All posts by Gunther Arnold

Fighter, Projects

Kugisho High-Speed Aircraft Project with DB 601A (Unicraft Models, Resin)

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TYPE: High speed fighter project

ACCOMMODATION: Pilot only

POWER PLANT: One Daimler-Benz DB 601A liquid-cooled engine, rated at 1,159 hp

PERFORMANCE: No data available

COMMENT: Every aircraft creator seeks to reduce drag in their designs. The more drag, the slower the aircraft moves through the air due to the resistance. Drag cannot be completely removed from a design, but even in the early years of aviation various methods for minimizing drag were investigated and many different solutions were tried.
Not surprisingly, such applications were valued by those providing the military with aircraft and in Japan, prior to the outbreak of hostilities with the US, the Dai-lchi Kaigun Kok[ Gijutsu-sho (Yokosuka Naval Air Technical Arsenal, Kugisho) would study such efforts in an attempt to produce fast flying aircraft.
With the war clouds looming on the horizon, the seeds planted by the air racers of the 1920s and early 1930s were germinating in the aircraft used by the air forces of the major powers. Designs by Curtiss for the US Army Air Force were influenced by the Curtiss racers while the retractable landing gear of the 1920 Dayton Wright RB racer would become a hallmark of Grumman aircraft such as the F2F. In Great Britain, R. J. Mitchell would draw heavily from his experience designing Schneider Trophy racers to build the Supermarine Type 300 which would eventually evolve into the Supermarine Spitfire.
On 26 April 1939 German test pilot Fritz Wendel flew to a new world speed record of almost 469 mph with a Messerschmitt Me 209. The Me 209 was solely designed to break speed records and was a completely separate aircraft from the Messerschmitt Bf 109 that entered service with the German Luftwaffe at that time. It shared only its Daimler-Benz DB 601 liquid-cooled engine with the Bf 109.
Consequentially, Japan sought to produce racing aircraft and planes designed to beat world speed records. In 1938, a group of designers sought to produce a high-speed aircraft to challenge the world air speed record. Once war had broken out this aircraft, called the Ken lll, was soon taken over by the Imperial Japanese Army (IJA). Redesignated the Ki-78, its development was continued under Kawasaki. During this time, it may have been the Imperial Japanese Navy (IJN) who decided to conduct its own studies of high speed aircraft with Kugisho assigned the task of doing so. Whether the studies were initiated in response to the IJA’s own high-speed aircraft project is unknown but the prevalent aircraft design philosophy of both the IJN and the IJA prior to the war was of speed, agility and range at the expense of fire- power, durability and protection.
Kugisho examined over half a dozen aspects of aerodynamics in order to produce data on what would be needed to realize an aircraft capable of significant speed. One leading point of research was the main wings. The shape of a wing is one of the more critical aspects of aircraft design. Factors such as wing loading, expected air speeds, angles of attack and the intended use of the aircraft all influence how the wing is shaped. For high speeds, a low aspect ratio wing is often considered. Typically, these are short span wings with the benefits of higher maneuverability and less drag. In addition, having a backward sweep to the wing also lowers drag. The drag most associated with wings is termed induced drag, which is caused by wing tip vortices that change how the air flows over the wings. This change results in less and less lift which then requires a higher and higher angle of attack to compensate and, from this, induced drag results. Elliptical wings offer less induced drag than more conventional straight wings. However, low aspect ratio wings are more prone to larger vortices because they cannot be spread out across a longer wing.
Kugisho’s study on wing shapes was the likely result of testing various airfoils in a wind tunnel to determine their effectiveness and record the results. Another aspect Kugisho engineers reviewed were the merits and flaws of using either an inline or a radial engine and how each type reduced the form drag. In both cases the engineers drew up two concept aircraft and each made use of streamlining. Streamlining is the process of shaping an object, in this case, a fuselage, to increase its speed by reducing the sources of drag.
One concept used the German 1,159hp Daimler-Benz DB 601A, a 12-cylinder, inverted-V, liquid-cooled, inline engine. This engine would be license built for the IJN as the Aichi AEl Atsuta (the ‘A’ stood for Aichi, ‘E’ for liquid-cooled and ‘l’ for first liquid-cooled engine.  Atsuta was a holy shrine in Aichi Prefecture) and for the IJA as the Ha-40, before it was renamed the [Ha-60] 22.
The second concept aircraft (Kugisho High-Speed Aircraft Project with NK-1B) used a 1,000hp Nakajima NKlB Sakae 11 which was a 14-cylinder, air-cooled, radial engine. This engine was a license version of the French Gnome-Rhone l4K Mistral Major (in engine nomenclature, the ‘N’ was for Nakajima, ‘K’ for air-cooled, ‘1’as the first air-cooled engine, while the ‘B’ was for the second version of the NKl; Sakae means prosperity in Japanese).
Kugisho would use the same basic airframe for the engine study. It consisted of a well streamlined fuselage with the pilot mounted in a cockpit set behind the wing and just forward of the vertical stabilizer. This style was found in a number of racing aircraft such as the American GeeBee Rl and Geebee Z. Both aircraft used a standard tail-sitter configuration for the landing gear. The concept equipped with the DB 601A engine had a fuselage shape that was not unlike the Kawasaki Ki-61 Hien (“Swallow”, codenamed “Tony” by the Allies) which would appear in prototype form in December 1941 . The wings were mounted low on the fuselage. The fuselage appearance was due to the inverted-V engine which, by design, offered lower height, weight and length when compared to more conventional engines.
By contrast, the concept using the Nakajima NKlB had a more ovoid fuselage shape, the result of the height of the radial engine. To maintain the aerodynamic streamlining a large spinner was used. Also, in contrast to the DB 601A equipped design, the wings were mounted mid-fuselage.
Kugisho would not produce any direct prototype aircraft from either concept. lnstead, results of the various studies were likely kept available as reference for engineers to access as a means of obtaining data on the aerodynamic problem. Perhaps Kugisho in hindsight considered themselves fortunate to not have expended additional expense and effort in producing working prototypes given the failure of the IJA’s Kawasaki Ki-78, a program that lingered on into 1944 and never met its design goals (Ref.: Dyer III, Edwin M.: Japanese Secret Projects, Experimental Aircraft of the IJA and IJN 1939-1945, Midland Publishing, Hersham, U.K., 2010).

