Frustated Projects

[Airframes]

Some very interesting projects, thanks for posting.

 

[vikingBerserker]

I agree!

 

[Gnomey]

Interesting stuff!

 

[gekho]

Similar in appearance to the Douglas B-18 Bolo, but intended to achieve significantly improved performance, the North American NA-21 bomber was developed at the company's Inglewood, California plant during 1935-3, the prototype being completed in March 1937. Powered by two 895kW Pratt Whitney R-218.0 Twin Hornet engines with F-10 turbo-superchargers, the XB-21 carried a six-man crew and armament comprised single 7.62mm machine-guns in nose and dorsal turrets, plus a similar weapon in each of the ventral and two waist positions. Short-range bomb load was 4536kg, reducing to 998kg over 3058km.

The Army Air Corps found the performance of the XB-21 to have been favorable enough to order five pre-production aircraft, to be designated YB-21. However, soon after this contract was awarded, it was cancelled, and none of the YB-21s were ever built, leaving the XB-21 as the sole example of the type ever constructed. Operated by North American Aviation, the XB-21 served as a research aircraft until its retirement.

 

[gekho]

Developed in 1936 as a mailplane for Deutsche Lufthansa, the Heinkel He 116 made use of design features of the He 70 and He 111, particularly the elliptical wing and tail surfaces. The aircraft was to have been powered originally by four 373kW Hirth engines, but these were not available in time and the 179kW Hirth HM 508 engine was substituted. Eight civil aircraft were built with the designation He 116A-0, the first making its maiden flight in the summer of 1937. Two of them were purchased by Manchurian Air Transport and made their 15,337km delivery flights from Berlin to Tokyo between 23 and 29 April 1938, in a time of 54 hours 17 minutes. Another was modified for record-breaking, with 179kW Hirth HM 508H engines, a wing of increased span and area and provision for rocket-assisted take-off equipment. Designated He 116R, it set a distance record of 10,000km in 48 hours 18 minutes, beginning on 30 June 1938. An He 116B long-range reconnaissance version was also developed, the last two civil aircraft serving as prototypes, and a total of six was built.

 

[gekho]

The SR.A/1 was directly inspired by the (modest) successes experienced by the Imperial Japanese Navy with seaplane fighters such as the Nakajima A6M2-N (an adaptation of the Mitsubishi Zero) and the Kawanishi N1K. In theory, seaplanes were ideally suited to conditions in the Pacific theatre, and could turn any relatively calm area of coast into an airbase. Their main disadvantage came from the way in which the bulk of their floatation gear penalised their performance compared to other fighters. Saunders-Roe realised that the new turbojet engine presented an opportunity to overcome this drawback. Not requiring clearance for a propeller, the fuselage could sit lower in the water and utilise a flying boat-type hull. The company approached the Air Ministry with the idea then known as the SR.44, which led to specification E.6/44 and an accompanying development contract for three prototypes in May 1944.

The first prototype, piloted by Geoffrey Tyson, flew on July 16 1947, and while it and its two sisters proved to have good performance and handling, the need for such aircraft had completely evaporated with the end of the war. Furthermore, the success of the aircraft carrier in the Pacific had demonstrated a far more effective way to project airpower over the oceans. In addition, the cockpit canopy was small and heavily framed, giving the pilot a poor view outside the aircraft. A fundamental problem was that production of the Beryl engine had ceased when Metropolitan-Vickers had withdrawn from jet engine development, and only a limited number of engines were available. The project was suspended and the prototype put into store in 1950, but was briefly resurrected in November 1950 owing to the outbreak of the Korean War, before realisation of its obsolescence compared with land-based fighters and an inability to solve the engine problem forced a final cancellation, the prototype last flying in June 1951. Although the aircraft never received an official name, it was referred to by company workers as 'Squirt'.

