The Vought-Hiller-Ryan (1963) or, as it was later known, Ling-Temco-Vought (LTV) XC-142, five prototypes were built; by late 1967 only one of these remained. The initial design approached VTOL demands with a tilting wing configuration. It was designed to accommodate thirty-two fully equipped troops. An XC-142A first flew (conventionally) on 29 Sep 1964. On 11 Jan 1965 it completed its first transitional flight by taking off vertically, changing to forward flight, and finally landing vertically.
Testing of a tri-service version included carrier operations, simulated rescues, paratroop drops, and low-level cargo extraction by parachute or by 'dump-truck' techniques. Performance was not as good as had been hoped for, partly due to the USAF waiving its weight-improvement program, and partly due to the propellors not delivering the expected thrust.
Development changes included a streamlined nose, larger fuselage, upgraded engines and simplified engine maintenance. A civilianised version, the Downtowner, was proposed as a solution to airport congestion problems in the USA. This was designed to carry 40-50 passengers at a cruise speed of 290 mph using only two of its engines.