Trainer

Dornier Do 335A-12 “Ameisenbär” (Anteater”), (Dragon)

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TYPE: Trainer aircraft

ACCOMMODATION: Pilot and Instructor

POWER PLANT: Two Daimler-Benz DB 603A-2, rated at 1,726 hp each

PERFORMANCE: 430 mph at 17,400 ft

COMMENT: The Dornier Do 335 “Pfeil” (“Arrow”) was a WW II heavy fighter built by the Dornier company. The two-seater trainer version was unofficially called “Ameisenbär (“Anteater”). The Do 335s performance was much better than other twin-engine designs due to its unique push-pull configuration and the lower aerodynamic drag of the in-line alignment of the two engines. It was Germany’s Luftwaffe fastest piston-engine aircraft of World War II. The Luftwaffe was desperate to get the design into operational use, but delays in engine deliveries meant that only a handful were delivered before the war ended.
The Dornier Do 335 V1 first prototype flew for the first time on October 1943. However, several problems during the initial flight of the Do 335 would continue to plague the aircraft through most of its short history. Issues were found with the weak landing gear and with the main gear’s wheel well doors, resulting in them being removed for the remainder of the V1’s test flights. The Do 335 V1 made 27 flights, flown by three different pilots. During these test flights the second prototype Do 335 V2 was completed and made its first flight on end December 1943. New to the V2 were upgraded DB 603A-2 engines, and several refinements learned from the test flights of the V1 as well as further wind tunnel testing.
In early 1944 the Do 335 was scheduled to begin mass construction, with the initial order of 120 preproduction aircraft to be manufactured by DWF (Dornier-Werke Friedrichshafen) to be completed no later than March 1946. This number included a number of bombers, destroyers (heavy fighters), and several yet to be developed variants. At the same time, DWM (Dornier-Werke München) was scheduled to build over 2000 Do 335s in various models, due for delivery in March 1946 as well.
The first preproduction Dornier Do 335A-0s were delivered in July 1944 to the “Erprobungskommando 335” (“Proving detachment 335”) formed for service evaluation purposes.
On May 1944, Hitler, as part of the developing “Jägernotprogramm” (Emergency Fighter Program) directive, which took effect on July that year, ordered maximum priority to be given to Do 335 production. The main production line was intended to be at Manzell, but bombing raids in March destroyed the tooling and forced Dornier to set up a new line at Oberpfaffenhofen.
Among the different variants of the Do 335 under construction were two further two-seat prototypes, the Do 335 V11 and V12, these being respectively prototypes for the Daimler-Benz DB 603A-2-powered Do 335A-10 and DB 603E-1-powered Do 335A-12 dual-control conversion trainer. Having a similar raised second cockpit inserted aft and above the normal cockpit, the Do 335A-10 was equipped with full instrumentation and controls and was occupied by the instructor. The first aircraft were delivered without armament, but similar armament to that of the Do 335A-1 was specified for production models which were interspersed on the Do 335A-1 assembly line, and the genuine production aircraft was, in fact, a Do 335A-12 trainer.
At least 16 prototype Do 335s were known to have flown (V1–V12, and Muster-series prototypes M13–M17) on a number of DB603 engine subtypes including the DB 603A, A-2, G-0, E and E-1. The first preproduction Do 335A-0s were delivered in July 1944. Approximately 22 preproduction aircraft were thought to have been completed and flown before the end of the war including approximately 11 A-0s converted to A-11s for training purposes.
When U.S. forces overran Dornier’s Oberpfaffenhofen factory only 11 Do 335A-1 single-seat fighter bombers and two Do 335A-12 conversion trainers had been completed, but a further nine A-1s, four A-4s and two A-12s were in final assembly, and components and assemblies for nearly 70 additional aircraft had been completed. Production of the Do 335A-6 night and all-weather fighter had been transferred to the Heinkel factory at Vienna, but despite high priority allocated to the program, circumstances prevented the necessary jigs and tools being assembled (Ref: 7, 12).

