The Myasishchev M-4 Molot (), USAF/DoD reporting name "Type 37", ASCC reporting name Bison) was a four-engined strategic bomber designed by Vladimir Mikhailovich Myasishchev and manufactured by the Soviet Union in the 1950s to provide a Long Range Aviation bomber capable of attacking targets in North America. The aircraft fell quite short of its intended range and was not really capable of attacking the most valuable targets in the United States. As this became clear, production was shut down. In spite of the failure to produce a capable strategic design and the resulting small numbers, the M-4 nevertheless sparked fears of a "bomber gap" when 18 of the aircraft were flown in a public demonstration on May Day in 1954. The US responded by building hundreds of Boeing B-47s and B-52s to counter this perceived threat. The design was updated with more efficient engines, inflight refuelling (IFR) support and the removal of the glass nose for optical bombing and moving the radar to this location. With these changes, production restarted as the 3M. Even with these modifications the design was not truly effective in the nuclear bomber role, and only 93 aircraft, both M-4s and 3Ms, were produced before the production line was shut down for good in 1963. Only 19 of these served on nuclear alert. M-4s and 3Ms were primarily used as long-range maritime reconnaissance and strike aircraft and other supporting roles. Most were converted in the 1970s and 80s to tanker aircraft, especially as the Tupolev Tu-22M took over the maritime missions. The tanker conversions remained in service until 1994. Most surviving examples were broken up as part of post-Cold War arms limitations agreements. Design and development Following World War II, the Soviet Union prioritized developing a long-range strategic bomber capable of delivering atomic weapons. Their first aircraft was the Tupolev Tu-4, a reverse-engineered version of the American B-29 Superfortress. The Tu-4 was only ever a stop-gap solution, as unlike the American strategic bomber force that could operate from bases in allied countries close to the USSR, it lacked the range to reach the continental United States, and experiences in the Korean War demonstrated piston engine bombers were extremely vulnerable to jet fighter interception. With the advancement of Western jet bombers like the B-47 Stratojet and Vickers Valiant, Vladimir Mikhailovich Myasishchev was directed to construct a strategichesky dalny bombardirovshchik (SDB) (стратегический дальный бомбардировщик (СДБ), "strategic long-range bomber")