The Bell XP-77 fighter was to have relied on non-strategic materials in its construction - only two prototypes were built.
Authored By: Staff Writer | Last Edited:
The deteriorating war situations in both Europe and the Far East during World War 2 began forcing American warplanners to think through to a possible direct war with one of the Axis powers. the war could very well restrict strategic war materials (oil, metals, etc...) and therefore cripple mass production efforts of weapons - particularly aircraft. Thus it fell to American aviation engineers to undertake development of a new "resource-friendly" fighter that would make heavier use of "non-strategic" materials for the lengthy war commitment that potentially lay ahead.
Bell Aircraft began work on such a proposal for the U.S. Army outlining a dimensionally compact, single-seat, single-engine fighter to be constructed largely of wood and under very quick and inexpensive conditions. The proposal was submitted to Army authorities on October 30th, 1941 - just two months before America's formal entry into World War 2.
Bell's approach brought about a most contained, streamlined form designed with inherent agility and speed suitable for clashing with the thoroughbreds fielded by the Empire of Japan and Nazi Germany - namely the Mistubishi A6M "Zero" and the Messerschmitt Bf 109 respectively. The aircraft would incorporate a long, yet slender, nose assembly housing the engine with a triangular cross-section fuselage. The cockpit was to be set aft of amidships due to the restrictive internal volume provided and a conventional tail unit would completed the aircraft's side profile with a single vertical tail fin and low-set horizontal planes The mainplanes of the aircraft would be straight in their general shape with clipped tips and mounted low along the sides of the fuselage. A high-aspect ratio wing was envisioned with a single spar in play. Internally, each wing would make use of wooden ribbing and held together through nails and glue. A resin/plastic bonded skin would cover the entire surface while itself being coated in a cotton fabric-based blend. In keeping with Bell's previous fighter designs, the undercarriage would be of the non-traditional tricycle arrangement featuring a single-wheeled nose leg under the engine compartment and a pair of single-wheeled main legs under each wing. Proposed armament was a single 20mm cannon firing through the propeller hub along with 2 x 0.50 caliber Browning M2 heavy machine guns, 200 rounds afforded to these two guns.
One of the primary concerns found with the project was the slim fuselage required which limited engine selection. This left the only choice to become the still-in-development and unproven Ranger-brand V-770 12-cylinder, air-cooled supercharged system of 500 horsepower output for the role. Coupled with the aircraft's small footprint, performance estimates envisioned a maximum speed reaching 400 miles per hour. The engine drove a simple two-bladed propeller.
On May 16th, 1942, with American fully-committed to war by now, the U.S. Army commissioned for 25 of the promising mini-fighters - given the designation of "XP-77". However, one revision called for support of a single 300lb bomb fitted under fuselage centerline for the ground attack role. Additionally, the hardpoint would have to support the carrying of a 325lb naval depth charge for hunting enemy submarines - the U-boats a great threat to American shipping along both coasts.
Additional problems were brewing when Ranger was unable to keep its V-770-9 commitment and offered the V-770-6 which was already in use with United States Navy service aircraft. While the V-770-6 engine could supply the needed 500 horsepower output, is performance dropped significantly above 12,000 feet - a detrimental quality for a fighter. The engines were not supercharged which did not help matters.
With the war progressing and the XP-77 falling further and further behind schedules (and its developmental costs rising), the U.S. Army returned to reduce their original 25-strong order to just six aircraft. With some life still being felt in the product, Bell sought to reduce the increasing weight of its little aircraft which led to the nixing of the 20mm cannon. The U.S. Army called again and reduced their order to just two aircraft - ringing the death knell for the machine. it also dropped all interest in the Ranger V-770-9 series engine.
Despite its early design start in the war, the completed XP-77 prototype did not record its first flight until April 1st, 1944. The U.S. Army had grown quite content with their stable of fighters and even Bell's interest on the product had waned as it attempted to fulfill various military orders for its other proven aircraft. When it finally did enter flight testing, the design proved a flawed one - stability issues were apparent and excessive vibrations noted along the airframe. Pilots noted a cramped and noisy cockpit and they were further restricted from conducting violent, aggressive maneuvers. Additionally, views from the pilot's seat were blocked by the long nose and the cockpit's placement behind and above the wings.
Two flyable prototypes were eventually completed and these served in testing at both Wright Field and Elgin Field. During one landing run, a prototype saw its nose leg collapse. in another flight, the aircraft entered into an uncontrollable spin, forcing the pilot to bail out -the aircraft crashed.
It was the crash that signaled the complete end to the XP-77 program and no more of it was furthered. Regardless, the Army held no need for the little aircraft anymore and the tide had finally turned in favor of the Allies. The surviving prototype was retained as a outdoor showpiece before time took its toll. From there, its weathered body was taken away and burned.
[ 2 Units ] : bell Aircraft Corporation - USA
- X-Plane / Developmental
22.83 ft (6.96 m)
27.49 ft (8.38 m)
8.20 ft (2.5 m)
(Showcased structural dimension values pertain to the Bell XP-77 production model)
2,866 lb (1,300 kg)
4,034 lb (1,830 kg)
(Showcased weight values pertain to the Bell XP-77 production model)
1 x Ranger V770-7 V12 engine developing 520 horsepower.
(Showcased powerplant information pertains to the Bell XP-77 production model)
329 mph (530 kph; 286 kts)
30,118 feet (9,180 m; 5.7 miles)
553 miles (890 km; 481 nm)
1,100 ft/min (335 m/min)
(Showcased performance values pertain to the Bell XP-77 production model; Compare this aircraft entry against any other in our database)
1 x 20mm Hispano-Suiza HS.404 cannon in propeller hub.
2 x 12.7mm M2 Browning machine guns
1 x 300lb bomb or 325lb naval depth charge under fuselage centerline.
(Showcased armament details pertain to the Bell XP-77 production model)
XP-77 - Project model designation; 2 prototypes completed.
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