The Supermarine Type 224 was a British gull-wing monoplane

fighter aircraft Fighter aircraft (early on also ''pursuit aircraft'') are military aircraft designed primarily for air-to-air combat. In military conflict, the role of fighter aircraft is to establish air supremacy, air superiority of the battlespace. Domina ...

Supermarine Supermarine was a British aircraft manufacturer. It is most famous for producing the Spitfire fighter plane during World War II. The company built a range of seaplanes and flying boats, winning the Schneider Trophy for seaplanes with three cons ...

in response to Air Ministry Specification F.7/30, which sought to introduce a new fighter to succeed the

Gloster Gauntlet The Gloster Gauntlet was a single-seat biplane fighter designed and produced by the British aeroplane manufacturer Gloster Aircraft in the 1930s. It was the last fighter to be operated by the Royal Air Force (RAF) to have an open cockpit, and ...

. The Type 224 was powered by a

Rolls-Royce Goshawk The Rolls-Royce Goshawk was a development of the Rolls-Royce Kestrel that used evaporative or steam cooling. In line with Rolls-Royce convention of naming piston engines after birds of prey, it was named after the goshawk. The engine first ...

engine, which used an experimental

evaporative cooling An evaporative cooler (also known as evaporative air conditioner, swamp cooler, swamp box, desert cooler and wet air cooler) is a device that cools air through the evaporation of water. Evaporative cooling differs from other air conditioning sy ...

system. Problems with the cooling system, combined with its disappointing performance during trials, led to the Type 224 being rejected by the

Air Ministry The Air Ministry was a department of the Government of the United Kingdom with the responsibility of managing the affairs of the Royal Air Force and civil aviation that existed from 1918 to 1964. It was under the political authority of the ...

, a contract for production aircraft eventually going to the

Gloster Gladiator The Gloster Gladiator is a British biplane fighter. It was used by the Royal Air Force (RAF) and the Fleet Air Arm (FAA) (as the Sea Gladiator variant) and was exported to a number of other air forces during the late 1930s. Developed privat ...

. The type is nevertheless notable because Mitchell learnt lessons from its design that were to contribute to his success with the

Supermarine Spitfire The Supermarine Spitfire is a British single-seat fighter aircraft that was used by the Royal Air Force and other Allies of World War II, Allied countries before, during, and after World War II. It was the only British fighter produced conti ...

Design and development

Air Ministry Specification F.7/30

Air Ministry Specification F.7/30, which developed from O.R.1, was formally issued to the British aircraft industry in October 1931, called for an all-metal day and night

armed with four machine guns, a high maximum speed and

rate of climb In aeronautics, the rate of climb (RoC) is an aircraft's vertical speed, that is the positive or negative rate of altitude change with respect to time. In most ICAO member countries, even in otherwise metric countries, this is usually expressed ...

, and a landing speed of less than . The importance of good visibility from the

cockpit A cockpit or flight deck is the area, on the front part of an aircraft, spacecraft, or submersible, from which a pilot controls the vehicle. The cockpit of an aircraft contains flight instruments on an instrument panel, and the controls th ...

was specified. Although the use of any suitable engine was permitted, the

expressed a preference for the

, then still being developed. Designs tendered to the specification came from

Bristol Bristol () is a City status in the United Kingdom, cathedral city, unitary authority area and ceremonial county in South West England, the most populous city in the region. Built around the River Avon, Bristol, River Avon, it is bordered by t ...

, Hawker, Westland,

Blackburn Blackburn () is an industrial town and the administrative centre of the Blackburn with Darwen borough in Lancashire, England. The town is north of the West Pennine Moors on the southern edge of the River Ribble, Ribble Valley, east of Preston ...

and Supermarine Of the proposals submitted by British aircraft manufacturers, three were officially selected to produce prototypes for the Air MInistry, Supermarine (the Type 224), Blackburn ( Blackburn F.3), and Westland ( Westland F.7/30). Hawker had both its biplane and monoplane designs rejected but built the Hawker P.V.3, as a private venture, similarly Bristol had three rejected and built both the Bristol Type 123 biplane and Bristol Type 133 (a monoplane) with its own money. Gloster had not tendered a submission as they were engaged on the Gloster Gauntlet, but later built their private venture Gloster SS.37 using Hawker construction techniques to improve their Gauntlet design. As a result of the success of Supermarine during the

Schneider Trophy The Coupe d'Aviation Maritime Jacques Schneider, also known as the Schneider Trophy, Schneider Prize or (incorrectly) the Schneider Cup is a trophy that was awarded first annually, and later biennially, to the winner of a race for seaplanes and ...

contests, Supermarine's chief designer R. J. Mitchell was confident that he could design a highspeed fighter. Less than four months after receiving the specification, Supermarine tendered a

monoplane A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple wings. A monoplane has inherently the highest efficiency and lowest drag of any wing con ...

design, the Type 224.

Mitchell's design

Mitchell's design for the Type 224 included an inverted gull-wing, chosen in order to shorten the undercarriage legs and so reduce drag. He chose a thick airfoil for the wing, in contrast to the type of airfoil for the Schneider Trophy racers. The fixed landing gear were encased in large fairings. The fuselage was of

monocoque Monocoque ( ), also called structural skin, is a structural system in which loads are supported by an object's external skin, in a manner similar to an egg shell. The word ''monocoque'' is a French term for "single shell". First used for boats, ...

construction, with one pair of guns mounted either side of the cockpit and the other pair in the 'trouser' fairings of the undercarriage, which was fixed. The wing had a single main spar. The engine cooling system's

condensers __NOTOC__ Condenser may refer to: Heat transfer * Condenser (heat transfer), a device or unit used to condense vapor into liquid. Specific types include: ** Heat exchanger#HVAC and refrigeration air coils, HVAC air coils ** Condenser (laboratory), ...

formed the wing's entire leading edge, the combination of the two producing a 'D-box' spar that had a high torsional

stiffness Stiffness is the extent to which an object resists deformation in response to an applied force. The complementary concept is flexibility or pliability: the more flexible an object is, the less stiff it is. Calculations The stiffness, k, of a ...

