Equipped with 4 engines and a wing capable of rotating at 100 degrees. The XC-142 was developed in the early 1960s and produced in only 5 units by Vought Aeronautics in collaboration with Ryan Aeronautical and Hiller Aircraft.
Several years back, Hiller Aircraft had already created one of the very first VTOL aircraft when in 1956, the US Air Force awarded the company a contract for the production of a prototype aircraft capable of taking off vertically.
Stanley Hiller, Jr., known for designing at the age of twenty years the XH-44, one of the first American helicopters, drew the plans of the new prototype aircraft which will then be designated X-18.
To reduce costs and development time, the X-18 consists of elements borrowed from other experimental programs. The fuselage is that of a Chase YC-122 and turboprops are taken on the prototypes of Lockheed XFV and Convair XFY Pogo aircraft.
The first flight of the X-18 took place on 20 November 1959. In total, the aircraft only realized 20 test flights before suffering a severe crash in the last test flight. This accident, as well as the poor performance of the prototype, observed during the tests, lead to the cancellation of the test flights in July 1961 and the program’s definitive end some time later.
Following this failure, Hiller Aircraft Company used the knowledge it had gained with the X-18 to help develop the future XC-142 program.
In 1959, the United States Army, the Navy and the Air Force ordered the development of another short or vertical takeoff and landing aircraft, that could be complementary to the existing transport helicopters such as the Sikorsky CH-37.
To meet this order, Vought Aeronautics, Hiller Aircraft, and Ryan Aeronautical combined their knowledge and in 1961 introduced the XC-142 project, a transport aircraft capable of taking off vertically.
The XC-142 had the cargo hold of a conventional cargo plane and could carry up to 32 fully equipped soldiers. At the rear of the aircraft, Vought Aeronautics decided to put a loading ramp, which made the aircraft convenient for loading light vehicles.
It was equipped with 4 General Electric T64 turboshaft engine.
These 4 turboshafts were mounted in the tilting wings and connected by a common drive shaft so that only one engine was able to turn the 4 propellers.
To help with its stability, the aircraft also had a separate tail rotor oriented horizontally to lift the tail when needed.
In September 1961, Vought Aeronautics concept was selected by the US defense authorities, and 5 units were ordered in 1962.
The first flight tests of the XC-142 begin late September 1964. And in July 1965, the first prototype is sent to the US Air Force test team who will test it for several months in various situations. The tests carried out included among others: paratrooper drops, carrier operations, low-level cargo extraction, and simulated rescues.
End of the project
Although the XC-142 prototypes were among the most successful convertiplanes of the time, no serial production took place, and the program never went beyond the prototype phase.
In fact, because the US Navy and the US Air Force were no longer interested in the capabilities of the aircraft, the program was stopped in 1967. And the only remaining XC-142 is given to NASA for additional tests until 1970; year when the program was permanently abandoned.
40 years later, among the 5 prototypes built, only one XC-142A survived and is still visible at the National Museum of the United States Air Force near Dayton, Ohio.
Based on the unfortunate experience of the XC-142 but also its experimental aircraft XV-3, Bel company, will successfully complete the flight of its XV-15 prototype on May 3, 1977. Tested by NASA, the XV-15 is the first tiltrotor prototype that really proved the superiority of this kind of aircraft against traditional helicopters, especially in terms of speed.
Following this success, Bell will begin to develop with Boeing the V-22 “Osprey” project some years later, in 1983. The project will last about twenty years and will give birth to the first truly mass-produced VTOL aircraft.
Commissioned in 2005 and ordered at several hundred copies, the V-22 was primarily produced for the US Marine who was seeking a replacement for its CH-46 Sea Knight and part of its CH-53 Sea Stallion transport helicopters.
Today the V-22 has for customers the United States and Japan. But following delivery delays with Japan, it is currently only put into service by the US Air Force and the US Marine Corps.