Monday, 17 January 2022

Hungarian StuH

The German StuG III assault gun inspired AFV designers in a number of nations, Hungary included. The Hungarian army was in desperate need of a support vehicle with a more powerful weapon than the 20 mm gun of the Toldi or 40 mm gun of the Turan. Based on German experience, Hungarian designers created their own assault gun called Zrínyi.

Hungary had a rather humble tank fleet at the moment of its entry into the Second World War. CV.33 and CV.35 tankettes purchased from Italy had negligible value on the battlefield. Domestic vehicles, the 38M Toldi light tank and 39M Csaba armoured car, were slightly better, but with some caveats. There were not a lot of these vehicles and they were armed with 20 mm cannons, essentially heavy anti-tank rifles. These weapons could fight against lightly armoured vehicles, but were powerless against field fortifications or walls. This drawback became obvious when the 1st Mobile Corps was first used during Operation Barbarossa.

Let's make an assault gun

On orders from the Hungarian Ministry of Defense, Captain Yozhef Barankai prepared a report justifying the creation of assault artillery units in June of 1942. The report landed on the desk of the head of the Department of Supply, Lieutenant General Árpád Denk-Doroszlay, who read it carefully. In August, he wrote a letter to the leading Hungarian armoured vehicle company, Manfréd Weiss, proposing the development of an assault gun with a 105 mm howitzer. The conditions were right, as production of the Turan medium tank based on the Skoda T-21 was entering production, which was suitable as a chassis. The DIMAVAG company already had 105 mm 40M towed howitzers in production. All that was left was to put the pieces together. The company's lead designer, Ernő Kovacsgazi, rapidly prepared a draft project that was quite reminiscent of the German StuG III.

Hungarian assault gun inspired by the StuG III.

The project was presented to Miklós Horthy in October of 1942. The regent liked the project, unlike the Inspector General of the Tank Forces, Lieutenant General Jenő Major. Major had no idea that an assault gun was being designed, even though he was the one responsible for production of the Turan tank. This happened because the assault gun was being developed by the Department of Artillery, which did not consider it necessary to inform the tankers. A scandal erupted. Major refused to allocate Ajax brand armour steel for SPG production. This steel was produced by the MAVAG conglomerate and was in short supply due to the use of imported alloying elements.

The second obstacle was training for the SPG crew. Sure, they could wear artillery uniforms, but they would still have to be trained in tank schools. Lieutenant General Major spoke out against this as well, claiming that the schools were busy training crews for the 1st and 2nd Tank Divisions. The steel was eventually allocated, but the artillerymen had to train their own crews at a school in Hajmáskér and also in Germany.

Drawings of the 40/43M Zrínyi assault gun.

Production of a mild steel prototype began on December 12th, 1942. The chassis of the Turan tank prototype (serial number H-801) was used. The prototype was completed on January 28th of the following year. The contract for 40 production vehicles was signed two days prior, on January 26th. The SPG was indexed 40/43М Zrinyi rohmtrack: Zrinyi assault howitzer model 40/43. It was named in honour of Miklós IV Zrínyi, a 16 century commander who fought against the Turks.

A group of engineers and technologists were sent to Germany to study organization of SPG production. Their conclusions were not encouraging. It would be too difficult to produce the SPG in large numbers due to its complex chassis. The Ministry of Defense also received a report claiming that the Zrinyi was useless since it could not fight against the T-34 tank. The situation was somewhat corrected by the installation of the 75 mm 43M anti-tank gun. Its armour piercing shell had a muzzle velocity of 770 m/s and penetrated 76 mm of armour angled at 30 degrees from 600 meters. This variant of the SPG was indexed 44M Zrinyi I rohamagyu: Zrinyi I assault gun model 44. The howitzer variant was retroactively renamed Zrinyi II. Designations Zrinyi 75 and Zrinyi 105 were also used. 

Zrinyi I SPG in the foreground and a Zrinyi II in the background.


The Hungarian General Staff had truly Napoleonic plans for SPG production. Each infantry and cavalry division was to have a battalion of SPGs. The organization was generally the same as the analogous German unit: three batteries of 10 SPGs (three platoons of 3 each plus the commander's vehicle) plus one battalion commander's SPG for a total of 31 vehicles. Two batteries were armed with Zrinyi I SPGs and the third with the Zrinyi II. The battalion commander would use a Zrinyi I. The TO&E listed 387 men (29 officers and 358 privates and NCOs), 31 SPGs, 57 cars, and 14 motorcycles. Interestingly enough, the Hungarians considered the combat power of one assault gun battalion to be equal to five infantry battalions.

