Wood floats are installed along the whole body armored PB-4. 1933 year.
PB-4 - Soviet amphibious armored vehicle, are developed BSC. The authors have been developing a design engineer Emmanuilov, Deputy Chief and Chief of Grigoriev Pomerantcev Bureau.
The last modernization of PB-4 – wooden float length is shortened (ASKM). 1935 year.
AT 1933 year's May Day parade in Leningrad was shown to the general public the first Soviet floating armored railcar-BAD-2, created on the basis of a three-axle chassis "Ford Timken" American truck. His armored waterproof body with a pointed nose was shaped like boats, machine and moved on the water using a propeller, mounted on the end of a worm transmission rear axle. Maneuvering afloat performed by turning the front wheels, and to overcome the viscous soil. At the coast the rear wheels armored car could be put on the metal tracks. Arming supplements-2 consisted of the 37 mm gun in front of the conical tower and 7.62 mm machine guns DT aft cylindrical tower.
Designing floating armored engaged Izhorsk plant design team headed by an engineer H. I. Obukhov. The first experience in this matter was the construction of armored car BDC-2, which was tested. However, military officials have demanded to increase the reliability of the machine and increase its armor and armament. New floating armored vehicle, designated PB-4, It was built based on the same three-axle chassis 1935 year. He had only one tower, which were placed 45 mm tank gun and the coaxial machine gun DT.
Form armored housing has changed, and armored acquired the traditional view of the time. The thickness of the frontal, stern and side armor plates increased to 7 mm. Accordingly, the increased weight of the car, and to preserve the buoyancy of its sides mounted pontoons, filled molded plug. For movement on water PB-4 had the same, like BAD 2, three-bladed propeller, However major drawback precursor – Engine overheating afloat – avoided. The engine cooling system of a heat exchanger was inserted, washed by seawater, and heated air from the engine compartment through the gap was removed, located behind the driving compartment. On land motor armored cooled through the lower nasal hatch, closing before entering the water.
PB-4 was only released a small series, intended for military trials. Although in general this machine was quite successful, shortcomings it has lacked. Primarily it should be noted small specific engine power, which greatly affected the speed of the armored car. Despite the presence of caterpillars and removable rotating spare wheels, installed on the sides, PB-4 patency during entry into the water and out of it is poor. Add to this poor maneuverability afloat because its mass is too large and insufficient reliability overloaded chassis.
Developing the next version of the floating armored car, designers focused mainly on reducing its weight. PB-7, made in 1937 year, weighed 4,5 m and had a more streamlined body shape, thus eliminating the airborne pontoon. Frontal bronelisty hull and turret were mounted with an increased slope, and their thickness is reached 8 mm. The speed and agility of the new machines has increased significantly due to the use of domestic motor power 50 l. from. and a three-axle chassis GAZ-AAA.
PB-7 also built a small series, since all of the shortcomings of his predecessors failed to eliminate, and besides, he had a relatively weak armament. The conical tower was installed only one 7.62-mm aircraft machine gun with ammunition ShKAS 1000 rounds. As a result, during the Second World War floating armored cars were used on the fronts and wide distribution they received only after the war.
Performance characteristics armored PB-4
Crew, pers.: 4
developer: KBS
Manufacturer: Ižorskij Bureau
years of production: 1933—1935
The number of issued, PC.: 6
The layout: AND 3
Weight PB-4
– 5,28 tonnes
Dimensions PB-4
– body Length, mm: 5300
– housing width, mm: 1980
– Height, mm: 2250
– Clearance, mm: 240
Armor PB-4
– housing forehead, mm / city.: 7
– body board, mm / city.: 7
– housing feed, mm / city.: 7
– Bottom, mm: 4
– corps roof, mm: 5
Armament PB-4
– Caliber guns and stamp: 45-mm gun 20K
– gun ammunition: 52 shell and 2268 rounds (36 CDs)
– sights: telescopic TOP, periscope TP-1, mechanical machine gun
– Shotgun: 2 x 7,62-mm machine guns DT
Engine PB-4
– engine's type: GAS-AA, carburettor, liquid cooling
– Engine power, l. from.: 40
PB-4 Speed
– Road speed, kmh: 50
– Speed over rough terrain, kmh: 20 (on country road), 2 (afloat)
– Cruising on the highway, km: 197
– Cruising cross country, km: 138
– Kolёsnaya formula: 6 × 4
– Gradeability, city.: 15
Photos PB-4
