POWER PLANT: Two Lockheed L-1000 axial-flow turbojets 2,345 kp thrust each
PERFORMANCE: 625 mph
COMMENT: The Lockheed L-133 was an exotic design started in 1939 which was proposed to be the first jet fighter of the United States Army Air Forces (USAAF) during World War II.
The radical design was to be powered by two axial-flow turbojets with an unusual blended wing-body canard design capable of 612 mph in level flight. The USAAF rejected the 1942 proposal, but the effort speeded the development of the USAAF’s first successful operational jet fighter, the Lockheed P-80 Shooting Star, which did see limited service near the end of war. The P-80 was a less radical design with a single British-based Allison J33 engine, with a conventional tail, but it retained a wing which was the same shape as the outer wing sections of the Lockheed P-38 Lightning.
The Lockheed aviation company was the first in the United States to start work on a turbojet-powered aircraft, the L-133 design started in 1939 as a number of “Paper Projects” by engineers around Clarence L. „Kelly“ Johnson. By 1940 preliminary work on a company-financed turbojet-fighter had been started, which progressed to several different versions on the drawing board. In the meantime, Lockheed was working on an axial-flow L-1000 turbojet engine of their own design, which was intended to power the culmination of the twin-engine jet fighter project, the Model L-133-02-01.
Throughout World War II, the development of a jet-powered fighter had the potential to bring a decisive advantage in the air battles of the war; as history played out, only Germany built significant numbers of jet fighters before the war ended, but they reached service in the Luftwaffe too late to make a difference.
On March 30, 1942, Lockheed formally submitted the L-133-02-01 to the USAAF for consideration. Powered by two L-1000 turbojets and featuring a futuristic-appearing canard design with slotted flaps to enhance lift, the single-seat fighter was expected to have a top speed of 612 mph in level flight, but a range of only 310 mi.
The L-133 had a main wing shape that was essentially identical to the outer wing sections of the Lockheed P-38 Lightning. In many respects the L-133 was far ahead of its time, with futuristic features including: canard layout, blended wing-body planform, and two engines in a very low-drag integral fuselage location.
The USAAF considered the L-133 to be too advanced for the time, and did not pursue the project. The experience gained with the design served Lockheed well in the development of the USAAF’s first operational jet fighter, the P-80 Shooting Star. Although entering combat service after the war had ended, the P-80 was less advanced than the L-133. Because the USAAF didn’t give the L-133 project the go-ahead, the advanced engines intended for the L-133 had long pauses in their development. The most expedient engine choice for the P-80 thus became the Allison J33, based on British centrifugal compressor designs. The P-80 was a cheap-to-build single-engine aircraft with a conventional wing and tailplane design, not using the blended wing-body and canard layout of the L-133 (Ref.:24).
POWER PLANT: One Allison J-33-A-35 turbojet engine, rated at 2,100 kp thrust
PERFORMANCE: 492 mph at 40,000 ft
COMMENT: The Lockheed P-80 Shooting Star was the first jet fighter used operationally by the USAAF. Designed and built by Lockheed Aircraft Company in 1943 and delivered just 143 days from the start of the design process, production models were flying but not ready for service by the end of WW II. Designed with straight wings, the type saw extensive combat in Korea with the United States Air Force (USAF) as the Lockeed F-80.
The prototype XP-80 had a conventional all-metal airframe, with a slim low wing and tricycle landing gear. Like most early jets designed during World War II – and before the Allies captured German research data that confirmed the speed advantages of swept-wings – the XP-80 had straight wings, similar to previous propeller-driven fighters. It was the first operational jet fighter to have its engine in the fuselage, a format previously used in the pioneering German Heinkel He 178 V1 of 1939, and the later British Gloster E.28/39 Pioneer demonstrator of 1941. Other early jets generally had two engines because of their limited power, these being mounted in external necelles for easier maintenance. With the advent of more powerful British jet engines, fuselage mounting was more effective, and it was used by nearly all subsequent fighter aircraft.
Concept work on the XP-80 began in 1943 with a design being built around the blueprint dimensions of a British Halford H-1 B turbojet (later called the de Havilland Goblin), a powerplant to which the design team did not have actual access. Lockheed’s team, consisting of 28 engineers, was led by the legendary C. L. „Kelly“ Johnson. This teaming was an early product of Lockheed’s Skunk Works, which surfaced again in the next decade to produce a line of high-performance aircraft.
