 The design was later abandoned in favor of a more conventional tailed delta wing.The advent of relaxed stability flight control systems in the 1970s negated many of the disadvantages of a fixed platform.No new variable-sweep wing aircraft have been built since the Tu-160 (produced until 1992), though it has been noted that the F-14's replacement – the F/A-18E – has a reduced payload/range capability largely because of its small fixed wings.