BAC TSR-2

However, a ministerial ruling on 9 July 1962 decreed that all future tactical nuclear weapons should be limited to a yield of 10 kt.

The RAF issued a new version of the OR.1177 specification, accepting the lower yield, while making provision in the design for it to be capable of adaptation later for a higher yield, in the event of the political restriction being lifted.

Meanwhile, the RAF explored ways of compensating for the lower yield by including, in the specifications for both the bomb and TSR-2, provision for releasing the smaller weapons in salvoes, dropping sticks of four of the revised OR.1177, later named [Vous devez être inscrit et connecté pour voir ce lien], at 1,000 [Vous devez être inscrit et connecté pour voir ce lien] intervals to prevent the detonation of the first weapon destroying the succeeding ones before they could, in turn, detonate.

This led to the requirement that the TSR-2 must be able to carry four WE.177As, two internally and two on external underwing [Vous devez être inscrit et connecté pour voir ce lien] - the width of the TSR-2 [Vous devez être inscrit et connecté pour voir ce lien] (originally designed to accommodate a single Red Beard weapon) necessitating the reduction in diameter of the WE.177A to 16.5 in, the bomb’s width and fin span being constrained by the need to fit two WE.177 bombs side-by-side in the aircraft's bomb bay.

A drawback of carrying the weapons on external pylons was a limitation due to [Vous devez être inscrit et connecté pour voir ce lien] on the bomb's casing, WE.177A being limited to a maximum carriage time of five minutes at Mach 1.15 at low level on TSR-2, otherwise the bomb's temperature would rise above its permitted maximum.

This would impose a severe operational restriction on TSR-2, as the aircraft was designed for M=1+ cruise at this sort of height.

Nuclear [Vous devez être inscrit et connecté pour voir ce lien] were also proposed for the TSR-2. These included an air-launched development of the [Vous devez être inscrit et connecté pour voir ce lien] missile, carried underwing, or semi-recessed in the bomb bay, and an air-launched [Vous devez être inscrit et connecté pour voir ce lien], referred to as Grand Slam, with a warhead derived from that intended for the [Vous devez être inscrit et connecté pour voir ce lien] missile, and a range of 100 nautical miles.[Vous devez être inscrit et connecté pour voir ce lien]

After the cancellation of the TSR-2, the RAF eventually filled the tactical strike requirement using [Vous devez être inscrit et connecté pour voir ce lien] with [Vous devez être inscrit et connecté pour voir ce lien], but continued their attempts to get the 10 kt limit lifted.

Development of WE.177A was delayed by several years due to the [Vous devez être inscrit et connecté pour voir ce lien] (AWRE) at Aldermaston being inundated with work on other warhead developments.

AWRE workload eased after completion of the [Vous devez être inscrit et connecté pour voir ce lien] warheads and work was able to resume on the WE.177A, deliveries to the RAF beginning in late 1971 for deployment on Buccaneers of [Vous devez être inscrit et connecté pour voir ce lien], a year after WE.177A deliveries to the Royal Navy.

Approval for high-yield tactical weapons was eventually gained in 1970, and by 1975 the RAF had WE.177C, at almost 200 kt, a weapon very similar to that which they had planned for the TSR-2 in 1959.

Design

[Vous devez être inscrit et connecté pour voir ce lien], manufacturer of the Canberra, and [Vous devez être inscrit et connecté pour voir ce lien] had been judged to have made the best submissions for GOR.339.

The two companies combined their ideas for the specification and put forward their joint design with a view to an aircraft flying by 1963.

No order was forthcoming, and by the time the Ministry had made a decision the various companies had been amalgamated as the [Vous devez être inscrit et connecté pour voir ce lien] in 1960.

EE had put forward a delta winged design and Vickers a swept wing on a long [Vous devez être inscrit et connecté pour voir ce lien].

The EE wing, born of their greater supersonic experience, was judged superior to Vickers, while the Vickers fuselage was preferred.

In effect, the aircraft would be built 50/50: Vickers the front half, EE the rear.

