Voroshilovets (1939)
Artillery tracked tractor 1939-1942, 1123 made.
Development
USSR was familiar with Holt (later Caterpillar) tractors already in WWI and started to use these in 1920-21. With the need for towing artillery in the Red Army in other ways than by horse-drawn carriages in the mid-1930s, especially high-power guns from 152 to 305 mm (6-in to 12-in) posed the problem the amount of horses. By having instead a large tractor with winch, tracks and enormous traction of 12 nm while moving with a mass 20 t at speeds up to 30 km/h. In addition, the adoption of new medium and heavy tanks above 28 tons in the Red Army also posed the issue of recovery. These considerations led to a joint assignment by the State Autonomous University and design bureaus for a new heavy tractor with tank engine, ideally from the specialized Kharkov Locomotive Plant "Comintern" in 1935.
Design work started this summer with a large team of designers from the department 200 gathered to create an outstanding tractor, latter called “Voroshilovets”, following naming traditions after the Komomolets. The layout was carried out by D.M. Ivanov and the engine by P.E. Libenko and I.3. Stavtsev, the transmission by V.M. Krichevsky, as well as S.3. Sidelnikov and V.P. Kaplin. The chassis was designed by P.G. Efremenko and A.I. Avtomonov and the auxiliary equipment by I.V. Dudko and Yu.S. Mironov. All worked under the direction of chief designer N.G. Zubarev, deputy for the Army D.F. Bobrova. They stayed overtime and by the end of the same year, in a matter of months, they published all the technical documentation.
"Voroshilovets" undergoing testing
From start, this design included the high-speed tank diesel power unit BD-2 (400 hp) which was a V12, 4 valve, with direct injection. The tractor's body was made of aluminum alloys, which was unusual, but enabled to avoid corrosion. The 400 department worked hard to refine and fine-tune the final vehicle prototype and by 1936, two were built for factory and field testing until 1938. By March 1937, one was publicly reevealed at Moscow's Kremlin without breakdowns, shown to the whole political gathering and Marshal K.E. Voroshilov, after which it was named. It made a great impression on all and was approved.
In the summer of 1938, a new tank diesel engine was tested under the name B-2B, in a derated modification, showing sufficient reliability, with the right performances and high efficiency, easy to start and operat in all modes. This was the start of widespread use of high-speed/light diesel engines of the B-2 type on medium and heavy tractors for 40 years... On instructions of the engineering department of the Red Army from the Voroshilovets a high-speed rotary excavator (BE trench-digger) prototype was built and tested.
The Voroshilovets tractor had a classic layout close to the previous Komsomolets, with the engine at the front, low-mounted and shorter, the transmission unit, winch and rear drive sprockets. It was long but moderately high and the engine was rationally placed under the cabin floor (COE), which became the norm for future tractors. The engine could accessed from its hood, and through the cabin's floor's hatches. This diesel had four air-oil filters, two in the cabin and main starting system with two electric starters of 6 hp each. plus pneumatic aircraft type backup using compressed air from a cylinder.
At low temperatures the engine still needed long preheating. The radiator was assembled from removable tubular sections, placed forward with a 6-bladed fan driven by a belt simultaneously dampion torsional vibrations. The lubrication system used a dry sump and a separate oil tank, whatever the inclination of the tractor. The main clutch used a multi-disc dry clutch of tank type with pedal control. There was a multiplier connected by driveshaft doubling gears with a total power range of 7.85. The next 4-speed gearbox was installed in the same housing with multi-disc (steel on steel) side clutches, with brakes, inspired by the
BT tank from the same 183rd plant. Breakdowns in the transmission started to appear however, but engineers gained experience. Overall, when the summer 1941 campaign started, the red army had more artillery trucks that any oher nation.
In fact this went to far as each type of weapon had its own designated class of tractor. The lighter ones towed 45mm antitank guns and 76mm regimental howitzers, either the Komsomolets or GAZ truck and the 76mm divisional guns by a larger tractors or larger truck (in 1944, Studebaker US6). The Komintern and Voroshilovets belonged to the heavy class. Both shared a relatively simple cabin based on, or derived from the GAZ AA truck's cabin; with a utility flatbed at the rear, generally used to seat all the gun's crew and some ammunition. The Voroshilovets tractor umtimately was intended to two "heavy Troika" with fixed trail and folding spade, either 152mm Br-2 heavy field gun, 203mm B-4 howitzer, and 280mm Br-5 heavy mortar of which only 48 were made as opposed to 977 B-4 howitzers. The latter could be could be towed in either one piece with limber or two loads, barrel carried separately. One piece became the norm in wartime.
