Bell XP-77

Bell XP-77
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Type	Fighter aircraft
Manufacturer	Bell Aircraft Corporation
Maiden flight	1 April 1944
Retired	December 1944
Primary user	U.S. Army Air Force
Number built	2 prototypes

The Bell XP-77 development was initiated by the U.S. Army Air Corps to produce a simplified 'lightweight' fighter aircraft using so-called "non-strategic" materials. Despite being innovative, the diminutive prototype proven tricky to handle and the project was cancelled when the XP-77 did not live up to its projected performance.

Design and development

The project with the Bell Aircraft Corporation was initiated in October 1941. Originally a design study for the P-39, the XP-77 was intended to be a small, light fighter much in the mold of the 1930s air racers. The aircraft featured a single-engine, low-wing monoplane with mainly wood construction, equipped with tricycle landing gear, a Bell trademark that bestowed good ground handling. A sleek bubble canopy also provided great visibility in all directions except forward (a key requirement for a fighter).

While originally conceived using an air-cooled 500 hp Ranger XV-770-9 twelve cylinder engine with a supercharger, the prototypes were delivered with the unsupercharged XV-770-7 engine due to development delays. The planned armament was two 20 mm cannon and two 0.5 inch machine guns, with the option of either a 300 lb bomb or 325 lb depth charge.

Testing

The project suffered numerous delays, many for correction of excess weight issues. The first XP-77 flew 1 April 1944 at Wright Field. These trials revealed vibration problems due to directly mounting the engine to the airframe, without vibration isolation. The long nose and rear-mounted cockpit inhibited visibility relative to operational aircraft of the time.

The XP-77 proved to be difficult to fly and despite flying without guns or armour, it did not come up to the expected performance estimates mainly because it was woefully underpowered. Further trials were conducted at the A.A.F. Proving Ground at Eglin Field with the second aircraft where it was destroyed due to entry into an inverted spin while attempting an Immelmann, and the pilot left his aircraft to its own devices. The development was terminated in December 1944.

Specifications (Bell XP-77)

Data from Jane's Fighting Aircraft of World War II and War Planes of the Second World War

General characteristics

• Crew: 1 pilot
• Length: 22 ft 10 in (6.96 m)
• Wingspan: 27 ft 6 in (8.38 m)
• Height: 8 ft 2 in (2.49 m)
• Wing area: 100 ft² (9.3 m²)
• Empty weight: 2,855 lb (1,295 kg)
• Max takeoff weight: 4,028 lb (1,827 kg)
• Powerplant: 1× Ranger V-770-7 inverted V12 engine, 520 hp (388 kW)

Performance

• Maximum speed: 330 mph (290 knots, 530 km/h)
• Range: 550 mi (480 nm, 890 km)
• Service ceiling: 30,100 ft (9,180 m)
• Rate of climb: 3,600 ft/min (1098 m/min)

Armament

• Guns:
  
  • 1× 20 mm (0.787 in) cannon, firing through the spinner
  • 2× .50 in (12.7 mm) M2 machine guns
• Bombs:
  
  • 1× 300 lb (140 kg) bomb or
  • 1× 325 lb (147 kg) depth charge

References

• Green, William. War Planes of the Second World War - Fighters (Vol 4). London: Macdonald, 1961.
• Jane, Fred T. "The Bell XP-77." Jane’s Fighting Aircraft of World War II. London: Studio, 1946. ISBN 1-85170-493-0.
• Winchester, Jim. The World's Worst Aircraft: From Pioneering Failures to Multimillion Dollar Disasters. London: Amber Books Ltd., 2005. ISBN 1-904687-34-2.

Related content

Comparable aircraft

• Miles M.20

Designation sequence

• P-73 - P-75 - XP-76 - XP-77 - XP-78 - XP-79 - P-80

Bell Aircraft/Bell Helicopters

Fighter aircraft: YFM-1 · P-39 · P-59 · P-63 · XP-77 · XP-83

Commercial Helicopters: 47 · 204 · 205 · 206 · 210 · 212 · 214 · 222 · 230 · 407 · 412 · 417 · 427 · 429 · 430

Military Helicopters: H-13 · UH-1 · 207 · 209 · AH-1 · 309 · YAH-63 · OH-58 · ARH-70

Tiltrotors: V-22 · BA609 · TR918 · QTR

Experimental aircraft: X-1 · X-2 · X-5 · X-20 X-22 · XV-3 · XV-15 · 533 ·