The impetus for development of the P-80 was the discovery by Allied intelligence of the Messerschmitt Me 262 ‘Schwalbe’ (‘Swallow’) in spring 1943, which had made only test flights of its own first quartet (the V1 through V4 airframes) of design prototypes at that time, all fitted with retracting tailwheel landing gear. After receiving documents and blueprints comprising years of British jet aircraft research, the commanding General of the Army Air Forces, Henry H. Arnold, believed an airframe could be developed to accept the British-made jet engine, and the Materiel Command’s Wright Field research and development division tasked Lockheed to design the aircraft. With the Germans and British clearly far ahead in development, Lockheed was pressed to develop a comparable jet in as short a time as possible. Kelly Johnson submitted a design proposal in mid-June and promised that the prototype would be ready for testing in 180 days. The Skunk Works team, beginning 26 June 1943, produced the airframe in 143 days, delivering it to Muroc Army Airfield on 16 November.
The project was so secret that only five of the more than 130 people working on it knew that they were developing a jet aircraft, and the British engineer who delivered the Goblin engine was detained by the police because Lockheed officials could not vouch for him. After the engine had been mated to the airframe, foreign object damage during the first run-up destroyed the engine, which delayed the first flight until a second engine (the only other existing) could be delivered from Britain.
The first prototype was nicknamed „Lulu-Belle“ (also known as „the Green Hornet” because of its paint scheme). Powered by the replacement Halford H1 taken from the prototype de Havilland Vampire jet fighter, it first flew on 8 January 1944.The donated British jet program data had no doubt proved invaluable. In test flights, the XP-80 eventually reached a top speed of 502 mph at 20,480 ft, making it the first turbojet-powered USAAF aircraft to exceed 500 mph in level flight, following the August 1944 record flight of 502 mph by a special high-speed variant of the Republic P-47J Thunderbolt. Contemporary pilots, when transitioning to pioneering jets like the Shooting Star, were unused to flying at high speed without a loud reciprocating engine and had to learn to rely on the airspeed indicator.
The second prototype, designated XP-80A, was designed for the larger General Electric I-40 engine (an improved J31, later produced by Allison as the J33). Two aircraft were built. one was nicknamed the Gray Ghost after its “pearl gray” paint scheme, while the second aircraft was left unpainted for comparison of flight characteristics, became known as the Silver Ghost. The XP-80A’s first test flight was unimpressive, but most of the problems with the design were soon addressed and corrected in the test program. Initial opinions of the XP-80A were not positive and the aircraft were primarily testbeds for larger, more powerful engines and air intake design, and consequently were larger and 25% heavier than the XP-80.
The Shooting Star began to enter service in late 1944 with 12 pre-production YP-80As. A 13th YP-80A was modified to the sole F-14 photo reconnaissance model and lost in a December crash.
The initial production order was for 344 P-80As after USAAF acceptance in February 1945. A total of 83 P-80s had been delivered by the end of July 1945 and 45 assigned to the 412th Fighter Group (later redesignated the 1st Fighter Group) at Muroc Arma Air Field. Four were sent to Europe for operational testing (demonstration, familiarization, and possible interception roles), two to England and two to Italy, but after two accidents, one in England and one in Italy, the YP-80A was temporarily grounded. So the Lockheed Shooting Star saw no actual combat during the conflict.
After the war, the USAAF compared the P-80 and Messerschmitt Me 262 concluding, “Despite a difference in gross weight of nearly 900 kg, the Me 262 was superior to the P-80 in acceleration, speed and approximately the same in climb performance. The Me 262 apparently has a higher critical Mach number, from a drag standpoint, than any current Army Air Force fighter”.
Production oft he Shooting Star continued after the war, although wartime plans for 5,000 were quickly reduced to 2,000. A total of 1,714 single-seat F-80A, F-80B, F-80C, and RF-80s were manufactured by the end of production in 1950, of which 927 were F-80Cs (including 129 operational F-80As upgraded to F-80C-11-LO standards). However, the two-seat TF-80C, first flown on 22 March 1948, became the basis for the T-33 trainer, of which 6,557 were produced (Ref.: 24).