Zrinyi II battery on the move.

Formation of three battalions was planned before the end of 1944 and five more the following year. Total production of the Zrinyi I would number 200 units (90 in 1944 and 110 in 1945). 50 Zrinyi II would be produced for combat and 40 more for training. These plans were not carried out.

The first three SPGs ordered on January 26th, 1943, were finished in September. Like the prototype, these vehicles were made with mild steel. The SPGs with serial numbers 3H-00 - 3H02 were delivered to the 1st Assault Artillery Battalion. The rest of the vehicles in the first batch, numbered 3H-03 through 3H-39, were fully fledged fighting vehicles. Delivery was complete in January of 1944 (10 in October, November, and December, with the final 7 in January). Production of a second batch of 50 SPGs began then. 10 vehicles were delivered in April and June, but the production stalled because of a shortage of parts. On July 27th, 1944, Manfréd Weiss delivered another six SPGs, after which the factory was destroyed by American bombers. The surviving components and assemblies were evacuated to the Ganz factory, where six more vehicles were built and delivered on September 6th, 1944. Overall, only 72 SPGs were built out of the 290 planned. Only two battalions were formed: the 1st and 10th.

All production SPGs were built as the Zrinyi II. Only one Zrinyi I prototype was built in February of 1944, converted from a Zrinyi II. There were issues with ramping up gun production, which impeded the production of the SPG.

Service and combat

Captain Barankai and three other officers were sent to the German assault artillery school in Jüterbog in February of 1943. There they went through a six week training course. The 1st Assault Artillery Battalion commanded by Captain Barankai was formed in September. Since the variant with a long 75 mm gun was never put into production, the unit was equipped exclusively with the Zrinyi II. The battalion received its 31 SPGs by the end of December.

Zrinyi II at a firing range.

The battalion personnel went through training at the artillery school in Hajmáskér. The assault artillery training center was officially formed here on May 17th, 1944, a month after the first units of this new type were dispatched to the front. The battalion HQ as well as the 2nd and 3rd batteries (the first was not yet considered combat ready) were loaded onto trains on April 12th and arrived at Stanisławów (modern day Ivano-Frankovsk) four days later. The Zrinyi saw its combat debut on April 21st at the Bogorodichin village. SPGs from the 2nd battery engaged a Soviet rifle battalion with an anti-tank battery that was taking positions at a forest clearing. One of the SPG platoons successfully dispersed the anti-tank battery lines while another suppressed the infantry with an artillery barrage. Hungarian infantry that went through that forest later called it "forest of death", as they had never seen that many dead enemies in one place.

SPG crew at rest. A Turan tank can be seen behind this Zrinyi II.

The 3rd battery first went into battle on April 25th. It helped Hungarian infantry deflect a Soviet attack 20 km north-east of Stanisławów. The SPGs knocked out two out of eight T-34 tanks, the rest turned back. Later, both batteries fought in the vicinity of Stanisławów. The 1st battery joined them in mid-June. It took part in joint training with infantry near Nadvorna on June 16th. The 1st battery's combat debut near Grabitsa ended in failure. The SPGs hit a Hungarian minefield that they were not warned about. Two vehicles were blown up on mines, the crews abandoned them taking the gun breech blocks with them. One SPG was evacuated despite being under mortar fire, the other was left in the field.

A Zrinyi II crew.

The battalion HQ as well as the 1st and 2nd battery kept fighting in the Carpathians, taking noticeable losses. In part, Captain Barankai was killed in an attack by Soviet Sturmoviks. On November 22nd the 1st Assault Artillery Battalion was given his name.

The Soviet offensive began on July 21st. Zrinyi batteries were used for delaying actions, covering the retreat of German and Hungarian forces. The battalion barely avoided an encirclement at Vinograd on July 24th, escaping after a battle with Soviet tanks. On July 29th, remnants of the 1st and 2nd batteries along with the HQ gathered at Vygoda. Only three SPGs remained out of 21, only two of which were in running order. None had functioning guns. The remnants of the battalion were evacuted.

Zrinyi II SPG with spaced armour and tracks hung for added protection.

The 3rd battery fought away from the main battalion. A team of workers arrived from the factory in early July to equip their Zrinyi II with spaced armour. The battery fought near Delyatyn, retreated south over the river Prut, and ended up in Transylvania, then still a part of Hungary. The battery was attached to the 10th battalion (this was a sort of trade, as the 3rd battery of the 10th battalion was attached to the 1st). The 3rd battery was used to counterattack Soviet and Romanian forces near Oradea. It then transferred its SPGs to the 10th battalion and returned to Hajmáskér.

