the base of the Panzer III Ausf.C (marked as 3a. Serie Z.W.) and D (marked as 3b. Serie Z.W.).
The Heeres Waffenamt issued an order to Daimler-Benz to produce 25 Panzer III Ausf.D chassis. Other components, such as the turrets, were to be provided by Krupp-Gruson Werke and Alkett. The main guns were to be provided by Krupp-Essen and Rheinmetall. For the acquisition of necessary armored parts, numerous subcontractors, like AG Vochum, Deutsche Edelstahlwerke AG, etcetera were contracted. While the production of these vehicles began sometime in early 1938, it took several months to actually build them. The last of the 25 vehicles was completed either in July or September 1938. Five more chassis would be built by Daimler-Benz and merged with five Panzer III Ausf.B turrets during 1940.
Interestingly, according to H. Scheibert (Panzer III), 55 Panzer III Ausf.D were produced during 1938. If he includes the modified chassis and command vehicles based on the Panzer III Ausf.D in this counting is not clear.
The Panzer III Ausf.D received some modification to its overall design, in many aspects, like the armament and engine, it was virtually unchanged.
The engine compartment
While the engine type used was the same as on the previous versions, there were some changes and rearrangements of some elements of the engine compartment. The position of the two radiators was changed, as they were now placed completely vertical. They were previously in an angled position. In addition, these were provided with louvres which could be controlled by the crew (from the crew compartment) to provide a better flow of air, depending on the need. The previously used mechanical fuel pumps were replaced with electrically operated ones. Lastly, four smaller and armored fuel tanks (each could contain 75 liters) were placed under the engine in pairs.
The overall design of the engine compartment was changed due to the modifications of its interior. The rear part of the engine compartment was put at a steeper angle. Two cooling air grills were placed on each side of the engine compartment. While no additional ventilation ports were placed on the armor cover of the engine, the four hatches (two on top, and two more on the angled side) could be opened to act as improvised ventilation ports. The change in design of the engine compartment led to a slight extension of the whole Panzer III Ausf.D, from 5.66 m to 5.92 m.
Panzer IIIs from A to C incorporated a 5 speed transmission. The Ausf.D received an improved 6 speed SSG 76 type transmission. As the remaining components of the drivetrain were essentially unchanged, the drive performance was also left largely unchanged.
The Panzer III Ausf.D suspension was quite similar to the Ausf.C one in appearance and could sometimes be difficult to distinguish. The Ausf.D also employed the same 8 small road wheels. However, they were divided into three parts, with two pairs of double wheels placed in front and to the rear and four pairs in the middle. There were also three return rollers, one drive sprocket and one idler per side.
The change included the repositioning of the front and rear swing arms’ pivoting points. These were centrally placed. The leaf spring units’ positions on the first and last pairs of road wheels were placed diagonally in contrast to the vertical ones used previously. Lastly, two improved shock absorbers were placed on each suspension side. One was placed behind the drive sprocket and the second in front of the idler.
Regarding the precise armor thickness of the Panzer III Ausf.D, the sources are basically split into two camps. Authors such as D. Nešić, (Naoružanje Drugog Svetskog Rata-Nemačka) and Walter J. Spielberger (Panzer III and its Variants) mention that the overall armor protection was increased to 30 mm (same as the later built Ausf.E). The increase in armor, together with other modifications, raised the Ausf.D’s weight to nearly 20 tonnes.
On the other hand, authors such as T. L. Jentz and H. L. Doyle (Panzer Tracts No.3-1 Panzerkampfwagen III Ausf.A, B, C, und D) and P. Chamberlain (Encyclopedia of German Tanks of World War Two – Revised Edition) note that the armor thickness was the same as on the previous versions, up to 14.5 mm. In addition, the overall weight of the Panzer III Ausf.D was, again like the previous versions, at 16 tonnes. The reason for this divergence of sources is unclear. One possible culprit for this may be the command vehicle that was developed based on the Panzer III Ausf.D, as it had 30 mm of armor.
When the war with Poland broke out in September 1939, the Germans had less than 98 Panzer III tanks. Of these, some 87 saw actual combat service, while the remaining were used as replacement and training vehicles. These were distributed to Panzer Regiments in limited numbers. The exceptions were the 1st Panzer Regiment, which had 20, and the 2nd which had 6 Panzer IIIs.
To determine the precise combat engagements of the Ausf.D (but also other older versions) is difficult. The issue is that the sources list them simply as Panzer IIIs, without mentioning the precise version in question. For example, Panzer IIIs from the 4th Panzer Regiment were ordered to take the Polish barracks and train station at Kamionka on 19th September. While the barracks were successfully stormed, the train managed to leave the station. What followed was a race between the German Panzer III and IV tanks and the elusive train. After sustaining heavy damage from German fire, the Panzers, reaching a speed of over 40 km/h, eventually managed to capture the train. The Germans lost some 30 Panzer IIIs during the entirety of the campaign, but most of these would be repaired and put back into use.
