TSR2
Page 12
Carrying only a single Target Marker Bomb, a subsonic and mostly high-level sortie, descending only to attack the target, would give a combat radius of 600nm (690 miles; 1,110km) at a take-off weight of 45,000lb (20,400kg), and a take-off distance of 1,330yd (1,215m). With a full load of four drop tanks in addition, a combat radius of 500nm (575 miles; 925km) would be available for an entirely low-level sortie with a brief supersonic dash over the target. Alternatively, sticking mostly to high level would give the full 1,000nm combat radius required by the GOR.
Even after submitting a joint brochure with Avro, Hawker continued to work on improving its P.1121 submission, and around October 1958 produced a design for a ‘Stage B’ version of the P.1121 two-seat strike aircraft. This was to use the new Olympus 22R and had a modified front fuselage, lengthened to accommodate SLR. The rear fuselage was lengthened to keep the aircraft’s c.g. in the same place, providing extra room for fuel as a bonus. Rather than bag-style fuel tanks, integral tanks would be used, and this, along with the extra tanks and improved fuel consumption expected from the Olympus 22R, improved combat radius significantly. Wings of greater span improved take-off and cruise performance too. All of these changes meant that the low-level subsonic sortie could now be up to 780nm (900miles; 1,440km) in radius, with up to 1,200nm (1,800 miles; 2,900km) for the high-level sorties. A high speed, Mach 2.0, high-level attack to a target 300nm (345 miles; 555km) away was also now possible. A brochure on the P.1121 Stage B was submitted in a last-ditch attempt to get in on the GOR.339 act, but having confused the picture with a solo/joint/solo sequence of designs, Hawker never really had a chance.
Leading particulars: Hawker Siddeley P.1129 Development
Length
74.25ft (22.63m)
Height
20.2ft (6.16m)
Wing span
45.83ft (13.97m)
Wing area
600sq ft (55.74sq m)
Wing aspect ratio
3.5
Tailplane span
27.11ft (8.26m)
Tailplane area
210sq ft (19.50sq m)
Tailplane aspect ratio
3.5
Fin area
103sq ft (9.57sq m)
Engines
2 × RR RB142/3 or
2 × Olympus 22R
Max speed
Mach 1.7 @ altitude
Empty weight
45,410lb (20,610kg)
Max AUW
79,360lb (36,020kg)
Hawker Siddeley Aviation Group – P.1129 Development
With the embarrassing situation of both Hawker and Avro having submitted separate brochures in January, the Hawker Siddeley Group had done itself no favours. Hawker and Avro were none-too-gently ‘encouraged’ to go away and come back with a single proposal from the complete Hawker Siddeley Group. In a strange foretelling of what would happen when the TSR2 was designed, the two companies worked to combine their designs and submitted a joint proposal in July, some five months after the initial deadline for submissions (Hawker having quietly submitted its P.1121 Strike brochure just before, in another defiant attempt to go it alone). The two firms combined the Avro Type 739 and Hawker P.1129 into a single design under the initial banner of the ‘P.1129 Development’, retaining the small size, low cost and operational flexibility of the original P.1129 while incorporating the best features of the Avro 739. These improvements consisted of increasing internal fuel capacity by 750gal (3,410L) to a total of 3,000gal (13,640L) by using integral fuselage tanks; using all-moving tailplanes differentially for roll control at supersonic speeds (thus enabling the conventional ailerons on the wing to be reduced in size while increasing the size and power of the flaps); and using lower-pressure tyres for lower pavement loading. Unusual forward-swept intakes, found in neither of the original designs, were also incorporated into P.1129 Development.
An artist’s impression of the P.1129. BAE Systems
The combined design could now better meet the GOR, a 7 per cent increase in range meaning it could manage the 600nm low-level sortie on internal fuel alone, along with a shorter landing roll. Redesigning the structure to accept either of the proposed Rolls-Royce RB.142 or Olympus 22R engines with their higher thrust meant that the aircraft could fully meet the GOR’s 1,000nm combat radius requirement on internal fuel plus 1,000lb (450kg) of external fuel, while having a take-off roll a full 15 per cent shorter than required. Adding another 400lb (180kg) of external fuel would bring combat radius up to 1,200nm (1,380 miles; 2,220km), and take-off performance would still have a 5 per cent margin available. Service ceiling would be 70,000ft (21,000m), and top speed Mach 2.3 with partial reheat at high altitude, or sustained Mach 1.05 in dry power.
