SNAB-3000 "Crab"

The development of guided aerial bombs in the USSR began shortly after the war. The basis for the program was the study of captured German developments. Special attention was drawn to the radio-controlled aircraft bomb FX-1400 , also known as the "Fritz-X". Designed to deliver horizontal bomber strikes against heavily armored warships, the bomb demonstrated its capabilities in 1943 by sinking two hits of the latest Italian battleship Roma , which was about to surrender to Malta.

The trophy bomb interested the Soviet military, but its radio-controlled control equipment was considered ineffective in a modern combat environment. It was decided to develop a similar bomb design using infrared homing to defeat heat-consuming targets. Unlike the original, the bomb was supposed to be used against factories, power plants and large industrial centers - actively emitting heat targets.

The "Crab" bomb had a drop-shaped streamlined shape similar to the German original. In the rear part, stabilizers surrounded by a box-shaped frame were located, and in the central part of the hull there was an X-shaped wing. The projectile was controlled using interceptors located on both stabilizers and wings.

In the head part of the bomb was a homing head , consisting of two sulfur-lead photocells . Scanning was carried out using a modulating disk , one photocell in the vertical, the other in the horizontal plane. Two versions of GOS were developed - 01-53 and 01-54, the second of which was more sensitive. The capabilities of the GOS made it possible to capture a heat-emitting target, corresponding to the radiation of a power plant against a contrasting background from a distance of 9 km.

Corrections from the seeker were received on the electric autopilot located in the rear part, powered by a battery.

The total weight of the bomb was approximately 3200 kg, of which about 1285 accounted for the warhead.

The use of the bomb was preceded by a thorough ground preparation, during which the parameters of the combat mission were determined, the moment of switching on the GOS and the parameters of the target were established. In flight, the bomb was mounted on the external suspension of the aircraft. The bomber used the usual bomber sight to find the target and activated bomb systems 5-8 minutes before the reset. After separation from the aircraft, the bomb fell for a while at an angle of 50 degrees, stabilizing with the help of an autopilot, after which it turned on the GOS at the estimated time and began to search for the target.

The first tests of guided bombs began in 1950 with the dropping of unguided bombs in order to study their stability in flight. According to the results of throwing tests, changes were made to the design and in 1952, tests began on fully equipped bombs with an infrared seeker.

Bombs were dropped from the Tu-4 bomber on simulators of industrial facilities made up of burning bonfires. The Shchekinskaya Thermal Power Plant (CHP) in the Tula Region, the Krasnodar Oil Refinery (NPZ) and the Azovstal Iron and Steel Works (MK) in the Stalin Region, whose thermal radiation was previously measured and reproduced on mock-ups, served as standards for typical facilities. Practical tests demonstrated the autopilot's performance, but revealed a number of problems not previously considered - in particular, the loss of controllability by the bomb near the target due to strong thermal illumination of the seeker.

Modified bombs, with installed protective diaphragms , were tested in 1953-1954. Practice has shown that the bomb is quite easily aimed at training targets and the KVO is not more than 75 meters. Nevertheless, the bomb was difficult to operate, its assembly required almost 17 hours, and the reliability of the equipment was rather low.

At this point, due to the obsolescence of the Tu-4 as a carrier, the bomb tests continued on the Tu-16 jet bomber. At the same time, a number of problems were identified related to the peculiarities of placing large-sized bombs on a higher-speed jet aircraft. Infrared seeker bombs for successful target capture required external placement, which significantly increased aerodynamic drag and worsened the flight qualities of the bomber. New problems with the bomb were also revealed - its aerodynamics were not designed to discharge from a faster aircraft and when the speed was exceeded 0.9 M, the bomb began to lose stability.

In 1955, a series of tests was carried out with the following result:

• from 2 bombs dropped for the maximum brightness target (simulating the Azovstal steel plant), both hit the target with a deviation of less than 11 m;
• Of the 12 bombs dropped on a medium-brightness target (simulating the Krasnodar Oil Refinery), only four fell within a radius of 41 meters from the target and two more within a radius of 79 meters;
• Of the 4 bombs dropped on the target of minimum brightness (simulating the Shchekinskaya cogeneration plant), one fell with an unacceptable deviation of 85 meters, two did not capture the target, and one failed in flight.

As a result of the tests, it was stated that the requirements for the bomb were not fulfilled. The bomb showed acceptable accuracy only against very bright objects, use during the day was impossible due to the poor thermal contrast of objects in the sunlit area. In addition, due to the loss of stability by the bomb, the drop height was 10,000 meters - 2,000 meters lower than expected.

According to the recollections of the participants, the “Crab” ammunition was also tested with equipment from military radioactive substances ^[1] .

In 1956, work was discontinued.

• UB-2000F "The Seagull"
• UB-5000F "Condor"
• Ke-go

• Aerospace Review No. 1 of 2003
• Tupolev Tu-16 Badger Versatile Soviet Long-Range Bomber // Aerofax, 2004
• http://bastion-karpenko.narod.ru/Krab.pdf

1. ↑ "Dirty bomb" of Leningrad - Bellona.ru