Bell XP-77

Last updated
XP-77
Bell XP-77.jpg
Role Fighter aircraft
Manufacturer Bell Aircraft Corporation
First flight1 April 1944
RetiredDecember 1944
Primary user U.S. Army Air Forces
Number built2 prototypes

The Bell XP-77 development was initiated by the United States Army Air Forces during World War II to produce a simplified "lightweight" fighter aircraft using non-strategic materials. Despite being innovative, the diminutive prototype proved tricky to handle and the project was canceled when the XP-77 did not deliver its projected performance.

Contents

Design and development

The Tri-4 (Company designations, later changed to D-6 [1] ) project with the Bell Aircraft Corporation was initiated in October 1941. Originally a design study to meet the USAAF specifications for a "very light" interceptor, the XP-77 was intended to be a small, light fighter much in the mold of the 1930s Thompson Trophy air racers.

On 16 May 1942, the USAAF recommended the construction and testing of 25 XP-77s. [1] The aircraft featured a single-engine, low-wing monoplane with mainly wood construction, equipped with tricycle landing gear, a typical Bell feature that bestowed good ground handling. A bubble canopy also provided fair visibility except in the forward-downward direction due to the extended nose. [2]

While originally conceived using an air-cooled 500 hp (370 kW) Ranger XV-770-9 12-cylinder engine with a supercharger, the prototypes were delivered with the non-supercharged XV-770-7 engine due to engine development delays. With the anticipated delivery time of the original engine delayed for one and a half years, Bell proposed that seven XP-77s be built using the seven XV-770-7 engines then available. [1] The planned armament was one Hispano 20 mm cannon firing through the propeller hub (much like the larger caliber 37 mm moteur-canon of the SPAD S.XII) and two 0.5 inch (12.7 mm) M2 Browning machine guns, with the option of either a 300 lb (140 kg) bomb or 325 lb (147 kg) depth charge with the deletion of the cannon armament.

The mock-up inspection on 21–22 September 1942 produced some concerns from both the manufacturer and the USAAF inspection team. Weight had crept up beyond the 3,700 lb (1,700 kg) design limit but delays in the program were experienced when the company resorted to sub-contracting the wooden construction while the ongoing production at the Bell facilities did not allow for the XP-77 to take priority for research and development. Bell asked and received permission to reduce the production run of aircraft to two prototypes. [3]

Operational history

Testing

The XP-77 project continued to suffer numerous delays, many related to correction of the excess weight issues. A change in subcontractor for the wing assembly also caused headaches as the first subcontractor refused to release necessary parts. Concerns over structural integrity relating to the glue and its binding properties were also difficult to resolve. With the anticipation that contract costs would soon be exceeded, and no hope that the supercharged engine would become available, the USAAF would only continue the project as an experiment to evaluate the use of wooden construction and materials in combat aircraft. [4] The first XP-77 flew 1 April 1944 at Wright Field but the flight tests revealed vibration problems due to directly mounting the engine to the airframe, without vibration isolation. The long nose and rear-mounted cockpit also inhibited visibility relative to operational aircraft of the time.

The XP-77 proved to be difficult to fly and despite flying without guns or armor, it did not come up to the expected performance estimates mainly because it was woefully underpowered. [5] Further trials were conducted at the USAAF Proving Ground at Eglin Field with the second aircraft, which was destroyed on 2 October 1944 when it entered an inverted spin while attempting an Immelmann, and the pilot bailed out. All development was terminated in December 1944. [6]

Post-cancellation

First XP-77 post-war with spurious markings and 1947-style roundels. Bell XP-77 postwar.jpg
First XP-77 post-war with spurious markings and 1947-style roundels.

After the program's cancellation, the first prototype was sent to Wilbur Wright Field, then to Eglin Field, then back to Wright. The aircraft was seen at various airshows before being sent to an unknown air base as a gate guard. The aircraft remained on display for several years before deteriorating, after which it was burned. [6]

Specifications (Bell XP-77)

Bell XP-77 side view. Bell XP-77 SDASM.jpg
Bell XP-77 side view.

Data from Jane's Fighting Aircraft of World War II [7] and [8]

General characteristics

Performance

Armament

See also

Aircraft of comparable role, configuration, and era

Related lists

Related Research Articles

<span class="mw-page-title-main">Bell XP-83</span> Prototype escort fighter

The Bell XP-83 was a United States prototype jet escort fighter designed by Bell Aircraft during World War II. It first flew in 1945. As with most early first generation jet fighters, the design was hampered by a relative lack of power. With the rapid advancements in jet technology post-WWII, the XP-83 was soon eclipsed by more advanced designs and it never entered production.