POWER PLANT: Two Allison V-1710-49/53 liquid-cooled engines, rated at 1,225 hp each
PERFORMANCE: 390 mph at 25,000 ft
COMMENT: The Lockheed P-38 Lightning was an American piston-engined fighter aircraft of WW II. Developed for the United States Army Ai Corps, the P-38 had distinctive twin booms and a central nacelle containing the cockpit and armament. Allied propaganda claimed it had been nicknamed the fork-tailed devil („Gabelschwanz-Teufel“) by the Luftwaffe and “two planes, one pilot” by the Japanese. Along with its use as a general fighter, the P-38 was utilized in various aerial combat roles including as a highly effective fighter-bomber, a night-fighter, and as a long-range escort fighter when equipped with drop tanks. The P-38 was also used as a bomber-pathfinder, guiding streams of medium and heavy bomber; or even other P-38s, equipped with bombs, to their targets. Used in the aerial reconnaissance role, the P-38 would account for 90 percent of the aerial film captured over Europe.
The P-38 was used most successfully in the Pacific Theater of Operations (PTO) and was the primary long-range fighter of Unites States Army Air Forces until the introduction of large numbers of North American P-51D „Mustang“ toward the end of the war.
Lockheed designed the Model 22 in response to a February 1937 specification from the United States Arma Air Corps (USAAC). Circular Proposal X-608 was a set of aircraft performance goals for a twin-engine, high-altitude aircraft having the tactical mission of interception and attack of hostile aircraft at high altitude. The Lockheed design team chose twin booms to accommodate the tail assembly, twin engines, and turbo-superchargers, with a central nacelle for the pilot and armament.
The Lockheed design incorporated tricycle undercarriage and a bubble canopy, and featured two 1,000 hp turbosupercharged 12-cylinder Allison V-1710 engines fitted with counter rotating propellers to eliminate the effect of engine torque, with the turbochargers positioned behind the engines, the exhaust side of the units exposed along the dorsal surfaces of the booms. The aircraft was the first American fighter to make extensive use of stainless steel and smooth, flush-riveted butt-jointed aluminum skin panels It was also the first military airplane to fly faster than 400 mph in level flight.
Lockheed won the competition on June 1937 with its Model 22 and was contracted to build a prototype officially designated XP-38. Construction began in July 1938, and the XP-38 first flew on 27 January 1939. After speed testing the Air Corps ordered 13 YP-38s on April 1939, these few “hand made” YP-38’s were used as trainers and test aircraft.
Delivered and accepted production variants began with the P-38D model but the first combat-capable Lightning, as the aircraft was officially named by the USAAC by adopting the British service name, was the P-38E and its photo-reconnaissance variant the F-4
The first P-38E rolled out of the factory in October 1941. Because of the versatility, redundant engines, and especially high speed and high altitude characteristics of the aircraft, as with later variants over a hundred P-38Es were completed in the factory or converted in the field to a photoreconnaissance variant, the F-4, in which the guns were replaced by four cameras. Most of these early reconnaissance Lightnings were retained stateside for training, but the F-4 was the first Lightning to be used in action in April 1942.
After 210 P-38Es were built, they were followed, starting in February 1942, by the P-38F, the first truly operational Lightning. It incorporated racks inboard of the engines for fuel tanks or a total of 910 kg of bombs. 527 machines of this subtype were buit, including several variants. Lightnings of this type took part in their first large-scale operations during the North-African campaign, in November 1942, where mixed success was encountered. The twin engines restricted manoeuverability to some extent and it was unique among fightersof WW II in employing a wheel control instead of a conventional stick, a feature which may also have resulted in reduced ease of manoeuvre. Nevertheless, it proved an effective bomber destoyer and had a sensational zoom climb that could rarely be matched.
The Lockheed P-38F Lightning had also entered service in the Pacific area. Technical difficulties associated with intercooler operations in tropical conditions prevented the Lightning from entering service until the end of 1942, however, the first major engagement with Japanese aircraft occuring on December, when the 39th Fighter Squadron claimed 15 destroyed without loss (the model shown here is a P-38F of the 39th Fighter Squadron, 35th Fighter Group).
During production a continous series of improvements were being developed by Lockheed, some of which remained experimental but others being adopted for production. Among the most important in the latter category were long-range drop tanks and manoeuvring flaps. In early 1942, all P-38 carried the same long-range 75-US gal drop tanks as the Bell P-39 Aircobra and Curtiss P-40 Warhawk, one each side between the fuselage and nacelles. But Lockheed soon developed its own 150-US gal tank, and eventually 300-US gal versions, of laminar flow design. Stressing the wing section two such tanks could be carried by all variants from the P-38F onwards. To demonstrate the capability oft he Lightning with drop tanks, a P-38F was used late in 1942, to make an endurance flight lasting over 13 hrs and covering 4.677 km, with enough fuel remaining for more than 161 km. Thus, Lightning’s ability to fly long ranges, carrying two drop tanks, now proved especially useful and the P-38 became the most-preferred fighter type operating in the Pacific area.
