Oddball, Experimental, or One-off

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The Cunningham-Hall GA-21 was an American two-seat monoplane design to compete for the Guggenheim Safe Aircraft Competition in 1934. Its distinguishing feature was full span flaps which could be manually or automatically adjusted. The GA-36 was a military version of it with tandem, rather than side-by-side seating.

 

The GA-21M was all metal aircraft apart from the fabric covering of parts of the wing, otherwise metal-covered, and the control surfaces. The low-set wings were rectangular in plan out to rounded tips and had a high lift section. Both flaps and ailerons filled the whole straight part of the trailing edge, so the latter only opened upwards.

 

Apart from its unusual flaps and lateral control the GA-21M was conventional. Powered by a 145 hp (108 kW), seven cylinder Warner Super Scarab radial engine, it had a round-sectioned, metal-skinned, monocoque fuselage. An open cockpit over the forward wing seated two side-by-side. The tailplane was mounted just above the fuselage on the fin and could be trimmed; essentially triangular in plan, it carried rounded elevators. A rounded rudder reached down to the keel.

 

The GA-21Ms had conventional, tailwheel landing gear with the landing wheels ahead of the leading edge within aircraft fairings that also enclosed the legs.

 

The GA-36 was a 1936 military trainer rebuild of the Ga-21M. This included a revised, tandem cockpit and more trouser-like landing gear fairings, making it 15% heavier.

 

The automated flaps worked well but were more complicated than, for example, Fowler flaps and more expensive to construct. Simpler systems were preferred and the sole GA-21M/36 was sold in 1941, stripped of major components and dumped until the 1980s when it was recovered, fully restored and put on display at the Niagara Aerospace Museum.

 

GA-21M

 

GA-36

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The Martin XB-51 was an American trijet ground-attack aircraft. It was designed in 1945 and made its maiden flight in 1949. It was originally designed as a bomber for the United States Army Air Forces under specification V-8237-1 and was designated XA-45. The "A" ground-attack classification was eliminated the next year, and the XB-51 designation was assigned instead. The requirement was for low-level bombing and close support. The XB-51 lost out in evaluation to the English Electric Canberra which — built by Martin — entered service as the Martin B-57 Canberra.

 

This unorthodox design, first flying on 28 October 1949, was fitted with three General Electric J47 engines - an unusual number for a combat aircraft - two underneath the forward fuselage in pods, and one at the extreme tail with the intake at the base of the tailfin. The innovative, variable incidence wings, swept at 35° and with 6° anhedral, were equipped with leading edge slats and full-width flaps. Spoilers gave most of the roll control and undersized ailerons provided feel for the pilot. The combination of variable incidence and slotted flaps gave a shorter takeoff run. Four 954 lb (4.24 kN) thrust Rocket-Assisted Take Off (RATO) bottles with a 14-second burn duration could be fitted to the rear fuselage to improve takeoff performance. Spectacular launches were a feature of later test flights.

 

The main landing gear consisted of dual wheel sets in tandem in the fuselage, similar to the Boeing B-47 Stratojet, with outrigger wheels at the wingtips (originally proved on a modified Martin B-26 Marauder named "Middle River Stump Jumper"). The XB-51 was a large but aerodynamically "clean" design which incorporated nearly all major systems internally. The aircraft was fitted with a rotating bomb bay, a Martin trademark; bombs could also be carried externally up to a maximum load of 10,400 lb (4,700 kg), although the specified basic mission required only a 4,000 lb (1,814 kg) bombload. Eight 20 mm cannon mounted in the nose would have been installed in production aircraft.

 

Crew was a pilot under a "fighter"-type bubble canopy and a Short-range navigation and bombing system (SHORAN) operator/navigator in a compartment located lower than and to the rear of the cockpit (only a small observation window was provided). Both crew members were provided with a pressurized, air conditioned environment, equipped with upward-firing ejection seats. The XB-51 was the first Martin aircraft equipped with ejection seats, these being of their own design.Number built - 2.

 

 

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The Epic Victory was the second experimental jet designed by Epic Aircraft, a company that was based in Bend, Oregon. Epic Aircraft declared bankruptcy in 2009. Its assets were acquired by Aviation Industry Corporation of China and LT Builders Group; which as of July 2010 were in the process of restarting production of the Victory.

