Hiller X-18 V/STOL experimental cargo aircraft

Pics via Enrique 262 Tumblr Page.

Hiller X-18 V/STOL experimental cargo aircraft, the first tiltwing technology demonstrator, nicknamed the Propelloplane by its manufacturer. 

Only one unit was produced in 1959, which was cheaply made with parts salvaged from other experimental aircraft, and since it was an entirely new concept, it suffered from loads of issues that eventually led to the cancellation of the program only 20 flight tests latter. Nevertheless, the lessons learned from it helped pave the way for more advanced american V/STOL designs, which could come in the following years.

General characteristics

Crew: 2-3

Length: 63 ft 0 in (19.2 m)

Wingspan: 47 ft 11 in (14.6 m)

Height: 24 ft 7 in (7.5 m)

Empty weight: 26,786 lb (12,150 kg)

Max takeoff weight: 33,000 lb (14,969 kg)

Powerplant: 2 × Allison T40-A-14 coupled turboprop engines, 5,500 hp (4,100 kW) each

Powerplant: 1 × Westinghouse J34 turbojet, 3,400 lbf (15 kN) thrust for reaction jet pitch control

Propellers: 6-bladed Aeroproducts, 14 ft (4.3 m) diameter contra-rotating propellers

Performance

Maximum speed: 253 mph (407 km/h; 220 kn)

Service ceiling: 35,300 ft (10,759 m)

Can anyone explain why tilt wing lost out to tilt rotors in the development race?