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Aviation History
1961
1961 - 1122.PDF
PNEUMATIC MANIFOLD 1 FUEL Ij UQUID OXYGEN . LOX PN€UMATIC PRESSURE • NITROGEN STA»T T 1 (N2) Ignition detection wire breaks A Rolls-Royce circuit diagram for one of Blue Streak's two RZ.2 engines. Engine operation is discussed below and on the preyious page 224 FLIGHT, 17 August 1961 PROBABLE EUROPEAN SATELLITE LAUNCHER COMPLETE VEHICLE: three stages having overall height of 99ft 5.3in and liftoff weight of 230,7691b. THIRD STAGE: not yet designed. Estimated overall height, 20ft 8in; diameter, 54in; gross weight, with payload of 2001b, 5,0401b (vehicle, 500; fairings, 40; propellants, 4,300; all-burnt, 700); speed at burnout or cutoff, 17,000 to 24,000 m.p.h., depending on mission; altitude at burnout or cutoff, orbit height. SECOND STAGE: French rocket to a design nearing completion. Single gimballed thrust-chamber operating on N2O4 and UDMH, with thrust of about 68,0O0lb in vacuum conditions. Overall stage length, 21ft 6in; body diameter, 71 in; gross weight, without third stage, 18,1501b (propellants, 15,432; all-burnt, 2,718); estimated burning time, 6lsec; speed at burnout or cutoff, 14,500 m.p.h.; altitude at burnout or cutoff, about 105 miles; the spent stage would impact approximately 3,000 miles downrange. FIRST STAGE: Bricish rocket of known design. Twin gimballed thrust- chambers operating on Lox and K, with performance given hereunder. Vehicle dimensions: overall length including engines, with current separation bay, 61ft 6.3in; basic length of tank bay, at room temp., 46ft; tank diameter, l20in; length of propulsion bay, excluding engines, 75in; propulsion-bay diameter, lOSin. Vehicle weights: as first-stage of three-stage vehicle, liftoff weight, 207,5791b; as single stage with guidance bay and simulated payload, 210,5601b; all-burnt weight, 13.6871b; propellants, 193,8921b. Propulsion: present thrust per engine, 137,0001b at liftoff, rising to 168,0001b at cutoff after l60sec at about 250,000ft; uprated thrust per engine, 150,0001b at liftoff. Mixture ratio, by weight of Lox/K, in the range 2.2 to 2.5; specific impulse, 245 at liftoff rising to 285 at cutoff; complete weight of each engine, 1,5001b; chamber construction, 312 nickel tubes with wall thickness of 0.012m; area ratio combustion zone/throat, 1.8:1; ex- pansion ratio of nozzle, 8:1; combustion temperature, 3,I9O°C; chamber pressure in combustion zone, 544lb/sq in abs; chamber wall temperature, about 400°C in combustion zone rising to 470°C at throat. Engine gimballing: limits of thrust-chamber movement, anywhere within pyramid of 14" included angle; max programmed turnover rate, 0.7°/sec; hydraulic system pressure, 3,000lb/sq in. Lox system: tank capacity, 2,000 cu ft usable (12,000 Imp gal or 60.8 long tons); tank pressurization, 5lb/sq in empty, 26lb/sq in full; pressurization by oxygen gas from B heat exchanger. Ksystem: tank capacity, 1.250 cu ft usable (7,700 Imp gal or 26.3 long tons); tank pressurization, 2.5lb/sq in empty, ll.75lb/sq in full; pressuriza- tion by GN from A heat exchanger. Gas generator: working-fluid mixture strength, Lox/K, 0.351:1; mass flow rate, 2.6lb/sec Lox and 7.4lb/sec K; delivery temperature to turbine, 650°C, 425lb/sq in. Turbopump: turbine speed, at present engine rating, 29,400 r.p.m.; output, 2,470 to 2,500 s.h.p.; gearbox reduction ratio, 4.88:1; pump shaft speed, 5,987 r.p.m. at present engine rating; Lox impeller diameter, I tin; Lox-pump delivery, 385lb/sec at 787lb/sq in; K impeller diameter, I2.75in; K-pump delivery. I78lb/sec at 750lb/sq in. Ancillary systems: LN sphere, 1451b capacity; LN pressure to heat exchanger, l20lb/sq in; GN spheres, each l,037cu in; charge pressure, 3,0O0lb/sq in; min working pressure, l,000lb/sq in; Lox pressurization circuit bleeds Lox at about 700lb/sq in at 2"5lb/sec and delivers gas at [80°C at 60-70lb/sq in; lube-oil, 20 gal delivered at 750lb/sq in at 6gal/min total. EUROPE'S HEAVY LAUNCHER . . . tanks are closed and the tanks vented. The RZ.12 system is thenself-sustaining, and full liftoff thrust is reached approximately 4sec from the