The Blackburn Buccaneer

The Blackburn Buccaneer was designed in the mid-1950s as a low-level carrier-based maritime strike aircraft. It proved to be far more long-lived than its designers ever intended, serving with distinction not only with the British Royal Navy's Fleet Air Arm (FAA) but with the Royal Air Force (RAF) for decades, and as a finale demonstrating its usefulness in the Gulf War. This document provides a history and description of the Buccaneer.

Blackburn Buccaneer origins

During the early 1950s, the Soviet Navy underwent a major fleet expansion to challenge US and NATO naval supremacy, posing a serious threat with their new of SVERDLOSK-class cruisers. In response, the British Royal Navy decided to obtain a low-level carrier based attack aircraft. This aircraft was intended to penetrate the defenses of Soviet naval battle groups by streaking in at low level and high speed, then destroy them with a nuclear weapon in a "toss-bombing" attack.

The requirement was formalized as "Naval Staff Requirement Number 39 (NA.39)" in June 1952, which called for a two-seat carrier-based aircraft that could carry a nuclear weapon internally, fly at a speed of Mach 0.85 at an altitude of 60 meters (200 feet), and operate over a combat radius of at least 740 kilometers (460 miles). It was to have an offensive radar system and a radar altimeter. Total weapons load was to be 1.8 tonnes (4,000 pounds); the length could be no more than 15.5 meters (51 feet) in stowed configuration to allow accommodation on existing carrier-deck elevators; and the maximum weight was to be no more than 20.4 tonnes (45,000 pounds). The aircraft was to be able to act as a tanker.

Most of the major British aircraft manufacturers submitted proposals for the requirement, with the proposals whittled down to three finalists: the Armstrong-Whitworth "AW.168", the Shorts "PD.13", and the Blackburn "B.103".

The Armstrong-Whitworth AW.168 was a conservative design, with a conventional layout, moderately swept wings, and twin Bristol Siddeley "Gyron Junior" turbojet engines, mounted in nacelles attached to the bottom of the wings. It was to feature leading edge flaps and a "boundary layer control (BLC)" or "blown flaps" scheme, in which engine bleed air was dumped over the top of the flaps to reduce the stall speed. An exhaust deflector scoop was to be fitted behind each engine to direct thrust down at an angle of 45 degrees, permitting short takeoffs. The aircrew sat side-by-side under a bubble-type canopy, and the wings folded up just outboard of the engines.

The Shorts PD.13 was a very unconventional design, a tailless aircraft featuring a highly swept "aero-isoclinic" wing, a concept developed by Geoffrey Hills of Shorts, in which the wingtips pivoted up and down to provide flight control. It was to be powered by twin Rolls Royce Avon RA.19 turbojets, with exhausts that could be deflected downwards. A fighter-style cockpit was fitted on the left side of the nose for the pilot, while the navigator sat under a hatch on the right side of the nose. There was a teardrop fairing on the rear of each wing, used to store the backward-retracting main landing gear assemblies. The PD.13 might have looked bizarre, but Shorts had flown an aero-isoclinic wing demonstrator, the "SB.4", and it had been very pleasant to fly.

The Blackburn B.103

At the time, Blackburn was building nothing more warlike than transport and cargo aircraft, but the company's B.103 design seemed very competent. The B.103 featured twin engines. Blackburn originally considered the Armstrong Siddeley Sapphire Sa.7 turbojet, but it proved too bulky and heavy, and the Gyron Junior engine was selected instead. The flight surfaces were moderately swept, with the tailplane mounted high on the tailfin in a "tee" configuration. Since smooth low-level flight dictates small wings but small wings mean a "hot" landing speed, Blackburn engineers designed a BLC system, with 10% of engine compressor airflow blown not only over the flaps, but also over the tee tail -- the scheme providing deicing as a plus.

The B.103 incorporated the new "area rule" aerodynamics, where abrupt changes in the cross-sectional area of the aircraft were avoided to improve high-speed handling. Area ruling means that the fuselage shrinks where the cross-section includes the wings, and then expands again after the wings, giving the fuselage a graceful "wasp waist" or "coke bottle" appearance. Blackburn engineers used area-ruling to improve the design's aerodynamics, while also increasing the storage capacity of the aircraft's fuselage, giving the aircraft a distinctive set of full-bodied curves.