 

The Victory is a single-engine very light jet that was intended to be powered by a single Pratt & Whitney Canada PW600. Epic used the Williams FJ33 engine for testing but planned to switch to the PW600 for final production.

 

The aircraft seats 4 to 5, including the pilots, in a 2+2 or a 2+1+2 configuration. The aircraft took Epic six and a half months to design from concept to a flying prototype, with the first flight on 6 July 2007 from Roberts Field in Redmond, Oregon.

 

The company had intended that the jet would be available for less than US$1 million. The aircraft was displayed at the Experimental Aircraft Association's AirVenture fly-in in 2007 at Oshkosh, Wisconsin, where the company began accepting down payments.

The prototype's Federal Aviation Administration registration expired on 31 May 2017. It has not been renewed and the aircraft has been deregistered.

 

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The Douglas XTB2D Skypirate (also known as the Devastator II) was a torpedo bomber intended for service with the United States Navy's Midway- and Essex-class aircraft carriers; it was too large for earlier decks. Two prototypes were completed, but the dedicated torpedo bomber was becoming an outdated concept, and with the end of World War II, the type was deemed unnecessary and cancelled.

 

In 1939, Douglas designers Ed Heinemann and Bob Donovan began work on a VTB Proposal to replace the TBD Devastator torpedo bomber. In 1942, the team led by Heinemann and Donovan began work on a new project named the "Devastator II". On 31 October 1943, just four days after the very large Midway-class aircraft carriers were ordered into production, Douglas received a contract for two prototypes, designated TB2D, receiving the official name: "Skypirate".

 

The TB2D was powered by a Pratt & Whitney R-4360 Wasp Major driving contra-rotating propellers. Four torpedoes (such as the Mark 13 torpedo) or an equivalent bomb load could be carried on underwing pylons. Defensive armament consisted of two 20 mm (.79 in) cannon in the wings and .50 in (12.7 mm) machine guns mounted in a power-operated dorsal turret.

 

Very large for a single-engined aircraft, the TB2D would have been the largest carrierborne aircraft at the time; it could carry four times the weapon load of the Grumman TBF Avenger. With only limited support from the US Navy, and facing a recommendation for cancellation on 20 May 1944 due to the aircraft being designed only for the CVB carriers, the TB2D project was in peril even at the design and mockup stage.

 

 

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The Dyle et Bacalan DB-70 was a large three engine French airliner with a thick airfoil centre section which accommodated the passengers. Two fuselages, part of the centre section at the front but distinct further aft, carried the empennage. First flown in 1929, only one was built.

 

In 1925 the large naval ship builders Société Anonyme de Travaux Dyle et Bacalan, established in 1879 and based in Bordeaux, developed an aircraft manufacturing interest. They built several all-metal prototypes incorporating very thick wings. The DB-70 was the largest of these and the last to carry the company name: Dyle et Bacalan ceased trading in July 1929, before the DB-70 had flown, though the company reformed as Société Aérienne Bordelaise (SAB) that same month. As a result, the aircraft is sometimes referred to as the SAB DB-70; the letter prefix DB was retained, though aircraft designed later by SAB used the AB- form .

 

The DB-70 was a very large, all metal aircraft built, like all Dyle et Bacalan aircraft, largely of duralumin. As on the 1926 DB-10, the centre section of the wing of the DB-70 was extremely thick and twice the chord of the outer wings, with a chord/thickness ratio of about 25%. The layout of the two designs was different, though; the otherwise conventionally laid-out DB-10 had thick wings inboard of its two engines, whereas the DB-70 was built around its thick centre section with twin fuselages, developed from it rearwards, carrying the empennage. The centre section also mounted the three 450 kW (600 hp) Hispano-Suiza water-cooled inline engines and the pilots' cockpit and enclosed the passenger accommodation.

 

More details here.

 

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The Hanriot H.110 was an unusual pusher configuration, twin boom, single seat fighter aircraft built in France in the early 1930s. It proved to be slower and less manoeuvrable than its contemporaries and failed to reach production, even as the Hanriot H.115 after receiving a more powerful engine and cannon armament.

