The Zrínyi Assult Tanks
Zrinyi II assult gun
In October, 1942 the iron made sample vehicle of the Turán was disgarnished from it's turret, the chassis was cut in half along the centerline and widened with 400mm to keep the armaments traverse, elevation and depression angles. The frontal armor plate was hightened with 350mm and the gun was placed a little to the left from the centre. A new 75mm thick frontal armor plate was made too.
The Zrínyi's iron made prototype was ready in December 1942. Ground test were assigned between December 12, 1942 and January 28, 1943 but the test had to be extended to February 5, 1943 because the test were pulled back by numerous engine failures and by the fact that the Zrínyi used separate loading ammunitions. However the tests weren't even finished when the HM ordered 40 Zrínyis on January 26, 1943.
The artillery experts of the Hungarian Army suggested unified ammunitions for the Zrínyi but that didn't materialize. However another of their suggestions was made - the Zrínyi assault gun had a pneumatic trigger equipment and the artillery experts suggested to install a foot operated, mechanical trigger equipment which helped to eliminate failures in the firing mechanism by decreased airpressure. The gun depression angle was also increased from -5° to -8°, however the artillery experts wanted it to be -15°.
The Zrínyi 105 was capable for both direct and indirect fire. For the later one the gunner used the 8/14. gunsight which could be pushed out of the vehicle with a sliding rod through a narrow, plate-covered hole in front of the gunner's hatch. However the crew rarely used indirect fire.
Because the gun's recoil was almost 1m the loader and the commander - who sat right behind the gun - were protected by a recoil cage which was fixed on the gun cradle. Another ingenious mechanism served their protection too. There were buttons on the cage which had to be pushed by both hands of the loader and the commander. This formed a closed circuit and the gun could be fired only then. If one of the buttons was not pushed in the trigger mechanism did not worked. However by using that the commander could not used the radio to communicate with the crew so the engineers built in a horn next to the driver which could be sounded by the commander by pushing the button above him with his head. With this the commander could give orders to the driver with agreed sound signals even when both of his hands were busy.
Both the commander and the gunner could give signals to the driver. The commander used the aforementioned horn while the gunner used lights. There were two buttons in front of the gunner at knee height. By pushing one a green or red colored lamp ignited on the instrument panel in front of the driver which gave him the signal to turn the vehicle right or left. The gunner could push the buttons either with his hands or knees. To signal the gunner the commander used the same azimuth indicator assembly which were used in the Turán tanks but in the Zrínyi's case both the driver and the gunner had a circle shaped dial in front of them and the commander had to keep his periscope on target.
Mass-production started, but the production went slowly because of coordination problems. The guns were made by MÁVAG, the 75mm thick armor plates were made by Ironworks of Ózd and the vehicle was made in Manfred Weiss. Because of that the first three Zrínyi 105 assault guns were ready in September 1943. These vehicles differed from the later producted versions because these three had the same visors of the driver which was used on the Turán tanks - they also differed from the prototype because that had a circle shaped viewport for the driver and the gunner too on the frontal armor plate, the gunner's viewport was abandoned on the serial vehicles.
The remaining 37 vehicles of the first HM order were made in October, November-December, 1943 and January, 1944. Back in 1942 the HM ordered a second series of 50 vehicles which were started in March 1944 and deliverances started in April. On July 27, 1944 the factory was seriously damaged by an American bombing raid, production was transferred to the Ganz factory where 6 vehicles were made. A total number of 66-72 Zrínyi IIs were made in the war.
Because it was originally designed to destroy enemy bunkers and machine gun positions for the infantry the Zrínyi II was not the best anti-tank vehicle Hungary had but it still performed exceedingly in that role thanks to the HEAT shells and the bravery of the crews.