After production of 2,410 P-38F, -G and –H and corresponding reconnaissance variants the production switched over to the most built P-38J and –L Lightnings (Ref.: 3, 9, 24).
POWER PLANT: Two General Electric J31-GE-5 turbojet engines, rated at 750 kp each
PERFORMANCE: 413 mph at 30,000 ft
COMMENT: The Bell P-59 “Airacomet” was a twin turbojet-engine fighter aircraft, the first produced in the United States, designed and built by Bell Aircraft Corporation during WW II. The United States Army Air Force was not impressed by its performance and cancelled the contract when fewer than half of the aircraft ordered had been produced. Although no P-59s entered combat, the fighter paved the way for another design generation of U.S. turbojet-powered aircraft, and was the first turbojet fighter to have its turbojet engine and air inlet nacelles integrated within the main fuselage.
Major General H. H. “Hap” Arnold became aware of the United Kingdom’s turbojet program when he attended a demonstration of the Gloster E.28/39 in April 1941. He requested, and was given, the plans for the aircraft’s powerplant, the Power Jets W.1, which he took back to the U.S. He also arranged for an example of the engine, the Whittle W.1X turbojet, to be flown to the U.S in October 1941 in the bomb bay of a USAAF Consolidated B-24 “Liberator” along with drawings for the more powerful W.2B/23 engine and a small team of Power Jets engineers. On 4 September, he offered the U.S. company General Electric a contract to produce an American version of the engine, which subsequently became the General Electric I-A. On the following day, he approached L. D. Bell, head of Bell Aircraft Corporation, to build a fighter to utilize it. Bell agreed and set to work on producing three prototypes. As a disinformation tactic, the USAAF gave the project the designation “P-59A”, to suggest it was a development of the unrelated Bell XP-59 fighter project which had been canceled. The design was finalized in January 1942, and construction began. In March, long before the prototypes were completed, an order for 13 “YP-59A” preproduction machines was added to the contract.
In September 1942, the first XP-59A was sent to Muroc Army Air Field in California by train for testing. While being handled on the ground, the aircraft was fitted with a dummy propeller to disguise its true nature. The aircraft first became airborne during high-speed taxiing tests on October although the first official flight one day later. A handful of the first “Airacomets” had open-air flight observer later cut into the nose; over the following months, tests on the three XP-59As revealed a multitude of problems including poor engine response and reliability – common shortcomings of all early turbojets – , insufficient lateral stability, i.e., in the roll axis, and performance that was far below expectations. Chuck Yaeger flew the aircraft and was dissatisfied with its speed, but was amazed at its smooth flying characteristics. Nevertheless, even before delivery of the YP-59As in June 1943, the USAAF ordered 80 production machines, designated P-59A “Airacomet”.
The 13 service test YP-59As had a more powerful engine than their predecessor, the General Electric J 31, but the improvement in performance was negligible, with top speed increased by only 5 mph and a reduction in the time they could be used before an overhaul was needed. One of these aircraft, the third YP-59A was supplied to the Royal Air Force, in exchange for the first production Gloster “Meteor”. British pilots found that the aircraft compared very unfavorably with the turbojets that they were already flying. Two YP-59A “Airacomets” were also delivered to the U.S. Navy where they were evaluated as the YF2L-1 but were quickly found completely unsuitable for carrier operations.
Faced with their own ongoing difficulties, Bell eventually completed 50 production “Airacomets”, 20 P-59As and 30 P-59Bs; deliveries of P-59As took place in the fall of 1944. Each was armed with one 37 mm M4 cannon and 44 rounds of ammunition and three 12.7 mm machine guns with 200 rounds per gun. The P-59Bs were assigned to the 412th Fighter Group to familiarize USAAF pilots with the handling and performance characteristics of jet aircraft. While the P-59 was not a great success, the type did give the USAAF experience with the operation of jet aircraft, in preparation for the more advanced types such as the Lockheed P-80 “Shooting Star” that would shortly become available. Nevertheless, early in 1944 Bell designers began the development of a turbojet powered fighter of similar configuration as the P-59 “Airacomet” but improved performance, the Bell XP-83. But the performance was somewhat disappointing, too, and the project was cancelled, only two prototypes were built (Ref.: 8, 24).