The Vorosjlivets was called an artillery prime mover (tyazheliy tyagach) and the first prototype and its downrated 400 hp M-17T gasoline engine could not provide the adequate range. Thus the BD-2 high speed diesel was swapped for in 1938, again in a downrated version, of which derived the V-2 diesel used on all Soviet wartime medium and heavy tanks. It was rated for 375 HP in its downrated variant, traded for a monstrous torque, with 22 tons towing capacity. The powerful winch installed was used for recovering tanks, or as artilery prime mover. The Voroshilovets entered service in 1939 and production ran in parralel to the T-34 until the factory was evacuated in late 1941. Several hundred were built at that stage, but it was stopped.
Indeed tank production in Nizhniy Tagil from October 1941 had all priority. Production was setup again for the Voroshilovets but at the Stalingrad Tractor Factory. By the end of 1942 it was terminated as factory fell to the Germans after some 1,100 built. The "Voro" was very durable, rock-solid but its narrow tracks were a liability in snow and the "rasputitsaé in the spring. Brakes and transmission wore down fast also when towing the B-4. More than 330 were still in service in 1945. The Germans captured many tractors as well at Stalingrad. Production chassis received different numbers, with the KhPZ prefix first in the 1939-1941 Kharkiv run and VTZ in 1941-1942 at the Volgograd Tractor Factory.
At least 230 were built in KhPZ for 1.123 total. In German servoce it became the Gepanzerter Artillerie Schlepper 607 (R).
Design of the voroshilovets
General layout
The Voroshilovets was a tracked prime mover, more powerful alternative to the Komintern with a tracked chassis useful due to bad roads and adverse climate. The basic chassis of was based on the
T-24 tank with two main bogies featuring 4 doubled, ruberrized roadwheels each. It kept both the rear drive sprocket of the tank, but its new engine was mounted under a squarish bonnet at the front. The cab was wide enough for a driver's seat and a bench for two more personal(generally the gun commander and his second), not counting the gun crews seated in the flatbed behind. This flatbed shared many elements with trucks of the time, with a folding back panel. It had frame to be covered by tarpaulin.
Cargo capacity was 16 men on two doubled benches and their gear or 3 t of cargo, but the vehicle could tow artillery and trailers up to 18 t. The Voroshilovets was equipped as recovery vehicle with a powerful winch for medium and heavy tanks stuck in mud or snow. The tracked chassis provided sufficient all terrain mobility but at the low speed of 34 km/h, high fuel consumption, oil consumption, wear and tear, the more the terrain was difficult and payload heavy. The chassis ladder type frame was welded from two longitudinal channels connected by numerous cross members, gussets and platforms.
The back plate displayed a rotary locking hook with buffer springs for increased traction. The final production electrical system comprised a 24-volt kilowatt generator, four batteries, and all lighting and alarm. The driver sat on the left with a dashboard comprising 10 monitoring gauges, not counting the clock. The cabin wa the same as for the Komsomolets, a ZIS-5 truck cabin, but noticeably re-equipped and expanded. For ventilation and communication with the crew on the flatbed behind, there were two hatches at the rear of the cabin. The 5.76 m2 flatbed had two 550 liter fuel tanks underneath as well as the batteries, an oil supply, tools and fire extinguishers. The initial cabin bank was replaced by two seats, for three removable transverse seats total, with an additional one in case.
Engine and performances
The chassis rested on eight equally spaced double road wheels arranged in pairs under two balanced bogies using lever-spring equalizer suspension. This provided a good smooth ride and even load distribution along the track. All rollers were rubberized, reducing vibrations and enabling more speed. But the tracks were standard small-ringed tank type, with small lugs which procured had insufficient traction and high ground pressuere in ice/snow. Its design made it poorly cleared of dirt. Still, the engine procured a traction force beyond 13,000 kgf (Kilo Force), whereas the engine could procure up to 16,900 kgf. By removing additional lugs, traction was increased, but just over 50 km.
The reversible winch was located in the middle, under the body with an horizontal drum (30 meters long, diameter 23 mm) steel cable extending forward along the rollers, usable as unditching cable as well if the tractor was bogged down. The 15.5 tonns tractor with a 3t payload capacity in flatbed, could tow a trailer of 22t. It towered at 3,087 mm with the canvas cargo tarp mounted. Ground clearance was 46.2 cm, Track width, 42.8 cm, ground pressure 0.748 kg/cm2. The B-2B V12 diesel engine rated for 375 hp at 1.500 rpm allowed a road range of 270 km for 1.100 L fuel in two tanks, off road range of 130 km (both without trailer) with a top speed of 36.2 kph on road down to 20 km/h on road towing a load and off road 16 km/h towing a load.