The aircraft met the carrier-deck elevator dimension limits through a number of features. Its wings folded straight up through 120 degrees from a hinge at half-span, and its nose cone could be pivoted back to allow access to its radar and reduce length. The tail cone was split and could be hydraulically opened to the sides to act as a variable air brake and also reduce length. All these features allowed the B.103 to fit neatly on an elevator and in the hangar deck.

The B.103 was designed to be fitted with two stores pylons under each wing, for a total of four, but also had a bomb bay, which was to accommodate four 450 kilogram (1,000 pound) bombs or a single nuclear weapon. A conventional bomb bay was not regarded as suitable for high-speed low-level attack, and so the B.103 was given a rotating bomb bay door, with munitions attached to the door itself. The door could snap around rapidly, reducing aerodynamic interference. The rotating bomb bay not only simplified weapons release, but made it easier to load munitions and perform servicing. Other stores, such as a reconnaissance camera pallet, were also planned to be carried in the bomb-bay.

The design was frozen by the summer of 1954. In July 1955, the British Admiralty selected the B.103 from the three finalists, on something of a "Goldilocks" line of reasoning. The Armstrong-Whitworth AW.168 was too cold; it would present the least risk and get into service the fastest, but it would also be obsolete the fastest. The Shorts PD.13 was too hot: it was the most advanced of the designs, but the risk level was high. The Blackburn B.103 was just right, neither too stodgy nor too daring.

Blackburn B.103 development batch

The contract placed an order for 20 "development batch (DB)" aircraft. This was an unusually high number of pre-production aircraft, but the Royal Navy was in a hurry and wanted to ensure that loss of a prototype would not delay the program. The service also wanted to pursue development of various subsystems in parallel.

Development work on the B.103 proceeded in deep secrecy. The Admiralty requested that a prototype be flying by April 1958, and the first prototype managed to take to the air on 30 April. Successive prototype production gradually incorporated features for operational aircraft. Carrier trials began in early 1960, having been delayed several months by the stall and crash of one of the prototypes, with both crew members killed after ejecting from their inverted aircraft.

On 20 August 1960, the new aircraft was given its official name: "Buccaneer". The initial version was designated "S Mark 1 (S.1)", with the "S" indicating that it was a strike aircraft. All 20 DB aircraft had flown by the end of 1961, though there were further losses. One went down in October 1960 due to a flight instrumentation failure, the two crewmen ejecting safely. Another was lost in August 1961 on takeoff during carrier trials, with both crewmen drowning because they were unable to escape from the aircraft.

The flight test program otherwise went well, and the first Buccaneers were delivered to the Royal Navy in August 1961. Number 801 squadron became the first operational Buccaneer unit in July 1962, with operational cruises beginning in 1963. Ground-based Buccaneers operated out of a number of naval air stations, but the Buccaneer would be particularly associated with the naval air station at Lossiemouth, on the northeast coast of Scotland. The 20 DB aircraft were originally all retained by Blackburn for development and trials, but some were eventually brought to service fit and handed over to the Royal Navy.

The Blackburn Buccaneer S.1

The production Buccaneer S.1 embodied the design considerations outlined for the B.103: two non-afterburning Gyron Junior Mark 101 turbojets providing 35.6 kN (3,630 kgp / 8,000 lbf) thrust each, one mounted in a nacelle with a circular intake on each side of the fuselage; mid-mounted swept folding wings of relatively modest area, with a boundary layer control or "supercirculation" system; a high tee tail; an area ruled fuselage; a folding nose cone; a split tailcone / air brake; and four stores pylons plus the rotating bomb bay door. The airframe was designed with an emphasis on strength, and the aircraft would generally be described as being "built like a brick outhouse".

The wing sweep was 40 degrees at the root; 38 degrees 36 seconds in midspan; and 30 degrees 12 seconds for the outer span. The wing was set at an incidence angle of 2 degrees 30 seconds. Each wing featured a flap on the inboard (non-folding) section, and an aileron on the outboard (folding) section. The flaps had four positions, the maximum being 45 degrees. There was a somewhat complicated arrangement of ductwork in the wing for the BLC system, with a duct running behind the front of the wing to provide bleed air out the leading edge and another duct on the rear of the wing to provide bleed air over the flaps and ailerons. How the ductwork handled the wing folding is an interesting minor mechanical question.

