R-40 (AA-6 “Acrid”)
The R-40R and R-40T air-to-air missiles, (AA-6 Acrid according to NATO designation), were designed between 1959 and 1961 to be able to shoot down the XB-70 Valkyrie supersonic bomber projected by the USAF. This bomber would reach Mach 3 and would be invulnerable to the Soviet fighters and missiles of the time. In anticipation of the arrival of this aircraft, (which was finally canceled), the Soviets produced a response to this threat in the form of an interceptor, the Mig-25P “Foxbat A”, capable of reaching Mach 3 and the R-40 missiles, which would be their main weapons.
R-40 (AA-6 “ACRID”) gallery and more info