Slide rules and punch tapes produced a working tiltrotor 30 years before the V-22 ever launched.
In the mid 50’s the US military (especially the Navy) had a dilemma–designing and producing aircraft with long range, that were more maneuverable and faster than helicopters of the era. The goal was simple: land an aircraft across a wide range of surfaces in order to better serve a variety of potential missions. Yes!…the military wanted to have their cake and eat it too.
Enter the Ling-Temco-Vought XC-142! Initially, the go-ahead was to produce five prototypes. The genius of the project was a tilt wing, designed to have long-range ability of a fixed wing, and the landing ability of a helicopter while maintaining faster speeds (Hmmm…sounds a lot like the Osprey program). Four GE T-64 Turboshaft engines provided plenty of oomph to fly combat missions, and were outfitted with four propellers to complete the design. 400 MPH meant it could get in and get out!
Early success didn’t lead to adoption
Unfortunately, the LTV XC-142 had several variables that would not cooperate…vibrations caused instability, and the wings had issues. The program was mired by these problems, and following a crash the project was scrapped. Only the five prototypes were produced, with just one intact at the National Museum of The United States Air Force at Wright-Patterson Air Force Base.