Soviet post-war 85mm self-propelled artillery units
In the 1950s-1970s, the USSR worked on creating light self-propelled artillery units armed with 85-mm guns. Such self-propelled guns were primarily intended for paratroops, and in the Ground Forces they were considered as a battalion-level anti-tank weapon. Light wheeled self-propelled guns on an armored personnel carrier chassis, which had high mobility, in addition to fighting enemy armored vehicles, could also be used to provide fire support to infantry units and for patrol and reconnaissance activities.
Self-propelled artillery unit ASU-85
The adoption of the airborne 1949-mm self-propelled gun in 57 artillery The ASU-57 installation did not completely solve the problem of equipping the Airborne Troops with a truly effective tank destroyer capable of providing fire support to the "winged infantry" during an offensive and partially compensating for the lack of other armored vehicles among the paratroopers, which revealed the need to create a self-propelled gun with a larger-caliber gun. In addition, the command of the Ground Forces in the first post-war decade expressed interest in creating a light assault self-propelled gun, which was to replace the morally and physically obsolete SU-76M.
Based on the experience of World War II and post-war realities, the Soviet military leadership wanted to obtain a light self-propelled gun suitable for transporting aviation and parachute landing, sufficiently mobile on rough terrain and equipped with a powerful weapon capable of penetrating the frontal armor of modern medium tanks at that time tanks potential enemy. In addition, it was highly desirable to increase the destructive and lethal effect of the fragmentation grenade.
By the beginning of the 1950s, it became quite obvious that the armor penetration of 57-mm anti-tank guns, even with the use of new high-speed sub-caliber "coils" with hard-alloy cores, had practically reached its limit, and the 76-mm divisional guns, which had proven themselves well in wartime, no longer fully met the requirements for range, lethality and high-explosive effect of a fragmentation shell.
Calculations showed that acceptable characteristics in terms of armor penetration, fragmentation and high-explosive action can be obtained on an 85-mm artillery system. The use of armor based on light alloys made it possible to meet the characteristics of air mobility and protection required of the new self-propelled gun.
The design of the 85-mm self-propelled gun (Object 573) began in the early 1950s at the Mytishchi Machine-Building Plant Design Bureau under the leadership of the plant's chief designer N. A. Astrov and was synchronized with the creation of new turboprop transport aircraft capable of carrying light armored vehicles in the cargo compartment.
Initially, the new self-propelled gun received the "universal" designation SU-85, and it was envisaged that, in addition to the Airborne Forces, it would be supplied to the anti-tank divisions of the Ground Forces. However, after some time, the "ground" generals decided that they did not need a self-propelled gun with "aluminum" armor, and they relied on tanks with powerful anti-shell armor, as well as self-propelled guns with larger caliber guns.
After that, the vehicle was produced only for the Airborne Forces, and it was given a purely airborne designation - ASU-85. Serial production continued from 1959 to 1966. In 7 years, it was possible to build about 500 vehicles. In the Airborne Forces, the ASU-85 was used in separate self-propelled artillery divisions (30 vehicles), which were the anti-tank reserve of the division commander.
Unlike the ASU-57, which was mass-produced at Plant No. 40 in Mytishchi, the ASU-85 self-propelled artillery unit had a different layout: the driver was located in front, followed by the fighting compartment with the gunner's workstations (to the left of the gun), and the commander and loader were located on the right. The engine-transmission compartment was in the rear of the combat vehicle. In height, the fighting compartment was slightly larger than the engine-transmission compartment, and the vehicle externally resembled the German StuG tank destroyer. IV.
ASU-85 prototype
The upper frontal plate of the hull, 45 mm thick, had an angle of 60°, and the lower one of the same thickness was located at an angle of 40°. The side armor plates of the hull, 13 mm thick, were installed at an angle of 40° from the vertical. The maximum thickness of the remaining armor plates of the hull parts did not exceed 6 mm. The frontal armor could successfully withstand small-caliber armor-piercing shells and in terms of protection in the frontal projection of the ASU-85 was approximately at the level of the T-34 medium tank. The side armor was capable of withstanding shell fragments and rifle armor-piercing bullets fired at point-blank range, as well as 12,7 mm bullets at a distance of more than 400 m.
