Why has the Royal Navy naval strike monoplane aircraft development been delayed for so long ?

British companies designed five major monoplane aircraft for the Royal Navy over the course of WWII, not counting the navalised Sea Hurricane or Seafire. The Blackburn Skua was in service as a dive-bomber and fighter at the start of the war. The Fairey Fulmar was built as a fighter and recon aircraft in 1940-43; the Fairey Firefly, developed by the same company for a similar role, would enter service in 1943. Fairey's other contribution was the Barracuda, a dive/torpedo-bomber, which also entered service in 1943. The last aircraft was Blackburn's Firebrand, first conceived as a fighter, which wound up being stuck in development hell for the duration of the war and only entered service as a strike fighter in September 1945. Other aircraft, like the Sea Mosquito, Sea Hornet, Sea Fury or Spearfish, were largely postwar developments.

To understand the difficulty that the Fleet Air Arm had with procuring new aircraft during the war, it is important to understand the pre-war organisation of British naval aviation. I've previously covered this in another answer, but I will summarise it here. In April 1918, the Royal Naval Air Service and the Army's Royal Flying Corps were merged to form the Royal Air Force. The vast majority of the RN's pilot, and senior officers interested in or experienced with aviation, joined the new service. This meant that the RN had few officers who understood what aircraft could do, or how the technology was changing. The RAF, for its own part, was much more interested in winning wars through strategic bombing, rather than cooperating with the Navy. While there were a number of compromises over the course of the interwar period that shifted power over the Fleet Air Arm back towards the RN (culminating with the Inskip Award of 1937-9 that handed it over to the Navy), it remained a neglected part of both services. This was particularly true of aircraft procurement. The Royal Navy was responsible for setting the parameters it wanted for new aircraft, but didn't have a strong idea what aircraft could do; the RAF was responsible for funding new naval aircraft, which it didn't want to do. This resulted in severe compromises being made with naval aircraft, as we shall see.

In the late 1930s, the state of the art in the Fleet Air Arm's carrier force was the Blackburn Skua, a monoplane dive-bomber/fighter and the biplane Fairey Swordfish torpedo-reconnaissance aircraft. While they were relatively new aircraft, with the Swordfish entering service in 1936 and the Skua in 1938, it was clear that they would soon be overtaken by the pace of new technology. In 1936, two new specifications were set out for strike aircraft. M.7/36 called for a new torpedo-bomber, while S.41/36 was for a new dive-bomber-reconnaissance aircraft. M.7/36 was aimed purely at Fairey at the Admiralty's request, while S.41/36 was open to tenders from other companies; none applied, and the two were combined in February 1937. Fairey produced two designs to the new specification, with both monoplane and biplane versions. The Air Ministry advised the Admiralty that the monoplane was too radical, and that the biplane was more appropriate. The Admiralty followed this advice, and the result was the Albacore. While this had incremental improvements over the Swordfish, such as an enclosed, heated cockpit, flaps, and a variable pitch propeller, it was not so clear an improvement to completely supercede it. Instead, its worse reliability and handling meant that it was outlasted by the aircraft it was intended to replace. While the Albacore could replace the Skua and Swordfish in the dive/torpedo-bomber roles, the RN would still need a fighter and reconnaissance aircraft. This role would be filled by another Fairey product. The company had produced a prototype light bomber to the RAF's P.4/34 specification for a light bomber to replace the Battle. This aircraft suited many of the Navy's needs, being fairly long-ranged, having a second seat for an observer to navigate and spot enemy ships, and being capable of making the radical manoeuvres that a fighter would need to make. Specification O.8/38 was written for a navalised version of this aircraft, which would become the Fulmar. While redesigning the aircraft to have the features the Navy wanted took some time, the trials phase of Fulmar was shorter due to the existence of the prototype P.4/34. It entered squadron service in June 1940, and first saw combat service in the Mediterranean in September. It was a fairly capable aircraft, but not up to the standards set by contemporary land-based aircraft. It also had a degree of strike capability, with the Fulmar II model (built from January 1941) having provision for 500 lbs of bombs.