Work continued on improving the design so that it better met the requirements of the GOR, which was itself undergoing changes, and to improve combat radius and supersonic performance. A formal brochure was put together several weeks after the submission of the basic July proposal. The major changes were that the engines were now to be either the RB.142 or Olympus 22R; the wing had been reduced in thickness and area, now had leading- and trailing-edge blown flaps; and some attention had been paid to area ruling. The aircraft could now meet the 1,000nm sortie requirement on internal fuel only, weighing in at 75,000lb (34,000kg) and with a take-off distance to 50ft (15m) of 1,650yd (1,510m) (RB.142) or 1,350yd (1,235m) (22R). Landing distance would be 680 to 690yd (620 to 630m).
The weapons bay had been redesigned, and could now accommodate a single Red Beard, two Bullpup air-to-ground missiles (AGMs), three 1,000lb HE bombs, ninety 2in rockets, twenty-four OR.1099 rockets, a high- or low-altitude reconnaissance pack or a flight refuelling package. Two reconnaissance packs were proposed, the low-altitude version consisting of two 8ft (2.4m) Q-band SLR aerials with moving target indicator unit, three 70mm cameras with 3in lenses and electronic flash units for night use, two F.96 cameras with 6in lenses for daytime use, linescan plus associated recording and control gear. The medium/ high-altitude version had no moving target indicator unit, 24in lenses fitted to the F.96 cameras, and the Q-band SLR aerials would be increased to 14.5ft (4.4m) in length.
A general-arrangement drawing of the Hawker-Siddeley P.1129 development of November 1958. Damien Burke
An integrated navigation, bombing and flight control system was proposed, based on Avro’s work on the Blue Steel nuclear missile, with Doppler/inertial navigation mixing with SLR provided for mapping and position fixing, with a 7ft (2.1m) X-band aerial on each side of the nose above the undercarriage bay. An FLR based on the Ferranti Blue Parrot as used in the NA.39 was to be used, but with some provision for the additional space and dish elevation requirements that would be required of a terrain-clearance version. Avro’s Weapons Research Division had carried out some preliminary work on a simple terrain-clearance system using only a radar altimeter, and believed it could be developed to enable safe flight at 500ft (150m) over most of the terrain the aircraft could be expected to encounter. Unusually steep slopes could be identified in pre-flight planning and avoided accordingly.
For radar camouflage, the intakes would be lined with radar absorbing material and the boundary layer bleeds covered with an inclined metal grid; glassfibre honeycomb panels containing a carbon-based foam would be installed behind the FLR and SLR aerials. Metal film used for demisting the canopy would double as a radar camouflage measure for the cockpit. While no specific electronic countermeasures (ECM) kit was proposed, space was set aside for up to 300lb (135kg) and 8cu ft (0.23cu m) of such equipment.
Hawker Siddeley had also put together its proposed grouping of companies to deal with production; Hawker plus Avro and Gloster, with some windtunnel staff available from Armstrong Whitworth (the remainder of that firm being too busy on civil work to assist with GOR.339). Assuming an Intention to Proceed in January 1959, the availability of a detailed specification by mid-1959 and the placement of a contract by the end of the year, Hawker predicted it would be able to complete the first airframe
by the middle of 1961, with first flight four months after that. A development batch of twelve aircraft, the last three fully equipped, would be required, main assembly taking place at Hawker’s Kingston, Surrey, plant and sub-units being built elsewhere (such as wings and tail control units at Manchester; presumably the Avro plant at Woodford). An interim CA release for December 1963 would be followed by full CA release in mid 1964.
Vickers-Armstrongs Type 571
The most interesting of all the submissions apart from English Electric’s P.17 was that from Vickers-Armstrongs (Aircraft) Ltd. Design work on an aircraft to satisfy GOR.339 was carried out at the Hursley Park site, a large variety of layouts being sketched out before Vickers settled on an overall configuration with which it was happy. The aircraft’s general configuration was fairly conventional, with high-mounted wings with blown flaps and leading-edge slats, tip tanks, an anhedral all-moving tailplane, an all-moving fin and a tricycle undercarriage retracting into the fuselage. Forward-slanting intakes with prominent splitter plates were about the only unusual item. A single large airbrake behind the bomb bay doubled as an access door for the engine accessories bay.
