upgrade. X-14 - USAF 56-4022 X-14A - NASA 234 (N234NA). X-14B - NASA 704 (N704NA). Surviving aircraft The X-14B was rescued from the scrap yard in 1991 and is undergoing renovation as part of the Ropkey Armor and Aviation Museum. Specifications (X-14B) See also References Further reading X-014 X-14, Bell V/STOL aircraft by thrust vectoring Twinjets NASA aircraft Mid-wing aircraft Aircraft first flown in 1957