20世纪70年代中期,苏联的主力攻击直升机是著名的米-24。尽管米-24性能优良,但是苏联国防部领导认为米-24没有完全实现“飞行的步兵战车”设计概念。受到米-24的影响,美国陆军在20世纪70年代初开始招标采购新型攻击直升机。贝尔公司推出了YAH-63,休斯公司则拿出了YAH-64。最终美国陆军选中了YAH-64,后来发展成著名的AH-64“阿帕奇”攻击直升机。 The 20th century, the mid-70s, the main attack helicopters of the Soviet Union is famous m-24. Despite the excellent performance of the Mi-24, the leadership of the Soviet Defense Ministry said that the Mi-24 did not fully realize the “flying infantry fighting tank” design concept. Affected by the Mi-24, the U.S. Army began bidding for new attack helicopters in the early 1970s. Bell introduced the YAH-63, while Hughes came up with the YAH-64. Finally, the U.S. Army selected YAH-64 and later developed into the famous AH-64 Apache attack helicopters.