In Vickers’s opinion the aircraft was going to have to be a large one to meet all the requirements, so it would be of enormous benefit to engineer all the equipment for the aircraft to minimum size and weight, while splitting separate military tasks into bomb bay packs that could be fitted to the aircraft as necessary. The basic idea was that the aircraft would be designed as a strike aircraft, with the ability to fit alternative equipment packages to carry out the day and night reconnaissance roles. This policy of miniaturization was a unique suggestion, and Vickers actually proposed a pair of basic designs, the larger twin-engined aircraft to meet every aspect of GOR.339, and a much lighter and smaller single-engine aircraft relying on the use of miniaturized equipment, which would be particularly viable if the supersonic requirement could be relaxed and a typical strike sortie be carried out entirely at subsonic speeds.
Leading particulars: Vickers-Armstrongs Type 571
Small aircraft
Large aircraft
Length
59.4ft (18.10m)
77ft (23.47m)
Height
19.6ft (5.97m)
Span(including tanks)
32ft (9.75m)
41.5ft (12.65m)
Wing area
200sq ft (18.58sq m)
430sq ft 39.94sq m)
Wing aspect ratio
4
4
Tailplane area
65sq ft (6.04sq m)
Tailplane aspect ratio
2.76
Fin area
50sq ft (4.64sq m)
Engines
1 × 14,000lb (6,350kg) RB.142R
(22,700lb (10,300kg) in reheat)
2 × 14,000lb (6,350kg) RB.142R
(22,700lb (10,300kg) in reheat)
Max speed
725kt (835mph; 1,340km/h) or
Mach 2.1 @ 36,000ft
(11,000m)
725kt (835mph; 1,340km/h) or
Mach 2.1 @ 36,000ft
(11,000m)
Max AUW
45,420lb (20,615kg)
94,075lb (42,700kg)
An artist’s impression of the Vickers-Armstrongs Type 571. BAE Systems via Brooklands Museum
All equipment would be packaged in modules measuring 8in × 8in × 18in deep (20 × 20 × 45cm) and mounted on racks within a single large equipment bay accessible from either side of the fuselage so as to be able to be removed and replaced with ease. There would be twenty-two compartments on either side with cooling air or possibly freon gas circulated through the racking surrounding the modules. Mission packs, such as a reconnaissance pack with linescan, would be fitted in the bomb bay, enabling a role change in a matter of hours. Thus the aircraft would not be carrying anything it did not need, with the attendant weight, drag and fuel requirements of dragging around these pieces of equipment. The use of up-to-date techniques, such as transistorization of electronics and printed circuits, would also assist greatly with miniaturization, and Vickers expected to be able to reduce the amount of space taken up by equipment directly related to the military portion of the aircraft’s equipment fit by up to 40 per cent. Packaging and modular racking would reduce the space required for equipment from 300cu ft (8.5cu m) down to just 80 (2.26); enough space to hold two-thirds of the internal fuel.
A general-arrangement drawing of the Vickers-Armstrongs Type 571 (small) of January 1958. Damien Burke
Getting to the target was to be aided by a comprehensive navigation system consisting of SLR using twin 4ft (1.2m) unstabilized aerials, Doppler and an inertial platform (based on a miniaturized Blue Steel platform). A roller-map cathode ray tube (CRT) display would be driven by the Doppler/ inertial system, with position fixes maintained by the navigator. Provision would be made for an FLR for terrain clearance, and possibly a navigational/targeting aid, if such a radar could be developed in time. The navigator would have an FLR repeater display, normally hidden, which he could view by stowing the roller-map display to reveal the radar scope. As he would only need the FLR for the attack run it did not need to be visible at all times. No particular FLR was specified, as Vickers expected EMI to develop a new one for the aircraft, but Vickers based its size and weight provision for this equipment on the American APG-53 ranging and terrain search radar with a 22in (55.8cm) dish.
