by Damien Burke
While visually the aircraft would change little, the packed nose section had to make room for extra flying controls, displacing some equipment and reducing the aircraft’s strike capabilities accordingly. BAE Systems via Brooklands Museum
Construction and structural breakdown of the new forebody section for the trainer version. BAE Systems via Brooklands Museum
In terms of external appearance, the trainer would differ only in the area of the canopy. Windtunnel tests had shown that the new one-piece canopy had little effect on the aerodynamics other than minor flow separation at higher speeds, thus reducing the maximum attainable Mach number and slightly reducing fuel economy. The much larger area of canopy transparency would also introduce temperature limitations, further cutting down on the top speed, but this was an acceptable limitation. More significant was the loss of some items of equipment to make room for the added flying controls and rear pilots displays, etc. The most serious effect would have been on the FLR, as the items to be dropped included the groundspeed and drift indicators from the CCS, and the FLR scope normally found in the navigator’s cockpit. Without these items the terrain-avoidance system would be limited in usefulness, with a 500ft (150m) safe limit rather than 200ft (60m).
The trainer version had to be able to be converted to a strike version in time of need, and back again if need be. The design study brochure detailed the process and the various items of equipment that would be needed. BAE Systems via Brooklands Museum
The loss of the navigator’s role panel would remove the ability to aim and release weapons, though the airframe would remain capable of carrying them and they could all be jettisoned in an emergency as normal using the ‘wing clearance’ switch in the front cockpit. The role panel would normally supply the signals to the FLR and HUD to generate and display the aiming and release cues for conventional weapons, while the CCS provided nuclear-weapon aiming cues. The instructor would instead be given switches to simulate the pull-up signal and pilot’s warning light operation, enabling the practice of release manoeuvres. The other major task of the navigator was operation of the SLR and dealing with fix points to keep the aircraft’s position accurate. Without any of the navigator’s panels all of this was redundant, and so a simpler navigation system using the Doppler, moving map and gyro-magnetic compass would be used instead, with a consequent loss in navigational accuracy. For the anticipated length of training sorties this was again an acceptable degradation in overall performance.
TSR2 trainer – instructor’s cockpit layout. BAE Systems via Brooklands Museum
Trainer canopy separation trials with a wind tunnel model. BAE Systems via Brooklands Museum
The loss of weapon aiming and release capability in trainer configuration obviously made the ability to convert trainers back into strike aircraft not just useful, but practically essential if maximum value was to be had from the TSR2 fleet. Accordingly, BAC concentrated its efforts on making this conversion a straightforward task. The intention was that complete conversion kits would be built, consisting of various modules that would be pre-tested and ready for RAF personnel to use to carry out conversions as required. To facilitate rapid conversions, aircraft built as trainers (or built as strike aircraft with provision for trainer conversion) would have a large number of changes incorporated within the forebody section, such as a reinforced rear-canopy hinge, flying and engine control connections under the floor and within the side consoles, trainer canopy demisting tubes, and various minor structural changes for attaching the changed panels used in the trainer rear cockpit. All of these would be permanently fitted, with the aircraft in strike role carrying a small weight penalty of 40lb (18kg) as a result (in trainer fit, the aircraft would be 2,400lb (1,090kg) lighter than the strike version).
The entire conversion process from trainer to strike was predicted to take just under a week, and a couple of days longer for strike to trainer, assuming continuous 8hr shifts with up to twelve men working on each shift.
Cockpit arrangement
The front (pilot’s) cockpit would be basically identical to that of a normal strike TSR2, but the rear (instructor pilot’s) cockpit was almost entirely different from the navigator’s cockpit. The existing port console, instrument panel and flooring would all be replaced. The floor, and thus the rear pilot’s eye level, was raised 6in (15cm) compared with the normal navigator position, and the ejection seat would be identical to the pilot’s, giving two inches of additional upward adjustment.