 

[gekho]

From 1937 Tachikawa produced a number of interesting designs which did not go into series production. These included the TS-1 single-seat ultra-light low-wing cabin monoplane; the R-38 two-seat parasol-wing monoplane primary trainer; the SS-1 twin-engined low-wing monoplane developed from the Lockheed 14 and intended for high-altitude research; the Ki-70 twin-engined high-speed reconnaissance monoplane; and the A-26, later redesignated Ki-77, a long-distance record aircraft with a remarkably slim fuselage and finely tapered wide-span monoplane wings. However, it was the Tachikawa Ki-74 monoplane which attracted the greatest official support. By 1941 the project had been confirmed as a long-range high-altitude bomber reconnaissance aircraft, and the first of the prototypes, powered by 1641kW turbocharged Ha-211-Ru radials, flew in March 1944. Thirteen pre-production machines followed, powered by more reliable 1491kW Ha-104 Ru engines, giving a maximum speed of 570km/h at 8500m. They carried 1000kg of bombs and were defended by a single remotely-controlled 12.7mm machine-gun in the tail. Although not used operationally, the Ki-74 received the Allied codename 'Patsy'.

 

[gekho]

Displaying a close conceptual similarity to the Messerschmitt Me 262, the Su-9 single-seat fighter, also known as Samolet (Aircraft) K, entered flight test in the autumn of 1946. Of all-metal construction with a semi-monocoque, oval-section fuselage and single-spar wings, the Su-9 had an armament of one 37mm and two 23mm cannon, and was powered by two 900kg Junkers Jumo 004B turbojets (which had been copied for manufacture in the Soviet Union as the RD-10). The Su-9 embodied a number of innovatory features insofar as Soviet technology was concerned, these including hydraulically-boosted control surfaces, a cordite-fired ejection seat, a variable-incidence tailplane, provision for assisted take-off rockets and a braking parachute. Racks under the centre fuselage permitted carriage of one 500kg or two 250kg bombs. The Su-9 was shown publicly over Tushino on 3 August 1947, and with completion of State testing in the following December, series production was recommended. However, although possessing no more than a superficial resemblance to the Me 262, its configurational similarity to the German fighter was a stigma which led Yosif Stalin to reject the Su-9 out of hand.

 

[gekho]

Designed by Alessandro Marchetti and flown for the first time on 31 January 1944 at Varese, the SM.93 was a fascinating aeroplane in several respects. Firstly, it was powered by a Daimler-Benz DB 605A 12-cylinder inverted-vee liquid-cooled engine rated at 1,475 hp at sea level and 1,250 hp at 5800 m which was installed beneath the pilot's cockpit; secondly, the pilot occupied a prone position with a gunner/observer occupying an orthodox aft-facing seat, and thirdly, it was entirely of wooden construction, which, unusual for combat aircraft at the time of the SM.93's debut, was unique among aircraft designed specifically for the dive bombing mission.

The SM.93 had a two-spar three-piece wooden wing with ply and fabric skinning and a wooden monocoque fuselage. Armament consisted of a 20-mm cannon with 150 rounds firing through the propeller hub, a 12,7-mm machine gun with 350 rounds in each wing and a similar weapon on a flexible mounting in the rear cockpit. A bomb load of 820 kg was intended to be carried on the fuselage centreline. The prototype had made 16 flights totalling 6 hrs 40 mm by 29 March 1944 -during these diving speeds of the order of 900 km/h had been achieved - but on that date the German Control Commission ordered the termination of flight testing.

 

[gekho]

The HD.730 was constructed completely in metal, except the control areas which were finished in fabric. The wings were foldable for onboard storage. Undercarriage were twin floats. The twin vertical stabilizers carried rudders on the ends of the horizontal fins, and the crew of two was housed onder a long cabin roof made from transparent material. In March 1938, two prototypes were ordered, which received an inline engine of type Renault 6Q-03 for propulsion. In February 1940, the trial sample HD.730.01 took off for the first time from the Etang de Berre (a lake near the Mediterranean coast, very well known as many French seaplanes were operated there, RT).

