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Aviation History
1962
1962 - 2224.PDF
FLIGHT International. 27 September 1962 539 Static firing of B/ue Streak in progress on the C3 test stand at Spadeadam. Exhaust gases are deflected horizon tally by a 70-ton, water-cooled steel fame-bucket beneath the pad. Fir ings can be made up to the full flight duration of approximately three minutes Testing Blue Streak By D. B. POLLOCK, M.I.E.E., A.M.i.Mech.E. Administrative Manager, de Havilland Aircraft Company THE equipment instrumentation and supporting facilities needed for firing or launching a large liquid-fuelled rocket are considerable and account for a major part of the cost of the whole project. For Blue Streak, separate systems have to be provided to supply the rocket with liquid oxygen, liquid nitrogen, kerosine and high-pressure nitrogen gas. In addition, large quantities of water may be needed for cooling the efflux deflector bucket for fire protection. During the development and trials stage a great deal of instru mentation is needed to provide information on the functioning of the various vehicle components and systems. In flight, this require ment, which is met by telemetry, still remains of vital importance because it must be possible to track down the cause of any failure so that it can be avoided in subsequent rounds. Preparation forfiring After a vehicle is taken to the site a period of roughly three weeks' preparation is required before a firing can take place. Approximately five days is allowed for erecting and connecting up the vehicle on the stand, and the remaining period is equally divided between completely setting up and checking out the site and vehicle systems. A few days before firing there is a further, more limited check of the site systems and instrumentation, including a simulated countdown to minus two seconds. Certain preliminary work which will save time during the countdown is carried out on the vehicle the day before firing. This includes flushing the engine with tri- chlorethylene, filling the gearbox lubrication tank and transferring kerosine to the vehicle tank and checking for leaks. Finally, before the actual countdown starts, all controls are checked and set ready for operation. The countdown, which takes roughly six hours, falls into three phases. During the first period there is a complete individual check out of all vehicle systems; this is carried out from the test post under the launcher causeway using specially designed check-out equip ment. Up to this point there is free access to the vehicle. During the next phase, when liquid oxygen is transferred to the stand, access is restricted and there is a "hold" period for range warning before the more dangerous period when lox has been fed into the vehicle tanks. From then on, the countdown is remotely controlled from the consoles in the control room, some 1,500yd away from the stand. The countdown sequence, with the actions which must be taken by each console operator, is set out in a specially prepared docu ment which contains more than 1,000 separate action items. The last ten minutes of the countdown, up to and including firing, are initiated by an automatic sequencer unit. During this period, the check-out equipment also is placed on an automatic routine and is continuously monitoring a previously selected number of the more important parameters of the vehicle systems. If any of these fall outside normal tolerance, the countdown stops; action is then taken to reverse the countdown and bring the vehicle to a safe state so that the defect can be investigated. Recycling procedures for doing this at any stage in the countdown are available. If a delay is more than, say, half an hour, or the vehicle has to be
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