The 10th Assault Artillery Battalion was formed in march of 1944. The unit did not have time to fully form before it was sent to put out a figurative fire on the southern border caused by Romania changing sides. Only the 1st and 2nd batteries were ready for battle. The two batteries plus the HQ arrived at Csíkszentmárton (modern day Sânmartin) to join the humble forces covering Transylvania. The SPG crews first saw battle on September 20th in the Uzh river valley near Frumoasa. The battalion's first SPG was lost here. Later on, the 10th battalion fought as a part of a rear guard, retreating into the Someș river valley in early October with the rest of the 2nd Army.

Zrinyi II with a full set of additional armour (skirt armour and spare track links) used as a hearse during a funeral.

On November 5th, 1944, the 10th battalion took part in street fighting in Poroszlo, in northern Hungary. By that point, the battalion consisted of only the 1st battery and an assault company formed from "unhorsed" crews and untrained recruits. The battalion managed to achieved a localized success, freeing other Hungarian units from encirclement, but lost every single SPG as a result. The unit was evacuated to the rear on November 10th.

The 1st Assault Artillery Battalion was included in the Budapest garrison in mid-October 1944. Its composition changed: the 1st battery was now armed with heavy infantry weapons, the 2nd was composed of infantry, and only the third received a few (no fewer than five) new Zrinyi II. Three of them took part in the counterattack at the Ferihegy airport. On November 4th and 5th the SPGs took part in fighting for Vecsés (a south-eastern suburb of Budapest) in support of the 8th SS Cavalry Division Florian Geyer. Later on the 1st battalion took part in the street fighting in Budapest. It was joined by the 10th battalion in December. Each had just one Zrinyi battery remaining (between 4-5 and 10-11 total, depending on how many vehicles could be repaired). The 1st battalion ceased to exist on February 11th, 1945. All personnel were taken prisoner by the Red Army. The remnants of the 10th battalion demolished their own SPGs, broke out of encircled Budapest, and dispersed. A portion were captured by the Americans, and some by the Soviets.

Sad end: a destroyed Zrinyi II in Budapest.

Captured Zrinyi II were used by the Red Army. A battalion of captured tanks was formed by the 18th Army on September 9th, 1944. It consisted of 32 combat vehicles including 15 Hungarian ones: 8 Turan medium tanks, 2 Toldi light tanks, 3 Zrinyi SPGs, and 2 Nimrod SPAAGs. While the Red Army considered the tanks to be terrible, the SPGs were evaluated much more favourably. The battalion first saw action on September 15th, 1944, at Uzhgorod. Later the unit was attached to the 5th Guards Tank Brigade. Only two Zrinyi remained in service by October 14th, and only one by January 15th, 1945. There is also information that captured Zrinyi were used by Romanians.

Zrinyi II captured by the Romanians.

Overall, the Zrinyi II design can be considered successful, but it was built in such small numbers that it could not have an effect on the flow of the war.

Technical description

The SPG used a Turan chassis widened by 450 mm. The silhouette was quite low at just 1900 mm in height. An immobile casemate in the front of the hull carried the main armament, a 105 mm L/20.5 howitzer equipped with a muzzle brake. The gun was shifted 650 mm to the left from the vehicle's axis.

The howitzer's ammunition had separate propellant. The vehicle carried 52 rounds: 30 HE, 16 AP, and 6 smoke. Inside there was also room for the crew's personal weapons and three submachine guns. 

The armour of the vehicle was attached with bolts to a metal frame. The maximum armour thickness was 75 mm. The crew entered the vehicle through two hatches in the roof. A third two-flap hatch in the rear of the casemate was used to load ammunition and extract the gun for maintenance.

The SPG's crew consisted of four men. The driver sat to the right of the gun, the loader/radio operator sat behind him. The gunner and commander wer located on the left.

The engine and running gear were the same as on the Turan tank. The Manfréd Weiss Z gasoline engine put out 260 hp of power. The transmission included a multi-disk dry friction clutch, planetary gearbox (with three speeds forward and three reverse), and final drives. The running gear consisted of eight small road wheels with rubber rims per side, joined into bogeys of two each. Two bogeys in turn are supported by two half-ellipse leaf springs. An extra doubled road wheels is installed between the front bogey and idler to soften blows when crossing vertical obstacles. The drive sprockets were located in the rear. The suspension provided the SPG with relatively smooth travel.

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