The Zrínyi II had two gun sights - the 43.M gun sight for direct fire and the 40/43.M artillery sight for indirect fire which could be operated with the 8/14.M artillery binocular. The 40/43.M was a howitzer gun sight which was inside the vehicle, with the help of the 8/14.M binocular the gunner of the Zrínyi could aim inside the safety of the tank.
Many don't know that the Zrínyi II was capable for indirect fire too like a self-propelled artillery gun. However the Zrínyi was rarely used in such way, thus pictures when the 8/14.M artillery binocular can be seen are extremely rare.
Armament
105 mm (4.13 in) MÁVAG 40/43M L20.5 howitzer
depression/elevation: -8° / +25°
traverse: 11°-11°
max ammo: 52 rounds (official), 90-92 rounds (in practice)
rate of fire: 6/min
Ammo:
theoretically 52 separate-loading ammunition, in-practice 90-92 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 42.M páncélrobbantó gránát (HEAT-T), 444m/s
38/33. M 105mm Smoke grenade, theoretically 6 items
Penetration with HEAT at 60°: 80mm on 500meters.
10,5 cm 40.M tank howitzer: this gun was used in the Zrínyi II assault howitzer. The main structure of the gun didn't changed but it had a different firing mechanism and safety systems. The gun had a primary pneumatic and a secondary mechanical firing mechanism. The safety system was an electric circuit, the loader had to push two buttons with his thumbs two close the circuit which made it possible to fire the gun otherwise it didn't fire, this procedure was used to prevent the loader being hit by the gun when fired.
Armor
Since the only difference between the Zrínyi I and Zrínyi II was the gun,the same armor layout is the same for both of them.
The Zrínyi had a 75mm frontal armor and an additional 25mm thick gun shield, because of that the frontal armor is 100mm thick around the gun where the gun shield is riveted to the frontal armor.
engine roof: 13mm at 5° and 25mm at 18° (25mm above the ventilation and transmission)
fighting compartment roof: 13mm at 4° (front) and 40° (rear)
SIDE SKIRTS
dimensions: ?
numbers: 4 per side
lashing points: 4 per plate
thickness: 5mm
distance from armor: 580-600mm
Zrinyi II specifications
GENERAL
name: 40/43.M Zrínyi
number built: 66-72
type: SPG
year: 1943-1944
length: 5,900m
width: 2,890m (3100mm with side skirts)
height: 1,9m - 0,380m from the ground
track width: 0,420m
track length: ~0,111m
track links: 106-107
max climb: 50% (can stop on a 50% climb without sliding down)
step: 0,8 m
trench: 2,2 m
ford: 0,9 m
turning radius: 4 m
max weight: 21,6t with 52 rounds (22,6t with side skirts)
22,4t with 90-92 rounds (23,4t with side skirts)
pressure on the ground: 0,72 kg/cm2 with 52 rounds (0,75 kg/cm2 with side skirts)
0,79 kg/cm2 with 90-92 rounds (0,82 kg/cm2 with side skirts)
radio: R-5 radio (stick radio antenna)
crew: 4
max speed: 43 km/h on road (40 km/h with side skirts)
ENGINE
name: Weiss Manfréd V-8 H4
power: 260 hp a 2200 rpm
power-to-weight ratio: 12 hp/t with 52 rounds (11,6 hp/t with side skirts)
11,6 hp/t with 90-92 rounds (11,2 hp/t with side skirts)
engine displacement: 14.866cc
gears: 6 + 6
max speed 1st gear: 3,3 km/h
max speed 6th gear: 43 km/h (40 km/h with side skirts)
max speed reverse gear: ?
fuel: petrol
fuel capacity: 445L
autonomy: 220km
44M Zrínyi I
The Zrínyi 105 assault gun project was already under development when the Hungarian Ministry of Defence (HM) decided to develop an assault gun armed with a 75mm tank gun in Spring-Summer, 1943 for anti-tank role. The sample vehicle of the Zrínyi - which was made of iron - was already available but the engineers had to wait months for the gun to arrive. The Machine and Fighting Vehicle Supply Department of the HM reported that the prototype of the vehicle would be ready only in July 1944 at best because the tank gun's production progressed slowly.