. Behind the main spar the wing was fabric-covered. The Type 224 was powered by the Goshawk II. The evaporative cooling system used by the Goshawk involved allowing the cooling water to reach a temperature greater than without boiling by keeping it under pressure while circulating through the engine: this superheated water was then allowed to boil off by releasing the pressure, the resulting steam then being cooled in a condenser, collected as water and then recirculated through the engine. The system had been experimentally flown in other aircraft, but these were all biplanes, and the condensers and collector tank for the condensed water were all mounted in the upper wing. In the Type 224 the collector tanks were in the undercarriage fairings, and, as the condensed water was nearly at boiling point, it was liable to turn to steam under any slight change of pressure; this frequently occurred in the water pumps and would cause them to stop working.

Tests and subsequent development

Mitchell was not a proponent of the use of

wind tunnel A wind tunnel is "an apparatus for producing a controlled stream of air for conducting aerodynamic experiments". The experiment is conducted in the test section of the wind tunnel and a complete tunnel configuration includes air ducting to and f ...

tests, but the

Vickers Vickers was a British engineering company that existed from 1828 until 1999. It was formed in Sheffield as a steel foundry by Edward Vickers and his father-in-law, and soon became famous for casting church bells. The company went public in 18 ...

wind tunnel was used to test aspects of the design of the Type 224, and the results obtained indicated the superiority of a gull-wing design. Wind-tunnel tests were carried out on a full-size model of the open cockpit area to ensure that the pilot would not be subjected to undue buffeting due to the design of the windscreen. Supermarine submitted information on the predicted performance of the Type 224 to the Air Ministry based on the wind-tunnel data, which suggested that the aircraft would perform well, and in response, the ministry issued a production contact for a prototype. The Type 224 first flew on 19 February 1934, piloted by "Mutt" Summers. Its performance was disappointing—the maximum speed was and it took 9.5 minutes to climb to , well below the predicted performance of a speed and climb to in 6.6 minutes. The wing design created issues with lateral stability, and further wind-tunnel tests were carried out before the design was finalised, when Mitchell enlarged the

fin A fin is a thin component or appendage attached to a larger body or structure. Fins typically function as foils that produce lift or thrust, or provide the ability to steer or stabilize motion while traveling in water, air, or other fluids. F ...

Fate

Mitchell was in discussions about a number of improvements to the Type 224—a new wing,

tailplane A tailplane, also known as a horizontal stabilizer, is a small lift (force), lifting surface located on the tail (empennage) behind the main lifting surfaces of a fixed-wing aircraft as well as other non-fixed-wing aircraft such as helicopters ...

, and engine arrangements—which would give it a top speed of , but the Air Ministry decided that a new aircraft, rather than a modification of the Type 224, was called for. In 1933. In January 1935, further construction was cancelled. Mitchell was disappointed in the Type 224’s under-performance, and came to doubt the reliability of the data produced by wind-tunnel tests. Gloster's private venture was ordered in mid-1935 as the Gladiator to equip the expanding RAF. On 25 May 1937 the aircraft was transferred to the Aeroplane and Armament Experimental Establishment at

RAF Martlesham Heath Royal Air Force Martlesham Heath or more simply RAF Martlesham Heath is a former Royal Air Force station located southwest of Woodbridge, Suffolk, England. It was active between 1917 and 1963, and played an important role in the development o ...

. It ended its career during the summer of 1937, when it was used as for target practice at

Orford Ness Orford Ness is a cuspate foreland shingle spit on the Suffolk coast in Great Britain, linked to the mainland at Aldeburgh and stretching along the coast to Orford and down to North Weir Point, opposite Shingle Street. It is divided from th ...

Suffolk Suffolk ( ) is a ceremonial county in the East of England and East Anglia. It is bordered by Norfolk to the north, the North Sea to the east, Essex to the south, and Cambridgeshire to the west. Ipswich is the largest settlement and the county ...

Legacy

The failure of the Type 224, coming soon after the Schneider racer successes, did not cause Mitchell to lose faith in his ability to design a fighter. He completely redesigned the type, producing a new design with straight wings and a thinner airfoil shape. The Air Ministry quickly realized that Mitchell’s new design was a new airplane. It wanted a fighter designed by Mitchell and his team, and in January 1935 it issued Specification F.37/34, for the sole purpose of covering a new design by Supermarine. The specification, essentially an addendum to specification F.7/30 mentioning Supermarines specification 425a and drawing, led on to the design of the

. Supermarine had asked the Air Ministry for the name ''Spitfire'' to be reserved for the type. The name was adopted, but Mitchell disliked it, and the use of it for the Type 224 was later dropped.

Specifications (Supermarine Type 224)

Notes

References

Sources

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External links

Images of the Type 224
from Destination's Journey
Archived
from the original on 29 March 2024). {{Supermarine aircraft Type 224 1930s British fighter aircraft Low-wing aircraft Inverted gull-wing aircraft Single-engined tractor aircraft Single-engined piston aircraft Aircraft with fixed conventional landing gear Aircraft first flown in 1934 Cancelled military aircraft projects of the United Kingdom