TSR2

by Damien Burke

  APPENDIX I

  General Operational Requirement 339

  The following is the text of the general operational requirement to which each firm submitted a design. Various modifications were made to it at one time or another, but this is the first issue, as issued in March 1957.

  SECRET

  AIR STAFF GENERAL OPERATIONAL REQUIREMENT NO. GOR.339

  TACTICAL STRIKE/RECONNAISSANCE AIRCRAFT

  INTRODUCTION

  1. The advent of the hydrogen bomb has enormously strengthened the power of the deterrent and the likelihood of global war has decreased. It is now recognised that, provided the deterrent is maintained, the main threat to our freedom and security will come from an intensification of the cold war and an increasing danger of limited wars. Thus, our defence forces must be adequately equipped and prepared not only for global war but also for the outbreak of limited wars, in which the possible use of nuclear weapons cannot be excluded. Weapons systems in the tactical field must therefore have the best possible limited war capability as well as meeting such global war requirements as are called for by our commitments to SACEUR.

  2. In a nuclear land/air battle, the ability of tactical air forces to provide timely nuclear counter bombardment and reconnaissance becomes a decisive factor in the conduct of operations. Conventional air support is also essential if the small forces at our disposal are to be capable of dealing with outbreaks of limited war, in which HE weapons only are used.

  3. The vulnerability to nuclear attacks of large fixed targets in the tactical area is well appreciated and every effort will be made to achieve dispersal. Thus, the tactical strike/reconnaissance task is likely to demand a primary ability to seek out and destroy a large number of targets whose positions are not accurately known.

  4. A ballistic missile offers advantages of easy dispersal and relative invulnerability but it has no capacity for attacking unknown position targets, has no reconnaissance capabilities, is unsuitable for meeting cold war requirements and is a most uneconomical means of delivering HE should this be required. The Air Staff believe that the tactical strike/ reconnaissance requirements can more adequately be met by a manned aircraft weapon system.

  5. The need is for a self-contained all-weather bombing system with adequate range to permit effective operations from our limited number of overseas bases or, in global war, from outside the highly vulnerable tactical area. Ideally complete independence of airfields is desirable. However, if runways must be used, the need is to keep take-off and landing requirements to the minimum to facilitate operations from existing airfields which may have been damaged, or from dispersed strips.

  6. The Canberras must continue to provide our tactical strike and reconnaissance force far some time to come. It is difficult to say for how long they can be regarded as an effective tactical force but, operated strictly at low level, they may continue at best to 1965 in terms of limited war, or 1963 in global war. Thus, there is an urgent need to define an Operational Requirement for a tactical strike/reconnaissance aircraft for use in conducting the tactical offensive.

  ROLES

  7. The roles of the aircraft, in order of priority are:-

  (a) Delivering effectively the tactical nuclear weapon from low altitudes up to the maximum ranges obtainable and with a minimum consideration for prevailing weather conditions, by day and by night.

  (b) Meeting the tactical requirements for day medium and low-level and night low-level photographic reconnaissance.

  (c) All-weather electronic reconnaissance within the limits set by the necessity that this requirement is not to compromise performance in the primary role.

  (d) Delivering effectively by day and by night tactical nuclear weapons from medium altitudes under visual conditions or, regardless of visibility using blind bombing techniques.

  (e) Delivering effectively under visual conditions HE bomb or rocket loads as an alternative to the tactical nuclear weapon.

  GENERAL DESIGN CONSIDERATIONS

  8. In order to minimise the effect of enemy defences, the greatest possible portion of the flight to and from the target will be made at a mean height of 1,000 feet, or less, above the ground. This is accepted as implying an average cruising altitude of 1500ft above sea level. No defensive armament is required.

  9. To increase the flexibility of the system an alternative medium-altitude capability is highly desirable. It is appreciated that requirements for low-altitude operation, long range and assisted take-off on the one hand and good medium altitude performance on the other are not readily compatible. Low-altitude capability is to be considered of primary importance and the aim must be to provide the best possible medium-altitude performance that does not compromise requirements for the low-level role.

  10. Close attention is required to minimise permanent base requirements, and it is also necessary to cater for operations from dispersed sites. The increasing importance of dispersal emphasises the need to reduce the required runway dimensions to the minimum. The Air Staff wish any worthwhile, though possibly unconventional, means of improving take-off and landing performances to be thoroughly examined. If runways are used operation is to be practical from strips 3,000ft in length. A LCN not exceeding 40 is desired.

  11. The aircraft is to be suitable far worldwide operation.

  PERFORMANCE

  Radius of Action

  12. Without resort to in-flight refuelling the aircraft must be capable of attacking targets at a radius of 1,000 nautical miles from base with at least the final 200 nautical miles to and the 200 nautical miles from the target being flown at low level. A ferry range of 2,000 nautical miles is required. These figures are to be extended appropriately when in-flight refuelling is used.

