The Mil Mi-42 was a projected assault/transport helicopter featuring the NOTAR concept, fit to replace the Mi-40 program. The Mi-40 did not attract that many customers. Because of this and other reasons, The Mi-42 program (originally part of the Mi-40 program) was launched in 1985. The entire Mi-40 program, including the Mi-42 program, was cancelled because of the Soviet Union's Collapse.
Starting in 1985 a further development along the lines of the Mil Mi-40 was sought which would provide higher performance in the "Aerial Infantry Fighting Vehicle" category. Primary roles included landing troops, providing rapid redeployment, escort, close air support and tactical strikes. Its secondary roles would include transport of equipment, medivac, SAR/CSAR, reconnaissance and communications. Requirements specified day, night and all weather capability as well as diverse operating conditions.
A vectoring NOTAR system would replace the tail rotor. It was hoped that this would be more durable and increase safety of people working in the vicinity of the tail. Finally, it was planned that, as the aircraft picked up speed and aerodynamic forces began to have a stabilising effect, the vectoring system would angle the NOTAR nozzle so that it faced straight backward - hopefully allowing the Mi-42 to achieve its required top speed of 380-400kph.
The design was intended to be heavily armored and carry a mobile forward firing cannon and four hardpoints (equivalent armament to the Mil Mi-28 gunship). As a result of the complex requirements (essentially mixing those of a truck, transport helicopter, attack helicopter and strike aircraft) the design uncontrollably took on complexity and weight.
