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Aviation History
1958
1958 - 0465.PDF
FLIGHT, 11 April 1958 481 | In the control room, viewing windows and engine controls can be seen I on the right and a circuit diagram is mounted high on the left. On the | right the test cell itself is seen opened for installation of a rig engine. HIGH-ALTITUDE FACILITY system of annular rings, there is a central "bullet" behind the| ramjet nozzle, all units being fitted with "Fognozl" impingeing I jets which produce a true mist and not a spray. Safety devicesi in this section include a Minerva smoke-detector and a Graviner \ photo-multiplier flame-detector, either of which can initiate a| Graviner chlorobromomethane purge system for the tunnel and E outlet ducting. Exhaust ducting is taken below ground level to the silencingtower. The great lagged entrails, with their massive expansion bellows at intervals, present a bizarre sight. They look particularlyweird where they are divided into the triple trunk which allows either extraction by the six steam ejectors, or simple dumpingIO atmosphere in the middle of the silencing tower. The 250 lb/sq in steam supply is reduced to 120 lb/sq in (absolute)by reducing valves before it reaches the nozzles. At-present two nozzle sizes are used, rated at 33 and 40 lb/sec. The test house control room looks much like that of any othermodern engine test house—save that it is rather quieter and more spacious—with a large observation window overlooking the testcell, a control table and banks of instruments. Engine controls and instruments are grouped along the window side, with thetest plant bank of instruments on the left wall, beneath a coloured system-diagram with tell-tale lights which indicate the position ofeach valve. On the right wall is a multiple manometer connected to the mass of pressure-tapping tubes from the tunnel. It may beworth noting here that, dainty as the 16-inch Thor engine looks, it is very thirsty when delivering full thrust; and, since the presenttest cell can accommodate ramjets of very much greater diameter, the fuel-supply gallery is of formidable dimensions.Adjoining the control room is a chamber where dial readings are recorded by photography. Other readings, totalling over onehundred, are transmitted to the central recording room, where they are taken on a high-frequency tape recorder and Honeywell-Brown stylo charts. The tape recordings are processed with a Briiel and Kjaer spectrum analyzer and recorder, while informationfrom the charts is transferred to punched cards and processed on Bristol Aero-Engines' English Electric Deuce computer. A mobilerecording van—a three-ton Austin signal truck—is also used for recording material which cannot be transmitted over a lengthylandline. Equipment in the van includes a 25-channel film recorder for galvanometers up to 6 kc/s natural frequency and, on the elec-tronic side, a 12-channel recorder for frequencies up to 150 c/s and high frequencies up to 4 kc/s, plus a four-channel monitor. Security prevents more than a cursory comment on the actualramjet testing. There are two types of test, short runs simulating missile conditions in which actual flight engines are used and longerruns with bench ramjets, which have heavy-gauge watercooled combustion zones. When a take-off is being simulated, strontiumflares aTe used for light-up, otherwise high-energy igniters are used. Because of the limited running times, the fuel system is auto-matically controlled to a programme. The curve shows a typical example, in which a step exploration is made at a particularMach number over the full combustible range from weak-mixture flame extinction to rich-mixture extinction. Normally a ramjethas an automatic fuel/air control based on measured intake air pressure (speed and altitude, i.e. Mach number) to give maxi-mum thrust. For test runs, die tunnel maintains the ramjet in a constant-Mach airstream and the fuel/air ratio is artificiallystepped by an inching control switch, which re-sets the ratio at short intervals, with a delay, by feeding pressure signals to thefuel/air ratio control unit. Simulated flight conditions are set up in steps, with the appro- The disposition and inter-relation of the major thermodynamic portions of the facility can be assessed from this flow diagram. A, three Economic steam boilers; B, four steam accumulators; C, high-pressure header; D, steam reducing and regulating valves; E, low-pressure receiver; F, steam- operated ejectors; G, exhaust silencing tower; H, altitude test ceil; J, controlled blow-off valves; K, future rigs; L, electric storage-cype air heater: M, water-cooled air coolers; N, unsilenced intake (removable blank); O, blow-off valves; P, four Venturis; Q, dump valves; R air compressors; S, water outlet drain; T, emergency door; U, water spray rings; V, swinging stand; W, settling chamber; X, explosion panels; Y, cooling bullet; Z, blowing nozzle; a, b, 14in motorized shut-off valves; c, 16in hydraulic blow-off valves; d, 14in solenoid-trip anti-surge valves; e, 16in controlled blow-off valves; f, 36in motorized heater shut-off valve; g, 24in motorized cooler shut-off valves; h, 36in hydraulic wedge-gate air temperature control valves (175 Ib/sq in, 450 deg C); i, 6in electric blow-off valve; j, 36in hydraulic blow-off valve; sotating valves; s, 6in man outlet valves; w, 5in motorized pr hydrauli l i Sbm hydrauli blow-on valve: I, 36in main rig valve; m, 16in auxiliary rig valve; n, 36in cell bleed-in; p, 60in exhaust shut-off valves; q, 36in cell purge; r, 36in ejector lanual boiler stop valves; t, 6in auto-pneumatic pressure-retaining modulators; u,4in manual accumulator charging valves; v, 12in accumulator otorize pressure-balance valves; x, 20in isolating valves; y, 16in auto-pneumatic regulating modulators; z, 15in motorized ejector isolators. itJUL "ULJL LJUL/ / IT y JeJL x a w STEAM 25O Ib/tq In STEAM I2O Ib/sq In 'COOLED ENGINEEXHAUST COOLINGWATER ENGINEEXHAUST AIR SUPPLY
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