  Speed

  13. The continuous operating speed throughout the aircraft’s route through enemy early warning and defence cover is to be as high as possible. This penetration speed is to be not less than M = 0.95 at sea level. Additionally a supersonic dash capability at sea level is desirable and the Air Staff wish to be advised on the penalties incurred. It may be assumed that for half the radius of action the use of more economical cruising settings will be acceptable.

  Handling

  14. The aircraft must he capable of releasing a bomb in a loft manoeuvre at low level or in a dive toss attack from medium level.

  15. The loft manoeuvre is an attack in which the aircraft approaches the target in level flight and commences a loop. The bomb may be released between 45° and 110° to the horizontal and the aircraft continues to loop with a roll out to escape.

  16. In a dive toss attack, the aircraft approaches the target in a dive and releases the bomb whilst decreasing the angle of dive. The aircraft completes the attack by a loop and roll out to escape.

  OPERATIONAL EQUIPMENT

  Armament

  17. The aircraft is to be capable of carrying the bomb specified in OR.1127. As an alternative secondary role, it is desirable that the aircraft should carry a normal load of 4 × 1000lb bombs and a minimum of 6 × 1000lb in an overload case.

  18. The aircraft is to be capable of carrying either of the following alternative rocket loads:-

  (a) A minimum of 74 two-inch rockets.

  (b) A minimum of 12 OR.1099 rockets

  Navigation

  19. A self-contained navigation system is to be incorporated to provide a clear display showing actual or DR position continuously in a form that will enable the navigator to adhere closely to track and on the correct heading right up to the moment of bomb release. The system is to permit the aircraft to be flown along the chosen route to an accuracy of 1 nautical mile when operating at low altitude and 2 nautical miles when operating at medium latitude. In addition positive position fixes must be possible when using ground aids to navigation.

  Bombing

  20. When using the bomb to OR.1127 a bombing accuracy of 1,200ft CEP is required. The Air Staff are prepared to accept that, at low altitudes, this accuracy will be achieved only under visu
al conditions at any radius of action and under blind conditions up to a radius of action of about 200 nautical miles from ground radio stations. However, future developments of nuclear weapons may permit same relaxation of the required bombing accuracy. An all weather bombing capability at any radius of action is most desirable and the Air Staff wish to know the accuracy which could be expected from an adaptation of the self contained navigation system for blind bombing.

  21. A HE bombing accuracy of 600ft CEP is required. Visual bomb aiming may be effected by means of either a pilot attack sight or a standard navigator operated sight. It is accepted that effective blind HE bombing will be achieved only within the ranges at which the ground based radio aid gives adequate accuracy.

  Photographic Reconnaissance

  22. Photographic reconnaissance is required at low and medium altitudes. The Air Staff are prepared to accept that the full photographic reconnaissance capability may be possible only as an alternative role. Nevertheless, for reasons of flexibility it should be possible easily to convert between the strike and reconnaissance roles.

  23. Low altitude. The following photographic capability is required:-

  (a) Vertical photography, by day, in poor light and at night from 500ft to 5,000 feet. Lateral angular coverage to be not less than 60° and film for forward coverage at 500ft must be sufficient for at least 80 nautical miles. The scale of photography should be not less than 1:10,000.

  (b) Oblique photography by day from 200ft to 5,000 feet. Both forward facing and lateral oblique cameras are required; the camera field of view is to extend from the horizon to a 30° depression angle.

  24. Medium Altitude. Vertical photography by day is required from 5,000ft to 36,000 feet. The overall lateral angular coverage of this camera system is to be not less than 30° sufficient film for forward coverage, at 36,000 feet, of at least 200 nautical miles must be carried. A scale of 1:18,000 at the maximum height is required, but if it can be shown that there are significant advantages in accepting smaller-scale photography at maximum altitude, the Air Staff are prepared to consider granting concessions.

  25. General. The ground position of each photograph is to be recorded, and the record must be available for first phase interpretation. Automatic control of image movement compensation is required. Automatic control of exposure is desirable and should be provided for poor light conditions.

  Radar Reconnaissance

  26. An all-weather radar reconnaissance capability is desirable. Full advantage is to be taken of the possibilities of adopting the self contained navigation system to meet this requirement.

  Line Scan Reconnaissance

  27. The timely receipt of reconnaissance information can be of decisive importance. Line scan techniques are being developed to permit in-flight transmission of reconnaissance information and it is desirable that this equipment be fitted in the aircraft.

