The concept of an armoured vehicle dedicated to the role of destroying tanks had first been realised by the Germans as the Panzerjäger I. While this vehicle proved the concept, it was quickly getting long in the tooth, especially when compared to the towed PaK 40 anti-tank cannons that were starting to appear at the front through 1942. The hasty rush to get this gun into a similar armoured self propelled mount lead to the Marder series of vehicles, before finally settling on upgunning the StuG.

The 7.5 cm L/48 armed StuGs were an instant success: cheap and quick to manufacture and very effective on the battlefield in their new anti-tank role. With this in mind, the requirements for new design of StuG were issued in September of 1942: thicker armour, lower height and mounting the new 7.5 cm L/70 gun. Several designs were submitted, with that by Vomag being accepted. It was based on the Panzer IV hull, modified with a low armoured casemate and sloped frontal armour. The L/70 gun was needed to arm the new Panther tanks, and so the first production of the new vehicles were armed with the older L/48.

Production started in December 1943, several months behind schedule, and would continue until November the following year, when all production had switched to the L/70 armed variant. By Mid spring of 1944, the design had been changed to eliminate the difficult to use left-hand machinegun port, and experiments had shown that the muzzle brake was not required to deal with the recoil and so was removed from production. Somewhere in the region of 800 were produced, and ours was made by Matt Baker from Omni and AceS's Jagdpanzer IV/70.

The Sturmpanzer was designed to meet a requirement for an armoured self propelled heavy howitzer that could provide fire support to the infantry. Based on the hull of the Panzer IV Ausf.G with a large armoured superstructure fitted to the top, it housed a newly designed Skoda StuH 43 L/12 howitzer, that used the same ammunition as the existing sIG 33 infantry gun.

The first series of 60 vehicles were produced starting in April 1943, and several saw action at Kursk that summer. This trial by combat resulted in a second series of vehicles, now based on the Ausf.H chassis. Changes consisted primarily of the fitting of a ventilator fan and sprung steel roadwheels on the front pair to cope with the extra weight. 60 series 2 were produced from December 1943, with production switching to the series 3 in March 1944. The driver's sight was replaced with periscopes and the gun replaced with the 800 kg lighter StuH 43/1.

The fourth series took over production in June, and featured a redesigned superstructure that included a frontal ball mount for an MG34, as well as the commander's cupola from the StuG. This series was also based on the Ausf.J hull.
The Sturmpanzer was known to the Germans affectionately as Stupa, while Allied Intelligence knew it as the Brummbär. In total 306 across all series were produced, and ours were made by Mike, Stubbfan and Matt Baker.

Jagdpanzer IV Ausf. F (early)
Class: Tank Destroyer
Speed: 40 km/h
Armament: 7.5 cm Pak 39 L/48

Jagdpanzer IV Ausf. F (mid)
Class: Tank Destroyer
Speed: 40 km/h
Armament: 7.5 cm Pak 39 L/48

Sturmpanzer IV Ausf. III "Stupa"
Class: Assault Gun
Speed: 40 km/h
Armament: 15 cm StuH 43/1 L/12

Sturmpanzer IV Ausf. IV "Stupa"
Class: Assault Gun
Speed: 40 km/h
Armament: 15 cm StuH 43/1 L/12
1 x 7.92mm MG 34