Author: Károly “Karika” Németh

Hello everyone, we have another article from Károly Németh here, this time about the Zrínyi assault guns. Enjoy! -SS

Above: The Zrínyi I assault gun prototype. A Zrínyi II assault howitzer on the background.

History:

Zrínyi II

Based on the German war experiences, in 1942 the HM (Hungarian Ministry of Defence) decided to arm the Hungarian Army with self-propelled artillery and tank destroyer units. At first, they tried to buy a proven German vehicle (such as the StuG III), but Germany refused to sell any of their modern tank or SPG design. To solve this problem as soon (and as cheap) as possible, the Hungarian engineers combined two (separately not too successful) ingredients: the 40. M 105mm field howitzer and the chassis of the Turán medium tank, creating the Zrínyi assault howitzer.

The 40. M 105mm howitzer was originally designed to be a towed field howitzer, but because of some problems with the suspension of the gun carriage (it could not bear the high speed towing) the project were unfinished and the manufactured 60 gun barrels became useless. These barrels were used in the Zrínyi project later.

Above: The 40.M 105mm field howitzer

The Weisz Manfréd (WM) factory was charged to make the Turán chassis capable to carry the 105mm howitzer. The Turán turret could not handle the fairly big howitzer, so the turret was dismounted, and the gun was placed inside the hull. In order to provide the necessery horizontal deflection, the Turán chassis was made 400 mm wider, and for ergonomical reasons, the gun was mounted a bit on the left side of the vehicle. After the successful tests with the wooden model, a prototype vehicle (made of iron) was ordered in October 1942. The first prototype Zrínyi was created from the very first Turán I prototype, and later this vehicle (Turán I, licence plate: H-801) was converted to be the prototype of the Zrínyi I assault gun. After the successful trials in the winter of 1942/43, the new assault howitzer entered into service under the name of 10,5cm 40/42. M Zrínyi II, and the HM ordered 40 of them.

It was named after the famous XVI century Hungarian/Croatian general Miklós Zrínyi (Nikola Zrinski in croatian), who died a hero’s death in 1566 in defence of Szigetvár against the Ottoman Turks.

Above: Zrínyi II assault howitzer

Zrínyi I

The Zrínyi II had excellent stability, low profile, good terrain passability and traverse speed. However it was an assault howitzer, designed for infantry support role, which means its gun was designed more against live force or bunkers than enemy armour. The Zrínyi II missed the high-velocity gun (and the frontal armour) that would made it good against the newer Soviet tanks, like the T-34 or the KV series. The HM was aware of this, so before the first series of the Zrínyi IIs were done, they started to develop the Zrínyi I assault gun, which would carry the same 43. M 75mm gun as the Turán III, the licenced version of the german 75mm Pak 40.

Because of the „not so good” situation of the eastern front, and the unsuccessful Turán upgrade attempts, the main manufacturing focus went from the light and medium/heavy tanks (the Turán II was heavy in the Hungarian terminology) to the Zrínyi assault guns and howitzers, because they were easier to assemble and more useful in defensive role. The original plan was to build the Zrínyi Is and Zrínyi IIs in 2:1 ratio, 90+110 Zrínyi I and 40+50 Zrínyi II (first number would have been built in 1944, + second series would came in late 1944 and 1945).

However, the development of the 43. M 75mm gun was very slow, so the first prototype Zrínyi I was only completed in February 1944 with one of the first prototype 43. M 75mm gun. Because of this delay, after the first series of 40 Zrínyi IIs were finished in January 1944, the WM and Ganz factories didn’t started to assemble the first series of Zrínyi Is. But, to maintian the production, they continued to build Zrínyi IIs, which second series were originally scheduled to 1945. Later, because of the continuous malfunctions of the prototype 43. M gun, the mass-production of the Zrínyi I was postponed until Autumn 1944.
In August 1944 the DIMÁVAG weapon factory stated that they could not start the mass-production of the long 75mm gun, because of the lack of some crucial raw materials, so no more Zrínyi I (or Turán III medium tanks) could have been ever made after the prototype. After the occupation of Hungary in the Autumn of 1944, the fate of the Zrínyi I prototype is unknown.

