by Damien Burke
Combining forces
Vickers and English Electric agreed in January that they needed to work-up a datum aircraft design as soon as possible, from which they could then proceed with detailed design work. English Electric believed it already had such a design, the P.17 as it already stood, but Vickers had so many objections to various features of the P.17 that it was unwilling to start from this point. Vickers insisted that reducing equipment space and striving to attain STOL was the priority, even if meant reducing the margins between the aircraft’s predicted superior performance and the requirements laid down in OR.339. These tight margins between expected and required performance would result in the ‘Tight Datum’ aircraft. English Electric predicted (correctly, as it turned out) that this choice to allow the margins to tighten up would only lead to problems in the future. A joint team began work on 2 February drawing up a datum aircraft design, beginning by using the Vickers fuselage married with the English Electric wings and tailplane.
By the beginning of March 1959 Vickers and English Electric had also thrashed out a formal agreement for how they would work together to undertake the design and development of the airframe. Vickers-Armstrongs (Aircraft) Ltd had been nominated as the prime contractor, and would carry this responsibility throughout the development period. Vickers was led by Sir George Edwards, with Henry Gardner (Vickers’s Technical Director) acting as Chief of Staff and co-ordinating all work on the project. A Joint Project Team had already been formed at Vickers’s Weybridge plant, consisting of engineers from both companies (though somewhat English Electric-heavy), led by George Henson of Vickers. Creating the aircraft would require a number of stages, starting with the Project or Study Stage. During this stage, lasting approximately six months, joint studies would be carried out in conjunction with the various governmental organizations and subcontractors to put together a firm specification. This would be followed by the Pre-Guarantee Stage, nine months’ work on detailed engineering, construction and cost investigations, together with windtunnel and rig tests, leading, as Vickers/ English Electric hoped, to a contract for the development and delivery of the completed Weapon System with guarantees as to performance, timetable and cost.
The longest stage would then follow: Detail Design and Development, taking 3½ years and covering detail design and development of every component of the aircraft, leading to the first flight of the first aircraft. Once TSR2 was airborne, the Primary Flight Development Stage would be entered: ¾ years and 1,200hr of flight development leading to initial CA release in the strike role. A six-month Secondary Flight Development Stage would follow, to clear the reconnaissance equipment, and during this time the aircraft could be introduced into service with the RAF in the strike role, assuming orders for production aircraft had been placed in time.
While work was to be split equally on a fifty-fifty basis, it was recognized that each company had strengths in certain areas. Thus specialists on each side would act as authorities in particular areas, regardless of whether those areas were being built by their own company. For instance, while Vickers was going to build the wings, English Electric was the specialist authority for aero structures, which took in aerodynamics, aeroelasticity, aeroloadings and control. The division of effort in both design and production split the aircraft into a number of components, half assigned to Vickers and half to English Electric. The division was initially as follows:
Vickers – Wings, front fuselage including bomb bay, undercarriage, equipment.
English Electric – Remainder of airframe, powerplant, power supplies.
After a sustained argument between English Electric and Vickers, Vickers had reluctantly agreed that the P.17’s delta wing was the one to go for, and it made little sense for Vickers to continue having the wing in its half of the project when it was the English Electric design that was going to be used. Discussions on fuselage design continued, but in the meantime the work division was adjusted, and English Electric now had responsibility for the wing. The first two airframes would be assembled by a joint team at Weybridge, the intention being to split the team into two after that so that both companies would assemble airframes on an alternating basis from airframe No. 3 onwards.
Work on the Joint Datum Aircraft
Meanwhile, the Joint Project Team had been working on the Tight Datum aircraft, soon renamed the Joint Datum aircraft. This became, in effect, a detailed engineering assessment of Vickers’s work on the fuselage, something English Electric had been keen to do, as it believed this was impractical in terms of equipment space and glossed over or omitted many vital items. (There was a commonly held view at English Electric that Vickers had carried out the bare minimum of design-study work.) The complex fuel tank arrangement within the Type 571 fuselage was simplified, and minor changes were made to various other items in the rear fuselage. English Electric was not at all keen on Vickers’s forward-retracting main undercarriage, but reluctantly accepted the situation as it was, intending to return to it later.