initiation of the start sequence. Complete shutdown occurs automatically should any of a numberof operating parameters, such as Lox-pump bearing temperature, go outside specified limits. A predetermined degree of roughcombustion also results in shutdown. Programmed shutdown in flight is triggered by the vehicle control system, the gas-generatorvalve closing some 0.05sec in advance of the main Lox and K valves. The K valve has a longer closing time, and the K-richcutoff gives more repeatable decay and lower residual impulse. The RZ.2 thrust chamber is gimballed for vehicle control (bothengines together for pitch and yaw, and in opposition for roll), although the high-pressure propellant pipes are connected at then-other ends to the fixed turbopumps. Stainless-steel piping is used, and flexible bellows sections accommodate the chamber movement.Each chamber is hung from a cruciform bearing block bolted to the Lox inlet elbow. The bearing is a plain steel surface, and its exactlocation may be adjusted in order to achieve precise alignment of the thrust axes. Gimballing of each chamber is effected by twohydraulic jacks, one for each axis. From the turbopumps the fuel-rich gas-generator exhaust isducted down through a pair of exhaust pipes each incorporating a heat exchanger, discussed in the next (Systems) section. Finaldischarge takes place through pipes which are pivoted outwards by GN actuators immediately after liftoff, in order to minimize re-circulation of the fuel-rich mixture beneath the vehicle. The exhaust burns away to one side of the motor effluxes, the small lateral thrustthus imparted being allowed for in the control system. Systems Lox The balloon tank containing the Lox is pressurized by GN from a ground supply and by oxygen gas in flight. Before launch this pressure is supplied from the ground pneumatic control unit(PCU), which maintains a nominal 51b/sq in in the tank-empty condition and 261b/sq in for flight. This pressure is fed through oneof the main probe couplings in the base of the vehicle. Lox from ground storage is fed to the vehicle tank through a branch pipecoupled to the main delivery line to the engines. The latter is a 9in-diameter pipe, double-walled through the K tank and downto the main butterfly valve, which is locked open mechanically during flight. Mass flow through this valve is of the order of21 tons/min. Immediately downstream the pipe bifurcates to feed the two turbopumps. K Pressurized to a nominal 2.51b/sq in when empty, the fueltank is charged to 11.751b/sq in by the PCU before liftoff, pressure thereafter being maintained by the liquid-nitrogen (LN) system.The K leaves through an anti-vortex baffle at the base of the tank, and enters the 7in-diameter stainless-stee! delivery pipe. Down-stream of the main butterfly valve the pipe splits into two 5in lines to serve the two turbopumps. Gaseous oxygen Under flight conditions, the Lox tank is pres-surized by Lox, bled off via a control orifice at the rate of about 2.51b/sec from the gas-generator bootstrap line and converted togaseous oxygen in a heat exchanger in the exhaust from "B" turbopump. From this multi-tube cross-flow unit the gas emergesat about 180°C, and is fed up along a 3in pipe, fabricated in 0.01 Oin stainless steel, with an expansion bellows every 10ft, to the top ofthe Lox tank. Two high-pressure relief valves and one low-pressure relief valve are fitted on the top dome of the tank, holding internalpressure to about 51b/sq in during fuelling. Prior to liftoff, of course, pressurization is provided by the ground PCU. LN Following disconnection of the PCU shortly before liftoff,pressure in the K tank is maintained by nitrogen gas obtained from a liquid-nitrogen system. The fluid is stored in a single sphericaltank in the propulsion bay, with an inner shell of stainless steel some 22in in diameter jacketed by a 23.5in-diameter glass-fibreouter shell, the boil-off gas being vented to the inter-layer space. The LN is expelled by GN at 120lb/sq in, and is piped as a fluidthrough a control orifice to the heat exchanger in the "A" turbo-
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