The existing front pilot’s seat headrest was large, and would have blocked a significant amount of the instructor’s forward view, so the intention was to reshape the headrest and reduce its width to improve the view for the rear pilot. Alternative headrests would be part of the conversion kit. The new forward instrument panel for the instructor was designed to mimic the front pilot’s panel closely, as was the port console. The starboard console was left unchanged, with its controls slightly further from the pilot than would normally be the case owing to its lower position in relation to the new floor and seat height.
The new canopy was to be a one-piece, single-shell ‘blown’ canopy of ½inch-thick cross-linked acrylic (Oroglas 55), slightly bulged in comparison to the existing canopy lines, thus affording the instructor pilot more head movement and ejection seat height alteration than would otherwise be the case. No central joint or spine would be present, as there was no structural advantage in having one, though BAC did suggest it could be masked off to provide a better match of the strike aircraft’s more restricted view if necessary. The rear hinge on both the new canopy and the airframe would be strengthened, but designed to match the existing rear-canopy hinge physically so that no change was necessary in this area during role conversion. An additional latching hook would be installed in the cockpit sill to give the additional locking required by the longer trainer canopy.
At its heart the escape system would be basically unchanged, though command ejection would now be available for the rear pilot. In the strike role the navigator could only eject himself, while if the pilot ejected it would trigger the navigator’s seat to fire first. In trainer fit, either pilot ejecting would result in both going, the instructor’s seat always firing first.
The contract for the design study had specified that six aircraft would be built as trainers initially, followed by a further two, then sixteen strike aircraft embodying the latent trainer capability. The company recommended that, at a suitable point, it would make economic sense to manufacture all strike aircraft with the latent capability, to keep a common production standard. By the end of February 1965, however, the Air Staff were busily scrabbling for cost savings on the TSR2 and the intended trainer buy was reduced from the total of twenty-four down to just eight. Then the requirement was set aside to await the final decision on whether to continue with the TSR2 at all, after some questioning of whether the trainer version was at all necessary, given the test pilots’ high praise of the TSR2’s handling qualities in the take-off, approach and landing configurations.
Fighter version
English Electric had originally proposed a fighter version of the P.17, the P.22 (as briefly mentioned in Chapter 2), but had been careful not to make too much fuss about it, as it went against the concept of the 1957 Defence White Paper. It had even given it the P.22 designation for security reasons; any inadvertent mention of the P.22 would not lead back to the P.17 and draw adverse comment upon that project. Later the company had come to realize that in the P.22 it had an aircraft that could compete against its own P.1, with far greater endurance and combat radius and even, supposedly, slightly better manoeuvrability. With the GOR.339 project under way and the Lightning in production for the RAF, the P.22 was quietly killed off lest it affect either project’s chances. However, the basic concept was not forgotten.
A preliminary study entitled Vickers/ English Electric RB192D. Note on Performance in a Fighter Role was then undertaken, investigating the possible use of the TSR2 as a fighter. This was undated, but was p
resumably carried out during 1959 or 1960. It described the use of the basic TSR2 in the interceptor role. With a Mach 2 attacker detected at 250nm (290 miles; 460km) range by ground radar, a TSR2 interceptor could be scrambled within three minutes and intercept the target using a head-on attack while it was still 70nm (80 miles; 130km) away. Alternatively, a combat air patrol at 100nm (115 miles; 185km) from base could be carried out for 3.5hr on internal fuel only with a 2,000lb (900kg) load of unspecified air-to-air missiles. With a sea level rate of climb of 65,000ft (20,000m) per minute, and an acceleration profile that would enable it to reach Mach 2 at 60,000ft (18,300m) within four minutes of take-off, it was certainly a realistic option to use the aircraft as an interceptor. No mention was made of a manoeuvring fight; given the type’s high wing loading, it would not have made a very effective dogfighter.