However 2 of the 7.5cm PaK 40's licence built tank gun versions were finished in December, 1943 and because of that the Zrínyi I's prototype was finished way earlier, in February, 1944. Filed and shooting est were held in Spring, 1944 and the vehicle was accepted for mass-production. The HM ordered 200 44.M Zrínyi tank destroyers from the factories. They planned to estabilish the new Assault Gun Battalions with 2 Zrínyi 75 batteries and 1 Zrínyi 105 battery with each battery consisting 10 vehicles.
However no more Zrínyi Is were constructed because the lack of materials and the fact that after the Occupation of Hungary in March, 1944 Germany not allowed further tank and gun productions only at a spare part manufacturing level.
It is not known if the prototype fought in any battles because no datas were found to prove or disprove it. The fate of the Zrínyi I is unknown, it disappeared after the battles but was still in Budapest in Autumn, 1944.
Specifications
Gun depression, elevation: -8°, +25°
Horizontal gun arc: 22°
Crew: 4
GENERAL
name: 44.M Zrínyi
number built: 1
type: tank destroyer
year: prototype 1944
length: 7,350m
width: 2,890m
height: 1,9m - 0,380m from the ground
track width: 0,420m
track length: ~0,111m
track links: 106-107
max climb: 50% (can stop on a 50% climb without sliding down)
step: 0,8 m
trench: 2,2 m
ford: 0,9 m
turning radius: 4 m
max weight: 21,6t
pressure on the ground: 0,79 kg/cm2
radio: R-5 radio (stick radio antenna)
crew: 4
max speed: 43 km/h on road
ENGINE
name: Weiss Manfréd V-8 H4
power: 260 hp a 2200 rpm
power-to-weight ratio: 12 hp/t
engine displacement: 14.866cc
gears: 6 + 6
max speed 1st gear: 3,3 km/h
max speed 6th gear: 43 km/h
max speed reverse gear: ?
fuel: petrol
fuel capacity: 445L
autonomy: 220km
Armor
Since the only difference between the Zrínyi I and Zrínyi II was the gun,the same armor layout is the same for both of them.
(view armor layout image above at the Zrinyi II)
Armament
75mm 43 M. L/43 anti-tank gun (+ 6 Nebelwerfer 41 tubes (15 cm))
depression/elevation: -10° / +30°
traverse: 11°-11°
max ammo: 52 rounds
rate of fire: 12/min
Ammo types:
43.M páncélgránát (APHECBC-T),770m/s
43.M repeszgránát (HE), 770m/s
43.M páncélrobbantó gránát (HEAT-T), 770m/s
40.M különleges német páncélgránát (APCR-T, German Pz.Gr.40)970m/s
penetration with APHEBC-T at 60°: 85mm/100m, 80mm/300m, 76mm/500m, 66mm/1000m
penetration with APHEBC-T at 90°: 113mm/100m, 106mm/300m, 101mm/500m, 88mm/1000m
penetration with HEAT : 90mm-60° / any distance up to 1200m
penetration with APCR-T :~143mm/100m, ~120mm/500m,~97mm/1000m,~77mm/1500m, at 30° from vertical
* According to archive Hungarian documents the Hungarian 75 mm 43.M L/43 tank gun had the very same armor penetration as the German 7.5 cm KwK 40 L/43. The problem is that the majority of sources differs about the German gun's penetration data, some say more some say less. If we take the archive Hungarian documents into consideration then the Hungarian 75 mm 43.M L/43 tank gun should have the same armor penetration as the German 7.5 cm KwK 40 L/43.
Nebelwefer rockets:
6x 152 mm Nebelwefer rockets
was aimed from inside of the tank.
vertical movement: from 6,5° to 45°
horizontal: none(moves together with the tank)
Sight