The prototype and early series self-propelled guns did not have an armored roof, and in the marching position the top was covered with tarpaulin. Already after the adoption of the ASU-85 in the conditions of the proliferation of tactical nuclear weapons weapons The military demanded that the fighting compartment be covered from above, and since 1960, a modification with a roof 6-13 mm thick, in which there were three hatches, began to be produced. However, the fighting compartment of the self-propelled gun was not sealed, and it did not have a filtration unit or a device for creating excess pressure inside the vehicle.
Therefore, in areas exposed to chemical or radiation contamination, the crew was forced to work not only in gas masks, but also in insulating protective suits.
The 85mm D-70 cannon with a vertical wedge breech, semi-automatic copying mechanism, a two-chamber muzzle brake and an ejector for removing powder gases after firing is installed in the frontal plate with a slight offset to the left.
The D-70 gun traced its lineage back to the towed 85-mm anti-tank gun D-48 and was also created under the supervision of F. F. Petrov. The round for the D-48 had an increased volume of powder charge and used a re-crimped case from a 100-mm artillery munition used for firing from the towed gun BS-3 and tank D-10.
Shots for the 85mm D-48 anti-tank gun
Due to the increased energy, the recoil devices, breech and barrel of the D-48 were strengthened compared to the 85 mm D-44 cannon. Due to the significantly increased muzzle velocity of the projectile, armor penetration increased significantly. But at the same time, the barrel life was significantly reduced and the weight of the gun increased. Since the airdroppable SPG was limited in size when placed inside a military transport aircraft, the D-70 barrel became 48 calibers shorter than the D-6 and, accordingly, the muzzle velocity of the projectile dropped by 35 m/s. But, nevertheless, the characteristics of the gun remained quite high.
The muzzle velocity of the BR-372 armor-piercing projectile weighing 9,3 kg was 1005 m/s. At a distance of 1000 m, when hitting at a right angle, it could penetrate a 190 mm armor plate. The BR-367P subcaliber tracer projectile weighing 4,99 kg with an initial velocity of 1150 m/s under the same conditions penetrates homogeneous armor up to 220 mm thick. HEAT projectiles 3BK7 weighing 7,22 kg and with armor penetration of 160 mm were also used for firing at armored vehicles. The thickness of the armor penetrated by the HEAT projectile does not depend on the range. The 85-mm OF-372 high-explosive fragmentation grenade weighing 9,7 kg contained 741 g of TNT and was significantly superior in fragmentation to the 76-mm projectile.
The firing range for armored vehicles reached 2500 m, but the effective range for moving targets did not exceed 1600 m. The maximum firing range for a fragmentation projectile reached 10 m. The TShK-000-2 telescopic hinged sight was used for firing at visually observed targets. When firing from closed positions, the S-79-71 mechanical sight with the PG-79 gun panorama was used. For firing in the dark at a distance of up to 1 m, the TPN-500-1-79 night tank sight with the L-11 infrared illumination searchlight was intended. With aiming correction, the rate of fire reached 2 rounds/min. The gun has vertical aiming angles from -7 to +5 °. The horizontal firing sector is ±15 °. The gun is paired with a 15 mm SGMT machine gun. The ammunition load for early production vehicles consisted of 7,62 unitary artillery rounds and 45 rifle-caliber rounds. The R-2000 VHF radio was used for external communications, and the R-113 TPU was used for internal communications.
The ASU-85 received a chassis that was quite advanced for that time, consisting of six single-row rubberized support rollers, a rear drive roller and a front guide roller with a track tensioning mechanism for the wheels on each side of the vehicle. The suspension was individual, torsion. A smooth ride was provided by piston-type hydraulic shock absorbers. The YaAZ-206V two-stroke diesel engine with a power of 210 hp accelerated the 15-ton vehicle on the highway to 45 km/h. Due to its relatively small weight, the self-propelled unit had good mobility on rough terrain and cross-country ability on soft soils. Cruising range on the highway is 360 km. On a dirt road - 230 km.
The problem of crossing water obstacles was solved by using a 20-ton pontoon assembled from sections of the DPP-40 landing pontoon park.
After analyzing the combat use of armored vehicles in the Arab-Israeli conflicts, the self-propelled gun was modernized: a cylindrical commander's cupola with a TNPK-240A periscope observation device and a gun panorama appeared on the roof of the fighting compartment. On top of the cupola there was a hatch with a 12,7-mm DShKM anti-aircraft machine gun turret.
