Russians traditionally have quite the knack for engineering, especially when it comes to helicopters, but when it came to this one, in an ironic twist, it was an issue of competing technologies that drove this helicopter into redundancy. In fact, you might say that they just “out-technology-ed” themselves. Considered to be the world’s largest helicopter, the wondrous flying machine could carry up to 196 passengers, or 88,000 pounds of payload.
But its downfall was that it was unable to meet missile advancements. Although huge, its purpose was deploying ballistic missiles. Missile technology moved at lightning speed and during the ’70s, and the aircraft became outdated as missiles moved forward without its help.
Hiller X-18
The Hiller X-18 was sort of the guinea pig for tilt-wing and VSTOL technology and for some time things looked hopeful. One might even call this particular flying machine a prototype for the Osprey. Sadly things took a turn and the X 18 engineers discovered that it couldn't even withstand a gust of wind.
The engines were not cross-linked, resulting in engine failure and ultimate crashing. Less ideal for planes. Too much crashing deterred production, the Hiller X-18 came to a halt and all production was ceased. It did however inspire later models and laid the groundwork for more developed technologies.
Curtiss-Wright VZ-7
Army standards are high, as they should be. Equipment, tools, and especially aircraft need to be of an impeccably high standard. This is for combat after all and things need to run as smooth as possible. When the Curtiss-Wright VZ-7 burst onto the scene, it looked like it was born for the army.
It even got the nickname "the flying jeep," and all signs pointed to "yes." No doubt that this thing was dangerous and unique, there weren't any shrouds around the propellors. Nevertheless, the military did just not approve of it and it never really saw its potential. Farewell flying jeep, you tried.
Bartini Beriev VVA-14
If this thing had a spirit animal, it would be a walrus. To be honest, at the first glance at this monstrosity, one struggles to figure out what exactly it is. Is it a boat with wings? A plane? No one is entirely certain, but one thing is clear, it looks very bizarre.
Designers from the Soviet Union developed this machine in the 1970s as a wing-in-ground-effect aircraft to take off from water and fly at high speed over extended distances. The designers meant for the plane to fly at high altitudes, as well as hovering just above the sea utilizing aerodynamic ground effect. The first flight was in September 1972. There were not that many since and now it's just an old weird plane.
North American F-82 Twin Mustang
Two heads are generally better than one, as they usually say. With this theory in mind, one would think it could be applied to plane design. And thus the North American F-82 Twin Mustang was born.
Unfortunately, things did not go according to plan and the "double P-51" that was designed as a long-range escort fighter for WWII, was called off before it was even operational.