POWER PLANT: One Lycoming XH-2470-1 liquid-cooled engine, rated at 2,300 hp
PERFORMANCE: 381 mph at 28,500 ft
COMMENT: The Vultee Company had submitted a proposal in response to a US Army Air Corps request for an unusual configuration. The Vultee design won the competition, beating the Curtiss XP-55 “Ascender” and Northrop XP-56 “Black Bullet”. Vultee designated it Model 84, a descendant of their earlier Model 78. After completing preliminary engineering and wind tunnel tests, a contract for a prototype was awarded on January 1941. A second prototype was ordered on March 1942..
The XP-54 was designed with a pusher engine in the aft part of the fuselage. The tail was mounted rearward between two mid-wing booms, with the 12-ft propeller between them. The design included a “ducted wing section” developed by the NACA (National Advisory Committee of Aeronautics) that enabled installation of cooling radiators and intercoolers in the inverted gull wing. The Pratt & Whitney X-1800 engine was initially proposed as the power plant but after its development was discontinued, the liquid-cooled Lycoming XH 2470 was substituted.
In September 1941, the XP-54 mission was changed from low altitude to high altitude interception. Consequently, a turbo-supercharger and heavier armor had to be added, and the estimated empty weight increased from 5,200 to 8,200 kg.
The XP-54 was unique in numerous ways. The pressurized cockpit required a complex entry system: the pilot’s seat acted as an elevator for cockpit access from the ground. The pilot lowered the seat electrically, sat in it, and raised it into the cockpit. Bail-out procedure was complicated by the pressurization system and necessitated a downward ejection of the pilot and seat in order to clear the propeller arc. Also, the nose section could pivot through the vertical, three degrees up and six degrees down. In the nose, two 37 mm T-9 cannon were in rigid mounts while two .50 cal. machine guns were in movable mounts. Movement of the nose and machine guns was controlled by a special compensating gun sight. Thus, the cannon trajectory could be elevated without altering the flight attitude of the airplane. The large nose section gave rise to its whimsical nickname, the “Swoose Goose”, inspired by a song about Alexander who was half swan and half goose: “Alexander was a swoose.”
Flight tests of the first prototype, Serial Nr. 41-1210, began on 15 January 1943. Initial trials showed performance to be substantially below guarantees. At the same time, development of the XH-2470 engine was discontinued and, although it appeared possible to substitute the Allison V-3420 engine without substantial airframe changes, the projected delay and costs resulted in a decision not to consider production buys.
The prototypes continued to be used in an experimental program until problems with the Lycoming engines and lack of spare parts caused termination. The second prototype, 42-108994 (but mistakenly painted as 42-1211) equipped with an experimental General Electric supercharger, only made one flight before it was relegated to a “parts plane” in order to keep the first prototype in the air (Ref.: 24).
POWER PLANT: Two Continental XI-1430-1 liquid-cooled engines, rated at 1,600 hp each
PERFORMANCE: 406 mph at 15,000 ft
COMMENT: The Lockheed XP-49 was a further development of the P-38 “Lightning” for a fighter in response to U. S. Army Air Corps proposal 39-775. Intended to use the new 24-cylinder Pratt & Whitney X-1800 engine, this proposal, which was for an aircraft substantially similar to the P-38, was assigned the designation XP-49, while the competing Grumman Model G-46 was awarded second place and designated XP-50 “Skyrocket”, US Army Air Corps version of the US Navy Grumman XF5F-1 “Skyrocket”.
Ordered in October 1939 and approved on January 8, 1940, the XP-49 would feature a pressurized cockpit and armament of two 20 mm (0.79 in) cannon and four .50 in (12.7 mm) machine guns. Two months into the contract, a decision was made to substitute the Continental XI-1430-1 (or IV-1430) for the X-1800. The XP-49 first flew on 11 November 1942. The prototype force-landed on 1 January 1943, when the port landing gear failed to lock down due to combined hydraulic and electrical system failures. The XP-49 next flew 16 February 1943, after repairs were made. Preliminary flight data showed performance was not sufficiently better than the production P-38, especially given the questionable future of the XI-1430 engine, to warrant disruption of the production line to introduce the new model aircraft. Consideration of quantity production was therefore abandoned (Ref.: 24).