The Zrínyi I did not differ much from the Zrínyi II, only its 75mm gun was mounted a bit lower (to ensure the same gun depression-elevation as on the Zrínyi II), and the gun mantlet shape was a bit different.

Before the end of the war in Hungary, from the ordered 50 second series of Zrínyi IIs around 31 more vehicles were finished. Only one known assault howitzer survived the war, which could be found in the Kubinka Tank Museum, Russia.

Even though that the Zrínyi assault howitzer was developed earlier, the Zrínyi assault gun was the preffered (and more needed) project/vehicle, and that’s why the Hungarians called the Zrínyi 75 assault gun “Zrínyi I”, and the Zrínyi 105 assault howitzer “Zrínyi II”.

Zrínyi II:

Zrínyi I:

Zrínyi I (the shape of the gun mantlet of the Zrínyi I is wrong on these drawings, made by Iván Bajtos, so I cut them down, and below I posted the correct one)

Details:

Name: 40/43M. Zrínyi II (Zrínyi 105)
Year: 1942-44
Manufacturers: WM, Ganz
Combat weight: 21,5 t
Combat weight with side-skirts: 22,5 t
Engine: WM V-8H, 8 cylinders, 260 hp at 2200 r/m, 14866 cm3, petrol
Dimensions in mm:
- Full lenght: 5500
- Full lenght with barrel: 5900
- Lenght of the hull: 5100
- Full width: 2890
- Height: 1900
- Ground clearance: 380
Suspension: Zrínyi II (the undercarriage is identical to the Turán’s)
- Track gauge: 2398
- Chain width: 420
- Number of chains: 2×106-107
- Front-rear axis distance: 4690
Ground pressure: 0,72 kp/cm2
Ground pressure with side-skirts: 0,75 kp/cm2
Armour: riveted, bolted
- front: 75 mm
- gun mantlet: 75+25 mm spaced armor
- side, rear: 25 mm
- top, bottom: 13 mm
- side skirts: perforated, 5 mm
Gun:
- 40. M 105mm L/20 howitzer (historical)
barrel lenght: 2148 mm
muzzle velocity with the maximal cartridges: 471 m/s with HE, 444 m/s with HEAT
max. range: 10 500 m
rate of fire: 6 rounds/min
gun depression, elevation: -8° +25°
penetration: ?
Ammo: theoretically 52 separate-loading ammunition, in-practice 90-95 items
- 38/33. M 105mm HE grenade, projectile weight: 15,04 kg, max 7 gunpowder cartridges (0,95 kg together), theoretically 30 items
- 42. M 105mm HEAT grenade, 17 kg, max 6 cartridges (? kg), theoretically 16 items
- 38/33. M 105mm Smoke grenade, theoretically 6 items
- unhistorical: 37. M 105mm AP grenade, 14,16 kg, max 5 cartridges (0,595 kg) muzzle velocity with 5 cartridges: 377m/s (this type of ammo was not used in the Zrínyi II)
Gun depression, elevation: -8° +25°
Horizontal deflection: 11°-11°
Radio: R-5/a
Max. speed forward: 43 km/h,
Max speed with side-skirts: 40 km/h
Crew: 4, Commander, Driver, Gunner, Loader

Name: 44M. Zrínyi I (Zrínyi 75) prototype (in many ways identical to the Zrínyi II)
Year: 1944
Manufacturer: WM
Combat weight: 22 t
Engine: WM V-8H
Dimensions in mm:
- Full lenght with barrel: 7350
Suspension: Zrínyi I (identical to Zrínyi II)
Ground pressure: 0,79 kp/cm2
Armour: same as the Zrínyi II, but different mantlet shape
Gun:
- 43. M 75mm L/55 tank gun (historical, however not much data can be found about it. It might be very similar to the german 7,5cm Pak 40. Same as the Turán III’s gun)
barrel lenght: 4125 mm
muzzle velocity: 770 m/s
rate of fire: 12 rounds/min
ammo: ?
penetration: ?
Gun depression, elevation: -8° +25°
Horizontal deflection: 11°-11°
Radio: R-5/a
Max. speed forward: cca. 40 km/h,
Crew: 4, Commander, Driver, Gunner, Loader

