Monthly Archives: November 2019

Fighter, Projects

Heinkel He P.1073.09-44 (Revell Models, Parts scratchbuilt)

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TYPE: Fighter project, forerunner of the Heinkel He 162

ACCOMMODATION: pilot only

POWER PLANT:  one Heinkel-Hirth HeS 011 turbojet engine, rated at 1.300 kp thrust

PERFORMANCE: 615 mph in 19615 ft

COMMENT: The summer 1944 saw limitations of the Messerschmitt Me 262 becoming readily apparent. The basic design predated the war. It was heavy and expensive, and required to precious turbojet engines. A cheap high-performance replacement was needed so in July 1944 the RLM issued a requirement for a new single-turbojet high-performance fighter, known as the “1-TL-Jäger”. Germany’s aircraft companies were quick to realise that this was potentially the most important competition in which they had so far had the opportunity to participate. Designing a successful single-seat fighter carries a huge amount of prestige and the most famous firms – Blohm &Voss, Focke-Wulf , Heinkel, Junkers and Messerschmitt – jumped at the chance to create the successor to not only on the me 262 but perhaps also the Bf 109 and Fw 190 too. The engine was to be a Heinkel-Hirth HeS 011 turbojet and the companies were allowed two months to prepare their first designs, Blohm & Voss had two months more time.
On September 1944 the designs were presented at a meeting at Messerschmitt’s Oberammergau facility. It is not known which designed were presented by Messerschmitt and Heinkel, though it is likely that these were one of the earliest versions of the former’s Me P.1101, and the latter’s He P.1073 or a variant of it. Focke-Wulf put forward a twin-boom design Nr.280 it had been working on since early 1944. Blohm & Voss’s design (P.212) was apparently not ready and furthermore it was agreed that Junkers should also be allowed to submit a tender for the requirement.
On the last day of the meeting, a new requirement was suddenly and for most part unexpectedly issued for what would become the “Volksjäger” (Peoples Fighter). This called for a fighter powered by a single BMW 003 turbojet engine that could reach a maximum speed of 466 mph and have an endurance of 30 minutes at full throttle. It also had to be able to operate from poor airfields.
This urgent demand for new single-turbojet fighter designs that could be built in a hurry from low grade non-strategic materials effectively stalled work on the “1-TL-Jäger” competition for several months, particularly Blohm & Voss, Focke-Wulf, Heinkel and Junkers all hastily drafted entries for the “Volksjäger” contest.
The Heinkel He P.1073, originally designed before July 1944 as a fighter with two Junkers Jumo 004C turbojet-engines, one under the nose and one at its back but now altered to fly with just one Heinkel-Hirth HeS 011, was already close to meeting the “Volksjäger” specification. The Heinkel “Volksjäger”-design He P.1073.01.18 was dated from September 1944, just one day after the specification was issued. This only was possible because Heinkel’s design team had several different variants of the design on the drawing board. The documentation describes the He P.1073.01.18 as a “Kleinst-Jäger” (Midget Fighter) and states it is ”a simplification of the design with HeS 011”. It bears remarkable resemblance to what would become the Heinkel He 162 “Spatz” (Sparrow”) except the wings are simpler and both nose wheel and main gear retract forward into the fuselage. Heinkel’s design received a similarly lukewarm reaction, probably because it was based heavily on the company’s already known “1-TL-Jäger” project. But Heinkel’s representatives pointed out that with aircraft such as the Heinkel He 177 bomber no longer in production there was now spare capacity available at its capacious and well-equipped factories. There is some evidence that on September 23rd 1944 Hitler himself ordered the He P.1073 into mass production as Heinkel He 162.
The variant of the He P.1073 design that finally led to the definitive Heinkel He 162 “Volksjäger” is shown here. The design is dated back from September 10th, 1944 and shows the installation of the turbojet engine on the back. The wings are swept back at 35 degree, the tail plane had a positive dihedral and two fins. Under the fuselage on ventral starboard side a streamlined pannier was fitted holding a MK 108 machine canon and two MG 213C machine guns were oblique mounted in the front at both sides of the pilot’s seat. Work on the final version of the Heinkel “Volksjäger began on October 25th, 1944 and its maiden flight took place on December 6th that year (Ref.: Sharp, Dan: Luftwaffe. Secrets Jets of the Third Reich. Mortons Media Group Ltd, Horncastle, 2015).

