More Stingrays!
After 22 Stingray Mk. II were delivered to the RBCN, the FAA decided to order 14 more. These were slightly modified, being armed with four Browning machine guns instead of two Vickers machine guns. Otherwise identical to the Mk. II, the
Stingray Mk. III were delivered in 1934, painted in the overall Cerrux grey scheme authorised that year. Though sufficient to needs, the Stingrays were not especially popular with pilots during the winter!
The Stingray Mk. II and Mk. III were somewhat underpowered, so upon learning of Hoffar's new prototype engine, the Petrel, the Admiralty ordered a single Mk. III to be modified to use the new engine in 1935. The resulting
Stingray Mk. IV prototype was the first aircraft to be powered by the experimental HLV-12X engine. At 600 hp, the Petrel produced 75 hp more than the Harrier engine that powered the earlier Stingrays, and while not an enormous jump, it was noticeable. Add to that the fact that the production version of the Petrel was to produce 700 hp, and the FAA decided this was a worthwhile project and decided to continue.
The RBCN ordered the construction of two new prototypes, designed from the outset to use the new HLV-12A engine, the first production version of Hoffar's Petrel engine. This produced 700 hp, which finally gave the Stingray the performance it needed to become more than 'adequate'. The new design also addressed pilots' major complaint, the open cockpit being unfriendly in the winter. The two
Stingray Mk. V prototypes were built to the new specifications, with an all-new fuselage being built for the first prototype, whilst using the wings, floats and empennage of a damaged Mk. II; the second prototype, X16, was built all-new. Delivered to the Navy in mid 1936, they were extensively tested, then after production was ordered, the two remained in use as conversion trainers until the end of 1937.
The Admiralty ordered the production of 32 Mk. Vs in December of 1936, but when Hoffar informed the Navy that an uprated version of the Petrel would enter production in March of 1937, the FAA decided to delay the order. The new engine, the HLV-12A-2, replaced the direct fuel injection of the 12A with an updraught Bendix carburettor, and along with some other modifications, the result was a major performance boost. With 880 hp available, the
Stingray Mk. VI was a capable fighter, and Supermarine immediately began working on a more advanced variant, with all-new wings, with an eye to keeping up with the advances being made at Hoffar's. In the end, however, development of further Stingray variants was abandoned in favour of the new float-based Sea Skemcis SF.
The sky grey over white scheme introduced at the end of 1936 for flying boats and permanently float-equipped aircraft turned out to be short-lived, as in the spring of 1938 a new scheme was introduced, of extra dark sea grey and dark slate grey camouflage over Cerrux grey undersides. The Stingray Mk. VI entered squadron service in the summer of 1937, but by the autumn of 1940 they began to be withdrawn, to be replaced by the newly-arriving Sea Skemcis SF Mk. I. However, the outbreak of the Pacific war in December 1941 resulted in a brief respite for the Stingrays. New squadrons were raised to operate the newly-built Sea Skemcis SF Mk. I and SF Mk. II aircraft, and around a dozen Stingrays remained in service until late 1942, when they were finally replaced by the Sea Skemcis SF Mk. III.