Testing this aircraft, and the HD.730.02 as well, showed that a stronger engine was necessary. For serial production, a Bearn-6D-piston engine delivering 258 kW (350 hp) was foreseen. When France surrendered, the trials of the HD.730 prototypes were temporarily stopped. Despite the surrender, a third, modified aircraft appeared, designated HD.731.02. Compared to the HD.730, it was smaller, and equipped with the Bearn-6D-engine provided for serial production. It flew for the first time on 11 March 1941. Lots of modifications were done, until it was found out, that a bigger wing area was necessary. Subsequently the further development was stopped. Meanwhile, also the both original prototypes became equipped wit the Bearn-6D, but only the HD.731.02 made it into the air. For five years, the aircraft flew in a begin-change-end-manner. A training variant, HD.732 with Renault 6Q engine, was not followed up with.

 

[Gnomey]

The Saunders Roe SR.A/1 is a funny looking aircraft. More good stuff!

 

[vikingBerserker]

Fascinating. This has quickly became my favorite thread.

 

[gekho]

The Brewster XA-32 was developed in response to an Air Corps requirement for a large single-engine dive bomber/ground attack aircraft carrying just the pilot. The success of German dive bombers during the early Blitzkrieg campaigns in 1939 and 1940 convinced the United States of the need to develop and test dive bombers of its own. The development of the XA-32 was relatively slow and took more than a year to progress from mock up (spring/summer 1942) to first flight (spring 1943).

The aircraft featured eight forward firing .50-cal. machine guns (four in each wing) and a 3,000-pound maximum bomb load. Each wing had a hardpoint capable of supporting one 1,000-pound bomb, and an internal bomb bay could handle up to 1,000 pounds of bombs. The aircraft was powered by a 2,100-hp Pratt Whitney Double Wasp radial engine, turning a large four blade propeller with a large spinner. The wing was mounted at mid-fuselage to allow room for the internal bomb bay. A wide stance inward retracting landing gear was also necessary because of the bomb bay, but resulted in good ground handling characteristics. The vertical stabilizer was relatively small and the horizontal stabilizer was mounted at the midpoint of the vertical stabilizer. The mock up had a more conventional tail assembly, but this was changed before the prototype was built.

The XA-32 performed poorly in its flight evaluation. The aircraft was heavy and underpowered. The XA-32 had a cruising speed of less than 200 miles per hour and a small combat range of 500 miles. The North American A-36A Apache was selected by the Air Corps to fill the ground attack/dive bomber role and served adequately from mid-1943 into 1944, primarily in North Africa, the Mediterranean and India. The XA-32 never progressed past the prototype development phase; however, the second aircraft built was retrofitted with four 20mm cannons in place of the .50-cal. machine guns and tested as the XA-32A.

 

[gekho]

The Manx (which appropriately shares the same name as a breed of vestigial-tailed cat) was built to participate in a flight research program investigating problems associated with tailless aircraft. The partially-swept wings supported the vertical stabilizers of a twin tail, with elevons for pitch and roll control. Construction of the prototype was subcontracted to Dart Aircraft of Dunstable. There were serious issues encountered early in the development phase that caused a delay in the testing program. After it was delivered in 1939, redesigns had to be made because the Manx was too heavy, and there were also structural integrity issues with the main spar. An unorthodox aspect of the Manx design incorporated into the aircraft was that the main undercarriage was retractable, while the nose gear remained fixed.

Taxi tests began in early 1940, but inspection revealed serious deterioration of the wing structures, which required extensive repair. These and further problems delayed the maiden flight until June 1943 (sources conflict as to whether it was 11 or 25 June.) The first flight was terminated early when the canopy was lost in mid-flight, but the pilot managed to land the plane safely. The Manx had only accumulated about 17 hours of flight time over approximately 30 flights when flight tests were finally terminated in April 1946. The sole example built was scrapped in 1952.

