From the Planes You’ve (Probably) Never Heard Of Department of Wingspan, we bring you the Bell XP-77.
In the early stages of WWII, the US was faced with two problems, one potential, and the other frighteningly real. The first was the possibility that the light metal alloys used in the construction of aircraft might become scarce, mainly because the production of these metals for aircraft could soon outstrip the country’s ability to produce them. If that became the case, then other materials would have to be used, and there was one thing the US had in abundance: wood. The second, very real problem was the Japanese Mitsubishi A6M Zero, a lightweight, agile fighter that took the Americans by surprise in the Pacific. Heavier, less maneuverable American fighters had suffered greatly in dogfights with the Zero, so a comparable, lightweight fighter might be the answer to the scourge of the Zero-Sen.
To solve both problems at once, the Bell Aircraft Corporation proposed the Tri-4 in 1941. Inspired by the small and light racers that had taken part in the Thompson Trophy air races of the 1930s, the Tri-4 was constructed mainly of wood, and its aft fuselage was made as small as possible. Bell estimated that the Tri-4, soon to be designated the XP-77, would have a top speed of 410 mph at 27,000 feet while carrying two .50 caliber machine guns and two 20mm cannons. Its thin wings allowed no room for fuel tanks, so a single tank containing just 56 gallons of fuel was placed ahead of the cockpit. Complete with a supercharged Ranger V-770 inverted 12-cylinder engine, they projected that the XP-70 would weigh no more than 3,700 pounds.
The US Army Air Corps initially ordered 25 aircraft for testing in 1942, but delays in procuring a supercharger meant that the first flight didn’t take place until 1944, by which time the USAAC had already canceled the project, as aircraft aluminum had not become scarce, and traditional fighters had come to grips with the Zero. Tests with the unsupercharged Ranger engine proved less than spectacular, with the little fighter only reaching 330 mph at 4,000 feet. Problems with the wooden wings and persistent vibrations from the engine’s being mounted directly to the airframe meant that the XP-77 was difficult to fly, even without the added weight of guns and armor plating. Though testing continued, the loss of the second prototype in a crash doomed the wooden wonder to termination in December 1944.
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