During the 1960s a strategic shift was taking place in nuclear deterrent doctrines as the United States Navy began putting to sea increasing numbers of Polaris sea-launched ballistic missiles (SLBMs) aboard nuclear-powered ballistic missile submarines beginning in 1960 with the first deterrent patrols of the George Washington-class. With improvements in the Polaris missile coming rapidly that bestowed even greater range, the Soviet Union, lacking a blue-water navy in the 1960s looked to unique if not creative answers to seek out and destroy the American SSBNs which no longer needed to lurk close to Soviet shores to reach remote ocean areas not normally patrolled by the Soviet Navy.
In 1965 the Beriev OKB was tasked with developing one of the most impressive unbuilt flying boat designs that had as its core mission to seek out and destroy the SSBNs in remote ocean areas. The Beriev A-150 built on the design bureau's already extensive expertise in flying boats that included the jet powered Be-10 that saw limited service with the AV-MF (naval air force) in the 1950s. The A-150 was to have been a multi-role amphibian with a large delta wing that bestowed on it a large internal volume for missions that not only included long range anti-submarine warfare, but also anti-suface vessel warfare, maritime reconnaissance, search and rescue and an inflight tanker. In addition, Beriev developed transport variants that not only had military roles, but could also have been used for resource development in the Soviet Far East where ground networks of roads and rails were near non-existent.
The A-150 would have been 163 feet long with a wingspan of 137 feet. Paired nacelles above the wings would have housed Kuznetsov NK-8 turbofans (used on the Il-62 and Tu-154 jetliners). In addition, twelve Kolesov RD36 lift engines would have been installed in the leading edge roots to help shorten the takeoff run of the A-150. Inside the wing center section on each side of the fuselage were equipment bays that could accommodate interchangeable mission pods depending upon the mission tasking. Each bay and mission pods had standardized connections allowing the A-150 to be retasked in minimal time. Each pod had a volume of just over a thousand cubic feet. Some pods were weapons bays, others included ASW equipment like dunking sonar, sonobuoys and torpedoes. With a crew of 5 and a range of nearly 11,000 miles, the A-150 would have been an impressive machine.
Beriev also developed the A-150DT version which had a larger fuselage and a clamshell "tailgate" that allowed heavy loads to be driven directly into the fuselage cargo deck. The total cargo capacity of the A-150DT was nearly 70,000 lbs and it had 16 instead of 12 RD36 lift engines to handle the increased weight. There was even exploration of a VTOL version with 32 lift engines! The A-150DT was intended as an assault transport but its capabilities also made it useful in Siberian resource development and supporting the Soviet fishing fleet at sea. The assault transport version also had two twin-cannon turrets, one for the tail and one in the nose section.
Ultimately Beriev's ambitious A-150 proved to be too much aircraft for the prevailing technology of the day and the Soviet answer to the American SSBN fleet was to increase its own fleet of nuclear-powered hunter killer subs (SSNs).
Source: Beriev's Jet Flying Boats (Red Star Volume 28) by Yefim Gordon, Andrey Sal'nikov, and Alexandr Zoblotskiy. Ian Allan/Midland Publishing, 2006, p96-97.