Kawasaki Ki-100-I Otsu, 5th Sentai (Hasegawa)

TYPE: Fighter

ACCOMMODATION: Pilot only

POWER PLANT: One Mitsubishi Ha 112-II radial engine, rated at 1,500 hp

PERFORMANCE: 360 mph at 19,700 ft

COMMENT: In mid-1944, the Kawasaki Ki-61”Hien” (Allied code “Toni”) was one of the best fighters of the Imperial Japanese Army Air Service. It was the only production Japanese fighter to have an in-line Kawasaki Ha-40 power plant, a Japanese adaptation of the German Daimler-Benz DB 601 engine, as well as the first one with factory-installed armor and self-sealing fuel tanks. It also had respectable performance, more in line with contemporary American and European designs of the time, with speed and rate of climb emphasized instead of maneuverability and range. It was an effective design, but suffered from engine shortages and reliability problems.
hese problems as well as the performance advantage of enemy fighters, especially the Grumman F6F “Hellcat”, led to the development of an improved model, the Ki-61-II (later Ki-61-II-KAI), powered by the new 1,500 hp Kawasaki Ha 140 engine, which was unfortunately heavier than the Ki-61-I-KAIc it replaced. Maximum speed increased from 370 to 380 mph as well as general performance. However, it was never able to perform as planned due to the continued degradation of quality of the engine’s assembly line, with far fewer engines produced than were required, while many of the engines that were built were rejected due to poor build quality. At this point of the war, the IJAAF was in desperate need of effective interceptors to stop the enemy bomber raids over the Japanese mainland, so in October 1944 it was ordered that a 1,500 hp Mitsubishi Ha 112-II “Kinsei” (“Venus”), a 14-cylinder, two-row radial engine should be installed in those airframes. The need for the re-engined fighter was made yet more urgent on January 1945, when a Boeing B-29 “Superfortress” raid destroyed the engine’s production plant, leaving 275 finished Ki-61s without a power plant.
The Mitsubishi Ha-112-II was some lighter than the Ha-140 and produced the same power more reliably. After the study of an imported German Focke-Wulf Fw 190, an example of an aircraft in which a wide radial engine had been successfully installed in a narrow airframe, three Kawasaki Ki-61-II-KAI airframes were modified to carry this engine and to serve as prototypes.  As a result, on February 1945, the new model, Kawasaki Ki-100, was flown for the first time. Without the need for the heavy coolant radiator and other fittings required for a liquid-cooled engine, the Ki-100 was lighter than the Ki-61-II, resulting in a reduction of wing loading. This had an immediate positive effect on the flight characteristics, enhancing landing and takeoff qualities as well as imparting increased maneuverability, including a tighter turning circle.
The army general staff was amazed by the flight characteristics of the plane, which surpassed the Ki-61 in all but maximum speed (degraded by a maximum of 18 mph]by the larger area of the radial engine’s front cowling, and the model was ordered to be put in production. The company’s name was Ki-100-1-Ko. All of the airframes were remanufactured from Ki-61-II Kai and Ki-61-III airframes; the integral engine mount/cowling side panel was cut off the fuselage and a tubular steel engine mount was bolted to the firewall/bulkhead. Many of the redundant fittings from the liquid-cooled engine, such as the ventral radiator shutter actuator, were still kept. The first 271 aircraft, or Kawasaki Ki-100-1-Ko, with the raised “razorback” rear fuselage were rolled out of the factory between March and June 1945. A further 118 Ki-100 I-Otsu are built with a cut-down rear fuselage and new rear-view canopy from May through to the end of July 1945. This version also featured a modified oil cooler under the engine in a more streamlined fairing. In total 396 Kawasaki Ki-100 were built before Japan surrendered (Ref.: 24).

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).

Messerschmitt Me 262 V1 (Frank-Airmodel, Vacuformed)

TYPE: Prototype of Me 262

ACCOMMODATION: Pilot only

POWER PLANT: Two BMW P.3302 (BMW 003) turbojet engines, rated at 550 kp thrust each, plus one Junkers Jumo 210G liquid-cooled engine, rated at 720 hp

