Belfast Development
To go back to the original question. The Belfast was built to continue industry employment in Northern Ireland and like most other government funded projects was not subject to proper cost control. The design used an adapted Britannia wing which was attached at a reduced dihedral angle when it should have been anhedral. This meant the lateral control close to the stall was poor such that it couldn't get a civil ticket, although the military accepted the shortcoming, thus affecting civil sales. The govt cut the order from 30 to 10 and bought Hercules. The aircraft was civil certified by Marshalls 20 years later for Heavylift, using a stick pusher for stall recovery. Also, initially, the performance was 15% down due to Reynolds number effects round the rear fuselage (ie the wind tunnel predictions were optimistic), sorted by copying the Russians and fitting underfins. (Ironically the Hercules has the same problem, still unsorted). The Belfast was also WAT limited at ISA, sea level, which meant that for any temperature above standard day or anywhere above sea level you have to offload. Answer bigger engines, never fitted as not being available. Heavylift sorted this somewhat by stripping out vast quantities of excess internal structure and trims.
"No sign of scurvy" Not apocryphal, but an actual message sent back from 366 during the first route-proving trip to the Far East, circa 1966.
Shorts were going to do a jet version with look-alike C-141 wing.
Have you noticed that the A400 is Belfast sized but with a good wing on at the right angle and proper power. The Belfast was a fine aircraft that should have had a better chance.