Category Archives: Fighter

Fighter

Bell P-59B “Airacomet” (MPM Models)

TYPE: Fighter

ACCOMMODATION: Pilot only

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).

Vultee XP-54 “Swoose Goose” (Planet Models, Resin)

TYPE:  High-altitude interceptor

ACCOMMODATION: Pilot only

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).

Lockheed YP-49 (Anigrand, Resin)

TYPE: Fighter

ACCOMMODATION: Pilot only

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).

Bell Model 3 (Unicraft, Resin)

TYPE: Fighter, fighter-bomber. Project

ACCOMMODATION: Pilot only

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).

Republic P-47 D-15-RA ‘Thunderbolt’, 61 FS, 56 FG (Matchbox)

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)

Bell XP-77 (Frank-Airmodel, Vacu formed)

TYPE: Lightweight fighter

ACCOMMODATION: Pilot only

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).

Vultee XP-54 Swoose Goose (Execuform, Vacu formed)

TYPE: Long-range fighter

ACCOMMODATION: Pilot only

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).

Curtiss XP-55 Ascender (MPM)

TYPE: Interceptor fighter

ACCOMMODATION: Pilot only

POWER PLANT: One Allison V-1710-95 liquid-cooled engine, rated at 1,250 hp

PERFORMANCE: 390 mph at 19,300 ft

COMMENT: One of the most radical fighter designs to fly during WW II, the Curtiss XP-55 was evolved as a result of Circular Proposals R-40C which called for a fighter powered by the Pratt & Whitney X-1800-A3G engine which, by employing an conventional design, offered enhanced pilot visibility and armament installation, and a considerable reduction in overall drag by comparison with similar powered single-seaters of conventional configuration. An US Army Air Corps specification issued on November 1939 set forth performance requirements and, in addition to Curtiss-Wright, the Vultee and Northrop companies submitted design proposals, these eventually appearing as Vultee XP-54 and Northrop XP-56 and also employing unorthodox configurations. On July 1943 a contract was issued for three XP-55 fighters powered by the Allison V-1710, which engine was selected in preference to the Pratt &N Whitney X-1800 on the basis of reliability and availability. The first XP-55 was completed on July 1943, and flight testing began immediately. This aircraft was destroyed on November 1943 during stall tests. While the second prototype began flight test on January 1944 under restricted conditions, extensive modifications were incorporated in the third XP-55 that began flight test on September 1944. The results of these trials indicated that, in general, the handling characteristics of the XP-55 were satisfactory. A serious handicap was engine cooling which was critical during all phases of operation. The XP-55 attained a maximum speed of 377.5 mph at 16,900 ft. The official conclusions were that the performance did not compare favourably with standard production fighters and further development was abandoned (Ref.: 13)

Northrop XP-56 Black Bullet (MPM)

TYPE: Interceptor fighter

ACCOMMODATION: Pilot only

POWER PLANT: One Pratt & Whitney R-2800-29 radial engine, rated at 2,000 hp

PERFORMANCE: 465 mph at 25,000 ft (estimated)

COMMENT: After the accident of the first XP-56 prototype it was decided to re-balance the second prototype and move the center of gravity forward. Other changes included a major increase in the size of the upper vertical surface, and the incorporation of a novel form of rudder control which made use of air bellows to operate wingtip split flaps for directional control. The control of the bellows was achieved by valving air to or from the bellows by means of wingtip venturis. On March 1944 the second XP-56 was flows for the first time. Nose heaviness, relative low speeds, high fuel consumption and control instability led the N.A.C.A. to test the aircraft in the wind tunnel at Moffett field. Meanwhile, some more flight test have been performed but proved not satisfactory. It was decided that further flight test were too hazardous and after the project had been inactive for more than a year the decision was taken to abandon the project (Ref.: 13).

Northrop XP-56 (MPM)

TYPE: Interceptor fighter

ACCOMMODATION: Pilot only

POWER PLANT: One Pratt & Whitney R-2800-29 radial engine, rated at 2,000 hp

PERFORMANCE: 465 mph at 25,000 ft (estimated)

COMMENT: One of the most radical American wartime experimental fighters was Northrop’s XP-56, a unique tailless interceptor built entirely of magnesium. It was designed around the projected Pratt & Whitney X-1800 liquid cooled engine which, installed as a pusher, was to drive contra-rotating airscrews. A prototype was ordered on September 1940, but shortly after development began, Pratt & Whitney requested authority to abandon further work on the X-1800 engine. So, on July 1941, it was decided that the Pratt & Whitney R-2800-29 should be installed. In the meantime, flight trials with the Northrop N1M Flying Wing, which had an essentially similar wing of the XP-56 fighter, had confirmed the stability of the radical configuration about all three axis, and, realizing the impracticability of having only one prototype under construction, on February 1942, the U.S.A.A.F. ordered a second XP-56. Taxi trials with the first XP-56 were undertaken in April 1943 but due to many problems with the power plant the first flight was not made until September 1943. Further flights at low altitudes were completed, but during taxiing the port tire blew out and the first XP-56 was destroyed (Ref.:13).