Fighter

Lavochkin La-7 (Italeri)

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TYPE: Fighter aircraft

ACCOMMODATION: Pilot only

POWER PLANT: One Shvetsov Ash-82FN air-cooled radial engine, rated at 1,850 hp

PERFORMANCE: 411 mph at 19,685 ft

COMMENT: The Lavochkin La-7 was a piston-engine single-seat Soviet fighter aircraft developed during WW II by the Lavochkin Design Bureau. It was a development and refinement of the Lavochkin La-5, and the last in a family of aircraft that had begun with the Lavochkin-Gorbunov-Gudkov LaGG-3 in 1938. Its first flight was in early 1944 and it entered service with the Soviet Air Forces later in the year. The La-7 was felt by its pilots to be at least the equal of any German piston-engined fighter. It was phased out in 1947 by the Soviet Air Force.
By 1943, the La-5 had become a mainstay of the Soviet Air Forces, yet both its head designer, Semyon Lavochkin, as well as the engineers at the TsAGI (Central Aerohydronamics Institute), felt that it could be improved upon. TsAGI refined earlier studies of aerodynamic improvements to the La-5 airframe in mid-1943 and modified Lavochkin La-5FN to evaluate the changes. These included complete sealing of the engine cowling, rearrangement of the wing center section to accommodate the oil cooler and the relocation of the engine air intake from the top of the cowling to the bottom to improve the pilot’s view.
The aircraft was evaluated between December 1943 and February 1944 and proved to have exceptional performance. Using the same engine as the standard La-5FN had a top speed of 425 mph at a height of 20,180 ft, some 40 mph faster than the production La-5FN. It took 5.2 minutes to climb to 16,404 ft. It was faster at low to medium altitudes than the La-5 that used the more powerful prototype Shvetsov M-71 engine.
Lavochkin had been monitoring TsAGI’s improvements and began construction in January 1944 of an improved version of the La-5 that incorporated them as well as lighter, but stronger, metal wing spars to save weight. The La-5, as well as its predecessors, had been built mostly of wood to conserve strategic materials such as aircraft alloys. With Soviet strategists now confident that supplies of these alloys were unlikely to become a problem, Lavochkin was now able to replace some wooden parts with alloy components. In addition Lavochkin made a number of other changes that differed from La-5FN. The engine air intake was moved from the bottom of the engine cowling to the wing roots, the wing/fuselage fillets were streamlined, each engine cylinder was provided with its own exhaust pipe, the engine cowling covers were reduced in number, a rollbar was added to the cockpit, longer shock struts were fitted for the main landing gear while that for the tail wheel was shortened, an improved gunsight was installed, and a new propeller was fitted. Three prototype 20 mm Berezin B-20 autocannon were mounted in the engine cowling, firing through the propeller, arming the 1944 standard-setter.
The prototype only made nine test flights in February and March 1944 before testing had to be suspended after two engine failures, but quickly proved itself to be the near-equal of the La-5FN. It was 180 kilograms lighter than the earlier aircraft, which allowed the La-7 to outclimb the other aircraft. However it was 20.5 mph slower at sea level, but only 2.5 mph slower at 19,685 ft. The flight tests validated Lavochkin’s modifications and it was ordered into production under the designation of La-7, although the B-20 cannon were not yet ready for production and the production La-7 retained the two 20-mm ShVAK cannon armament of the La-5.
Five La-7s were built in March by Factory Nr. 381 in Moscow and three of these were accepted by the Air Force that same month. The Moscow factory was the fastest to complete transition over to La-7 production and the last La-5FN was built there in May 1944. Factory Nr. 21 in Gorky was considerably slower to make the change as it did not exhaust its stock of wooden La-5 wings until October. The quality of the early production aircraft was significantly less than the prototype.
Combat trials began in mid-September 1944 and were generally very positive. However four aircraft were lost to engine failures and the engines suffered from numerous lesser problems, despite its satisfactory service in the La-5FN. One cause was the lower position of the engine air intakes in the wing roots of the La-7 which caused the engine to ingest sand and dust. One batch of flawed wings was built and caused six accidents, four of them fatal, in October which caused the fighter to be grounded until the cause was determined to be a defect in the wing spar.
Production of the first aircraft fitted with three B-20 cannon began in January 1945 when 74 were delivered. These aircraft were 65 kilograms heavier than those aircraft with the two ShVAK guns, but the level speed was slightly improved over the original aircraft. However, the time to climb to 16,404 ft increased by two-tenths of a second over the older model. More than 2000 aircraft were delivered before the war’s end, most by Zavod Nr. 21.
Production of the Lavochkin La-7 amounted to 5,753 aircraft, plus 584 La-7UTI trainers. The follow-up model, the Lavochkin La-9, despite its outward similarity, was a completely new design (Ref.: 24).

Fighter

Messerschmitt Me 209 V1 (Huma Models)