Adding the P.17 wing to the Type 571 immediately resulted in an unbalanced aircraft, with a shortened tail arm. The obvious solution to this was to extend the fuselage 5ft (1.5m) to the rear, restoring the tail arm, though this also meant that a compensating forward-fuselage extension of 2.25ft (0.7m) was needed. While the aircraft’s weight would increase, the additional space could be used for more fuel to restore lost range. The longer rear fuselage necessitated increasing the height of the undercarriage to avoid the fuselage hitting the ground when rotating on take-off. Vickers could not see English Electric’s underwing intake ever working, so it stuck with its own intake length, though incorporating English Electric’s conventional wedge opening. This first attempt at combining the P.17 and Type 571 weighed in at 81,765lb (37,115kg) fully loaded for the OR’s 1,000nm sortie. Freddie Page, head of the Warton design team, had remarked on several occasions that if the aircraft ever got to the 75,000lb (34,000kg) mark it was ‘time to rub it out and start again’. That, however, was not about to happen.
The next change was to extend the fuselage again, by 1ft (0.3m) at the nose and 2.5ft (0.76m) at the rear, as the previous extension had not been enough to rebalance the aircraft. This then required that the wing and intake face be moved aft by 2.5ft (0.76m) to retain their relationship with the tailplane. Both tailplane and fin areas were slightly reduced, and provision was made within the fuselage for a water tank, heat shielding around the engines, and various ancillaries such as rain dispersal for the windscreen. With the fuselage looking as though it was going to need to be widened to accommodate the large low-pressure tyres, an attempt was also made to reshape the weapons bay, tapering it towards the forward end to allow the undercarriage to be stowed diagonally rather than vertically.
The engineering penalties of a forward-retracting main undercarriage were now beginning to become obvious, and the joint project team attempted to incorporate rearward-retracting gear. Engines could now be removed vertically via the undercarriage bay roof/engine bay floor, as per the P.17. However, additional heat shielding was necessary, and various weight penalties were incurred. This would further unbalance the aircraft on the ground, and this, combined with some changes in transonic behaviour owing to the larger tailplane, was going to make this change difficult to justify. The idea went on the back-burner.
Vickers now introduced the use of a new aluminium alloy, X2020, which promised much, being lighter and stronger than conventional alloys. As it promised a weight saving of 2,500lb (1,135kg) overall, despite its expense it was just the sort of improvement that Vickers liked, though Henry Gardner was fearful of ‘being first to uncover faults’, and English Electric was concerned about the cost. The next issue of the datum design drawing had the weapons bay returned to a rectangular shape, and the main undercarriage retracting forward and being stowed nearly vertically alongside. The tailplane area was reduced, and both leading- and trailing-edge flaps were added to the tailplane, allowing a reduction in the amount of tailplane movement and improving gr
ound clearance in the landing attitude. A braking parachute was also added. Because of the weight reduction brought about by the use of X2020 and the improved braking capability, the lighter and less powerful Olympus 15R engine was reverted to (the 22R having been under serious consideration before this point). For the first time in the design process, the upward trend of weight gain was reversed, this version weighing in at 75,004lb (34,044kg), though a re-estimating exercise would soon bring this up to 77,942lb (35,378kg).
VS571 Sheet 100, with P.17A wing and fuselage extensions to give the same tail arm as on the P.17A, February 1959. Damien Burke
The forward bomb bay and rearward-retracting undercarriage depicted on TSR2 Sheet 123, 9 March 1959. Damien Burke
Immediately afterwards, another problem confronted the joint project team. The Olympus 15R was proving to have lower thrust and higher fuel consumption than the brochure figures. The 22R was going to be needed after all to meet the OR figures, despite the reduction in airframe weight. The predicted costs of the 22R had tripled since the brochure had been issued, and it was a heavier engine, too. The airframe’s weight climbed again. George Edwards’s unhappiness with the forced selection of BSEL as the engine provider was one point upon which English Electric and Vickers agreed wholeheartedly. They even went so far as to suggest that the time might soon come when they would have to make it clear that the MoS’s decision to go with the Olympus was having a serious effect on the performance of the aircraft, to protect themselves from future criticism. Nevertheless, it was no surprise that the next issue of the design had the Olympus 22R back in place, and the 15R made no further appearance. Dive brakes were also now in place on the fuselage, and the tailplane area was increased once more.
