The de Havilland Firestreak
An air-to-air guided weapon employing infra-red homing Already in production for the Royal Air Force and the Royal Navy.

DE HAVILLAND Propellers Limited may now state that they have mastered the problems of the design and development of an air-to-air guided weapon which employs a system of infra-red target homing. This weapon, named Firestreak, has been chosen and ordered for the Royal Air Force and the Royal Navy: it will be fitted as standard equipment to certain of the most important British fighter aircraft, including the English Electric P.I., the Gloster Javelin, and the de Havilland Sea Vixen all-weather fighter now in production for the Royal Navy. A photograph of Firestreak in flight forms the cover of this issue of the Gazette.

Correct functioning of the systems of the complete weapon is checked on the overall test console.

An organisation for the production of Firestreak has already been built up in the Propeller Company's factories in the north and south of England, centred respectively on Bolton and Hatfield, and several thousand technical staff and manufacturing personnel are now engaged upon this work. When de Havilland Propellers Ltd. began work on Firestreak the aim was to develop a weapon with a guidance system which would enable it to engage high-speed bomber aircraft at great heights: the infra-red system was chosen for Firestreak after careful comparative study. This system, which possesses qualities of great range and sensitivity, is immune from the jamming which it is possible to employ against conventional radar weapons. It employs a detector eye which is sensitive to the infra-red rays emitted from an aircraft: this eye, once it has locked on to the target, feeds information into the control system to ensure that the weapon continues to travel in the correct direction, no matter what manoeuvre the target may perform. Firestreak is effective up to great heights, and may be fired from fighter aircraft travelling at supersonic speeds. The components of Firestreak fall into six main sections. These are the guidance, control and fusing systems, the power supply, the propulsion motor and the warhead: they are housed within an aerodynamic body tube fitted with four small wings and four control fins.

The parent fighter carries Firestreak on a launching shoe attached to the wing of the aircraft. Weapons may be fired singly or in pairs, and provision is made for jettisoning them in an emergency. The ancillary equipment required in the parent aircraft has been designed and developed also by de Havilland Propellers Ltd. in parallel with the main Firestreak project.

The Background of Firestreak

de Havilland Propellers Ltd. took the decision to enter the guided-weapons field at a time when the company already possessed wide experience of electronic. hydraulic and precision engineering which had been gained over many years in the design, development and manufacture of aircraft propellers. This provided the nucleus of technical direction upon which a completely new team was built. Starting from a handful of engineers under the technical lead of Mr. G. C. I. Gardiner, the company's Technical Director and Chief Engineer, an organisation of many hundreds has been built up. This staff, together with the manufacturing personnel, now totals several thousand engaged upon this work alone. There has also been a large addition to the company's facilities for the design and manufacture of its other important products such as propellers, radar scanners and aircraft air. conditioning systems. The first members of the guided-weapons team were Mr. G. H. F. Brown, Mr. R. N. Hadwin, and Mr. J. Mullin, who had been until then respectively chief designer, chief vibration engineer and chief dynamicist of de Havilland Propellers Ltd.

When the Ministry of Supply awarded de Havilland a development contract for a turbo-alternator, a compact form of electrical power supply which was required by other companies engaged on the development of guided weapons, the company were encouraged to expand their equipment resources and to recruit further senior technicians. Key members of the team who joined at this time included Dr. G. H. Hough, now the chief systems engineer, Mr. C. de B. White, who is to-day the chief trials engineer, and Mr. F. J. Costigan, who came to the company with previous knowledge of guided-weapon design, and is now chief designer of air-to-air weapons.

Firestreak In Full Flight

Subsequently a contract was received for the development of an infra-red homing-head, on which early work had already been carried out by the Ministry of Supply Radar Research . Establishment. The guided-weapons team grew rapidly and the provision of additional factory space, manufacturing capacity and techniques was expanding at an equal rate both at Hatfield and in Lancashire. A development contract for a complete guided weapon was awarded in the light of the successful completion of the work on the turbo-alternator and the homing-head. The main design requirement was that the weapon should be reliable and easy to handle in service. At an early stage of the work, therefore, de Havilland Propellers Ltd. decided to design and manufacture all components of the weapon themselves, with the exception of the propulsion and explosive units which could be produced by existing facilities within Government establishments, Although many of the problems required specialist knowledge, it was felt that the basic skill existed within the company, and thus the difficult and complex problems of co-ordinating design and development between several different companies spread ' throughout the country could be 'avoided. This decision contributed largely towards achieving the final results in the shortest possible time.

A weapon is prepared for firing in one of the Propeller Company's laboratories.