The design was a large aircraft, to be powered by two [Vous devez être inscrit et connecté pour voir ce lien], with a large shoulder-mounted slab-wing with down-turned tips, an all-moving swept [Vous devez être inscrit et connecté pour voir ce lien] and a large all-moving [Vous devez être inscrit et connecté pour voir ce lien].
The engines were a development of those used in the [Vous devez être inscrit et connecté pour voir ce lien], and would later be developed further for [Vous devez être inscrit et connecté pour voir ce lien].

The design featured [Vous devez être inscrit et connecté pour voir ce lien] across the entire trailing edge of the wing to achieve the short takeoff and landing requirement, something that later designs would achieve with the technically more complex swing-wing approach.

[Vous devez être inscrit et connecté pour voir ce lien] was by differential movement of the tailplanes, i.e., [Vous devez être inscrit et connecté pour voir ce lien].

The aircraft featured some extremely sophisticated [Vous devez être inscrit et connecté pour voir ce lien] for navigation and mission delivery — far ahead of anything else available at the time — which would also prove to be one of the reasons for the spiralling costs of the project.

Some features, such as forward looking radar (FLR) for terrain clearance, side-looking radar for mapping and the sophisticated [Vous devez être inscrit et connecté pour voir ce lien], only became commonplace on military aircraft later.

The [Vous devez être inscrit et connecté pour voir ce lien] was high for its time, enabling the aircraft to fly at very high speed and low level with great stability without being constantly upset by thermals and other ground-related weather phenomena.

This in turn made the innovative terrain clearance and autopilot system feasible.

There were considerable problems with realizing the design.

Some contributing manufacturers were employed directly by the Ministry rather than through BAC, and the Ministry itself took on design tasks, with the usual long deliberations and meetings typical of [Vous devez être inscrit et connecté pour voir ce lien].
^{[Vous devez être inscrit et connecté pour voir ce lien]}
BAC had a high degree of responsibility for the equipment that would be fitted which was a change in British practice.

There was equipment that would be supplied by the Ministry from "associate contractors", that which would be designed and provided by BAC subject to ministry approval and that in which BAC had automony.
This made it the largest aircraft project in Britain to date.

Under the development batch procedure chosen, the prototypes would be built using the production line jigs.

This meant that a batch of nine prototype aircraft could be assembled rather than built from scratch, but slowed their construction.

Operational history

Testing

Despite the increasing costs (which were inevitable, given the low original estimates), two [Vous devez être inscrit et connecté pour voir ce lien] aircraft were completed.^{[Vous devez être inscrit et connecté pour voir ce lien][Vous devez être inscrit et connecté pour voir ce lien]}

Test pilot [Vous devez être inscrit et connecté pour voir ce lien] made the first flight from [Vous devez être inscrit et connecté pour voir ce lien], Wilts, on 27 September 1964.

In the course of testing, the TSR-2 was found to easily meet the demanding GOR.339 performance specification.

Aerodynamically the aircraft was almost entirely trouble-free, but there were continual problems with the engines and the [Vous devez être inscrit et connecté pour voir ce lien].

Engine problems led to delays for the first flight which meant that the TSR-2 missed the opportunity to be displayed to the public at that year's [Vous devez être inscrit et connecté pour voir ce lien].

In the days leading up to the testing, the [Vous devez être inscrit et connecté pour voir ce lien] had criticised the aircraft saying that by the time it was introduced it would face "new anti-aircraft" missiles that would shoot it down making it expensive at 16 million per aircraft (on the basis of only 30 ordered).

Initial flight tests were all performed with the undercarriage down and engine power strictly limited - with limits of 250 kt and 10,000 ft on the first (15 minute) flight.

^{[Vous devez être inscrit et connecté pour voir ce lien]} Shortly after takeoff on XR219's second flight, vibration from a fuel pump at the [Vous devez être inscrit et connecté pour voir ce lien] of the human [Vous devez être inscrit et connecté pour voir ce lien] caused the pilot to throttle back one engine to avoid loss of vision.[Vous devez être inscrit et connecté pour voir ce lien]