Throughout the work on the drawing up of a datum design, Vickers and English Electric were also keeping abreast of changes being made to the operational requirement. The fourth and final draft of OR.339 had been issued back in December 1958, but it was to be superseded by a new OR, OR.343, the first draft of which was issued in March 1959. Vickers’s George Henson attended a meeting at the MoS on 11 March to discuss runway requirements, fighting off an attempt to require tyres of such low pressure (45 to 60psi (3.16 to 4.22kg/sq cm)) that the aircraft would need to be substantially enlarged just to fit the resulting large tyres in the fuselage. About the best Vickers could offer was 80psi (5.62kg/sq cm), with 70psi (4.92kg/sq cm) for the nosewheel, though this would rule out operation from a grass surface. This was agreed, along with an aircraft LCN requirement not to exceed 22. While Vickers had taken the STOL requirement more seriously than English Electric to begin with, it was now English Electric that was becoming concerned about the aircraft’s runway performance. High thrust and flap settings on take-off would tend to force the nose down to begin with, delaying the point at which the nose could be lifted, and thus extending the take-off roll. Consideration of a shorter tail arm would make the problem worse. Various methods had been discussed to try to get the nose off earlier in the take-off run, such as using the nose gear doors for lift, auxiliary lifting engines in the forward fuselage, nose flaps, and so on, but no firm decisions had been made other than to investigate an extending nose gear leg.
An Airframe Advisory Design Conference between English Electric and Vickers was held on 22 March 1959, to discuss work so far on the airframe configuration. Discussions also began between Vickers and the MoS in the first week of April as to the terms of a contract covering the design work that by then had already been under way since the start of the year, along with further meetings to discuss individual aspects of the ‘new’ OR.
Two variations on nose flaps tested on a windtunnel model to see if they could assist with lifting the nose earlier during the take-off run. They were found to give only a small nose-up trim change and were not proceeded with. Damien Burke
OR.339 is dead; long live OR.343
On 19 February 1959 the Air Staff informed the MoS that ‘GOR.339 was dead’ and the new aircraft would be known as OR.343. The existing description of TSR2 would be retained, however, as ‘it was popular with the politicians’. OR.343’s final draft was completed on 26 March 1959, and introduced some significant changes to the requirement when compared with OR.339. The first official issue of OR.343, Issue 1, was completed on 8 May 1959 (see Appendix II).
One no-doubt-intended side effect of renumbering the requirement was that Short Brothers & Harland was now truly left out in the cold, no longer able to claim any rights in the joint English Electric/ Shorts P.17 proposal to GOR.339 because the TSR2 was now supposedly being built to an entirely new OR. There was substantial anger at Shorts, which felt betrayed by both English Electric and their part owner, the government. This boiled over at a meeting on 10 July between the Controller (Aircraft) (Air Chief Marshal Sir Claude Pelly) and representatives of Shorts (Sir Matthew Slattery) and English Electric (Robin Caldecote), at which Shorts forcefully expressed its disappointment at being ‘completely excluded from the TSR2 project, despite the fact that much of the aircraft which is emerging from the Vickers/English Electric collaboration bears a close resemblance to the English Electric/ Shorts submission to GOR.339’. The mood at Shorts was not improved when, less than two weeks later, English Electric informed Shorts that Vickers was working on a proposal to use RB.108 lift engines on the TSR2 to improve rotation at take-off. Shorts immediately wrote to Sir Claude, claiming design rights on this type of jet lift, pointing out that it was contained within the joint English Electric/Shorts submission. Shorts had already carried out a considerable amount of work on jet lift, and expected to receive some recognition in the form of work under contract or a licence fee. The MoS was unimpressed, considering Shorts claim ‘a try-on’ and ‘preposterous’. It pointed out that the SC.1 research aircraft and the RB.108 were both entirely funded by the Ministry, and that anything deriving from this work would ‘… fall to the Ministry to exploit for defence purposes as they wished’. Shorts would continue to be excluded from the project.