Trials
The first flight trials were begun under the direction of Mr. C. de B. White. These were carried out at the Royal Artillery range at Larkhill in Southern England. After initial trials to check boost separation a number of weapons were fired with the turbo-alternator installed to check the performance of the power system under the high stresses occurring during flight. Although the weapons were, for reasons of safety, destroyed in the air after a flight of a few seconds, adequate information on the performance of the specific system under test could be transmitted to the ground receiving station in that time.

Weapons containing both power and control systems were fired next to check the response of the control system to pre-arranged signals. The final stage before a fully guided round could be fired was to check the performance of the homing-head in flight when locked on to a target but not controlling the flight path of the weapon : as in the previous phase all data during flight were transmitted to the ground by telemetry. At last, with full control and guidance systems linked together, the first complete Firestreak was fired at Larkhill. The launching was carried out at night. Firestreak was fired at a target several miles distant from the launching site: this target took the form of a large wire frame which carried heaters to simulate the radiation from an aircraft. Immediately upon completion of the firing , the eager team of observers, which included Mr. G. C. I. Gardiner and Mr. C. de B.White, drove rapidly down the range to examine the target. They found that Firestreak had scored a direct hit.

The exceptional merit of the team's early work had been proved. The early model of Firestreak was a success. An extensive re-equipment programme was commenced at the main Lostock factory to make ready for the full flow of production. A large quantity of machine tools and equipment, suited to the new and exacting standards demanded for weapon manufacture, was purchased.

The first air trials of Firestreak began during the middle of the ground launching tests. Trials were carried out over the Aberporth range off the coast of Wales, initially to test that the weapon could be jettisoned safely. The aircraft used was a de Havilland Venom, flown by Mr. D. de Villiers, then chief test pilot of de Havilland Propellers Ltd. The first round launched from under the wing of an aircraft was fired from the Venom standing on Pendine Sands, hear the Aberporth range. The nose of the aircraft was pointed out to sea and jacked up, and an anti-blast door was fitted over the undercarriage. Mr. de Villiers and Mr. C. de B. White entered the cockpit and adjusted their safety straps.

Mr. White pressed the firing button and, the missile left the Venom successfully. No damage or marking was sustained by the aircraft. The way was now clear for flight firing trials to begin, and a weapon was fired from a Venom flying over the Aberporth range. This was merely a trial launching: no target was employed. The weapon left the aircraft successfully and followed the designed flight pattern after launching. Information on the behaviour of the components was automatically transmitted by telemetry to the ground receiving station.

After further air launching trials, the Venom was armed with the first complete operational round. A radio-controlled target aircraft, fitted with heaters to simulate radiation from a modern aircraft, was put into the air, and Mr. M. P. Kilburn, the new chief test pilot of the Propeller Company, set off in pursuit in the fighter. The weapon was launched and scored a direct hit on the target, which crashed into the sea. A continuous programme of air firing has since been carried out at Aberporth. Every firing has yielded valuable information and has led to progressively greater precision. The percentage of direct hits has become consistently higher.

It had always-been recognised that the Aberporth range was too limited in, size to allow high-speed target aircraft, necessary for trials as development advanced, to be used. An additional disadvantage was the impracticability of recovering weapons from the sea after their flight. Excellent facilities, however, were available at the rocket range at Woomera, in Australia, and a small test team was established there early in 1955 with the assistance of Mr. T. W. ~iP,-of the de Havilland Aircraft Proprietary Limited of Australia.

The Woomera test programme began with a number of successful familiarisation tests using the Sabre aircraft. Firings which were carried out later at Jindiviks, high-speed target aircraft developed by the Government Aircraft Factory in Australia, were completely successful and several targets were destroyed.

In a brief space of time de Havilland Propellers Ltd. have designed, developed and put into production a weapon which has proved to be of exceptional merit. Existing factories have been re-equipped, and new premises have been acquired. A large factory is nearing completion beside the company's existing factory at Walkden, near Bolton, in Lancashire, and this will be used solely for the assembly of Firestreak.

1957 Advertisement For Firestreak

A servicing organisation has been built up. Instructors at Hatfield are busy initiating Service personnel into the use of their new weapon. In Australia the Propeller Company has set up two establishments at Salisbury and Woomera, and in that country valuable assistance in staffing these is given by de Havilland Aircraft Proprietary Ltd. from their factory near Sydney. Throughout this work the closest support and encouragement has been given to de Havilland Propellers Ltd. by the ' Ministry of Supply and their various technical establishments, by the Royal Air Force, the Royal Australian Air Force, the range authorities at Larkhill and Aberporth, and the Weapons Research Establishment at Woomera. Thanks go to them for the parts each has played.