In WWII, a pilot of a ground attack airplane or bomber flying at several hundred kph had a hard time placing a bomb next to a small target. And what if the target is moving, and what if it's well armoured?
In order to guarantee the destruction of an enemy medium tank with a FAB-100 bomb, the pilot needed to hit within 3 meters of the vehicle. This was difficult, and it was not surprising that the VVS was very interested in the special anti-tank bomb project proposed by I. A. Larionov.
This bomb, indexed PTAB 2.5-1.5 weighed 2.5 kg. The bomb used a HEAT type warhead, capable of penetrating 60 mm of armour 30 to 90 degrees. This was enough to destroy any German tank; even the well armoured Tiger only had 28 mm of armour on its hull and turret roof.
The Soviet Il-2 ground attacker could carry four cassettes, each of which carried 48 PTABs, or 220 individual bombs without cassettes. They were dropped simultaneously, covering a large area. The fact that most bombs would blow up ineffectively was meaningless, since one destroyed tank cost much more than the entire cassette of bombs put together.
The PTAB 2.5-1.5 was first used on July 5th, 1943, at Kursk, and proved themselves an effective weapon. Pilots of the 3rd and 9th corps of the 17th air army reported that 90 German tanks were destroyed with these new bombs by the end of July 6th. As the days went on, the effectiveness of the bombs was reduced, since the Germans started spacing out their vehicles. However, the PTAB was still more effective than conventional high explosive or fragmentation bombs.
The inventor of the bomb, I. A. Larionov, was rewarded with an Order of Lenin in 1944 and the Government Grant of the USSR in 1946.