 

[gekho]

The Ro.57 was preceded by another twin engine fighter design, the Ro.53, which never entered production. The Ro.57 consisted of an all-metal, semi-monocoque fuselage with a steel skeleton and Duralumin structure. The wings were also Duralumin. Powered by two 840 hp (630 kW) Fiat A.74 radial engines giving a maximum speed of 516 km/h, which in 1939 was better than that of the main Italian fighter, the Macchi C.200 (504 km/h). After testing at Guidonia it was proposed by IMAM for use as a dive bomber. This transformation, which involved the addition of dive brakes, provision for 500 kg bombs and an improved forward firing armament (adding two 20 mm cannon), took time and delayed production. The resulting aircraft was designated the Ro.57bis. Performance dropped to 457 km/h maximum speed and to 350 km/h at cruise speed. The Ro.57bis was ordered into production in 1942 and entered service with the 97° Gruppo in 1943. About 50-60 aircraft were delivered. It is said that the Ro.57 could have been the long range interceptor that Italy lacked throughout the war. It proved to be too costly for the limited weapons it carried and it never was assigned a clear role. A better-armed version with more powerful engines was developed as the Ro.58.

 

[gekho]

These two aircraft, derived from the mass-produced Messerschmitt Bf 110, were quite similar, with only a slightly different glazed nose arrangement. The Bf 161 was intended to be a reconnaissance airplane and the Bf 162 a fast light bomber/ground attacker. They were powered with two 986-hp Daimler-Benz DB 601 A inverted-V-12 liquid-cooled engines; they had a maximum speed of 480 km/h (298 mph) and a range of 780 km (485 miles). Span was 17.16 m (56 ft 3.5 in), length was 12.75 m (41 ft 10 in), and empty weight was 4,400 kg (9,700 lbs). They had a crew of three. Proposed armament consisted of two MG 15 machine guns. The Bf 162 could carry ten 50- kg (110-lb) bombs and eventually two additional 250-kg (551-lb) bombs. First flown in 1937, they never made it, as the RLM preferred the Junkers Ju 88 because of the high production pressure on Messerschmitt (Bf 109 and Bf 110). Material for these airplanes were used in the Bf 110 production. Only three test prototypes were made in 1937 and 1938. Bf 162 prototype V1 was scrapped after trials. V2 and V3 were eventually later used for research.

 

[gekho]

The I-190 was an experimental fighter prototype produced by the Soviet Polikarpov Design Bureau, which sought in the late 1930's to enhance the performance of its I-153 biplane fighter. The I-153 was developed from the I-15, which had fought with distinction in the Spanish Civil War. The I-153 itself saw combat in a Soviet-Japanese border clash at Halhin Gol in Mongolia in 1939, proving itself a match for the Nakajima Ki-27, a state-of-the-art monoplane fighter with fixed landing gear.

The I-190's proponents at Polikarpov, encouraged by the brass in the Soviet VVS who believed biplanes would retain a role in the world's air forces, sought to extend the I-153's viability with improved performance in the face of a wave of new monoplane fighters introduced by the other major powers. Both the I-153 and the I-190 had a distinct look due to the inverted gull dihedral of the upper wing, a design aspect that was retained despite its unpopularity among pilots since it reduced their visibility. The I-190 had an enlarged double-row Shvetsov M88 radial engine of 1,100 horsepower, requiring a larger, longer, re-designed cowl. It also differed in appearance from the I-153 in having a spinner over the propeller, giving it a slightly more aerodynamic look.

 

[gekho]

In January 1945 Nakajima was ordered by the Imperial Japanese Army to design and develop, as quickly as possible, a basic aircraft that could carry a bomb of up to 800kg weight for use in kamikaze attacks. The resulting Nakajima Ki-115 low-wing monoplane prototype was of mixed construction, powered by a Nakajima Ha-35 radial engine and had welded steel-tube main landing gear units, without any form of shock absorption, which were intended to be jettisoned after take-off on a kamikaze mission. Flight tests showed that ground handling was unacceptable in this configuration, leading to the introduction of main landing gear units with simple shock absorbers. In this form, and incorporating some minor modifications, the aircraft entered production as the Ki-115a Tsurugi (sabre). However, Nakajima had built only 104 production aircraft by the time the war ended, and none of these was used operationally

 

[gekho]