Turn radius was 5 m minimum, Power to weight ratio 22.6 hp/t. When tested it could overcome a 1.5 m wide trench, ford 1.3 m with preparation. It was neither armed (but its towed payload and personal weapons of the crew) nor armoured. Some of these tractors were through, expecting to make improvized tanks,
⚙ voroshilovets specifications |
| Displacement | 15.5 t |
| Dimensions | 6.22 m x 2.35 m x 2.74 m cab roof (3.09 m with tarpaulin cover) |
| Suspension | Tracked, 8 roadwheels, Gd Pressure 0.58 kg/cm2 |
| Propulsion | V-2V 12-cyl. diesel 375 hp/1.500 rpm, p/w 22.6 hp/t |
| Speed | 16-36 kph off road to road |
| Range | Fuel 1.100 L. 130/270 km with/without trailer off road |
| Armament | None |
| Payload | 3 t, towed 18-22t |
| Crew | 1 + 18 (driver, 2 cabin seats, 16 platform seats) |
The voroshilovets in service
The Voroshilovets was produced in only a single version which differed from the Komintern prime mover by its stockier, shorter bonnet. The Voroshilovets was widely used by Soviet forces during World War 2, bringing to the fight th heaviest artillery pieces in invetory. It was used until the 1950's. By the end of 1939, production amounting to an average of 1.5 vehicle per day and by late August 1941, at the evacuation of the plant to Nizhny Tagil, 1,123 had bee produced total including by June 22, 800 in inventory. From July rpdiction rose to 3-4 tractors daily at Stalingrad. Records showed by April 1941, 733 Voroshilovets in service whereas by January there were only 228 in servoce, so just 1.1% of the tractors fleet. KhPZ delivered 170 more Voroshilovets in total.
This tractor beame the most powerful prime mover of the USSR, being able of recovering even the mighty T-35 and KV-2. It was used for towing the 210-mm M1939 with separate carriage and barrel, the 152-mm cannon M1935 model, 203mm M1931 also in separate carriage and barrel, the 280mm mortars M1939, 305 mm howitzer M1939 also in separate carriage and barrel. Many were used for towing both an artillery piece and a 18ton trailer with ammunitions. The diesel was an early multifuel using also gas oil, gasoline, aviation gasoline, even a mixture of motor oil and kerosene. It was even tested on road without any load up to 390 km with an hourly fuel consumption of 20 kg-24 kg with trailer.
The shortage of V2 tank diesel engines in high demand for the T-34 other engines were trialledsuch as the 300 hp V-4 which was a halved V-2 gasoline M-17T (400 hp) used by the BT-7 which production ceased. Artillery plant No. 8 in Podlipki tested a conversion into a self-propelled 85-mm 52K anti-aircraft gun, but this never made it as the factory was evacuated. The Voroshilovets soldiered on all fronts, but especially for the heavy artillery Reserve of the Supreme High Command. It had shortcomings but generally received positive reviews.
This powerful tractor having no equivalent in German inventory, the few captured, unofficially called “Stalin” (Gepanzerter Artillerie Schlepper 607(R)) worked mostly for tank recovery, which the army lacked. However as the war dragged on, the shortcomings piled up until any work on in design bureaus stopped and the lack of spare parts except for engines meant each tractor needed a complete overhaul after 1,200 hours of operation, which compounded with combat losses by September 1, 1942 led to 528 operational only and 336 in 1945. They were still in Berlin in sufficient numbers for taking part in the Victory Parade. Those that survived the war were gradually replaced by the AT-T tractor.
The tracks were criticized as being too narrow for true all weather/all-terrain use, and the tractor ended bogged down often in extremes, whereas the poor mud extraction caused the drive sprockets to be clogged and even fell off. There were frequent breakdowns of the main clutch (after 200-300 hours of operation) and for those in the first series, shafts and gears of the second group of multipliers also failed. After 300-400 hours of operation the bearings of the final drive drive gears was escessibe. Seals were leaking which wa common for KhPZ vehicles, vibrations broke pipes. There were cases in which the rear tow hook unbending, and over hard uneven surfaces, the lower frame skin sagged and tore off.
According to the drivers, the winch was inconvenient to use and the the cold start of the V-2B diesel down to -20 °C and below temperatures was hard. The procedure was repeated heating the started with water and warming oil over 3-4 hours. Electric starters also failed to bring the engine to 550-600 °C for fuel self-ignition. It was observed the rapid wear of the chassis hinges and suspension axle bushings due to leaks and insufficient lubrication or just poor dirt protection. Road wheels, support rollers Bearings and idler wheels were often clogged. To reduce wear and prevent roller bearings breakage, they had to be disassembled, washed and generously lubricated almost every day. Eventually the inaccessibility of certain part of the transmissiona nd engine for maintenance and repair on the field made it difficult; aggravating the problems. All this combined explained why production was never resumed.