PERFORMANCE: 350 mph

COMMENT: Several years before World War II, the Germans foresaw the great potential for aircraft that used the turbojet engine constructed by Hans Joachim Pabst von Ohain, engineer with the Heinkel Company, in 1936. After the successful test flights of the world’s first jet aircraft—the  Heinkel He 178, Messerschmitt and his design bureau adopted the turbojet engine for an advanced fighter aircraft. As a result, the Messerschmitt Me 262 was already under development as “Projekt 1065” (P.1065) before the start of World War II. The project originated with a request by the Reichsluftfahrtministerium (RLM, Ministry of Aviation) for a turbojet aircraft capable of one hour’s endurance and a speed of at least 530 mph. Dr. Waldemar Voigt headed the design team, with Messerschmitt’s chief of development, Robert Lusser, overseeing.
Plans were first drawn up in April 1939, and the original design was very different from the aircraft that eventually entered service, with wing root-mounted engines, under development by BMW as 003 or by Junkers as Jumo 004, rather than podded ones, when submitted in June 1939. The progression of the original design was delayed greatly by technical issues involving the new turbojet engine. Because the engines were slow to arrive, Messerschmitt moved the engines from the wing roots to underwing pods, allowing them to be changed more readily if needed; this would turn out to be important, both for availability and maintenance. Since the BMW 003 jets proved heavier than anticipated, the wing was swept slightly, by 18.5°, to accommodate a change in the center of gravity. Funding for the turbojet engine program was also initially lacking as many high-ranking officials thought the war could easily be won with conventional aircraft.
Test flights began on 18 April 1941, with the Me 262 V1 example, bearing its “Stammkennzeichen” (radio code letters) of PC+UA, but since its intended BMW 003 turbojets were not ready for fitting, a conventional Junkers Jumo 210 piston engine was mounted in the V1 prototype’s nose, driving a propeller, to test the Me 262 V1 airframe. After successful trials demonstrating good flying characteristics of the design two prototypes of the BMW P.3302 turbojet engines, forerunner of the BMW 003 turbojet engine, were installed.  The Jumo 210 piston engine was retained for safety, which proved wise – so often reported in literature – as both turbojet engines failed during the first flight and the pilot had to land using the nose-mounted engine alone. Original test-flight protocols published some years ago show reasonable doubt on that report.
In total the Messerschmitt Me 262 V1 successfully completed 74 flights but only one under turbojet power. The prototypes V2 through V4 were purely turbojet driven, but with the more powerful Junkers Jumo 004 turbojet engines.
The V1 through V4 prototype airframes all possessed what would become an uncharacteristic feature for most later jet aircraft designs, a fully retracting conventional landing gear setup with a retracting tailwheel. Indeed, the very first prospective German “turbojet fighter” airframe design ever flown, the Heinkel He 280, powered by a Heinkel HeS 8A turbojet engine, used a retractable tricycle landing gear from its beginnings, and flying on turbojet power alone as early as the end of March 1941. From prototype Me 262 V6 onwards all aircraft featured a fully-retractable, hydraulically-operated tricycle undercarriage. Dubbed unofficially the “Schwalbe” (“Swallow”), the first production sub-type off the new warplane, the Messerschmitt Me 262A-1a single-seat interceptor fighter entered service with the “Erprobungskommando (EKdo) 262” at Lechfeld in July 1944  (Ref.: 7, 24).

Mitsubishi Ki-200 “Shusui” (“Sharp Sword”) (Hasegawa)

TYPE: Interceptor

ACCOMMODATION: Pilot only

POWER PLANT: One Toku-Ro.2 /KR10) bi-fuel liquid rocket, rated at 1,500 kp thrust

PERFORMANCE: 559 mph at 32,808 ft

COMMENT: The Mitsubishi J8M “Shūsui” (literally “Autumn Water”, used as a poetic term meaning “Sharp Sword” deriving from the swishing sound of a sword) was a Japanese WW II rocket-powered interceptor aircraft closely based on the German Messerschmitt Me 163 “Komet” (Comet”). Built as a joint project for both the Japanese Navy and the Army Air Services, it was designated J8M (Navy) and Ki-200 (Army).
The Ki-200 and the J8M1 differed only in minor items, but the most obvious difference was the JAAF’s Ki-200 was armed with two 30 mm Type 5 cannon (with a rate of fire of 450 rounds per minute and a muzzle velocity of 720 m/s, while the J8M1 was armed with two 30 mm Ho-105 cannon (rate of fire 400 rounds per minute, muzzle velocity 750 m/s). The Ho-105 was the lighter of the two and both offered a higher velocity than the German MK 108 cannon of the Messerschmitt Me 163 (whose muzzle velocity was 520 m/s).
The Toko Ro.2 (KR10) rocket motor did not offer the same thrust rating as the original, and Mitsubishi calculated that the lighter weight of the J8M1 would not offset this. Performance would not be as good as that of the Me 163 “Komet”, but was still substantial. The engine still used the German propellants of T-Stoff oxidizer and C-Stoff fuel (hydrogen peroxide/methanol-hydrazine), known in Japan as “Ko” and “Otsu” respectively.
At the end of the war “Shusui” production was already under way. Additionally, the Navy had instructed Mitsubishi, Nissan and Fuji to design a further Navy version as J8M2 with only one cannon thus giving additional space for more fuel and by that more endurance, while the Army ordered Rikugun Kokugijutsu Kenkyujo the development of an enlarged version of the Ki-200 with increased fuel tankage, known as Rikugun Ki-202 “Shusui Kai” to be built by Mitsubishi (Ref.: 1, 24).