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TYPE: Racing aircraft

ACCOMMODATION: Pilot only

POWER PLANT: One Daimler-Benz DB 601 ARJ liquid-cooled engine, rated at 1,775 hp

PERFORMANCE: 469 mph

COMMENT: The Messerschmitt Me 209 V1 was a single-engine racing aircraft which was designed for and succeeded at breaking speed records.
The designation Me 209 was used for two separate projects during World War II. The first was a record-setting, single-engined race aircraft, for which little or no consideration was given to adaptation for combat. The second Me 209  V4 was a proposal for a follow-up to the highly successful Messerschmitt Bf 109 which served as the Luftwaffe’s primary fighter throughout World War II.
Designed in 1937, the Me 209 V1 was a completely separate aircraft from the Messerschmitt Bf 109, solely designed to break speed records. It shared only its Daimler-Benz DB 601 engine with the Bf 109, which in the Me 209 was equipped with steam cooling. Willy Messerschmitt designed the small aircraft with a cockpit placed far back along the fuselage just in front of its unique cross-shaped tail section. Unlike the Bf 109, the Me 209 featured a wide track, inwardly-retracting undercarriage mounted in the wing section.
The aircraft achieved its purpose when test pilot Fritz Wendel flew it to a new world speed record of almost 469 mph on 26 April 1939, bearing the German civil registration D-INJR. This record was not officially broken by another piston-engined aircraft until 16 August 1969 by Darry Greenamyer’s highly modified Conquest F8F “Bearcat”.
The Me 209 V1’s speed record was itself shattered in terms of absolute speed, eighteen months later by Heini Dittmar, flying another Messerschmitt aircraft design, the Messerschmitt Me 163A V4 rocket fighter prototype to a 624 mph record in October 1941.
The idea of adapting the Messerschmitt Me 209 racer to the fighter role gained momentum when, during the Battle of Britain, the Messerschmitt Bf (Me)109 failed to gain superiority over the Royal Air Force’s Supermarine “Spitfire”. The little record-setter, however, was not up to the task of air combat. Its wings were almost completely occupied by the engine’s liquid cooling system and therefore prohibited conventional installation of armament. The aircraft also proved difficult to fly and extremely hard to control on the ground. Nevertheless, the Messerschmitt team made several attempts to improve the aircraft’s performance by giving it longer wings, a taller vertical stabilizer, and installing two synchronized 7.92 mm MG 17 in the engine cowling. Several modifications on the aircraft, designated Messerschmitt Me 209 V4, however, added so much weight that the aircraft ended up slower than the contemporary Bf 109E. As a result the complete Messerschmitt Me 209 project was soon cancelled, but was revived later in form of the Messerschmitt Me 209 V5. (Ref.: 24).

Fighter, Projects

Kokukyoko “Syusuishiki Kayaku ”, (“Autumn Water”), Unicraft Models, Resin

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TYPE: Rammer aircraft

ACCOMMODATION: Pilot only

POWER PLANT: Four Type 4 Mk. 1 Model 20 solid fuel rockets with a combined 1,102 kp thrust

PERFORMANCE: 699 mph (estimated)

COMMENT: The practice of ramming, in Japanese “tai-atari”, which literally means “body crashing”, was not unique to Japan. During WW II the deliberate ramming of one aircraft by another aircraft was performed by the Russians, Germans as well as Japanese and all made ramming a part of their war doctrine.
The Japanese would use aircraft already in operational service for ramming attacks such as that Kawasaki Ki-45 and even stripped down Kawasaki Ki-61 “Hein” fighters. It was long thought that Japan never developed a dedicated rammer aircraft of its own but this is no longer the case. Recently discovered in the archives of the Japanese National Institute for Defense Studies is just such a project.
The aircraft was a joint venture between the Imperial Japanese Army (IJA) and the Imperial Japanese Navy (IJN), something that occurred with more regularity towards the closing stage of WW II. The design was based on the “Syusuishiki Kayaku” Rocketto (“Autumn Water”-type ram attack rocket), a project started in March 1945 for an unmanned, remote controlled anti-bomber missile. The plan was to ground launch the missile, guide it remotely towards the target, engage the target via ramming, and then recover the missile (if it survived the collision) for reuse.
Design work was carried out by the Kokukyoko (the Aeronautical Bureau) and, although a mockup was completed, the war ended before finalized production plans could be completed, let alone the missile ever being tested.
The piloted version used much the same design as the missile and was a small, tailless aircraft featuring low mounted 45′ swept wings. The fuselage was bullet shaped with a large vertical stabilizer into which the cockpit was blended. Located in the back of the fuselage were four Type 4 Mark 1 Model 20 rockets, the same as those used on the Kugisho MXYT “Oka” which on such a small aircraft pushed the maximum speed to an estimated 699 mph or just over Mach 0.91. lt is unknown if the design had swept wings because the designers  understood the principles in relation to overcoming compressibility problem at transonic speeds, or if the shape was chosen as a means to provide an angled cutting surface to facilitate ramming attacks, or as a drag reducing planform. The wings were strengthened to withstand the high impact forces experienced when striking the enemy bomber. Even though the rammer could rely on speed as a defense when under power, it still had to contend with the defensive armament of the B-29 and thought the pilot had some measure of armor plating and bulletproof glass to protect him. The aircraft was certainly capable of gliding back to base to be refueled and relaunched once it had conducted its attacks. Given the small size of the plane, no landing gear was fitted. As such, it is likely the underside of the fuselage was reinforced or had a skid installed. How it was to be launched is unknown – it could have been towed aloft, catapult launched or perhaps even vertically launched.
In a ram attack, typically the tail would be targeted because the loss of the tail assembly would send the bomber out of control. Striking the wings and engines was another focus of ramming attacks. Finally, the aircraft fuselage was the other key area to strike. The probable mission profile of the rammer flying from a ground base would include being positioned within very close proximity of likely bombing targets. With the short burn time of the rockets (8-10 seconds) the aircraft’s operational radius would have been very limited. After launching, as bombers came into range the pilot would attempt to ram into either the tail or wing of the target with the objective of severing it from the fuselage. If enough speed momentum remained after the initial hit, another ram attack would be made. Should the aircraft remain in flying condition and if the pilot did not elect to ram his entire plane into a target, he would return to base where the rockets would be replaced. If the bombers were still close by, he could fly another sortie. If the rammer was towed into the air, the rockets would most likely have been fired on approach and again after hitting a target. This would provide enough power to grant a second pass with sufficient speed to allow for significant damage to be inflicted on the bomber when it struck.
However, the Kokukyoko “Syusuishiki Kayaku” would remain a paper project only. It is unclear if the design was to be the definitive rammer model or simply a proposed concept (Ref.: Dyer III, Edwin M.: Japanese Secret Projects, Experimental Aircraft of the IJA and IJN 1939-1945, Midland Publishing, Hersham, U.K., 2010).