While work on these two new aircraft were underway, neither of them were expected to be in service for long. Work had already begun on designing their successors. On the 6th January 1938, the Air Ministry issued S.24/37, for a monoplane torpedo/dive-bomber and reconnaissance aircraft. Six companies produced designs: Blackburn, Bristol, Fairey, Hawker, Supermarine and Westland. Blackburn's design was rejected straight away as a poor design. Supermarine's design, which used a number of new technologies, was seen as too experimental. While two prototypes were built as technology demonstrators, it was not accepted for full-scale production. Prototypes were ordered from Fairey, Hawker and Westland, but the latter two companies were overstretched with work for the RAF. As such, the Fairey aircraft was ordered in January 1939 as the Barracuda. As originally designed, it was to be powered by the Rolls Royce Exe engine, an innovative 24 cylinder design that produced the same power as the Merlin, but in a smaller, lighter package. However, work on the Exe was suspended in December 1939, to allow Rolls Royce to put more energy into further developments of the already mature Merlin. The Barracuda would be re-engined with the Merlin, but this resulted in severe delays to the design. The heavier, longer new engine meant problems with the centre-of-gravity, which were hard to rectify with the RN's requirements for good visibility. The wing had to be moved to a higher position as a result, which in turn meant engineering problems for the retracting undercarriage. These problems took a lot of time to solve, and the Barracuda would only enter service in 1943 as a result. By this time, it was considerably overweight and underpowered, inferior to its American equivalent in the Avenger.

There were also two fighter specifications, N.8/39 and N.9/39, set out on the 21st June 1939. The former was for a two-seat fighter to replace the Fulmar, while the latter was for a turret fighter like the Roc or the RAF's Defiant. Five companies produced designs to N.8/39 - Blackburn, Fairey, Gloster, Hawker and Supermarine - while Blackburn, Fairey, Gloster, Hawker and Westland all produced turret fighter designs. Supermarine's design for N.8/39, an enlarged Spitfire with an inverted gull wing, was preferred. However, on the 23rd December 1939, the RN cancelled both specifications and released new ones, based on war experience. Now, there was no call for a turret fighter. Instead, the RN wanted a two-seat fighter capable of 300 knots, and a single-seater capable of at least 330. The design process for these aircraft was fairly swift, with the two-seater designs being considered on the 5th January 1940. Ultimately, Fairey's design, seen as being the most realistic and capable of those submitted, was ordered on the 1st March as the Firefly. This was to be the RN's main carrier fighter, and was to have two seats (as it wouldn't need to protect multiple dispersed targets like a land-based single-seater, speed was seen as less necessary at this stage of the war). The Firefly prototypes first flew on the 22nd December 1941, but a crash in one aircraft on the 26th June 1942 led to delays while the elevators were redesigned. This meant that the Firefly would not see fleet service until March 1943.

While the RN saw its main carrier fighter as a two-man aircraft, it still felt it needed a single-seat fighter. This was to protect naval bases, or to act as an interceptor in defence of ships at sea. These were ordered from Blackburn, partly to spread around naval contracts and avoid giving every contract to Fairey, partly because Hawker and Supermarine, which had produced superior designs, were busy with RAF work and partly because Blackburn's design had some interesting features the RN wanted to see expanded upon. The order was placed on the 25th July 1942, with the first prototype flying 18 months later in February 1942. Blackburn's design was originally fitted with a Napier Sabre. However, this engine would be allocated in its entirety to the RAF for the Hawker Typhoon. This meant that a new engine had to be fitted, the Bristol Centaurus. Re-engining the aircraft took time, during which the single-seat fighter role was filled by the Seafire. The Firebrand soon found itself taking the strike role, to avoid wasting the development work. However, the conversion process was slow. While 27 Firebrand TF.IIIs were produced from November 1944, most of these would be retained by Blackburns to work on improvements to the aircraft. The TF.4 was the first version to see real service, but only after the end of the war.