 

From 1916 until 1933, the only Hanriot fighter aircraft had been tractor biplanes. The Hanriot H.110, a twin boom pusher cantilever monoplane was therefore a considerable departure from the past. It was designed to compete in the STAé (Service Technique de l'Aéronautique or Technical Section of Aeronautics) 1930/31 C1 (single seat Chasseur of fighter) programme.

 

The all-metal H.110 had an open cockpit and engine in a short central nacelle. It was powered by a 485 kW (650 hp) Hispano-Suiza 12Xbrs supercharged upright water-cooled V-12 engine behind the pilot, driving a three-blade pusher propeller. The pilot's headrest was smoothly faired into the engine cowling. There was a circular Chausson radiator in the short nose ahead of the open cockpit, with a variable position central cone to control the airflow.

 

The wings were built around two spars. The central 25% of their span, between the booms, had constant chord. Immediately outboard they had a wider chord and beyond were double straight tapered to rounded tips. They carried almost full-span, narrow-chord Frise ailerons. Forward, the slim, square section and untapered tail booms blended into the wings at about mid-chord, the aft ends carrying a constant-chord tailplane slightly above them. This had rounded tips and a central elevator with a trim tab. A central, single, tall, round-tipped, wire-braced vertical tail was mounted on in it. The H.110 had a fixed, split, conventional undercarriage with each spatted mainwheel on a faired, near vertical shock absorber and a rearward leaning strut together forming a V, laterally braced with an inverted V-strut attached near the under-fuselage centre line. There was a central tailwheel on a long leg under the fin.

 

The H.110 began flight testing in April 1933. Tested against its smaller and lighter competitors, it proved slower and less manoeuvrable and was returned to Hanriot for modification. It flew in April 1934 as the H.115, with its HS 12Xbrs engine uprated to 515 kW (691 hp), a new four-blade propeller with variable-pitch and a revised nacelle, shortened forward of the cockpit by 360 mm (14.2 in). A 33 mm (1.30 in) APX cannon was now housed in a fairing below the nacelle as an alternative to the earlier pair of Chatellerault 7.5 mm (0.295 in) machine guns. With its new engine and propeller the H.115 was quicker than the earlier version, with a top speed of 390 km/h (242 mph). After more modifications over the winter of 1934-5 it returned to Villacoublay in June 1935 and was officially flight tested until mid August, but failed to attract a contract.

 

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The Hodkinson HT-1 was a U.S., eight place, three-engined sesquiplane, first flown in 1929. Despite an order for five, only one had been completed before Hodkinson Aircraft went bankrupt near the start of the Great Depression. It operated in Guatemala for several years.

 

Hodkinson Aircraft was founded in 1929 by William Wadsworth Hodkinson, one of the pioneers of the film industry who in 1916 had organized Paramount Pictures. He later went into film distribution, founding the W.W.Hodkinson Co. and then moved into the aviation business. The HT-1 was built by Valley Manufacturing Co. a division of Hodkinson Aircraft based in Glendale, California. Its designer, Don R. Berlin, later designed the Curtiss P-40.

 

The wings of the HT-1 were both built around spruce spars and had rectangular plans out to rounded tips. The upper wing, with three-quarters of the total wing area, provided most of the lift and mounted narrow chord, Friese ailerons that reached from wingtips to above the outer engines. The short, lower wings were braced to the upper ones with parallel interplane struts between the wing spars.

 

The HT-1 was powered by three 170 hp (130 kW) Curtiss Challenger radial engines, one in the nose and the others on top of the lower wing, braced by vertical struts to the upper spars. Behind the central engine the fuselage was flat sided, with the wing centre-section fixed to it by inverted V cabane struts faired into the fuselage's chrome-molybdenum tube structure. These provided a clear rear view from the pilots' cabin under the leading edge of the wing. Pilot and co-pilot sat side-by-side with dual controls, though the co-pilot's controls could be removed to allow an extra passenger to be carried. Their cabin was normally accessed through doors on either side but there was also a door in the rear which led down to the passengers' windowed, six seat cabin. There was a toilet at the back and also a baggage compartment, though this was only accessible from outside. Cabin access was via doors on either side, opening just ahead of the rear seats.

 

Its tail was conventional, The fixed surfaces, like the fuselage, had chrome-molybdenum tube structures and the tailplane was mounted on top of the fuselage. The fin was braced to the tailplane and had a cropped, roughly triangular profile. The balanced rudder had a blunted rectangular profile.