Cargo

Junkers Ju 352 “Herkules”, (“Hercules”), (Airmodel, vacu-formed)

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TYPE: Transport aircraft

ACCOMMODATION: Crew of three to four

POWER PLANT: Three BMW Bramo 323 R-2 Fafnir radial engine, rated at 1,184 hp with MW-50 each

PERFORMANCE: 230 mph at 16,565 ft

COMMENT: The Junkers Ju 352 “Herkules” (“Hercules”) was a German WW II transport aircraft that was developed from the Junkers Ju 252.
During the late spring of 1942, the Junkers-Dessau project office was instructed by the Reichsluftfahrtministerium (RLM, Reich Air Ministry) to investigate the possibility of redesigning the structure of the Junkers Ju 252 transport to make maximum use of non-strategic materials, simultaneously replacing the Junkers Jumo 211F engines of the Ju 252 (production of which could barely keep pace with the demands of combat aircraft) with BMW Bramo 323R radial engines. The result followed closely the aerodynamic design of the Ju 252 but was an entirely new aircraft. The wing of the Ju 352 was similar in outline to that of the Ju 252 but, mounted further aft on the fuselage, was entirely of wooden construction.
The Ju 352 also had a similar hydraulically-operated “Trapoklappe” (“Transportklappe”, rear loading ramp) to that of the Ju 252. The ramp allowed the loading of vehicles or freight into the cargo hold while holding the fuselage level. Theoretically it was possible for any wheeled vehicle up to the size of a large “Kübelwagen” to drive up the Trapoklappe into the freight hold, although in practice it proved necessary to winch the vehicle into the hold by means of a manually-operated block- and tackle arrangement owing to the risk of damaging the structure.
In general, the Ju 352 was considered a major improvement over the original Junkers Ju 52 but noticeably inferior to the Junkers Ju 252. Deliveries of the Ju 352 had only just begun to get into their stride when, during the summer of 1944, the worsening war situation resulted in the decision to abandon further production of transport aircraft. In September the last two Ju 352As rolled off the assembly line, 10 pre-production Ju 352s and 33 production Ju 352s having been manufactured. Several developments of the basic design were proposed before production was halted, these including the Ju 352B with more powerful engines and increased defensive armament (Ref.: 24).

Heavy Bomber

Boeing B-17G “Flying Fortress”, “Priority Gal”, 486 BG, 8th USAAF, (Hasegawa Models)

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TYPE: Heavy bomber

ACCOMMODATION: Crew of ten

POWER PLANT: Four Wright R-1820-97 “Cyclone” turbo-supercharged radial engines, rated at 1,200 hp each

PERFORMANCE: 300 mph at 30,000 ft

COMMENT: The Boeing B-17 Flying Fortress is a four-engine heavy bomber developed in the 1930s for the United States Army Air Corps (USAAC). From its introduction in 1938, the B-17 Flying Fortress evolved through numerous design advances becoming the third-most produced bomber of all time, behind the four-engine Consolidated B-24 Liberator and the multirole, twin-engine Junkers Ju 88,
The Boeing B-17 began operations in World War II with the Royal Air Force (RAF) in 1941, and in the Southwest Pacific with the U.S. Army. In July 1942, the first USAAF Boeing B-17Fs were sent to England to join the Eighth Air Force. Later that year, two groups moved to Algeria to join Twelfth Air Force for operations in North Africa. The B-17Fs were primarily involved in the daylight precision strategic bombing campaign against German targets ranging from U-boat pens, docks, warehouses, and airfields to industrial targets such as aircraft factories. In the campaign against German aircraft forces in preparation for the invasion of France, B-17 and B-24 raids were directed against German aircraft production while their presence drew the Luftwaffe fighters into battle with Allied fighters.
Soon, Boeing B-17Fs proved to be unsuitable for combat use over Europe. The defense expected from bombers operating in close formation alone did not prove effective and the bombers needed fighter escorts to operate successfully. Especially the head-on attacks of German fighters were dangerous, To improve defense a modification in form of a power-operated Bendix “chin” turret mounting two 0.5-in. machine guns was introduced in the last production model, the Boeing B-17G.  With the two “cheek” guns and the “chin” turret the protection against incoming fighters was increased enormously. In order to improve the field of fire to the rear a so-called “Cheyenne” tail gun mounting was fitted bringing the total number of guns from seven (B-17F) to 13 (B-17G). Incorporating all changes made to its predecessor, in total 8,680 B-17Gs were built, the last (by Lockheed) on July1945.
During World War II, the B-17 equipped 32 overseas combat groups, inventory peaking in August 1944 at 4,574 USAAF aircraft worldwide (Ref.: 24).
The aircraft shown here belonged to the 486th Bombardment Group (H), 832BS (Bombardment Squadron) stationed at Sudbury, UK. All B-17Gs were in natural metal. Group markings: W in square. In late 1944 red and blue bands forming chevron were painted on wing with blue band towards tip. From January 1945 wing tips and complete tail section painted yellow and three parallel bands of yellow round rear fuselage. In place nose bands and aircraft letter on fuselage (forward national insignia) in squadron color: 832BS in yellow, 833BS in medium blue, 834BS in red, and 835BS in bright green (Ref.: 2).

