The U.S. military-industrial complex has developed a whole lot of planes because the start of World War II. As aviation engineers pushed the boundaries of known science and engineering, they occasionally veered into oddball aircraft designs truly unlike anything then or since.
A lot of these truly weird designs never entered production, but all contributed to aviation history and our knowledge of what makes a great military aircraft design… and what doesn’t.
Vought XF5U “Flying Flapjack”
America’s entry into World War II in December 1941 saw the assorted armed services funding dozens of airplane projects on an emergency basis, lots of which never entered service. Some of the notorious was the XF5U “Flying Flapjack,” an unorthodox carrier-based fighter design for the U.S. Navy.
The XF5U utilized a novel blended wing and body configuration. The pancake-shaped wings were large and captured an incredible deal of lift, allowing the aircraft to take off and land briefly distances at low speeds—ideal characteristics for carrier-based fighters. The aircraft was equipped with two Pratt & Whitney XR-2000 radial engines and, unusual for a WWII-era aircraft, twin vertical stabilizers.
Unfortunately, the aircraft was affected by technical problems and, by 1945, was becoming obsolete with the appearance of the jet-powered fighter. The aircraft was canceled in 1947.
Bell X-22 Tiltrotor
The Bell X-22 Tiltorotor was an effort to construct a compact transport aircraft for the U.S. Navy. The limited real estate on aircraft carrier flight decks prompted the Navy to explore aircraft designs that utilized a compact wing design, or no wings in any respect.
The X-22 used 4 stubby wings, each of which resulted in a General Electric YT58-GE-8B/D turboshaft engine rated at 1250 horsepower. These engines drove three-bladed propellers 6.88 feet in diameter. The result was an aircraft that might carry a crew of two and 6 passengers or 1,500 kilos of kit. The aircraft could take off and land vertically, or rotate its engines 45 degrees forward for takeoff and landing on short airfields or small spaces.
Ultimately the X-22 concept didn’t pan out: a four-engine aircraft that might only carry six people was inferior to a helicopter just like the UH-1 “Huey” that might do the identical thing on a single engine. Ducted rotor designs still haven’t made the breakthrough many predicted they’d; even now, 43 years after the X-22’s final flight, the one ducted propeller scheme in recent memory was the ducted tail rotor of the Invictus attack helicopter—also a Bell design—and even that was recently deleted from the ultimate aircraft proposal and replaced with a traditional tail rotor.
CH-54 Tarhe
The early Nineteen Sixties saw an explosion of American helicopter designs, the results of the U.S. Army showing great interest within the airmobile concept, using helicopters to ferry troops and equipment across the battlefield.
The CH-54 Tarhe was designed to hold large numbers of troops, heavy equipment, and even specialized facilities. The CH-54 was the primary helicopter built with no fuselage, to permit it to hold slung loads corresponding to howitzers and specialized modules that might carry troops, medical equipment, or headquarters. The CH-54 could even carry the M551 Sheridan light tank.
The CH-54 was a highly specialized aircraft, and although a relative success, just over 100 of the aircraft were built. An analogous variety of the business version, the S-64 Skycrane, were built. In August 2023, a S-64 crashed in Southern California while fighting wildfires.
Convair NB-36H
In 1942, Enrico Fermi, the creator of the world’s first nuclear reactor, proposed using atomic power to propel airplanes. A nuclear-powered plane would never run out of fuel and have nearly unlimited range, needing to land only to vary crews. Naturally, the U.S. Air Force, which was the first nuclear-delivery service within the wake of World War II, took a shine to the thought of a nuclear bomber able to approaching a goal from any direction, infiltrating the vastness of the Soviet Union from unexpected, under-defended angles.
In 1955, the NB-36H, a heavily modified B-36 Peacekeeper bomber, took flight for the primary time. The NB-36H featured, along with its six radial and 4 jet engines, a 20 ton, 3 megawatt air-cooled nuclear reactor. The five-person crew was shielded from radiation by 11 tons of lead and plastic. The aircraft flew 47 flights between 1955 and 1957, and the reactor was operational for 89 out of 216 hours. The reactor never actually powered the plane but was used as a proof of concept.
In the long run, the bomber’s cost, slow development time, and the risks of contamination within the event of a crash (a C-97 transport loaded with Marines tasked to secure a crash site accompanied every flight) ended the trouble to construct a nuclear-powered bomber.
Lockheed XFV
Within the early years of the Cold War, NATO military planners recognized that just as in World War I and World War II, the success or failure of a war in Europe would depend on reinforcements from North America crossing the Atlantic Ocean. Aircraft, fast and able to quickly covering vast areas of ocean, were ideal submarine predators. While inexpensive escort carriers corresponding to the Bogue-class carriers were inbuilt large numbers during World War II, they carried more aircraft than really essential.
The result was the Lockheed XFV, a tail-sitting aircraft—meaning it pointed straight up, sitting on three small wheels on the rear of the fuselage and tail fins. This enabled it to be parked just about anywhere, including on cargo ships and the helicopter flight decks of warships. The plane would essentially take off vertically like a helicopter after which fly horizontally, looking for out enemy submarines and sinking them before they might dive to safety.
Unfortunately, the XFV was plagued with problems, and this system was eventually canceled. The requirement was effectively filled in 1961 when the P-3 Orion, a maritime patrol plane with a spread of 5,500 miles, entered service.