During the course of 1937, the Service Technique de l'Aeronautique (STA) prepared a requirement for a T3 (Triplace de Travail) aircraft, a light three-seat twin intended to perform a variety of roles ranging from tactical reconnaissance and army co-operation to light-bombing and crew training. In the same time, due to the nationalization of the French aviation industry, Dewoitine had been amalgamated into the SNCAM (Société Nationale de Constructions Aéronautiques du Midi). To meet the STA requirement, the SNCAM began the design of the D.700 T3 in January 1938 and first metal was cut in May 1938, but shortly thereafter the STA altered the requirement stipulating the observer to be housed in the nose of the aircraft rather than in proposed ventral gondola. The aircraft was redesigned and the powerplants were switched from the intended two 220 hp Renault 6Q six-cylinder air-cooled inverted in-line engines to two 500 hp Renault 12R 00/01 twelve-cylinder air-cooled inverted V-engines, and the aircraft was redesignated D.720 T3.

Immediately aft of the co-pilot's seat was a mounting for an oblique F30 of F50 or ventral F70 camera. Alternatively, a Type F and two Type J racks for a total of twenty 22 lb (10 kg) bombs could be installed in this position. A single fixed forward-firing 0.3 in (7.5 mm) MAC 34 machinegun was to be installed for the pilot, while the radio-operator/gunner was to have two of these machineguns in a manually operated SAMMA B33 dorsal turret, and a single-one on a flexible mounting firing through a hatch in the floor. The prototype was first flown at Toulouse-Francazals by Marcel Doret on July 10, 1939, and after the completion of the manufacturer's flight test program, the aircraft was flown to the Centre d'Essais du Matériel Aérien (CEMA) at Orléans-Bricy on September 25, 1939, but by this time deliveries of the Potez 630 variants had begun to the Armée de l'Air, and as the crew training variant of this, the Potez 63.16 T3, was nearing completion, further development of the D.720 T3 seemed pointless, and the project was abandoned.

 

[gekho]

The Praga E-210 was designed as a four-seat tourer or air-taxi. It seems to have appeared in public for the first time at the Paris Exhibition of late 1936, though it is not known whether it had made its first flight by then. It was a high wing cantilever monoplane, with an enclosed cabin for four ahead of the wing and in 1936 a conventional tailwheel fixed undercarriage and single fin. It was unusual in adopting a pusher configuration, with two engines close to the fuselage driving small propellers. Its layout was thus much like that of the Carden-Baynes Bee, its almost exact contemporary though a much smaller aircraft. The wing of the E-210 was made in a single piece, a wooden structure built around two spars and plywood covered. The leading edge was significantly swept, but the trailing edge was straight. The ailerons were steel framed and fabric covered. Between them and the engines were Schrenk type landing flaps. The 85/95 hp (63/71 kW) Walter Minor four cylinder inverted in line engines were cantilevered from the rear spar on steel frames, with fairings both above and below the wings.

The flat sided fuselage was built on a steel tube framework, narrowing to the rear. The rounded nose and the cabin were plywood skinned and the rest fabric covered. The spatted mainwheels were mounted on short cantilever struts, making only a shallow angle to the ground and with the shock absorbers inside the fuselage. On the original aircraft there was a small castorable tailwheel, but later this was supplanted by a spatted, steerable nose wheel with a faired leg. By mid-1937 the original single fin had been replaced by a twin endplate fin arrangement. The fixed surfaces were wooden framed and plywood covered, the tailplane attached to the top of the fuselage and braced externally from below. The split elevators were fabric covered over wood, with trim tabs and the horn balanced rudders were of fabric covered steel. The cabin was well forward of the leading edge, providing good visibility, and seated four in two rows, the front seats having dual control. There was a baggage compartment behind the rear seats, accessible from inside. Photographs show that access to the cabin was through a single, port side door.

The date of the first flight is not known, but by the July 1937 Prague Aero Show it had been flying long enough for the directional control problem implied by the revised empennage to have been both recognised and addressed. It is also not known when the undercarriage was altered. There is a report from March 1939which says that the E-210 was then in production, though March was also the month of the German occupation of Czechoslovakia, so it is not clear if any further aircraft were completed. If so, they or the prototype may have been used by the occupying forces as transports, or following Flight's suggestion, as Army Co-Operation machines.