Nightfighter

Heinkel He 219A-0 “Uhu”, (“Eagle Owl”), I./NJG 1 (Dragon)

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TYPE: Night fighter

ACCOMMODATION: Crew of two, Pilot and Radar operator/navigator

POWER PLANT: Two Daimler-Benz DB 603G liquid-cooled engines, rated at 1,900 hp each

PERFORMANCE: 416 mph at 22,965 ft

COMMENT: The Heinkel He 219 “Uhu” (“Eagle Owl”) was a night fighter that served with the German Luftwaffe in the later stages of WW II. A relatively sophisticated design, the He 219 possessed a variety of innovations, including Lichtenstein SN-2 advanced VHF-band intercept radar, also used on the Junkers Ju 88C and Messerschmitt Bf 110G night fighters. It was also the first operational military aircraft to be equipped with ejection seats and the first operational German World War II-era aircraft with tricycle landing gear. Had the He 219 been available in quantity, it might have had a significant effect on the strategic night bombing offensive of the Royal Air Force; however, only 294 of all models were built by the end of the war and these saw only limited service.
Development and production of the He 219 was protracted and tortuous, due to political rivalries between Josef Kammhuber, commander of the German night fighter forces, Ernst Heinkel, the manufacturer and Erhard Milch, responsible for aircraft construction in the Reichluftfahrtministerium (RLM – the German Aviation Ministry). The aircraft was also complicated and expensive to build; these factors further limited the number of aircraft produced.
When engineer R. Lusser returned to Heinkel from Messerschmitt, he began work on a new high-speed bomber project called Heinkel He P.1055. This was an advanced design with a pressurized cockpit, twin ejection seats (the first to be planned for use in any combat aircraft), tricycle landing gear — featuring a nose gear that rotated its main strut through 90° during retraction (quickly orienting the nose wheel into the required horizontal position for stowage within the nose, only at the very end of the retraction cycle) to fit flat within the forward fuselage and remotely controlled, side mounted FDSL 131 defensive gun turrets similar to those used by the Messerschmitt Me 210. Power was to be provided by two of the potentially troublesome, dual-crankcase Daimler-Benz DB 610 “power system” engines then under development, weighing on the order of about 1–​1⁄2 tonnes apiece, producing 2,950 hp each, delivering excellent performance with a top speed of approximately 470 mph and a 2,500 mi range with a 2,000 kg bomb load.
The RLM rejected the design in August 1940 as too complex and risky. Lusser quickly offered four versions of the fighter with various wingspans and engine choices in order to balance performance and risk. At the same time, he offered the Heinkel He P.1056, a night fighter with four 20 mm cannon in the wings and fuselage. The RLM rejected all of these on the same grounds in 1941. Heinkel was furious and fired Lusser on the spot.
About the same time as Lusser was designing the P.1055, Kammhuber had started looking for an aircraft for his rapidly growing night fighter force. Heinkel quickly re-designed the P.1055 for this role as the Heinkel He P.1060. This design was similar in layout but somewhat smaller and powered by two of the largest displacement  single-block liquid-cooled aviation engines placed in mass production in Germany, the Daimler-Benz DB 603 inverted V12 engine. As designed by Heinkel, these engines’ nacelle accommodations featured annular radiators similar to the ones on the Junkers Jumo 211-powered Junkers Ju 88A, but considerably more streamlined in appearance, and which, after later refinement to their design, were likely to have been unitized as a Heinkel-specific “Kraftei” (Power egg) engine unit-packaging design. Nearly identical-appearance nacelles, complete with matching annular radiators, were also used on the four prototypes Heinkel He 177B prototype airframes built in 1943-44, and the six ordered prototypes of Heinkel’s He 274 high-altitude strategic bombers with added turbochargers. The early DB 603 subtypes had poor altitude performance, which was a problem for Heinkel’s short-winged design, but Daimler had a new “G” subtype of the DB 603 power plant meant to produce 1,900 hp take-off power apiece under development to remedy the problem. Heinkel was sure he had a winner and sent the design off to the RLM in January 1942, while he funded the first prototype himself. The RLM again rejected the He 219, in favour of new Junkers Ju 88- and Messerschmitt Me 210-based designs.
Construction of the prototype started in February 1942 but suffered a serious setback in March, when Daimler said that the DB 603G engine would not be ready in time. Instead, they would deliver a 603A engine with a new gear ratio to the propellers, as the DB 603C with the choice of using four-blade propellers, as the similarly-powered Focke-Wulf Fw 190C high-altitude fighter prototypes were already starting to use into early 1943, with the DB 603. DB 603 engines did not arrive until August 1942 and the prototype did not fly until November 1942.
When Kammhuber saw the prototype, he was so impressed that he immediately ordered it into production over Milch’s objections. Milch – who had rejected the He 219 in January in favor of the Junkers Ju 388J was enraged.
Stability problems with the aircraft were noted but Heinkel overcame these by offering a cash prize to engineers who could correct them. Further changes were made to the armament during the development of the prototype He 219V-series. The dorsal rear defensive guns mounted atop the fuselage and firing directly rearward from a fixed, internally mounted, rear-facing dorsal “step” position, at a point just aft of the wing trailing edge, were removed due to their ineffectiveness. The forward-firing armament complement of the aircraft was increased to two Mauser MG 151/20 20 mm cannon in the wing roots, inboard of the propeller arcs to avoid the need for gun synchronizers, with four more MG 151/20 cannon mounted in the ventral fuselage tray, which had originally ended in a rearwards-facing “step” similar to and located directly under the deleted rear dorsal “step” – this rearwards-facing feature was also deleted for similar reasons.
The Heinkel He 219A-0 model featured a bulletproof shield that could be raised in the front interior cockpit, hiding the entire bottom portion of the windscreen, providing temporary pilot protection and leaving a sighting slot by which the gunsight could be aimed at a bomber. Production prototypes were then ordered as the Heinkel He 219A-0 and quickly progressed to the point where prototypes V7, V8 and V9 were handed over to operational units in June 1943 for testing.
The earlier prototypes, with four-blade propellers for their DB 603 engines (also used on the Fw 190C prototypes, with the same DB 603 engine) had blunt, compound-curvature metal nose cones also used for production-series He 219A airframes. The initial examples of these nose cones possessed cutouts for their use with the quartet of forward-projecting masts for the “Matratze” (“Mattress”) 32-dipole radar antennae on the noses of at least the first five prototypes, used with the early UHF-band “Lichtenstein” B/C or C-1 radar installation. These early He 219V-series prototype airframes also had cockpit canopies that did not smoothly taper aftwards on their upper profile, as on the later production He 219A-series airframes, but instead ended in a nearly hemispherically-shaped enclosure. The fourth prototype, He 219 V4, equipped with the earlier canopy design, had a small degree of internal metal framing within the rearmost hemispherical canopy glazing, apparently for a rear dorsal weapons mount or sighting gear for the deleted fixed “step”-mount rearwards-firing armament.
The first major production series was the Heinkel He 219A-0, although initially the pre-production series, it matured into a long running production series, due to numerous changes incorporated into the design, along with the cancellation of several planned variants. Production problems as a result of Allied bombing in March meant the A-0 did not reach Luftwaffe units until October 1943. The A-0 was usually armed with two 20 mm MG 151/20 cannon in the wing roots and up to four 20 mm or 30 mm cannon in a ventral weapons bay. The first 10–15 aircraft were delivered with the 490 MHz UHF-band FuG 212 “Lichtenstein” C-1radar with a 4 × 8-dipole element “Matratze” antenna array. 104 Heinkel He 219A-0s were built until the summer of 1944, the majority of them at EHW (Ernst Heinkel Wien) or Heinkel-Süd in Wien-Schwechat (Ref.: 24).

