Like with all great failures, the intention is grand. Built with the goal of combining the speed of a jet with the take-off abilities of a helicopter, the mechanics of this sadly, did not work out as and the aircraft production program as called off.
In 1988 the Sikorsky X-Wing came to an end. Long after its first successful prototype.
Handley Page Victor
This insect-like jet called the Handley Page Victor has an assuming look, that one might be surprised to learn that it's actually a high-powered strategic bomber jet. The first take-off happened in December 1952, but for the next few decades, engineers started to discover a fundamental flaw that resulted in fatigue cracks, worsened form the low altitude flights to avoid being intercepted.
Production was then called off in 1993, which is quite a long time considering the issues. Many of the functional Victors were re-appropriated to become ariel refueling tankers. Technical problems assist, the fact that it looks like a praying mantis is a questionable choice of design.
Vought V-173 "Flying Pancake"
Here's a crazy design that you would expect more on your plate than in the sky. The "Flying Pancake" as it is aptly called was designed during a time where the U.S observed an increased demand for ship-borne planes that could take off from shorter runways
The inexplicable shape was even once flown by the legendary Charles Lindberg. Considering the design, the great pilot actually said it handled a little better than expected, but it looked ridiculous and thankfully, they fell away after some time.
Blohm & Voss BV 141
The Blohm & Voss BV 141 is a strong reminder that balance and symmetry are not essential factors when creating an aircraft, though the thought of that fully defies all logic. This Germa flying machine, designed in the WWII-era was created as a reconnaissance aircraft.
But even after the initial success and the building of the first few dozen, it lost out to a competitor and never reached completion. At least it had its 15 minutes of fame, sadly that was not enough to keep it afloat. literally and figuratively speaking.
The Pregnant Guppy
Talk about chunky. This monster of a plane was once created in order to ship components for NASA's Apollo moon mission. Needless to say, this terribly clumsy aircraft was abandoned soon after production. Only one plane was ever created. First taking off September 19, 1962, it was then retired in 1979. It was also aptly the Pregnant Guppy.
Pregnant it was indeed, pregnant with clunky materials and a hefty production cost that proved to ultimately be too much of a burden.