  Flight Control System

  28. An automatic control sub-system consisting of auto flight control and instrument displays is to be provided which will allow the aircraft to be flown as easily as possible throughout all operational flight conditions. The sub-system is to respond to signals, set in manually by the pilot, or received from the navigation, bombing or automatic landing system. Signals from the bombing system may include a demand for a programmed loop and roll out manoeuvre. Emphasis must be placed on reliability and safety.

  Radio and Radar Sub-systems

  29. The following radio and radar sub-systems are required in addition to the components of the integrated flight control system:-

  (a) Two-way pilot operated communication up to extreme range at all altitudes, with facilities for automatic transmission of position data.

  (b) Intercommunication.

  (c) Attack warning system.

  (d) Flight refuelling positioning system.

  (e) IFF Mark 10.

  CREW STATIONS

  Crew Composition

  30. The crew will consist of a pilot and a navigator.

  Crew Comfort

  31. The greatest attention is to be paid to crew comfort. It will be necessary to provide some form of gust alleviation if tolerable crew comfort is to be maintained during long periods of high speed, low altitude flight. The Air Staff wish to be advised on the type of protection possible.

  32. It must be possible far the crew to carry cut all their duties without moving from their seats.

  View

  33. The crew must have good clear view at all times. There must be:-

  (a) Adequate forward and downward view:-

  (i) For the pilot to avoid obstacles and identify landmarks.

  (ii) For the navigator to map read.

  (b) Adequate side view for pilot and navigator to gather and co-relate information to ensure accurate track holding.

  (c) A downwards view for one of the crew members, approximately equal to the area being covered by the vertical cameras.

  (d) Means to enable a crew member to inspect the wings and control surfaces, to see whether condensation trials are being formed and to search the rear hemisphere for attack warning purposes.

  Heating and Ventilation

  34. It weneraill be essential to provide an adequate air supply for cooling and heating. Aircrew are to be protected against heat and cold at low level in the event of failure of cabin conditioning. The Air Staff would like to make the advisory recommendations contained in AP.970, Part 2, Leaflet 105/1 mandatory for this aircraft and wish to be advised if this is not acceptable.

  Pilot’s Station

  35. During high-speed low flying, it will be necessary for the pilot to give the greater part of his attention to obstacle clearance. Cockpit design, therefore, must ensure that instruments – in particular those required for low-level flight and combing manoeuvres – are suitably placed.

  36. The best possible view is required during take-off and landing. If there is any doubt about the efficiency of the means of ensuring clear vision at all tines, direct vision is to be provided for emergency use in approach and landing.

  Navigator’s Station

  37. Physical access between the pilot’s and navigator’s stations is desirable.

  DE-ICING AND DEMISTING

  Engine and Airframe

  36. Engine and intake de-icing is essential for protracted periods of flight at low altitude. Airframe de-icing is highly desirable but the penalties of incorporating it may be unacceptably severe. The Air Staff wish to be advised on this.

  FUEL SYSTEM

  General

  39. It is essential that the fuel system should be simple and, as far as possible, automatic in operation. The need for the pilot to distract his attention for the purpose of fuel management must be kept to a minimum.

  40. The aircraft is to be designed for the use of AVTAG fuel. However, if the use of AVTUR shows considerable performance advantages it may be assumed that this fuel will be used for certain operational missions.

  Flight Refuelling

  41. Provision is to be made for flight refuelling at a rate of not less than 300gal per minute. It must be possible to refuel all tanks this way. It may be assumed that a modified ‘V’-class bomber aircraft will act as the tanker. However, the Air Staff would like advice on the implications of the ‘Buddy’ system of flight refuelling. In the interests of weight saving, it is desirable that flight refuelling should be carried out through the same system as ground refuelling.

  Fuel Jettisoning

  42. In order to permit the pilot to reduce the aircraft’s weight in emergency or so as to return to base should a mission have to be abandoned soon after takeoff, a system of fuel jettison with a high flow rate is highly desirable. A study of the problem is to be made and the Air Staff informed of the penalties involved.

  SAFETY AND SURVIVAL

  Oxygen

  43. The demand oxygen system is required. Sufficient oxygen is to be provided for the full endurance of the aircraft when operated at maximum altitude. Provision is to be made for incre
asing the oxygen capacity so as to allow for the use of in-flight refuelling. The system is to be based on the use of liquid oxygen for crew breathing.

  Aircrew Protection

  44. Means must be provided to prevent contamination of the cabin and camera compartment by radio active material or BW and CW agents, when the aircraft is on the ground ready for flight and at all altitudes. In addition, integrating or rate meters may be needed and safe positions for this equipment should be considered.

  Ejection Seats

  45. Two fully automatic ejection seats are required. It must be possible to use these at all heights from ground level to the maximum attainable. It is desirable that escape should be possible also at all speeds. The Air Staff wish to be advised on the possibilities of meeting this latter requirement. It is essential that action to fire the seat should also clear the ejection path.