The primary method of attack would be to fly past a target, painting it on the SLR (at a range of up to 30nm (34.5 miles; 55.5km)) and then turning to attack it. Accuracy in the region of 400yd (365m) would be expected. Vickers considered the LABS technique of ‘over-the-shoulder’ weapon delivery unacceptably dangerous, as it exposed the aircraft to detection and attack. Its preferred method would be a much shallower ‘loft’ attack, climbing until weapons release and then turning away to escape at low level once more. Vickers’s studies into vulnerability had shown that increasing speed beyond Mach 0.9 at low level did not significantly decrease an aircraft’s vulnerability to attack by ground-based weapons, and supersonic dashes at low level would primarily be of use for crossing particularly heavily defended areas or fleeing from a fighter attack. The company acknowledged that supersonic high-level capability would be valuable for reconnaissance, but even above 50,000ft (15,000m) at Mach 2.5 the aircraft had a fifty-fifty chance of surviving a missile attack. The general thrust of the submission was to try and convince the Air Staff that the combined requirements – low-level operation, supersonic speed, and operating from very short strips – were going to lead to a large and expensive airframe. Compromise would give them something only slightly less capable but much smaller and therefore far more economical both to produce and operate.
A general-arrangement drawing of the Vickers-Armstrongs Type 571 (large) of January 1958. Damien Burke
The cockpit arrangement in the Type 571; note the side-stick for the pilot. Damien Burke
The ‘new’ 1,000nm sortie, including a Mach 2.0 burst at altitude and retaining the 200nm low-level section nearest the target, was not a problem for the lightweight singleengined Type 571. The take-off roll to 50ft (15m) was 1,630yd (1,490m), well within the 1,800yd (1,645m) required. Take-off weight, initially predicted as being 45,400lb (20,600kg), was reduced to 42,200lb (19,150kg) after input from the RAE on improved drag figures. Alternatively, the margin in take-off roll and weight could be traded for longer range, enabling a combat radius of up to 1,150nm (1,320 miles; 2,130km). Ferry range would be 3,300nm (3,795 miles; 6,100km). Fuel load would mostly be contained within fuselage tanks, with additional fuel in the wings and both tip-mounted and underwing drop tanks. In-flight refuelling was also catered for. With internal fuel only, however, the aircraft could not exceed Mach 1.6 and still achieve the required combat radii.
The issue of crew comfort at low level was to be dealt with primarily by the choice of a highly loaded wing (170lb/sq ft; 830kg/sq m), and possibly by having the navigator’s cockpi
t area suspended as an isolated ‘crate’ within the airframe so that he could carry out his duties with more freedom from the effects of turbulence. Both crew members would sit on hydraulically sprung and damped seats. While the GOR had mentioned good visibility for the navigator as a requirement, Vickers offered only an ‘adequate’ view, with a lens system for viewing the terrain being overflown (so the navigator could see what was being photographed on a reconnaissance mission), and no means of ascertaining whether a contrail was being formed except possibly via some variation of an icing indicator. Flying controls would be via duplex hydraulically powered controls with electrical signalling, plus a mechanical backup. Autostabilization (damping) on all axes was to be provided, plus auto-stiffening at high Mach numbers to make up for the loss of fin effectiveness at these speeds. A basic autopilot for heading, height and speed holding would be provided, Vickers recommending that a fully automatic control system be looked at, as it would enable the aircraft effectively to fly itself, based on signals from the navigation and bombing equipment.
A naval Type 571 is marshalled to its deck spot, while another is on final approach. BAE Systems via Brooklands Museum
The engine for both the single- and twin-engine designs was to be the Rolls-Royce RB.142, with 10 per cent of the engine’s high-pressure (HP) air being bled off to operate full-span BLC and blown flaps for improved take-off and landing performance. For the STOL aspect of the requirement Vickers had investigated the ‘Fire Hose’ portable catapult and arrester system developed by the US Navy, and believed that airstrips of just 150yd (140m) length would be viable if its Type 571 was fitted with a suitable hook. This also fitted in with Vickers’ belief that the smaller aircraft could be a viable joint RAF/RN type, the smaller dimensions allowing it to fit on existing RN aircraft carriers. Designing the aircraft to include built-in STOL capabilities was found to introduce substantial weight and size penalties, nearly doubling the aircraft’s size, so Vickers did not proceed beyond basic investigations on this score, mentioning rotating wingtip jets and also a large ducted fan mounted within the wing and blowing downwards, using engine bleed air. Neither scheme was as effective, pound for pound, as simply having a slightly larger wing with blown flaps and relying on a catapult/arrester system. Vickers had spent years trying to get the government to agree to funding of the production of a variable-sweep aircraft, preferably its Swallow bomber, and, no doubt tired of the fight and aware of Barnes Wallis’s own plans to submit a variant of the Swallow to GOR.339 himself, made no mention of variable sweep in its brochure.