Following the completion of the Polish Campaign, the Germans initiated a slow withdrawal of the earlier types of the Panzer III, including the Ausf.D. This was mainly done as more advanced versions were developed and became available in sufficient numbers to replace the older experimental Panzer IIIs. From February 1940 onwards, all available Panzer III Ausf.A to D tanks, after an extensive overhaul, were given to training units. This did not include the five modified Ausf.Ds that were equipped with Ausf.B turrets.
Variants based on the Panzer III Ausf.D
The Panzer III Ausf.D was used for the Panzerbefehlswagen (tank command vehicle) configuration. This included a number of modifications, some of which was reducing the armament to only one machine gun (located in the turret), using a dummy main gun (to hide its main purpose as a command vehicle), fixing the turret in place, replacing the gunner and the loader with one more radio operator and a commander adjutant, adding additional radio equipment, and, probably most noticeably, adding a large antenna to the rear of the turret. Another large change was that the armor protection was reinforced with another 14.5 m of armor, raising the overall protection to 29 mm. The driver’s visor and the machine gun ball mount were also replaced with newer models. Daimler-Benz produced 26 brand-new vehicles in 1938 and 4 more in 1939. This vehicle was designated as Panzerbefehlswagen Ausf.D1. These were used starting from Poland in 1939 up to possibly the invasion of the Soviet Union in 1941 or even after that.
Panzer III Ausf.D/B hybrid
During the late 1930s, the Germans were developing the Sturmgeschütz concept. For this purpose, some 5 Panzer III Ausf.B chassis were allocated to be rebuilt as Sturmgeschütz III test series. Not wanting to waste the turrets from these tanks, the Heeres Waffenamt gave Daimler-Benz instructions to build an additional five Ausf.D chassis to be merged with them. As these were never a huge priority, it took Daimler-Benz some two years (until October 1940) to actually complete these vehicles.
During their construction, Daimler-Benz introduced some improved components that were not present on the 25 original Panzer III Ausf.D vehicles. The best example is the use of the new Kugel Blende 30 type of machine ball mount. Additionally, these received a new idler and the position of the rear shock absorber was slightly lowered.
It is unclear how many, but likely all five were transported to Norway in the summer of 1941 and allocated to Panzer-Abteilung z.b.V. 40 (special assignment unit). These may have participated in the German combat operations in Finland during the Invasion of the Soviet Union.
The Panzer III Ausf.D would be a further improvement of the previously built Ausf.C. It would incorporate a majority of elements from this previous version, except for the suspension and some interior modifications. Following the completion of the Ausf.D series, Daimler-Benz and the German Army officials simply gave up on the idea of using the unnecessarily complicated 8 wheel suspension and instead developed a brand new torsion bar that would be used as standard from the Ausf.E onward.
The whole experimental Panzer III Ausf.A to D series, while not long in service, was vital for the Germans in gaining valuable experience in tank design, but also in training the Panzer crews. Given the fact that these were built by the yet underdeveloped German industry, they could be considered a success, as they paved the way for further Panzer development.
Panzerkampfwagen III Ausf.D Specifications
|Dimensions (l-w-h)||5.92 m x 2.82 m x 2.41 m|
|Total weight, battle-ready||16 tonnes|
|Crew||5 (Commander, Gunner, Loader, Radio Operator and Driver)|
|Propulsion||Maybach HL 108 TR 250 hp@ 2800 rpm|
|Speed (road/off road)||35 km/h, 10-12 km/h (cross country)|
|Range (road/off road)||165 km, 95 km|
|Primary Armament||3.7 cm Kw.K. L/46.5|
|Secondary Armament||Three 7.92 mm MG 34|
|Elevation||-10° to +20°|
- D. Nešić, (2008) Naoružanje Drugog Svetskog Rata-Nemačka, Beograd
- T.L. Jentz and H.L. Doyle (2006) Panzer Tracts No.3-1 Panzerkampfwagen III Ausf.A, B, C, und D.
- T.L. Jentz and H.L. Doyle (2010) Panzer Tracts No.3-4 Panzerbefehlswagen III Ausf.D1, E, H, J, und K.
- T.L. Jentz and H.L. Doyle (20) Panzer Tracts No.23 Panzer production from 1933 to 1945.
- P. Chamberlain and H. Doyle (1978) Encyclopedia of German Tanks of World War Two – Revised Edition, Arms and Armor press.
- D. Doyle (2005) German military Vehicles, Krause Publications.
- G. Parada, S. Jablonski and W. hryniewicki, Panzer III Ausf.L/M. Kagero.
- Walter J. Spielberger (2007) Panzer III and its Variants, Schiffer Publishing Ltd.
- Walter J. Spieberger, AFV Panzerkampfwagen III, Profile Publications
- B. Perret (1980) The Panzerkampfwagen III, Osprey Publishing
- A. Lüdeke (2007) Waffentechnik im Zweiten Weltkrieg, Parragon Books.
- G. L. Rottman (2008) M3 Medium tank Vs Panzer III, Osprey Publishing
- H. Scheibert (1994) Panzer III, Schiffer Publishing Ltd.