Helicopter, Trainer, Observation

Avro 671 Rota Mk. I, 529 Sqn RAF (RS Models)

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TYPE: Autogyro

ACCOMMODATION: Pilot and passenger/observer

POWER PLANT: One Armstrong Siddeley Genet Major IA radial engine, rated at 140 hp

PERFORMANCE: 110 mph

COMMENT: The Avro 671 Rota Mk. I autogyro based on the Cierva C.30 designed by Juan de la Cierva in Spain and built under licence in England by A V Roe & Co Ltd.
Avro obtained the licence in 1934 and subsequently built 78 examples under their model designation, fitted with an Armstrong Siddely Genet Major IA (known in the RAF as the Civet 1) 7-cylinder radial engine producing 140 hp . The first production aircraft was delivered in July 1934.
The first production design in the series was the C.30A, a radial-engined autogyro with a three-blade, 37 ft rotor mounted on an aft-leaning tripod, the control column extending into the rear of the two cockpits. The engine was the five-cylinder, 105 hp Armstrong Siddely Genet Major I. The fabric-covered fuselage carried an unbraced tail plane, without elevators but with turned-up tips. The port side of the tail plane had an inverted aerofoil section to counter roll-axis torque produced by the propeller. As with most autogyros, a high vertical tail was precluded by the sagging resting rotor, so the dorsal fin was long and low, extending well aft of the tail plane like a fixed rudder and augmented by a ventral fin. The wide-track undercarriage had a pair of single, wire-braced legs and a small tail wheel was fitted. This model flew in April 1933. It was followed by four improved machines designated C.30P (P here for pre-production) which differed in having a four-legged pyramid rotor mounting and a reinforced undercarriage with three struts per side. The rotor could be folded rearwards for transport. The C.30P used the more powerful140 hp Armstrong Siddely Genet Major IA radial engine.
Twelve C.30A’s built by Avro for the Royal Air Force (RAF) entered service as the Avro 671 Rota Mk.I. The twelve were delivered between 1934 and 1935. They equipped the School of Army Co-operation at RAF Old Sarum near Salisbury. At least one RAF C.30A was on floats as a “Sea Rota” in January 1935
Many of the surviving civil aircraft were also taken into RAF service between 1939 and 1940. In 1940 they equipped 1448 Flt at RAF Duxford. Later they equipped 529 Sqn at RAF Halton on radar calibration work, disbanded in October 1945, the twelve survivors were sold on to civilian owners (Ref.: 24).

Fighter, Projects

Messerschmitt Me 262 HG IV (Hochgeschwindigkeits Projekt IV, High-speed project IV), (Unicraft Models, Parts from Revell)

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TYPE: High-speed research aircraft

ACCOMMODATION: Pilot only

POWER PLANT: Two Junkers Jumo 004C, rated at 1050 kp each or two Heinkel/Hirth HeS 011 turbojet engines, rated at 1,200 kp each

PERFORMANCE: High sub-sonic speed (estimated)

COMMENT: The Messerschmitt Me 262 HG IV („Hochgeschwindigkeits-Projekt IV“, „High-speed Project IV“) was a high-speed concept which would be based on the Messerschmitt Me 262 „Schwalbe“ („Swallow“). The design dates back to early 1940 when attempt were made to test the revolutionary turbojet driven aircraft at critical Mach numbers.
Several proposals were calculated on the drawing board and even one design realized:
The Messerschmitt Me 262 V9 HG I was flight tested in January 1944. During the course various aerodynamic improvements were introduced into a basic Me 262 aircraft. The leading edge of the inner wing as well as of the vertical tail was increased to 45 degree, the leading edge of the horizontal tail was swept back to 40 degree, a shallow, low-drag cockpit canopy was installed, and the muzzles were faired over. The highest speed attained by this experimental aircraft being 624 mph.
On the drawing board remained the Messerschmitt Me 262 HG II and Me 262 HG III, both designs in various subtypes with different wings, conventional as well as with “Butterfly”-type tail plane, different engine installation and air intake.
Finally, the Messerschmitt Me 262 HG IV was a basic Messerschmitt Me 262 aircraft with original wing section and low mounted nacelles, housing the turbojet engines, but an intensively modified fuselage similar to the Me 262 HG III/3. The cockpit was placed to the rear of the fuselage merging into the tail plane, fuel tanks and armament was set at the front of the aircraft.
All Messerschmitt Me 262 HG II, Me 262 HG III and Me 262 HGIV were never realized

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).