Reconnaissance, Trainer, Observation

Nakajima E8N2 ‘Dave’, Training Unit, Kyushu (Wings Models, Vacu-formed)

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TYPE: Ship-borne reconnaissance floatplane, Trainer

ACCOMMODATION: Crew of two

POWER PLANT: One Nakajima Kotobuki 2 KAI 2 radial engine, rated at 630 hp

PERFORMANCE:  186 mph

COMMENT: The Nakajima E8N was developed as a replacement for the same company’s E4N and was essentially an evolutionary development of the earlier type, with revised wings of lesser area and taller tail surfaces. Seven prototypes were constructed, under the company designation MS, first flying in March 1934. These were duly engaged in comparative trials against competitors from Aichi and Kawanishi.
The MS was ordered into production, designated Navy Type 95 Reconnaissance Seaplane Model 1 in October 1935. A total of 755 E8Ns were built by Nakajima and Kawanishi, production continuing until 1940. Operating as a catapult-launched reconnaissance aircraft the E8N was subsequently shipped aboard all the capital ships then in service, battleships, cruisers and aircraft tenders. It was used successfully in the Second Sino-Japanese War and distinguished itself on several occasions by destroying opposing Chinese fighters. Occasionally the aircraft was operated as a dive-bomber but was more often employed as a reconnaissance and artillery spotting aircraft.
One E8N was purchased in early 1941 by the German Naval Attaché to Japan, Vice-Admiral Wenneker, and dispatched on board “KM Münsterland” to rendezvous with the German auxiliary cruiser “Orion” at Maug Island in the Marianas. The meeting occurred on 1 Feb 1941, and “Orion” thus became the only German naval vessel of the Second World War to employ a Japanese float plane.
Some aircraft remained in service with the fleet at the outbreak of the Pacific War, and one flew reconnaissance from the battleship Haruna during the Battle of Midway. The type was coded “Dave” by the Allies. Later, they were replaced by more modern aircraft such as the Aichi E13A and the Mitsubishi F1M and the remaining aircraft were reassigned to second-line duties for instance communications, liaison and training (Ref.: 24).

Reconnaissance

DFS 346 (Huma Models)

Gallery

TYPE: High-speed, high-altitude reconnaissance aircraft

ACCOMMODATION: Pilot only, in prone position

POWER PLANT: One Walter HWK 109-509 liquid-fuel rocket, rated at 3,400 kp thrust

PERFORMANCE: 560 mph (verified), 1,723 mph (estimated)