The jet-lift platform itself, while of no apparent interest to the RAF, was still considered a viable project by Shorts and, to a lesser extent, English Electric, and on that basis English Electric had come up with a way to keep Shorts on side. An agreement had been drawn up between the two regarding collaboration on any future VTO projects, whether they concerned a lift platform or a strike reconnaissance aircraft for a rumoured NATO requirement. This agreement spelled out that work would be shared equally between the two companies, design leadership being vested in either English Electric (if the aircraft using the platform was to be an English Electric design) or with Shorts (if the aircraft using the platform was to be from any other company, e.g. the Gnat). English Electric wrote to the MoS in June 1959, asking for an assurance that any future contract awarded to this English Electric/Shorts partnership would accept that the partnership was valid in and of itself, with no need for a third party; i.e. that there would be no repetition of the Ministry’s efforts to shut Shorts out of the English Electric/ Shorts/ Vickers grouping. The CA wrote back in July, apologising that he felt unable to give such an assurance. It seemed the government was happy for aircraft companies to band together, but only if they did so in a manner entirely approved by the government.
The first Joint Datum Aircraft
At a meeting at Weybridge on 17 April 1959 English Electric and Vickers agreed to accept the then-proposed Joint Datum Aircraft for continued work in all areas. English Electric was still unhappy with many items, believing, for instance, that an intake aft of the wing leading edge (as per the P.17) could be made to work and would provide valuable weight saving and a neater design. (However, its own windtunnel tests did not bode well, and later American experience with a similar intake on the TFX project would run into problems too). The company was also concerned with the emphasis on attaining a high lift coefficient for the wing at all costs (thus reducing approach speed), when weight, drag and parachute delay were all more important to meeting the OR’s needs in terms of STOL
performance. The undercarriage also seemed too complex, and the coincidence of wheels, intakes and weapon bay in the same area resulted in a large cross-section in a drag-critical area and a weapon bay of limited capacity. Clearance was more than adequate for a single Target Marker Bomb, but very tight for six 1,000lb conventional HE bombs. English Electric would only agree to the joint datum configuration as a basis for further work if work continued on an ‘acceptable’ forward-retracting undercarriage and a shorter engine installation tunnel (not enclosing the engine itself) was used.
The first Joint Datum Aircraft, depicted on TSR2 Sheet 21 Issue 1, 13 April 1959. Damien Burke
No company relies upon a single customer or a single contract, and TSR2 was not being designed in a vacuum. Vickers, flush from apparent success with the Scimitar, Valiant and Viscount airliner, was also busy with the Vanguard turboprop airliner and the VC10 jet airliner. However, it had badly underestimated the development effort required on these two aircraft, and the company’s financial position was taking a turn for the worse. Both projects were private ventures, as required by the MoS for all civil developments, and the burden was unexpectedly heavy. Vickers turned to a possible collaboration with de Havilland, which had a guaranteed BEA contract for a new airliner, as a means of pleasing its Ministry masters and convincing them to bail Vickers out with some government funding for the VC10 and a smaller aircraft, the VC11. De Havilland, however, was rightfully wary of an approach from Vickers, correctly judging that it was simply part of a plan to gain aid for the VC10. Moreover, the fact that the VC11 would compete against its own BEA airliner was also a serious problem. The MoS, by now led by Duncan Sandys, was keen to see another aviation industry merger, but less keen to offer government funding. For the time being, Vickers continued to slide into a financial mire. Its efforts on TSR2 suffered as a result, with George Edwards’s primary focus elsewhere and English Electric firmly believing that almost all of the real engineering at this stage was being carried out entirely by its own personnel.