This experiment in flight innovation by Grumman for NASA and the U.S. Air Force plainly flopped. Built with wings that look backward, called forward-swept wings, this design feature of the X-29 was supposed to optimize handling and maneuverability. Jet fighting at supersonic high speeds, with tight turns, even with the nose pointing straight up, was to be a breeze in the Grumman X-29. As it turned out, pilots could not even command the beast without autopilot.
While computer flight control is a miracle of aeronautics, the Grumman X-29 was unmanageable without it. The plane became completely unstable, no pilot could fly it. The experimental plane flew a total of 436 test flights and remained an active program from 1984 to 1992. Yet, while the aerodynamics of the X-29 failed, the research the aircraft provided was a boon to fighter jet technology.
The Rockwell XFV-12
The Rockwell XFV-12 is another experiment in vertical takeoff and landing (VTOL) that wound up in the dustbin. The futuristic-looking jet fighter was a sleek machine and a promising concept, but the Navy decided it was a failure and scraped the project in 1981 before the aircraft was ever able to lift off the ground and fly, literally burdened by its own weight. With costs ballooning and other developments, like the Harrier showing success, the Rockwell XFV-12 was let go.
Relegated to the dustbin of military technology, the two prototypes are now stored in a hangar somewhere. The ill-fated XFV-12 has yet to be preserved by any aeronautics or military air museum.
The Baade 152
German engineer Brunolf Baade was the mastermind behind the idea of converting a WWII jet bomber into a passenger airliner after the war ended and the need for bombers evaporated. VEB Flugzeugwerke Dresden took up Baade’s plan to build Germany’s first airliner. Three Baade 152s were built and testing at the Dresden Airport commenced in 1956.
During testing, an entire crew was lost after the airliner crashed on March 4, 1959. Continued testing revealed an issue with fuel supply had caused the plane to malfunction. The program was canceled, and no airliners went into production.
The Lockheed XFV-1 Salmon
In the 1950s, experimentation in VTOL technology was pursued by all of the world’s major militaries. The Lockheed XFV-1 was designed to take off and land from a tail mounted position. The U.S. Navy ordered the concept craft and Lockheed delivered two prototypes. In 1953, the first aircraft was named after its original test pilot, Herman Salmon.
Sitting on its tail, with three blades of contra-rotating propellers, the Salmon looked like a freak of nature, but could it perform? Short answer, no. It handled very poorly, and not even the pilot it was named after liked it. The powerful trio of propellers were difficult to control and they were the only option for landing or takeoffs. In the end, after 32 test flights, the Salmon was unable to make any VTOL maneuvers. The project was shelved by 1955.
The McDonnell XF-85 Goblin
This cute little guy was easy to fly, stable, and could recover from spins effortlessly. The McDonnell XF-85 Goblin was the smallest jet fighter ever built. But it wasn’t designed to land, and it could not takeoff from the ground. The Goblin was conceived as a fighter escort to large bombers as back up fighting power. To this end, it was stored in large bombers like the B-36 in case of an attack. The Goblin was then launched from the bomber's belly and dropped into combat.
The only problem was it didn’t work. The Goblin was easily lowered into flight from the mother ship, but issues arose when it was to be hooked and raised by a tether back into the ship. On a test flight, pilot Ed Schoch made three attempts to reconnect with the retractable tether. On the final try, the little jet fighter smashed into the tether so forcefully the plane was damaged and had to make an emergency skid landing. After seven attempts to re-tether produced just three results, the test program ended. One of the surviving two Goblins is interned at the U.S. Air Force Museum at Wright-Patterson air Force Base in Ohio.