Thanks folks! And
Brian, here's more trousered Supermarines
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Were it not for its connection to the
Spitfire, Supermarine's Type 224 fighter would be all but forgotten. Developed to Air Ministry Specification F.7/30, the Type 224 was flown in 1932 and then delivered to Martlesham Heath for trials. The single-seat fighter was judged overly large, lacking in manoeuvrability, and powered by a troublesome engine - the Roll-Royce
Goshawk steam-cooled V-12.
When returned to Supermarine, the fighter was rebuilt as a two-seater - the Type 224C - to meet Air Ministry Specification P.30/32 for a divebomber also capable of performing tactical support. This spec was meant as a complement to P.27/32 for a conventional light day bomber - the Fairey
Battle, P.30/32 demanded a relatively high performance with points for an airframe based upon an inservice type. Supermarine used the Type 224's extended tenure at RAF Martlesham Heath to claim that aircraft as an inservice type. [1] The rebuilt Supermarine Type 224C was returned to RAF Martlesham Heath for renewed trials.
Modifications to the Type 224 fighter were kept to a minimum. The fuselage was slightly extended to accommodate a lighter Rolls-Royce
Kestrel V engine and a second cockpit for the rear gunner. Forward-firing armament was reduced to two machine guns and flaps were introduced to the now metal-skinned wings. [2] Germain to the divebombing role was the mounting of pivoting stub-wings on the undercarriage fairings to act as dive brakes. Main armament was a swinging crutch-mounted 500 lb GP bomb (or a 250 lb GP on the crutch with up to 4 x 50 lb bombs on outer wing racks).
[Top] The Supermarine 224C (K3660) divebomber prototype upon its arrival at RAF Martlesham Heath
The Martlesham Health report criticized the pivoting dive brakes - that installation proving both ineffectual and to be the cause of extreme buffeting - and the new cockpit arrangement - the rear cockpit being extremely cramped while the side-hinged transparent hood did not afford the pilot a clear view on landing. Although the Type 224C was to be a temporary type, its dive brakes clearly needed redesigning. However, Supermarine had already planned for a more capacious rear cockpit and it was a simple matter to modify the pilot's canopy to slide aft for landings.
The Type 224C was also underpowered. To address this, the prototype was re-engined with a new 990 hp
Merlin C. Pending solving of the dive brake issue, Supermarine was given another contract for the production of 20 Type 224Cs to be known as the
Spectre in RAF service. [3] Rather than attempt to iron out problems with the pivoting stub-wings, Supermarine 'borrowed' a solution from contemporary US Northrop designs. The outer portions of the new wing flaps were perforated to act as dive brakes. The Air Ministry accepted this approach and production began.
The Supermarine
Spectre Mk.I entered RAF service in early 1936. On production models, the fixed, forward-firing armament consisted of two wing-mounted Vickers machine guns and a flexibly-mounted Lewis gun in the rear cockpit (although the latter was often not fitted in service). The '
Spinster' divebomber performed the role for which it was designed but was never popular with crews. The
Merlin I-powered
Spectre Mk.I equipped only one RAF squadron before being withdrawn from service in the early 1938.
Shortly after the
Spectre's withdrawl, reports on German use of their
Stuka in Spain began to be taken seriously by RAF intelligence. Planners mused on whether the
Spectre might not be used in training to familiarized RAF fighter pilots with the interception of such divebombers. By the end of 1938, the
Spectres had been returned to Supermarine for a refit and modernization. [4] Work proceeded slowly with Supermarine needing to give priority to its
Spitfire fighters. Extra urgency came with the declaration of war on Germany.
The events of September 1939 fully vindicated the German
Stuka and the RAF switch emphasis on the
Spectre rebuild to a fully operational service type. Although only 15
Spectres would be upgraded to full Mk.II standard, the goal was to fill a capability gap and train crews until the RAF's
Merlin-Skua divebombers came into service. In the end, the rebuilt
Spectres re-entered service in July 1940 - just in time for anti-invasion duty. After the invasion scare receded, the
Spectre squadron was stood down and the remaining aircraft transferred to target-tug duties.
[Bottom]
Merlin-engined Supermarine
Spectre Mk.II in late August 1940 (note 'gas patch' on upper rear fuselage)
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[1] Hawker submitted a slightly-strengthened
Hart biplane for P.30/32 although this aircraft failed to meet the Specification's top speed requirements.
[2] The wings were strengthened through the use of thicker-gauge metal covering (which also replaced the aft-of-spar wing fabric). The false rear spar was also beefed up.
[3] Supermarine has proposed the name
Surefire for the Type 224C but this was rejected.
[4] The most noticable external changes were enlarged rudders and new canopies - a bulged
Spitfire-style pilot's hood and moulded rear canopies replacing the earlier 'birdcage' type. Obvious on the ground were the new three-bladed de Havilland variable-speed propellers replacing the fixed-pitch Watts two-bladers.