YF-110B на испытаниях.
[подсказочка)]
Да, это МиГ-21. Если точнее МиГ-21Ф-13 от израильских друзей. Про испытания на Зоне 51 я помнил, а вот про индексы не знал.
MiG-21F-13 = YF-110B
MiG-17F "Have Drill"/"Have Ferry" = YF-113A/YF-114C
In the late 1960s the U.S. Air Force began to acquire Soviet fighter aircraft for the purpose of evaluation and air-to-air combat training. The acquistion and use of these aircraft was then highly secret, and operations were flown from the test facility at Groom Lake, Nevada (a.k.a. "Area 51"). The aircraft types flown included the MiG-17 and MiG-21 initially, and later also other MiGs (e.g. MiG-23) and presumably some Sukhoi types.
Just like any other USAF pilots, the men flying the secret aircraft had to log their flight hours in standard USAF forms (specifically, the "Form 5" flight records). These forms required the entry of the aircraft type flown, but of course you couldn't simply write "MiG-21" into that line! At some time early in the HAVE DOUGHNUT program (which evaluated the USAF's first MiG-21), someone had the idea to use "fake" cover designations, which looked like ordinary Air Force designations, but which were not used by any actual aircraft. It was decided to continue the old F-for-Fighter series of the USAF, which had reached F-111, but had been discontinued in 1962 when the DOD introduced a new joint designation system. Therefore, the numbers used were 110 (the original F-110A designation had been replaced by F-4C, so that -110B, -110C etc. were de facto unused), 112, 113, etc. All designations were prefixed by a "Y", indicating a test model. Over the years, the system of assigning YF-1xx designations was extended to U.S.-built secret aircraft as well
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