TSR2: the British F-111

From the early 1950s, there was a fixation by military establishments, in both the East and West, for supersonic bombers. Missile technology was still in its infancy, and the pointy end of a strike force was still conventional bomber aircraft. By the 1960s, however, supersonic bombers were increasingly coming into play. Large designs such as the British V-bombers were already showing their age, and American designers had a keen interest in moving towards smaller, multirole designs, eventuating in the famous F-111 Aardvark. Yet during this same period, the British were also working on a similar medium sized design, known as the BAC TSR2. Although it has largely been forgotten, this design – had it not been cancelled – may have been Britain’s competitor to the F-111.

HISTORY

The story of the TSR 2 goes back to the late 1940s. The full impact of the jet engine had not yet been felt. Aircraft designers for some time would continue to use old doctrine and practices when designing new fighters and bombers, but the flaws in this thinking would quickly be exposed.

Of interest to the British were medium bombers. During the war, the Mosquito had served well in a variety of capacities. This came down to its light weight, high speed, and agility. Following its success, the English Electric Canberra would take up the same role after the war. It too was seen as a success; it could achieve good speeds, and its wing shape allowed it to fly at altitudes which mitigated interception.

But by the early 1950s, things began to change. Rapid advancements in jet technology meant that the Canberra bomber was very quickly pushed to its limits to stay competitive. In 1952, RAF Air Vice Marshal, Geoffrey Tuttle, stated that he did not believe the Canberra would remain effective beyond 1955 – noting the deadly efficiency of the new MiG-15. Tuttle was actually incorrect; the Canberra was flown by many air forces for many decades into the late 20th century. Surprisingly, after 50 years of service, the Canberra was finally retired from the Indian Air Force on 11 May 2007. However, for the British, with the introduction of new Soviet surface to air missile systems in the late 50s, which also threatened the most advanced V-bombers and the B-52, the Canberra needed to be replaced. Thus, aircraft designers went back to the drawing boards with their sights set on supersonic designs.

By 1955, the Ministry of Supply had begun work with English Electric to produce a new bomber. It was to be capable of Mach 1.5 at altitude, with a range of 3,700km, or 1,100km at low level, and a capacity of 4000 pounds.

In 1956, similar requirements were publicly announced as General Operational Requirement 339. This project would be highly ambitious. The design would now need to be Mach 2 capable at high altitude, and Mach 1.2 capable at low altitude. Its primary role would be as an all-weather long-range bomber, operating during day or night, including all weather medium level blind bombing. Secondary roles included photo reconnaissance at medium and low levels, both during day or night, and all-weather electronic reconnaissance. Conventional air-to-ground capabilities – delivering rockets and standard bombs – would also be necessary.

These ambitious goals would be a challenge for the designers. For one, it was suggested that ‘low level’, referred to flying under 1000 feet, with an attack speed of Mach 0.95, and that the aircraft should be able to reach Mach 1.1 at 200 feet above the ground. It was also requested that the aircraft be either VTOL or STOL capable, allowing it to operate from runways less than 3000 feet in length. The project would be referred to as Tactical Strike and Reconnaissance Mach 2, or TSR-2 for short, and the RAF hoped it would be ready by 1964.

In May 1957, the first round of designs were submitted. Among those submitting included de Havilland, Hawker, Vickers/Supermarine, and Blackburn. The initial designs were not looking very hopeful. All could be delivered before 1964, but none of them came close to what was being requested. In September 1957, a second round of submissions were requested to be done by January 31st 1958. This time more companies were invited to enter, including Gloster, English Electric, Fairey, Bristol, and Avro.

In this second round the designs were far improved, and during selection the field was narrowed down to three concepts; those by Hawker-Siddeley, Vickers, and English Electric. Of the three, the Vickers design – named Type 571 – stood out. Not only had they presented a new aircraft concept, but also a total systems concept which included details on the avionics, support facilities, and logistics needed to keep the aircraft functioning. However, they also noted that English Electric had more practical experience, and that their concept – the P.17 – was also promising. Thus, it was decided that Vickers would lead the effort, with English Electric as sub-contractor, and a new goal of combining the best of both designs. In 1959, the program would officially begin, and development of the TSR-2 would start.

DEVELOPMENT

In 1960, under pressure from the government, Vickers, English Electric Aviation, and Bristol Aeroplane Company, would combine into the British Aircraft Corporation or BAC, which also had a controlling interest in Hunting Aircraft. Other major companies – de Havilland, Gloster, Hawker Siddeley, Armstrong, Folland, and Blackburn – would all combine to form Hawker Siddeley Aviation Ltd to concentrate on other government contracts.

