From Wikipedia: “The Northrop YF-17 (nicknamed "Cobra") was a prototype lightweight fighter aircraft designed by Northrop aviation for the United States Air Force's Lightweight Fighter (LWF) technology evaluation program. The LWF was initiated because many in the fighter community believed that aircraft like the F-15 Eagle were too large and expensive for many combat roles. The YF-17 was the culmination of a long line of Northrop designs, beginning with the N-102 Fang in 1956, continuing through the F-5 family.”
A copy of a very interesting article on the Northrup F-5 & YF-17 Fighter Design Philosophy. From the Air International magazine, Vol.10 of January 1976.
From Wikipedia: “Have Doughnut was the name of a Defense Intelligence Agency project whose purpose was to evaluate and exploit a MiG-21 "Fishbed-E" that the United States Air Force acquired in 1967 from Israel. Israel acquired the aircraft as the result of its Operation Diamond when, on August 16, 1966, Iraqi Air Force pilot Capt. Munir Redfa, in a defection pre-arranged by the Israeli Mossad intelligence agency, flew it to Israel during a training flight. In this multi-service project, Air Force and United States Navy pilots evaluated the MiG-21, redesignated as the "YF-110", in a variety of situations. The aircraft was referred to as "The Doughnut" due to the doughnut-shaped intake at the aircraft nose; this led to the project name "Have Doughnut". The inability of the Navy to disseminate the results of this highly classified project to combat pilots was part of the impetus to create the United States Navy Fighter Weapons School. The Have Doughnut tests were conducted at Groom Lake. A similar project occurred a year later known as Have Drill, which used a MiG-17 Fresco acquired in the same manner.”