<span class="mw-page-title-main">Bell P-59 Airacomet</span> 1942 fighter aircraft series by Bell

The Bell P-59 Airacomet was a single-seat, twin jet-engine fighter aircraft that was designed and built by Bell Aircraft during World War II, the first produced in the United States. As the British were further along in jet engine development, they donated an engine for the United States to copy in 1941 that became the basis for the General Electric J31 jet engine used by the P-59 a year later. Because the plane was underpowered, the United States Army Air Forces (USAAF) was not impressed by its performance and canceled half of the original order for 100 fighters, using the completed aircraft as trainers. The USAAF would instead go on to select the Lockheed P-80 Shooting Star as its first operational jet fighter. Although no P-59s entered combat, the aircraft paved the way for later generations of U.S. turbojet-powered aircraft.

<span class="mw-page-title-main">Curtiss-Wright XF-87 Blackhawk</span> Prototype all-weather interceptor

The Curtiss-Wright XF-87 Blackhawk was a prototype American all-weather jet fighter-interceptor, and the company's last aircraft project. Designed as a replacement for the World War II–era propeller-driven P-61 Black Widow night/interceptor aircraft, the XF-87 lost in government procurement competition to the Northrop F-89 Scorpion. The loss of the contract was fatal to the company; the Curtiss-Wright Corporation closed down its aviation division, selling its assets to North American Aviation.

<span class="mw-page-title-main">Curtiss-Wright XP-55 Ascender</span> 1943 prototype fighter aircraft

The Curtiss-Wright XP-55 Ascender is a 1940s United States prototype fighter aircraft built by Curtiss-Wright. Along with the Vultee XP-54 and Northrop XP-56, it resulted from United States Army Air Corps proposal R-40C issued on 27 November 1939 for aircraft with improved performance, armament, and pilot visibility over existing fighters; it specifically allowed for unconventional aircraft designs. An unusual design for its time, it had a canard configuration, a rear-mounted engine, swept wings, and two vertical tails. Because of its pusher design, it was sarcastically referred to as the "Ass-ender". Like the XP-54, the Ascender was designed for the Pratt & Whitney X-1800 engine, but was re-designed after that engine project was canceled. It was also the first Curtiss fighter aircraft to use tricycle landing gear.

<span class="mw-page-title-main">Consolidated Vultee XP-81</span> Prototype fighter aircraft

The Consolidated Vultee XP-81 is a development of the Consolidated Vultee Aircraft Corporation to build a single seat, long range escort fighter that combined use of both turbojet and turboprop engines. Although promising, the lack of suitable engines combined with the end of World War II doomed the project.

<span class="mw-page-title-main">Northrop XP-79</span> Prototype flying wing fighter aircraft

The Northrop XP-79, USAAF project number MX-365, was rocket and jet-powered flying wing fighter aircraft, designed by Northrop. The pilot was seated in a prone position, lying on their stomach, permitting them to withstand much greater g-forces in pitch. It also used a welded magnesium monocoque structure instead of riveted aluminum.

<span class="mw-page-title-main">Curtiss XP-46</span> 1941 prototype fighter aircraft

The Curtiss XP-46 was a 1940s American prototype fighter aircraft. It was a development of the Curtiss-Wright Corporation in an effort to introduce the best features found in European fighter aircraft in 1939 into a fighter aircraft which could succeed the Curtiss P-40, then in production.

<span class="mw-page-title-main">Curtiss P-60</span> 1941 fighter aircraft family

The Curtiss P-60 was a 1940s American single-engine single-seat, low-wing monoplane fighter aircraft developed by the Curtiss-Wright company as a successor to their P-40. It went through a lengthy series of prototype versions, eventually evolving into a design that bore little resemblance to the P-40. None of these versions reached production.

<span class="mw-page-title-main">Curtiss XP-62</span> Prototype fighter aircraft

The Curtiss XP-62 was a prototype single-engine interceptor aircraft, that was built at the request of the United States Army Air Forces, by the Curtiss-Wright Corporation. It first flew in 1943.

<span class="mw-page-title-main">Fisher P-75 Eagle</span> 1943 fighter aircraft series by General Motors Fisher Body Division

The Fisher P-75 Eagle was an American fighter aircraft designed by the Fisher Body Division of General Motors. Development started in September 1942 in response to United States Army Air Forces requirement for a fighter possessing an extremely high rate of climb, using the most powerful liquid-cooled engine then available, the Allison V-3420. The program was cancelled after only a small number of prototypes and production aircraft had been completed, as it was no longer required in its original role, could not be quickly deployed, and possessed no significant advantages over aircraft already in production.