Under BAC the TSR-2 program would continue as planned, with the expectation of meeting the high bar of a Mach-2-capable all-weather strike and reconnaissance aircraft. Comparing the two designs, it was decided that the fuselage would be from the Vickers designers, while the wing would be the delta wing design from English Electric, as this company had more experience with supersonic design.

OUTCOME

The result of the design process was a very long aircraft, coming in at 89 feet. It was a slim aircraft featuring a shoulder mounted delta wing, with turned down wingtips. The fin and all moving horizontal tail surfaces provided good movement in all axes, and powering the aircraft would be two Bristol Siddeley Olympus 320 engines equipped with afterburners. These engines – taken from the Vulcan and improved, would also be used on the Concorde.

The aircraft with its long fuselage and short wings allowed for higher wing loading. It was found that this resulted in smoother flight at lower altitude – a necessity for high speed low level missions.

It also had several features which were ahead of their time. The aircraft would use forward-looking and side-looking radars, allowing for an impressive terrain following autopilot; something which would later be utilised in the F-111. The aircraft would have an early line-scan system which used daylight, or artificial light, rather than infrared which would be used on later designs. These avionics systems were expensive to produce and would mark the beginning of serious hurdles during the program.

It had been decided that the TSR 2 would be developed using an American method – known as development batch – in which the first aircraft produced were not concepts, but rather production aircraft to be tested and then assigned to service. This was supposed to expediate the project, but for the Brits, with a smaller budget, it just led to more problems.
The prototype as production concept was expensive and weighed down with bureaucracy as aircraft needed to meet production standards, and a standard production needed to be established. Despite these hurdles, two aircraft were finished by 1964. The plan was to showcase them at the Farnborough Air Show, but thanks to bureaucratic process, they had missed the date.
On September 27, 1964, test pilot Roland Beamont took the aircraft for a slow, 15-minute flight, leaving the landing gear extended. Shortly after, a second flight took place. This time, a strange issue occurred in which the fuel pump began to vibrate at the resonant frequency of the pilot’s eyes, causing him to slowly lose vision. Easing off the throttle, these effects went away.

Further testing was done. On the tenth flight, the landing gear was retracted fully, and on the fourteenth flight the aircraft was taken supersonic for the first time. Mach 1 was achieved using military power, then Beamont engaged afterburner on one engine (the second engine’s reheat pump wasn’t working), and the TSR2 accelerated. According to Wing Commander Jimmy Dell – who was flying the chase aircraft – a Lightning – the TSR 2 immediately pulled away at high speed, and Dell had to use both his afterburners to keep up!

24 test-flights would follow, with test pilots testifying to the aircraft’s outstanding handling characteristics. These initial flights did not include most of the advanced avionics, but did prove what the airframe was capable of.

END OF PROGRAM

The Royal Australian Air Force showed some interest in the TSR-2, as they were looking for an aircraft to fill the long-range strike and recon profile this aircraft promised. However, despite the potential of the aircraft design, the project’s significant cost was becoming an issue. The American F-111 Ardvark could fill the same roles at a better price and delivery schedule than BAC could offer. The F-111 was similarly fast, all-weather capable, with terrain-following autopilot. The Australians opted for the F-111 in 1963. Soon thereafter, the RAF were offered a modified version – the F-111K – as a cost saving measure against the TSR 2 program.

Despite BAC employee protests, the TSR 2 program was cancelled in April, 1965. The government had made a financial decision to make an option agreement to acquire up to 110 F-111Ks, rather than continue the TSR 2 program.

Although many who worked on the project would go on to work on the Tornado, Jaguar, and Concorde, the end of the TSR 2 remains controversial. Some perceived the programs cancelation as demonstrating a lack of faith in the British aeronautical industry, with politicians and decision makers favouring better funded American designs over natively built aircraft. The failure to see the program through likely hindered domestic experience in the field, which British designers could have used to continue the long tradition of producing great military aircraft. Before the war, the British – along with the Germans and Japanese – led the way in terms of aeronautical designs, but it seemed this talent was being relinquished to the Americans.

The remaining aircraft on the production line were never finished. Some were scrapped, whilst others were turned into museum pieces. For the BAC employees, this marked the end of an era, in which Britain designed and built native, highly ambitious, supersonic designs, without much help from outside.

CONCLUSION

The TSR 2 represents yet another great design which never had the opportunity to prove itself. It also represents how the British aeronautical industry once flourished in experimental jet designs. Although the British could never have hoped to compete against the sheer scale of American military aircraft industry, they may have gained more value than the cost savings, by seeing the TSR 2 through.

As Sir Sydney Camm, (designer of the Hawker Hurricane) quipped about the TSR-2: “All modern aircraft have four dimensions: span, length, height and politics. TSR-2 simply got the first three right.”