 These "guerrilla warfare in the air" tactics generally proved successful during the course of the war.In December 1966 the MiG-21 pilots of the 921st FR downed 14 F-105 Thunderchiefs without any losses.The USAF and the US Navy had high expectations of the F-4 Phantom, assuming that the massive firepower, the best available on-board radar, the highest speed and acceleration properties, coupled with new tactics, would provide Phantoms with an advantage over the MiGs.