The Barracuda resulted from Air Ministry Specification S.24/37 issued in 1937 for a monoplane torpedo bomber to meet Operational Requirement OR.35. Of the six submissions, the designs of Fairey Aviation and Supermarine (Type 322) were selected and two prototypes of each ordered. The first Fairey prototype flew on 7 December 1940. The Supermarine Type 322 first flew in 1943 but with the Barracuda already in production it did not progress further.
The Barracuda was a shoulder-wing cantilever monoplane with an oval, all-metal fuselage. It had a retractable landing gear and non-retracting tailwheel. The hydraulically-operated main landing gear struts were of an "L" shape and retracted into a recess in the side of the fuselage, with the wheels held in the wing. A flush arrestor hook was fitted ahead of the tail wheel. The crew of three were in tandem under a continuous glazed canopy. The pilot had a sliding canopy and the other two crew members' canopy was hinged. The two rear-crew had alternate locations in the fuselage, with the navigator having bay windows below the wings for downward visibility. The wings had large Fairey-Youngman flaps that doubled as dive brakes. Originally fitted with a conventional tail, flight tests suggested stability would be improved by mounting the stabiliser higher, similar to a T-tail, which was implemented on the second prototype.
The Barracuda was originally intended to use the Rolls-Royce Exe X block, sleeve valve engine, but production of this powerplant was abandoned, which delayed the prototype's trials. The prototypes eventually flew with the lower-powered 12-cylinder Vee type Rolls-Royce Merlin 30 engine (1,260 hp/940 kW) and a three-bladed de Havilland propeller. Further experience with the prototypes and the first production machines (Barracuda Mk I) revealed the aircraft to be underpowered as a result of the weight of extra equipment that had been added since the initial design. Only 30 Mk Is were built (including five by Westland Aircraft), and used only for trials and conversion training. Replacing the Merlin 30 with the more powerful Merlin 32 (1,640 hp/1,225 kW) and a four-bladed propeller resulted in the definitive Barracuda Mk II variant of which 1,688 were manufactured; by Fairey (at Stockport and Ringway) (675), Blackburn Aircraft (700), Boulton Paul (300), and Westland (13). The Mk II carried metric wavelength ASV II (Air to Surface Vessel) radar, with the Yagi-Uda antennae carried above the wings.
The Barracuda Mk III was the Mk II optimised for anti-submarine work, with the metric wavelength ASV set replaced by a centimetric variant, the scanner for which was housed in a blister under the rear fuselage. 852 Mk IIIs were eventually produced (406 by Fairey, 392 by Boulton Paul). A total of 2,607 of all marks of Barracuda were built.
The Barracuda Mk IV never left the drawing board; the next and final variant was the Barracuda Mk V, in which the Merlin powerplant was replaced with the Rolls-Royce Griffon. The increased power and torque of the Griffon required various aerodynamic changes; the vertical stabiliser was enlarged and the wing span was increased with the tips clipped. The Mk V, converted from a Mk II, did not take to the air until 16 November 1944, and Fairey built only 37 before the war in Europe was over.
Early Merlin 30-powered Mk 1 Barracudas were underpowered and suffered from a poor rate of climb. Once airborne, however, the type proved easy to fly. Trials of the Mk 1 at Boscombe Down in October 1941 showed a weight of 12,820 lb (5,830 kg) when equipped with 1,566 lb (712 kg) torpedo; at this weight the Mk 1 showed a maximum speed of 251 mph (405 km/h) at 10,900 ft (3322 m), a climb to 15,000 ft (4572 m) took 19.5 minutes, with a maximum climb rate of 925 fpm (4.7 m/s)at 8,400 ft (2,560 m), and a 19,100 ft (5,822 m) service ceiling.
The later Mk II had a more powerful Merlin 32 with a 400 hp (300 kW) increase in power. Boscombe Down testing of the Mk II in late 1942, at 14,250 lb (6,477 kg) showed a climb to 10,000 ft (3048 m) in 13.6 minutes, with a maximum climb rate of 840 fpm (4.3 m/s) at 5,200 ft and an effective ceiling of 15,000 ft (4,572 m). Further testing at Boscombe Down in June 1943, showed a maximum range, with either a 1,630 lb (750 kg) torpedo or a single 2,000 lb bomb (909 kg), of 840 statute miles (1,355 km), and a practical range of 650 statute miles (1,048 km), while carrying 6 x 250 lb (114 kg) bombs reduced the range to 780 miles (1,258 km) and 625 miles (1,008 km), respectively.
Pilots came to appreciate the powerful flaps / airbrakes; carrier landings were simple due to the flaps and good visibility from the cockpit. Retracting the airbrakes at high speeds, whilst simultaneously applying rudder caused a sudden change in trim which could throw the aircraft into an inverted dive. This proved fatal on at least five occasions during practice torpedo runs, but the problem was identified, and appropriate pilot instructions issued, before the aircraft entered carrier service.
During the earlier part of its service life, the Barracuda suffered a fairly high rate of unexplained fatal crashes, often involving experienced pilots. In 1945 this was traced to small leaks developing in the hydraulic system. The most common point for the leak was at the point of entry to the pilot's pressure gauge and was situated such that the resulting spray went straight into the pilot's face. The chosen hydraulic fluid contained ether and as the aircraft rarely were equipped with oxygen masks (and few aircrew wore them below 10,000 ft/3,000 m anyway) the pilot quickly became unconscious leading to a crash. An Admiralty order issued at the end of May 1945 required all examples of the type to be fitted with oxygen as soon as possible, and for pilots to use the system at all times.