The Tushino Air Display in Russia on 9 July 1961 led to a revival of the fighter idea. At this air show various large Russian bombers were seen carrying stand-off missiles. This was a rude shock to NATO, which hitherto had only had hints that the Soviets were developing such weapons. The supersonic Blinder, subsonic Badger and turboprop Bear bombers were all clearly capable of reaching the UK, and each could carry stand-off missiles, the most worrying of which was suspected of having a range of up to 600nm (690 miles; 1,110km) and a top speed of Mach 2. Lightnings would be hard-pressed to cope with the missile, and unable to deal with the bombers before they had fired their missiles and turned for home. Radar coverage over such large distances was unavailable, and airborne fighter-style radars might not have been powerful enough to pick up small missiles. English Electric believed that by far the cheapest and quickest solution to the new threat was a fighter version of the TSR2, as it had the necessary range, volume and power for either interceptor or standing-patrol attacks. In January 1962 it produced a report on just such an aircraft.
General Arrangement of the two proposed fighter variants of the TSR2. The original report illustrated a Firestreak missile, but captioned it as Red Top; the staggered weapons bay missile stowage illustrated here is a speculative interpretation based on the report’s contents. Damien Burke
TSR2 fighter variant patrol and attack profile. The idea of an ‘armed AWACS’ had some attractiveness, but neither the RCAF nor the RAF saw a real need for an interceptor of this type. Damien Burke
The big difference between a standard TSR2 and this fighter (or, rather, interceptor) version would be in the radar fit. Ferranti was proposing a promising new development combining a sideways-looking X-band aerial for search within a 250nm (290-mile; 460km) range and a forward-looking 36in (90cm)-diameter dish for target illumination. To fit all of this within the TSR2 airframe required some changes. The larger SLR aerials would not fit in the space for the existing navigation SLR, and even an extension in nose length would still require cheek bulges. Accordingly, the nose would be extended by 39in (99cm) and the new SLR aerials installed as a shoulder fit, high up on the fuselage between the rear cockpit and the intakes. The equipment bay would be reduced in size as a result, but the deletion of navigation SLR (Doppler being sufficient for fighter tasks) would compensate for this. Some loss in fuel volume would also take place, to the tune of about 2,500lb (1,135kg). The new FLR would require a larger radome, so the nose would be bulged downwards and outwards to permit this. Compared with the strike version, the fighter version would be around 1,250lb (570kg) heavier.
The weapons bay could carry a single missile of up to 36in (90cm) span, with a cradle to lower it into launching position, and possibly an additional fuel tank taking up any unused space. Patrols could be carried out up to 470nm (540 miles; 870km) from base (with 1.7hr endurance), enabling the fighter TSR2 to deal with Blinders even before they reached their launch position. Alternatively, a patrol at 200nm (230 miles; 370km) from base would give an endurance of 2.7hr.
An alternative fit was also proposed, to avoid redesign of the nose. In this the new SLR would be installed in a large under-fuselage fairing. This would have a 6 per cent-thick aerofoil section and be 35ft (10.6m) long, with the weapons bay carrying a 600gal (2,725L) fuel tank. Missiles would need to be carried under the wings. Despite the drag of the SLR fairing and underwing missiles this version would also have slightly greater endurance because of its heavier fuel load; 2.8hr for the 200nm patrol and 1.8hr at 470nm.
As for weapons, the Red Top heat-seeking missile was the only available British type for dealing with high-performance targets, but with a range of less than 15nm (17 miles; 27km) it would be necessary to get uncomfortably close to the target. A radar-guided version had been studied, but nothing had so far resulted from this. BAC was also working on Sig.16, a ship-launched surfaceto-air missile for the RN, which would have twice the range and radar guidance, though it would need some rearrangement to cope with supersonic carriage and launch. The French Matra 530 was also suggested as a possible contender, though it had shorter range than Red Top. The normal load would be a pair of missiles underwing, assuming the external SLR fit, though up to four were possible with a reduction of around half an hour in patrol endurance.