Due to the need to additionally accommodate 12 boxes of 50-round belts for the large-caliber machine gun, the number of artillery rounds was reduced to 39 units.
At an early stage, the ASU-85 could be transported by An-12 and An-22 military transport aircraft.
But after the 1972P4 (P-134) platform was adopted into service in 16, it became possible to drop the aircraft with a multi-dome parachute system. Special brakes were activated immediately before landing. missile engines that dampened vertical speed. After landing, the self-propelled unit could be brought into combat readiness within 5 minutes, but the crew was parachuted separately.
Although by the mid-1970s the 85 mm D-70 gun no longer reliably penetrated the frontal armor of contemporary American and British tanks, the ASU-85 was very popular in the Airborne Forces and, until the Nona-S self-propelled gun was adopted, was effectively the only parachute-dropped Soviet self-propelled gun capable of providing fairly effective artillery support, firing at visually observed targets and from closed positions. The fragmentation shell of the 57 mm Ch-51 gun, which the ASU-57 self-propelled gun was armed with, was too light and contained only 220 g of TNT.
Before the BMD-1 and BTR-D were delivered, the ASU-85 self-propelled guns were actively used for transporting personnel, towing trailers and artillery systems.
After the ASU-85 was spotted during the Warsaw Pact invasion of Czechoslovakia in 1968, army wits nicknamed the airborne self-propelled gun the "Prague crocodile."
The ASU-85s, as part of the artillery battalion of the 103rd Airborne Division, also participated in the introduction of a "limited contingent" into Afghanistan. However, the 85-mm self-propelled guns did not stay "beyond the river" for long, and nothing is known about their use in combat.
In the early 1980s, 85-mm self-propelled guns began to be removed from the artillery battalions of airborne divisions and put into storage. Officially, the ASU-85 was removed from service in 1993, although by that time there were no more self-propelled guns in combat units.
A number of sources claim that the ASU-85 actually saw combat during the Six-Day War in 1967, and 50 vehicles were delivered to Egypt. However, there are no details of the combat use of the ASU-85 in the Middle East, and they were not among the Israeli trophies.
In 1964, the Soviet Union transferred 20 self-propelled guns to the GDR, and a year later 31 vehicles to Poland. In these countries, the ASU-85 was in service until the liquidation of the Warsaw Pact. Several Polish ASU-85s are currently on display in museums.
The only country that still has the ASU-85 in service is Vietnam. In 1979, light anti-tank self-propelled guns capable of maneuvering in the jungle were needed to repel Chinese aggression. However, the 85-mm self-propelled guns did not make it to the war in Southeast Asia, and about fifty self-propelled guns were used by the Vietnamese People's Army until the mid-1990s, after which they were mothballed.
In 2015, it became known that the Vietnamese had removed from storage and repaired some ASU-85s, and they were put into service with the 168th Artillery Brigade of the VNA.
Light wheeled 85-mm self-propelled artillery unit "Zhalo-S"
In the late 1960s, the Soviet military leadership expressed interest in creating a light wheeled tank destroyer that, in addition to countering enemy armored vehicles, could be used for reconnaissance and providing fire support to mobile units. In fact, the possibility of creating a so-called "wheeled tank" was considered, which would have a higher speed on roads, better fuel efficiency and lower cost compared to tracked vehicles of the same weight category.
The development of the light wheeled self-propelled gun 2S14 "Zhalo-S" was carried out in 1970-1975 at the Nizhny Novgorod Central Research Institute "Burevestnik" under the leadership of V.E. Serebryany. According to the technical specifications, the self-propelled gun, armed with an 85-mm smoothbore gun, was intended for the battalion link of motorized rifle troops.
The BTR-70 was chosen as the base chassis, which, in case of mass production, allowed to significantly reduce the cost of production and operation, and also simplified the training of driver-mechanics, supply of consumables and spare parts. The BTR-70 design made it possible to develop a new self-propelled gun on its basis without making serious changes to the design of the hull and chassis. The layout with the front location of the common habitable compartment and the aft power compartment allowed to install the turret in the central part of the vehicle and preserve the previous placement of the main units. The installation of the turret did not require significant reworking of the hull, with the exception of cutting in a new ring and some strengthening of the roof.
