backfire, видимо даже для нее не хватало
Вот что пишут заграничные "мурзилки".
The technical issue was that the Vigilante wasn't looking very promising in the nuclear strike role anyway. The linear bomb bay scheme sounded nice on paper, but it was a nightmare in practice. The bomb bay tube ran up the fuselage between the engines, and since it was much longer the nuclear store, expendable fuel tanks were tacked on in the rear of the store. During a strike, the entire assembly was popped out the tail with an explosive cartridge driving it down launch rails. Not only did the scheme prove unreliable, the store also tended to "draft" behind the aircraft, preventing the pilot from laying it down accurately. The linear bomb bay would never actually be used in practice
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