There was a row of small "vortex generator" vanes towards the front of the outboard section to prevent airflow separation. The original B.103 design had featured twin flaps on each wing and a leading-edge slat, but the BLC system rendered them unnecessary. The high-mounted tailplane was all-moving; what appeared to be elevators were actually flaps, used in conjunction with bleed air from the BLC system driven out the tailplane. BLC ductwork ran up the tailfin and along the leading edges of the tailplane. The tailfin itself of course had a conventional rudder.

The S.1 featured tricycle landing gear, with all gear assemblies featuring single wheels. The nose gear retracted backwards, while the main gear hinged in the wings just outside the engine nacelles and retracted in towards the fuselage. The nose wheel was steerable and could be pivoted 50 degrees off the centerline, and the landing gear featured an antiskid braking system. There was a small extendable bumper wheel on the rear fuselage to prevent damage to the tail on steep takeoffs, and a stinger-type arresting hook on the end.

Total internal fuel capacity was 7,092 liters (1,871 US gallons) in eight tanks in the upper fuselage. There were no fuel tanks in the wings. The internal fuel load could be augmented by two underwing "slipper" tanks, mounted around the inboard stores pylons against the wing, a configuration that minimized drag. Each slipper tank has a capacity of 1,136 liters (300 US gallons). A 2,000 liter (528 US gallon) ferry tank could also be plugged into the bombbay. Range was not a problem with the Buccaneer. Initial prototypes had a retractable refueling probe, but this didn't work out well in trials, and a bolt-on removeable offset probe was quickly designed in its place. The bolt-on probe was slightly offset to the right, and marked to act as a crude bomb-aiming system as a validation check for the aircraft's formal bombing system.

Although it seems a bit odd to American sensibilities, the catapult attachment was not on the nosewheel. There were attachments for a "bridle" cable under each engine nacelle, and when ready for a carrier takeoff the aircraft was strapped with the bridle so that the nosewheel was in the air. This scheme looks awkward, but it was used reliably with other Royal Navy jets and gave an aircraft a high angle of attack on takeoff to help it get off the deck.

The pilot and navigator sat in tandem, each on a Martin Baker ejection seat. The original seat fit appears to have been the Mark 4MS, which had a zero altitude capability but required a minimum flight speed for safe operation. The two seats were offset about 5 centimeters (2 inches) from the centerline, in opposite directions, and the rear seat was raised slightly. This gave the navigator in the back seat a better forward view. The two crew sat under a single bubble-type canopy that provided fairly good all-round vision and opened by sliding to the rear. There was a transparent blast screen between the two seats to protect the navigator when the pilot ejected or if the windscreen was shattered. However, the windscreen was very tough, being a laminate 6.35 centimeters (2.5 inches) thick and proof against birdstrikes.

Buccaneer Avionics

Avionics was state-of-the-art for the time, of course including UHF radios and an IFF (identification friend or foe) transponder, as well as an analog flight computer; a gyrocompass flight reference system; a radar altimeter, which was very important for low-level strike; and an Elliot autopilot. There was a strike camera in a blister under the nose, though apparently later in the Buccaneer's career the camera wouldn't actually be fitted.

Combat operations were supported by the Ferranti Blue Parrot (AIRPASS III) radar in the nose, which provided search and mapping functions, as well as semi-automatic toss bombing using a nuclear store. Once the aircrew established a target lock, the Blue Parrot would generate a steering signal for the pilot to keep him on target and tell him when to pull up for the bomb toss. The bomb would be automatically released at the proper time, with an audio tone cutting off at release so the pilot would know it was time to turn around and get out of the blast area as fast as possible.

The Blue Parrot did not have terrain-following capabilities, which would have been very handy for the low-level strike role. All later Buccaneer variants would retain the Blue Parrot radar. The only defensive countermeasures system was a simple broadband radar warning receiver (RWR), with the antennas in what looked like a little rocket tip sticking out of the middle of the leading edge of each outer wing panel. Since not all pictures of the S.1 show these little fairings, it seems they may have been removeable.