The absence of serious modifications to the chassis allowed the BTR-70 to retain its weight and dimensions. Thus, the length of the self-propelled gun along the hull was the same as that of the armored personnel carrier, and was 7510 mm. Length with a gun – 9950 mm. Width – 2790 mm, height – 2490 mm. Curb weight – 12,5 tons.
The hull consisted of armor plates no more than 8-10 mm thick with the most powerful protection in the frontal projection. Mobility and protection remained at the level of the BTR-70. The crew was 4 people. As on the BTR-70, the driver-mechanic was located in the front part of the hull. The commander could be located next to him. The control compartment had a pair of hatches in the roof. The gunner's place was in the turret, the loader's place was in the fighting compartment. There was one hatch on the turret, the fighting compartment could also be accessed through the side hatches. For observation in field conditions, the frontal glazing with armored shields was used, in a combat situation - periscope devices. For external communication, there was an R-123 radio station.
Two twin carburetor engines ZMZ 4605 with a total power of 240 hp could accelerate the self-propelled unit on the highway to 80 km / h. The engines were mounted on a common frame with a clutch and a manual gearbox. Fuel tanks were also located next to them. With the help of several shafts and differentials, the torque of the engines was distributed to eight driving wheels. Cruising range on hard-surface roads is up to 600 km. On a dirt road - up to 400 km. It was possible to force water obstacles by swimming. To move on water at a speed of 10 km / h, a stern water jet was used.
Model of the self-propelled gun "Zhalo-S"
The main armament of the Zhalo-S self-propelled gun was the 85 mm 2A62 smoothbore gun mounted in a rotating turret. This gun was created simultaneously with the towed version, designated 2A55 Zhalo-B. To reduce recoil, the 2A62 gun was equipped with a highly effective muzzle brake. The armor-piercing fin-stabilized discarding sabot projectile (APFSDS) could penetrate 1000 mm of armor at a distance of 230 m at normal angles. The ammunition complement also included cumulative projectiles with armor penetration of up to 400 mm and high-explosive fragmentation projectiles. The fighting compartment had space for 35-40 artillery rounds.
A turret welded from 85 mm thick sheets was developed for the 6 mm wheeled SPG. The lower part had the shape of an inverted truncated cone of small height. In the center of the front part of the turret there was a box-shaped unit with a gun mount, on the sides of which there were rectangular niches. The sides and rear of the turret were made in the form of another conical surface. On the roof curved in the center on the left side there was a turret with a hatch. In the rear part of the turret there was a small rectangular niche with a hatch for ejecting spent cartridges. On the experimental vehicle, only an 85 mm gun was mounted in the turret. But if adopted for service, the self-propelled gun could be additionally equipped with a rifle-caliber machine gun, paired with the gun or installed on the gunner's hatch, as well as smoke grenade launchers.
Although the Zhalo-S self-propelled gun used a ready-made chassis that required minimal modification, the creation and refinement of the vehicle dragged on. Testing of the only built example began in 1975 and lasted until 1980.
Self-propelled gun "Zhalo-S" at the training ground
Overall, the vehicle performed well and could move in the same marching and combat formations of units armed with the BTR-60. The firepower of the Zhalo-S self-propelled gun was quite sufficient to combat West German Leopard 1 tanks and French AMX-30s. However, the 85 mm APFSDS round fired from the 2A62 gun barrel did not guarantee reliable penetration of the frontal armor of well-protected tanks: the American M60 and the British Chieftain.
Considering that in the 1960s the American-West German MBT-70 tank was being developed, and after the project was split in Germany in 1979 the Leopard 2 was adopted, and in the US in 1980 the M1 Abrams, the prospects of an 85-mm smoothbore anti-tank gun with high ballistics, despite all its positive qualities, came to naught. The only branch of the armed forces that would have been in demand for the Zhalo-S floating self-propelled gun could have been the Marines, which until the early 1990s operated PT-76 floating tanks with 76-mm D-56T rifled guns, which were significantly inferior to the 2A62 gun in terms of armor penetration and the damaging effect of the projectile. However, in the USSR the marine infantry was relatively small in number, and for this reason it was considered impractical to adopt a new self-propelled gun.
After the tests were completed, the Zhalo-S self-propelled gun was kept for some time at the testing ground of the 38th Research and Testing Institute of Armored Vehicles in Kubinka, where it stood in the open air. Subsequently, the restored wheeled self-propelled gun took its place in one of the pavilions of the Armored Museum in the city of Kubinka.
To be continued ...
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