A typical sortie would entail take-off and climb to an economical cruising height for transit to the patrol area. The patrol line would be an arc of a circle with radius of 200nm (230 miles; 370km), and would be about 70nm (80 miles; 130km) long. With the SLR having a range of 250nm (290 miles; 460km), this meant a single fighter could continuously monitor a front of 200nm and, even in the worst case of the fighter carrying out its turn at either end of the patrol line, no target could reach further than 30nm (35 miles; 55km) within the patrol area before being detected. On detection of a target the fighter would turn towards it on to an interception course, climb from the patrol height (22,000 to 28,000ft (6,700 to 8,500m), depending on fuel state) to 36,000ft (10,970m) and accelerate from patrol speed (Mach 0.9) to Mach 1.7. The climb would then continue to 50,000ft (15,200m) and the attack would begin when the target was within range of whatever missiles the fighter was carrying. Return to base would be subsonic at economical cruise settings.
The sales division of BAC was very nervous of putting forward this version. It could have had a deleterious effect on Lightning sales, and there were serious doubts that a new supersonic interceptor was politically acceptable, even though several years had passed since the 1957 Defence White Paper. This changed in February 1963, when the Canadians began to get interested in the TSR2, though it was not until July 1963 that serious work began on a preliminary brochure. This was not for domestic consumption, but purely to be shown to the RCAF. More-effective missiles of US origin were now added to the mix, such as the Douglas MB-1 Genie, Hughes GAR11 Nuclear Falcon, Raytheon Sparrow IIIb and Hughes GAR-9 Phoenix. A BAC delegation then visited Canada in August 1963 to discuss, primarily, the TSR2 strike aircraft, and in this discussion they learned that the RCAF still required a manned interceptor for the period 1970 to 1980, which could intercept both subsonic and supersonic targets, identify them visually from long range and even deal with high-performance supersonic types similar to Concorde. The TSR2 fighter version was mentioned, and the delegation was invited to return in October with a proposal, having been told that ‘any guided missile available’ should be suggested if it could meet RCAF needs.
The delegation returned to RCAF HQ in October 1963 to make a further presentation on both the strike and fighter versions of TSR2, though the sales division had already suggested that they had nothing better than an ‘outside chance’ of selling the TSR2 interceptor to the RCAF. Unfortunately for BAC the reception was even worse than expected, the presentation being received ‘in polite – cordial – silence’. The RCAF was, it transpired, predicting a withdrawal from Europe-based NATO commitments in the near future, and saw no need whatsoever for the strike version. The fighter also provoked no obvious interest, which was surprising after the previous meeting, but perhaps not so surprising in the light of the 1959 cancellation of the Arrow.
Coincidentally, just after this, in December 1
963, the RAF’s OR department produced an internal paper on the subject of using TSR2 in both the interceptor and low-level, low-speed strike roles. (This was triggered by concerns that the USA’s new TFX aircraft was capable of performing more roles than the TSR2.) The OR department was obviously unaware of the details of BAC’s fighter proposal, and looked at the subject anew. It correctly considered the existing FLR clearly inadequate as an AI radar, lacking power and therefore range, and having an extremely limited azimuth and elevation scan. Installation of one of the proposed AI radars for the P.1154 was suggested as a possibility, as they all had some multirole capability. The most suitable such radar, however, had a 27in (69cm) dish, compared with the 15in (38cm) dish of the TSR2’s FLR, so (surprise, surprise) the nose would need to be redesigned. Both pilot and navigator would need extra displays; the pilot’s radar display could possibly be via the HUD (quite how this was to be achieved was not mentioned), and the navigator’s by a redesign of his existing radar plan position indicator. The navigator would also need a control stick for the AI radar. As for weapons, it appeared that the Red Top missile could be carried externally, though significant additional work would be needed to integrate it with the existing systems. The airframe configuration would handicap the aircraft at typical interception altitudes, as the TSR2 needed to be supersonic to stay in level flight above 38,000ft (11,600m), and at Mach 1.5 the best rate of turn would produce a 10nm (11-mile; 17km) turning circle. By the time the aircraft was at 50,000ft (15,000m) it would be struggling to remain airborne, let alone carry out an interception: ‘such a beginning in the intercept role could hardly be acceptable’. It seems BAC was wise to avoid trying to get the RAF interested in a fighter version, though, ironically, the aircraft’s lack of fighter capability would be used against it in some comparisons with the TFX in early 1965.