The Buccaneer had been designed specifically as a maritime nuclear strike aircraft. Its intended store was a guided nuclear gliding bomb with the odd named of "Green Cheese", but this weapon's development was cancelled, and in its place the designated nuclear store was the unguided 900 kilogram (2,000 pound) "Red Beard", which had been developed for the Canberra. Red Beard had an explosive yield in the 10 to 20 kilotonne range. It was mounted on a special bomb bay door into which it nested neatly to reduce aerodynamic buffet on the launch aircraft. Red Beard was an unsophisticated weapon and had to be armed before launch instead of in flight, clearly an undesireable feature.

The Buccaneer S.1 could carry an alternative conventional warload of up to eight 450 kilogram (1,000 pound) bombs, with four in the bomb bay and one on each of its four underwing pylons, though six total was a more typical fit. The S.1 could also carry unguided rocket packs on its underwing pylons. The Buccaneer originally used 50 millimeter (2 inch) rockets in 36-round packs, but this weapon was later phased out in preference to the 68 millimeter (2.7 inch) Matra SNEB rocket in 18 round packs. The Buccaneer was evaluated with the US-built AGM-12 Bullpup radio-guided air-to-surface missile in 1965. However, the Bullpup proved to be an unreliable and inaccurate weapon, and was rarely carried in practice.

The Buccaneer could be operated as a tanker, carrying a Flight Refueling LTD M20 probe-and-drogue refueling pack with a capacity of 636 liters (168 US gallons) under the right wing, augmented by a slipper tank under the left wing.

As mentioned, the bomb-bay could also accommodate a 2,000 liter ferry tank, as well as a photo-reconnaissance "crate" or a cargo container. The reconnaissance crate could accommodate a photoflash flare dispenser and up to six cameras, in various configurations of long-range, wide angle, and night vision cameras that could be mounted in vertical, oblique, or (using a blister in the pack) forward-looking orientations. The photoflash unit was rarely used, with the Royal Navy preferring to use the Gloworm rocket, with eight mounted on the Buccaneer's stores pylons, for night operations.

The cargo container would prove useful for transporting golf clubs and other essentials. There had been plans to develop a bombbay tanker pack, but the underwing pack proved to be an adequate solution. There was also a plan for a pack with twin Aden 30 millimeter cannon, but it was abandoned and the Buccaneer would never carry gun armament.

Two Royal Navy Fleet Air Arm operational squadrons and a training unit were equipped with the Buccaneer S.1. Navy pilots liked the aircraft. It was strong, handled well, provided a marvelous smooth and solid ride down on the deck, and the BLC system gave them slower landing speeds than they were accustomed to.

Early in development, the B.103 had been assigned the designation "ARNA", for "A Royal Navy Aircraft". This acronym became reinterpreted as "Banana", and the Buccaneer would from then on be nicknamed "Banana Jet". The press liked to call it the "Brick", to the annoyance of Buccaneer crews. Some early S.1s were painted in overall white to resist the flash of a nuclear explosion, with these machines sometimes called "peeled bananas", but S.1s typically were painted dark sea gray on top and white on the bottom.

The Buccaneer S.1 was a very good aircraft, but the Gyron Junior engines were not powerful enough, particularly with ten percent of the airflow siphoned off for the BLC system. The lack of power meant that the Buccaneer could not take off with a full fuel load. To obtain good range, the Buccaneer S.1 had to be launched with a partial fuel load and then refuel from a Supermarine Scimitar fighter configured as a tanker. Only 40 S.1s were built, and by the end of the 1960s the survivors had been relegated to training status.

The career of the Buccaneer S.1 came to an abrupt end in December 1970. On 1 December, an S.1 was making a landing approach when an engine surge disrupted the approach and forced the two crewmen to eject. On 8 December, an S.1 on a training flight suffered a turbine failure. The pilot successfully ejected, but due to a mechanical glitch the back-seater was killed. Inspections showed that the Gyron Junior engines were no longer suited for operations. All surviving S.1s were grounded immediately and for good.

Author: Greg Goebel