<span class="mw-page-title-main">Grumman XP-50</span> 1941 fighter aircraft prototype by Grumman

The Grumman XP-50 was a land-based development of the shipboard XF5F-1 Skyrocket fighter, entered into a United States Army Air Corps (USAAC) contest for a twin-engine heavy interceptor aircraft. The USAAC placed an order for a prototype on 25 November 1939, designating it XP-50, but it lost the competition to the Lockheed XP-49.

<span class="mw-page-title-main">McDonnell XP-67</span> Prototype fighter aircraft

The McDonnell XP-67 "Bat" or "Moonbat" was a prototype for a twin-engine, long-range, single-seat interceptor aircraft for the United States Army Air Forces. Although the design was conceptually advanced, it was beset by numerous problems and never approached its anticipated level of performance. The project was cancelled after the sole completed prototype was destroyed by an engine fire.

<span class="mw-page-title-main">Lockheed XP-58 Chain Lightning</span> 1944 fighter aircraft prototype by Lockheed

The Lockheed XP-58 Chain Lightning was an American long-range fighter developed during World War II. Although derived from the successful P-38 Lightning, the XP-58 was plagued by technical problems with its engines that eventually led to the project's cancellation.

<span class="mw-page-title-main">Republic XP-72</span> 1944 experimental fighter aircraft

The Republic XP-72 was an American prototype fighter-interceptor developed by Republic Aircraft as a progression of the P-47 Thunderbolt design. The XP-72 was designed around the Pratt & Whitney R-4360 Wasp Major 28-cylinder air-cooled radial engine with a supercharger mounted behind the pilot and driven by an extension shaft from the engine. The armament consisted of six .50 caliber (12.7 mm) wing-mounted Browning AN/M2 machine guns and underwing racks for two 1,000 lb bombs; Alternative armament packages included two 37 mm M4 autocannons with four .50 caliber AN/M2s, or four M4 autocannons.

<span class="mw-page-title-main">Republic XP-69</span> American fighter aircraft project

The Republic XP-69 was an American fighter aircraft proposed by Republic Aviation in 1941 in response to a requirement by the United States Army Air Corps for a high-speed fighter. Manufacturers were encouraged to consider unorthodox designs; although the design was ordered as a prototype it was canceled because of delays with the engine that was to power it.

<span class="mw-page-title-main">Vultee XP-54</span> Prototype fighter aircraft

The Vultee XP-54 Swoose Goose was a prototype fighter built by the Vultee Aircraft Company for the United States Army Air Forces (USAAF).

<span class="mw-page-title-main">Northrop XP-56 Black Bullet</span> Experimental fighter intercepter aircraft by Northrop

The Northrop XP-56 Black Bullet was a unique prototype fighter interceptor built by the Northrop Corporation. It was one of the most radical of the experimental aircraft built during World War II. Ultimately, it was unsuccessful and did not enter production.

<span class="mw-page-title-main">Curtiss XP-71</span> Twin-engined fighter aircraft proposal

The Curtiss XP-71 was a 1941 American proposal for an exceptionally large heavy fighter design. It was intended to serve as an extreme-range interceptor and escort fighter. While significant progress was made in the design phase, no prototypes were ever built, and the design was abandoned in 1943.

<span class="mw-page-title-main">Douglas XP-48</span> Light fighter project for U.S. Air Force, cancelled 1940

The Douglas XP-48 was a small, lightweight fighter aircraft, designed by Douglas Aircraft in 1939 for evaluation by the U.S. Army Air Corps. Intended to be powered by a small inline piston engine, the contract was cancelled before a prototype could be constructed, due to the Army's concerns about the projected performance of the aircraft.

<span class="mw-page-title-main">Ranger V-770</span>

The Ranger V-770 was an American air-cooled inverted V-12 aircraft engine developed by the Ranger Aircraft Engine Division of the Fairchild Engine & Aircraft Corporation in the early 1930s.

References

Notes
  1. 1 2 3 Schrader 1999, p. 19.
  2. Winchester 2005, p. 187.
  3. Schrader 1999, p. 20.
  4. Schrader 1999, p. 54.
  5. Winchester 2005, p. 186.
  6. 1 2 "Bell XP-77". www.joebaugher.com. Retrieved 2022-06-14.
  7. Bridgeman 1946, p. 208.
  8. Green 1961
Bibliography