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Aviation History
1960
1960 - 1993.PDF
FLIGHT, 16 September 1960 477 Each chamber is assembled from about 300 Nimonic tubes,brazed and welded together and secured against bursting by welded circumferential bands. Kerosine fuel is fed down alternatetubes to the end of the divergent section, returning along the intervening tubes to the injector plate in the head of the chamber.Above the chamber, and not directly attached to it, is the turbo- pump group. In the design of this large package of rotatingmachinery Rolls-Royce have produced a purely British system, although it is reminiscent of early Rocketdyne practice. Installedin the missile the gas generator and turbopump are bolted rigidly to the airframe, whereas the thrust chamber is mounted ongimbals and pivoted about both transverse axes by twin hydraulic actuators. To permit the chamber to gimbal freelythe high-pressure lox and fuel pipes from the turbopump incor- porate Powerflex bellows and flexible sections (which, unlikethose in America, appear to be completely trouble-free). The original RZ.l was rated at 135,0001b at sea level on lox andDTD.2486 wide-cut fuel, and it ran for the first time in 1958 on the P.2 stand at the RAE/RPD Westcott. The production engineis the RZ.2, which has a slightly different configuration. Com- ponents are made at the Rolls-Royce factories at Shrewsbury(the former Sentinel works), Derby, Barnoldswick and Hucknall. They are delivered separately to the SRE and built up into power-plants in the engine fitting shop. A photograph shows engines being assembled on vertical stands of two types, one of whichmay be turned horizontally (on right of picture). The engines are handed left and right into an A pack and a B pack, which arebrought together to provide the twin-engine powerplant for the Blue Streak. Leaving the engine fitting shop one passes through an instru-mentation laboratory. Most of the work so far done at the SRE has been on development engines and the instrumentation for acomplete powerplant frequently runs to well over 100 channels (an engine in full production might need to have only about 20channels monitored during its checkout firings). Close by are a chemistry laboratory, wherein are studied means whereby thehuge quantities of effluent from the test stands may be rendered innocuous to the local water supply, and a surprisingly largemachine shop, fully equipped for really heavy engineering. A short walk leads to the missile preparation area, to whichcomplete Blue Streaks are brought by road from Stevenage or Hatfield for their initial checkout before going on to a stand.There are three bays in this spacious building, but only one is at present in use. In it was a Blue Streak airframe, providing thefirst occasion upon which our late LRBM could be inspected at close quarters. The body consists largely of propellant tankage,10ft in diameter and about 50ft long. At top and bottom are added a tapered forebody carrying the re-entry vehicle and askirt fairing around the rocket engines (there are no verniers). The airframe is fabricated from stainless sheet. Forebody andskirt are stiffened by axial corrugations, but the lox tank is made like that of an Atlas, and like the ICBM Blue Streak must beeither pressurized or stretched to maintain its stability. The transporter in which the Blue Streak was lying was fabricatedfrom rectangular and tubular steel sections, braced to sustain an end-load of 16,0001b. This force is generated by four hydraulicjacks arranged around the base of the forebody and pressurized at 3631b/sq in by a hand pump. The rearmost 25ft of body(much longer than the fuel tank which it contains) has a ribbed exterior, and a stencil warned of gaseous-nitrogen pressurization(for purging and valve operation). Separated from the tankage, the propulsion skirt for this BlueStreak was supported in a rotating fixture and protected by a polythene cover as large as an average room. Ten sphericalnitrogen bottles were hung on its exterior—"which," said our D.H. guide, "is as good a place as any." A few minutes' drive leads to the liquid-oxygen factory run byBritish Oxygen Gases Ltd. At first-floor level are two complete plants, each with a daily output of 50 long tons of liquid oxygen(plus 60 tons of gaseous nitrogen and 8 tons of liquid nitrogen). At present one plant is shut down and the other never ceasesoperation. The principle employed is the familiar one of dis- tilling the atmosphere. A 3,000 h.p. compressor feeds air toliquefaction machines, wherein the air is cooled and expanded to below its boiling point. The liquid is then pumped to a distilla-tion column where the constituents are run off at different levels. The vital liquid oxygen is stored in a 500-ton tank, from whichit is drawn off by road transporters. Nitrogen gasholders serve a pumping station which distributes the inert environment at3,5OOlb/sq in to the operational portions of the establishment. Component Test Area This is the next part of the SREencountered by the visitor, and its purpose is to calibrate and test engine subassemblies prior to their incorporation into apowerplant. The CTA has nine concrete test cells arranged round a central blockhouse connected by instrumentation, TV, peri-scope and control linkages. Most of the cells have been stripped of their expensive equipment and are more-or-less mothballed.The largest building in the area is a water-test facility for the Test stand C3 in the Missile Test Area. Off to the right, out of the picture, is C2, which is not yet quite complete; C3 is ready for use "cold" testing and calibration of turbopumps, thrust chambersand injector plates. Its capacity of 2,000gal/min at 9501b/sq in and 6,000 gal at 3001b/sq in is greater than that of any other testcell in Britain. At the time of our visit a "boilerplate" Blue Streak propulsionsystem, mounted above a turbopump, was being subjected to lox recirculation tests. Although most of the system was heavilylagged, oxygen vapour was streaming from vents at various heights up to about 100ft. In the missile the two gas generatorsstart independently, but a sequencing system shuts both down if either should fail to run up to speed within the specified time(perhaps of the order of 2sec). As might be expected, the unit operates on a fuel-rich mixture at 600 °C, and the surplus kerosineburns noisily from a stack pipe (photograph last week). Elsewhere in the CTA is a cell where a pair of Avon RA.7 turbojets aregeared to provide 14,000 s.h.p. to test turbopumps independently. Engine Test Area Driving north from the facilities alreadyvisited the terrain becomes more bleak, and rises gently over Spadeadam Waste, on the south side of which is located the ETA.Here the individual propulsion units are tested in single or twinned form in four stands spaced about 250ft apart. Stand Alis capable of accepting an entire missile, and is temporarily being employed in functions more properly reserved for the MTA. Init is a Morfax prototype launcher and the tower contains five platforms to provide access to the entire missile. This standcan be employed to ensure compatibility of all portions of the missile, but no engine has yet been fired in it. Next comes Stand A2, wherein tests are run on complete BlueStreak powerplants. The 70-ton flame deflector bucket is cooled by water flowing at 24,000gal/min—too much for local streams;it is piped from the Irthing three miles away—and the effluent is collected in storage lagoons for processing. Above the engineunder test is mounted an ll,000gal kerosine tank topped by a 16,000gal lox tank (in America it is common practice to put thefuel above the lox). Both propellants are pumped from local storage, the lox being fed from a pair of 100-ton lagged yellowtanks submerged partly below ground level. To prevent cavita- tion at the engine turbopump inlets the tanks are pressurized bynitrogen, fed from 3,0001b/sq in bottles served from the pipeline already mentioned. Third of the stands is A3, which at the time of our visit wasoccupied by a single RZ.2 with its gimbal actuators replaced by rigid struts. Curiously, the local temperatures on the flame-bucket are much higher than the worst encountered on the twin- engine stand A2. The last of the stands is a novel erection ofreinforced concrete, known as A42. Much less lofty than its neighbours—and built for the fraction of the cost—it carries itspropellants on either side and may well become a future standard for such structures. Some 600ft east of Al is the control blockhouse for the entireETA, built of 24in reinforced concrete and generally below local
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