POWER PLANT: One Allison V-1710-35 liquid-cooled engine, rated at 1,150 hp
PERFORMANCE: 350 mph at 10,000 ft
COMMENT: In 1936 the Bell Aircraft Corporation’s design team began work on the Bell XP-39, a radical design of a single-seat fighter with the engine mounted behind the pilot, driving the airscrew by means of an extension shaft. This arrangement appeared to offer superior manoeuvrability, the engine weight being concentrated around the fighter’s center of gravity. But the first flight test proved that this unorthodox fighter had a low ceiling, slow rate of climb and relative lack of manoeuvrability. So alternatively the engine was mounted forward and the cockpit was positioned to the back. This and some more minor changes led to the design of the Model 3. But calculations proved no advantage of this model compared to the P-39 “Aircrobra”, so the project was not further followed (Ref.: 13).
TYPE: Long-range escort-fighter and fighter-bomber
ACCOMMODATION: Pilot only
POWER PLANT: One Pratt and Whitney R-2800-21 radial engine, rated at 2,300 hp
PERFORMANCE: 433 mph at 30.000 ft
COMMENT: The Republic P-47 D ‘Thunderbolt’ differed little from its predecessor P-47 C apart from changes in the turbo-supercharger exhaust system, water injection as standard for the R-2800-21 engine, and some minor changes. The P-47 D was the first version of the ‘Thunderbolt’ to serve with the USAAF in the pacific theatre. Towards the end of 1943, 8th Air Force ‘Thunderbolts’ began returning from escort missions “on the deck”, strafing targets of opportunity with their unused ammunition, and their success was partly responsible for the adaptation of the ‘Thunderbolt’ for what was to become its most successful role – that of a fighter-bomber. More than 5,800 P-47D ‘Thunderbolts’ are built, all possessed the original framed sliding canopy introduced on the initial production B-model. Later versions were equipped with an all-round vision bubble-type cockpit canopy (Ref.: 24)
POWER PLANT: One Ranger XV-770-7 air cooled engine, rated at 520 hp, driving a two-bladed propeller
PERFORMANCE: 330 mph at 4,000 ft
COMMENT: The rapid expansion of aircraft production in the USA before WWII inevitably led to shortage in the supply of light alloy. Interest therefore began to be focused upon the substitution of non-critical materials such as wood. In October 1941discussion between USAAF personnel and engineers of the Bell Aircraft Corp began with the view of developing a lightweight “non-strategic” fighter, designated XP-77. The aircraft was a very small low wing monoplane using resin-bonded laminated wood construction with a stressed skin. The engine was a 520 hp Ranger V-770 air-cooled in-line unit that was intended to be developed in a supercharged version, the V-770-9. Six prototypes of the XP-77 were ordered in September 1942, plus two static test airframes, a mock-up and a full-scale model for wind-tunnel testing. But the lack of the supercharged engine, growth in the bare weight of the prototypes, reduced performance estimates, overrunning costs and increasing supplies of light alloys let to interest in the XP-77 programme waning during 1943. The contract was reduced to only two flying prototypes and the first of these was not ready for flight test until April 1944. Both prototypes were tested briefly by the USAAF but in December 1944 the entire development contract was terminated, the consensus of opinion being that the XP-77 was operationally unsuitable and that its performance showed no improvement over heavier fighters of conventional construction (Ref.: 8).
POWER PLANT: One Lycoming XH-2470-1 liquid-cooled engine, rated at 2.300 hp
PERFORMANCE: 381 mph at 28,500 ft
COMMENT: The Vultee XP-54 had its origin in the US Army Air Corps Circular Proposal R-40C, which invited manufacturers to submit designs for fighters of high prospective performance, without the customary limitations on design orthodoxy. Besides Curtiss (XP-55 Ascender), Northrop (XP-56 Black Bullet), and McDonald (XP-67 Moon Bat) Vultee Field Division of Consolidated Vultee Aircraft Co submitted its design Model 78. This aircraft was powered by an Allison V-1710 (without supercharger) or Pratt & Whitney X-1800 engine driving a pusher propeller, and with a twin-boon layout. A unique feature was that the whole nose section could be varied in elevation to permit compensation for range of the guns it contained. Movement of this nose section was linked to a special compensating gun sight. A contract for the Vultee design, officially XP-54, was placed on June 1940 and the order for a prototype was given at the end of that year, followed by an order for a second prototype on March 1942. The supercharged Lycoming H-2470 engine was chosen to replace the X-1800 when the latter was discontinued. Work on the XP-54 made slow progress during 1942 and the first prototype did not fly until January 1943. It quickly became apparent that the top speed was as much as 100 mph below estimate, partly because the Lycoming engine was not performing as planned. Although substitution of Allison V-3420 was considered as an alternative for the XP-54, this effectively brought the Vultee fighter program to an end (Ref.: 9).
Scale 1:72 aircraft models of World War II
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