In World of Tanks:

As the Zrínyi I and II only differ in their armament they should be implemented as one vehicle. Although, there are many ways to implement them to the game:

With the historical armaments and characteristics, the two Zrínyis would be a pretty good Tier V vehicle: 75mm front armor, a choice between a 105mm “derp” gun or a more accurate 75mm gun, excellent camo rating (with the 1,9 m height even lower then than the StuG III, which is 2,16 m tall). Over all, it would be very similar to the in-game Tier V StuG III.

However, if it would be implemented as a Tier V TD, there would be a hole in the Hungarian TD line at Tier VI, as there are no other candidate between the Tier V vehicle (which could possibly be the Szebenyi/Nimród 80 tank destroyer project) and the Tas tank destroyer proposal, what is defenitely at least Tier VII material.
The other thing is, there are very few vehicles in WoT (are there any?), that are implemented to the game with its historical gun as top gun, most of the historical guns are the stock ones. I say, that the Zrínyi should be buffed up somehow to Tier VI to fill that gap. For example: some German engines and cannons were considered to mount on Hungarian vehicles, but in the end the Germans were unwilling to sell them. So unhistorically, the Zrínyi (together with the other Hungarian vehicles) could use them as an alternative.

As I said earlier, the only differences between the two Zrínyis were their cannons, so separating them to Zrínyi II at Tier V and Zrínyi I at Tier VI is IMHO not a good idea, but possible. That’s because the 75mm, nearly unsloped frontal armour would be fairly weak at tier VI, which tier could easily end up fighting against Tier VIII tanks, where anything could penetrate the Zrínyi, but with the historical 75mm gun, it would struggle to penetrate even the medium tanks, not to mention the heavily armoured TDs and heavy tanks. This could be solved with mounting an unhistorical, stronger 75mm gun (I think larger caliber could not be fitted), so at this rate, the Tier VI Zrínyi I would became a paper thin TD with medium-strong armament and really good camo ratings. But this could mean that the Tier V and Tier VI vehicles would have not much (different) modules to choose from.

But lastly, I just listed the possible options, balancing is not my job. It’s up to Wargaming to decide how to implement this vehicle to their game, if they want to implement it anyhow.

Possible/historical characteristics:

Tier: V or VI
Hull: Zrínyi
Optional hull: Zrínyi with side skirts
Suspension: Zrínyi II → Zrínyi I (identical)
Engine: WM V-8H
Gun: 40. M 105mm L/20 → 43. M 75mm L/55
Radio: R-5/a

Frontal view of the Zrínyis. From top to bottom:
- Zrínyi II prototype (iron) licence plate H-801;
- Zrínyi II instructor vehicle (iron);
- Zrínyi II serial vehicle;
- Zrínyi I prototype.

Zrínyi II armor and internal schematics:

 

 

Sources:

http://militiahungarorum.extra.hu/1920_f_k_tu_r_l_105.html#resz_14 (hungarian, the 105 mm ammo types)
Bonhardt Attila – Sárhidai Gyula – Winkler László: A Magyar Királyi Honvédség fegyverzete. Kecskemét, 1992. 96-101.
Bíró Ádám – Sárhidai Gyula: A Magyar Királyi Honvédség hazai gyártású páncélos harcjárművei 1914-1945. Bp., 2012. 227-248.
Bombay László – Gyarmati József – Turcsányi Károly: Harckocsik 1916-tól napjainkig. Bp., 1999. 106-111.