FAB-5000 bomb

The FAB 5000NG bomb (ФАБ-5000НГ, where NG stands for its inventor, Nison Gelperin) was a 5000 kg large air-dropped, general-purpose thin cased high explosive demolition bomb used by the Soviet Air Forces during WWII. The device was the most powerful aerial bomb in the Soviet inventory.

Development
The bomb was designed by Soviet chemical engineer ru (1903-1989) in 1942. Gelperin projected and built bombs with tiny metal casings, in order to reduce the use of iron cast and aluminium. In Gelperin developments, the weight of metal casings represented only the 35 percent of the bombs weight.

By 1942, the State Defense Committee of the Soviet Union perceived the need of weapons that could hit-hard industrial and military facilities, marshaling yards and fortifications, without the usual scattering of medium-weight bombs. The first attempt came in the form of an explosive unmanned aircraft, a modified version of the TB-3, but the trials of this flying bomb were less than satisfactory.

The Directorate of Logistics of the Air Forces eventually requested to Gelperin the development of a five-ton bomb, capable of being dropped by the Pe-8, the heaviest Soviet bomber of the time. The definitive version of the FAB-5000 was fitted with six contact lateral fuses, and the warhead was filled with 3200 kg of an explosive mixture of TNT, RDX, and aluminium powder. The number of fuses ensured that the force of the blast would disperse laterally, which increases the damage in areas such as industrial compounds and military facilities. In order to load the device, the bomb bay doors had to remain half-open. The tests, however, were successful. Two bombs were dropped, one from an altitude of 4,000 m and the other from 3,300 m. The first bomb fell in open ground, leaving a crater 6 m in diameter and 3 m in depth. Grass in a radius of 150 m was charred. The second bomb landed in the woods, and left a crater of 8 m in diameter and 3 m in depth. Some 600 trees were tore out within a 70 m radius, while 30 percent of the trees wihtin 135 m also fell down. Later tests produced craters up to 20 m in diameter and 9 m in depth. The project was brought to the assembly line and the bomb was hastily put in service on 15 February 1943. By the end of the war, 98 FAB-5000s had been delivered to the Soviet Air Forces, all of them produced in 1943.

Operational use
The first combat use of the FAB-5000 took place on the night of 28 April 1943, when coastal fortifications at Königsberg were hit. The Pe-8 bomber that launched the bomb from an altitude of 5,800 m was shaken by the shockwave of the explosion. On 19 July 1943, during the battle of Kursk, two Pe-8 dropped two bombs on a railroad yard near Orel, ripping apart a 100 m section of the railway and obliterating dozens of railcars and German military vehicles. Railroads and fuel depots had already been hit around Orel with one bomb on 4 June and with two bombs on 3 July. Two attacks were carried out on advancing German troops on 12 July, but further tactical use was suspended to avoid the risk of friendly fire. Soviet sources also claim that two buildings occupied by the Gestapo and the Belarusian Auxiliary Police were demolished by two FAB-5000 bombs at the city of Mogilev, Belarus, apparently on 26 May 1943. On 7 February 1944, another two FAB-5000 bombs were dropped on Helsinki, in the course of the 1944 Great Raids. The city's tram terminal and the train station were destroyed. A couple of days later, two more bombs fell on on Finland's capital. The last FAB-5000 was dropped on the railway station of, Ukraine, on 9 March 1944, during the Soviet offensive on Kamenets-Podolsky pocket, halting all railroad traffic for several days.