COMMENT: The DFS 346 was a German rocket-powered swept-wing aircraft subsequently completed and flown in the Soviet Union after WW II. It was designed by Felix Kracht at the Deutsche Forschungsanstalt für Segelflug (DFS, “German Research Institute for Sailplanes”). The prototype was still unfinished by the end of the war and was taken to the Soviet Union where it was rebuilt, tested and flown.
The DFS-346 was a midwing design of all-metal construction. The front fuselage of the DFS 346 was a body of rotation based on the NACA-Profile 0012-0,66-50. The middle part was approximately cylindrical and narrowed to the cut off to accommodate vertically arrayed nozzles in back. Probably for volume and weight reasons the DFS-346 was equipped with landing skids, both in the original German design and in the later Soviet prototypes; this caused trouble several times.
The wings had a 45° swept NACA 0012-0,55-1,25 profile of 12% thickness. The continuously varying profile shape caused a stall in certain flight conditions, which caused complete loss of control. This was later corrected by use of fences on the top of the wings.
The DFS 346 was a parallel project to the DFS 228 high-altitude reconnaissance aircraft, designed under the direction of Felix Kracht and his team at DFS. While the DFS 228 was essentially of conventional sailplane design, the DFS 346 had highly-swept wings and a highly streamlined fuselage that its designers hoped would enable it to break the sound barrier.
Like its stablemate, it also featured a self-contained escape module for the pilot, a feature originally designed for the DFS 54 prior to the war. The pilot was to fly the machine from a prone position, a feature decided from experience with the first DFS 228 prototype. This was mainly because of the smaller cross-sectional area and easier sealing of the pressurized cabin, but it was also known to help with g-force handling.
The DFS 346 design was intended to be air-launched from the back of a large mother ship aircraft for air launch, the carrier aircraft being the Dornier Do 217K as with the DFS 228. After launch, the pilot would fire the Walter HWK 109-509B/C twin-chamber  engine to accelerate to a proposed speed of Mach 2.6 and altitude of 100,000 ft. This engine had two chambers — the main combustion chamber as used on the earlier HWK 509A motor; but capable of just over two short 2,000 kp of thrust at full power, and the lower-thrust “Marschofen”, (Cruise chamber = throttleable chamber of either 300 kp (B-version) or 400 kp (C-version) top thrust levels mounted beneath the main chamber. After reaching altitude, the speed could be maintained by short bursts of the lower “Marschofen” (cruise chamber).
In an operational use the plane would then glide over England for a photo-reconnaissance run, descending as it flew but still at a high speed. After the run was complete the engine would be briefly turned on again, to raise the altitude for a long low-speed glide back to a base in Germany or northern France.
Since the aircraft was to be of all-metal construction, the DFS lacked the facilities to build it and construction of the prototype was assigned to Siebel Werke located in Halle, where the first wind tunnel models and partially built prototype were captured by the advancing Red Army.
On 22 October 1946, the Soviet OKB-2 (Design Bureau 2), under the direction of Hans Rössing and Alexandr Bereznyak, was tasked with continuing its development. The captured DFS 346, now simply called “Samolyot 346” (“Samolyot” = Aircraft) to distance it from its German origins, was completed and tested in TsAGI wind tunnel T-101. Tests revealed some aerodynamic deficiencies which would result in unrecoverable stalls at certain angles of attack. This phenomenon involved a loss of longitudinal stability of the airframe. After the wind tunnel tests, two wing fences were installed on a more advanced, longer version of the DFS-346, the purpose of fences was to interrupt the spanwise movement of airflow that would otherwise bring the boundary-layer breakdown and transition from attached to stalled airflow with loss of lift and increase of drag.
This solution was used on the majority of the Soviet planes with sweptback wings of the 1950s and 1960s. In the meantime, the escape capsule system was tested from a North American B-25J “Mitchell” piston engine medium bomber and proved promising. Despite results from studies showing that the plane would not have been able to pass even Mach 1, it was ordered to proceed with construction and further testing.
In 1947, an entirely new 346 prototype was constructed, incorporating refinements suggested by the tests. This was designated “346-P” (“P” for planer = “glider”). No provision was made for a power plant, but ballast was added to simulate the weight of an engine and fuel. This was carried to altitude by a Boeing B-29 “Superfortress” captured in Vladivostok and successfully flown by Wolfgang Ziese in a series of tests. This led to the construction of three more prototypes, intended to lead to powered flight of the type.
Newly built “346-1“ incorporated minor aerodynamic refinements over the 346-P, and was first flown by Ziese on September 30, 1948, with dummy engines installed. The glider was released at an altitude of 9700 m, and the pilot realized that he hardly could maintain control of the aircraft. Consequently, while attempting to land, he descended too fast (his speed was later estimated at 310 km/h). After first touching the ground he bounced up to a height of 3–4 m and flew 700–800 m. At the second descent, the landing ski collapsed and the fuselage hit the ground hard.
The pilot seat structure and safety belt proved to be very unreliable, because at the end of a rough braking course Ziese was thrown forward and struck the canopy with his head, losing consciousness. Luckily, he wasn’t seriously injured, and after treatment in hospital he was able to return to flying. Accident investigation research team came to the conclusion that the crash was a result of pilot error, who failed to fully release the landing skid. This accident showed that the aircraft handling was still very unpredictable, as a result, all rocket-powered flights were postponed until pilots were able to effectively control the aircraft in unpowered descent, requiring further glide flights.
The damaged 346-1 was later repaired and modified to 346-2 version. It was successfully flown by test pilot P. Kazmin in 1950-1951 winter, but nonetheless these flights also ended “on fuselage”. Furthermore, after the last flight of these series, the airframe again required major repairs. On 10 May 1951, Ziese returned to the program, flying final unpowered test flights with the 346-2, and from 6 June, unpowered tests of the 346-3 without accidents.
By the mid-1951 346-3 was completed, and Ziese flew it under power for the first time on 13 August 1951, using only one of the engines. Continuing concerns about the aircraft’s stability at high speeds had led to a speed limit of Mach 0.9 being placed during test flights. Ziese flew it again on 2 September and 14 September. On this last flight, however, things went drastically wrong. Separating from the carrier plane at 9,300 meters (30,500 ft) above Lukovici airfield, the pilot fired the engine and accelerated to a speed of 900 km/h (560 mph). The rocket engine worked as expected, and 346-3, quickly accelerating, started ascending and soon had flown in very close proximity of its carrier aircraft. Ziese then reported that the plane was not responding to the controls, and was losing altitude. Ground control commanded him to bail out. He used the escape capsule to leave the stricken aircraft at 6,500 meters (21,000 ft) and landed safely by parachute. With the loss of this aircraft, the 346 program was abandoned (Ref.:24).