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Aviation History
1959
1959 - 0821.PDF
410 FLIGHT, 20 March 1959 AERO ENGINES 1959 . . . chambers has a sea level rating of 1,500 lb thrust. LR11 Under this designation ReactionMotors have evolved a temporary stop-gap powerplant for the North American X-15hypersonic research aircraft. The first two X-15s (and possibly the third aircraft) are eachbeing equipped with two LR11-RM-5 rocket engines, mounted one above the other. TheLR-11 is an advanced derivative of the LR8, running on liquid oxygen and kerosine fed byturbopumps from tankage which occupies the major part of the aircraft fuselage. All eightchambers are believed to be individually con- trollable to provide thrust variation, althoughpresumably one of the engines would either be on or off as a unit and the other would beregarded as a vernier for fine control, perhaps during the approach and landing. Aggregatethrust of the complete installation is probably approximately 16,000 lb; this is not enoughto explore the X-15's performance envelope fully but it permits the initial phases of theflight test programme to be undertaken with a relatively tried and proven powerplant. LR99 This is the ultimate engine whichReaction Motors are developing for the X-15. Few details of the XLR99-RM-2 have beenreleased, beyond the fact that the rated thrust is in excess of 50,000 1b at sea level (a figureof 60,000 lb has been given unofficially) and that the prooellants are liquid oxygen andammonia. (These unusual propellants will be stored in the integral airframe tankage, whichwill be pressurized by helium gas to assist liquid expulsion.) The turbopump is drivenby H.T.P., and delivers at engine manifold pressure at a maximum flow rate in excess of10,000 Ib/min. The LR99 has a single fixed chamber. XLR99s have been fired severaltimes on the test stand, and should be delivered to North American before the autumn. ROCKETDYNE Rocketdyne, a Divi-sion of North American Aviation Inc., Canoga Park, California. Since 1946 Rocketdyne havebeen one of the world's leaders in the design, development and production of large liquid-propellant rocket engines. The division's major facilities comprise the Neosho plant, Neosho,Mo. (production and production test), a pro- pulsion field laboratory in the S?nta SusanaMountains, Cal., and a components facility at Slauson (East Los Angeles) in addition to themain plant and head offices at the above address. Purchases last year totalled over $75mand on January 17 of this year the personnel total was 14,071: floor a"-ea includes 660.000sq ft at Canoga Park and 224,000 at Neosho. Although all the engines described be'owemploy liquid oxygen and RP-1 hydrocarbon fuel as propellants, investigations have beenconducted into other combinations, including fluoTinc and derivatives of hydrazine—such asHydyne, the unique fuel employed in the first U.S. satellite launching achieved by the Armywith a Jupiter C—and in 1956 Rocketdyne began intensive studies into ion propulsion.Sponsored by the Air Force, the latter studies are expected to result in space vehicles withoutstanding performance; projected studies for the Moon and Mars were initiated in March1957 and the first propulsive ion jets were generated at Santa Susana last August. In1957 Rocketdyne received Air Force sponsor- ship for their work directed towards a nuclearrocket engine, thus accelerating a programme which had started in 1946. A major step-for-ward was the award last July of an Air Force contract for a single-chamber liquid-propellantrocket engine with a thrust of 1,000,000 lb; another engine, of some 600,000 lb rating, isbeing developed from design studies started in 1955. Rocketdyne's principal current unitsare described below; a back-up insurance engine for the N.A.A. X-15 aircraft has beencancelled. In addition, many hundreds of large rocket motors have been delivered forsupersonic sled applications, the most import- ant of these being the RS-1 and RS-2. AR-2 Bearing the Service designationYLR42-NA-2, this is the only rocket engine present in the flight-test stage designed anddeveloped for all-altitude boost propulsion of an American combat aircraft. Sponsored bythe Navy, it is engaged in a test programme to determine the improvement in performanceconferred upon the North American FJ-4 Fury, the FJ-4F having a single AR-2 abovethe turbojet nozzle. The AR-2 has a single fixed double-wall chamber fed with JP-4 or-5 and hydrogen peroxide by a turbopump energized by a gas generator. Combustiontemperature is approximately 4,600 deg F but the thrust remains classified. Ignition iseffected by the peroxide decomposition. The AR-2 contract was awarded in 1955 and theengine first flew on July 16 last year. A-7 For ten years Rocketdyne have beenengaged in the development and production Pratt & Whitney JT12A-3 Commercial single-shaft turbojet. Nine-stage compressor, annular combustionchamber with eight flame tubes and two-stage turbine. Overall diameter across flanges of intake, 18.79in; max carcase diameter, 21.9in; max height of engine, 27.Sin; length as depicted, 74.2in; dry weight, 430 Ib bare; maxsea-level rating, 2,900 Ib with s.f.c. of 0.928; max cruise at sea-level, 2,140 Ib with s.f.c. of 0.890. JT12-A-20 (J60-P-1) Military turbojet with afterburner. Configuration as above with addition of afterburner.Overall length, 126in; dry weight, 645 ib bare; max sea-level rating, 3,900 Ib with s.f.c. of 2.30 or 1,800 Ib at M 0.9 at 35,000ft or 3,650 Ib at M 2.0 at 35,OOOft or 1.400 Ib at M 2.0 at 55,000ft; military rating, 2,830 Ib withs.f.c. of 0.955; normal rated thrust, 2,350 Ib with s.f.c. of 0.925. Without an afterburner the military J60 gives 1,800 Ib with s.f.c. of 0.89 at 75 per cent power, and at 35,000ft at M 1.8 gives 993 Ib with an s.f.c. of 1.17. :' .* Pratt & Whitney PT2G-4 (TM-P-7W) Military single-shaft turboprop. Thirteen-stage compressor, com-bustion chamber with eight flams tubes and three-stage turbine. Max carcase diameter, 33.75in; max height of engine, 44.6in; length as depicted, 156.8in; dry weight, 2,670 Ib; max rating at sea level (maintained to 100 deg Fby water injection), 5,500 s.h.p. (6,000 e.h.p.) at 11,000 r.p.m. with s.f.c. of 0.63 ib/hr/s.h.p.; corresponding mass flow and pressure ratio, 67 Ib/sec and 6.7:1.PT2G-6 (T34-P-9W) Same configuration. Max carcase diameter, 34.06in; length, 155.12in; dry weight, 2,870 Ib; max.sea-lcvel rating, 7,500 e.h.p. with s.f.c. of 0.55 Ib/hr/s.h.p. of a series of liquid-propellant rocket enginesfor the U.S. Army medium-range Redstone ballistic missile and its derivatives. Theseengines originally owed much to the German A.4 (V-2) engine, and use similar propellants;they started bench trials in 1950, went into production in 1952 and flew in August 1953.The standard production engine is the A-7, illustrated. It is fitted to the M-5 RedstoneMRBM, the Jupiter C test vehicle (modified to burn Hydyne) and the Jupiter C satellitevehicle (booster propulsion for the Explorer series). The A-family of engines were thefirst in the U.S.A. to enter production with a rating greater than 50,000 lb. It is worthnoting that in the Explorer satellite launchings the single A-7 chamber in the first stage sup-plied over 98 per cent of the total effective impulse required; and the engine which placedExplorer 1 in orbit on January 31, 1958, func- tioned perfectly after being in storage foralmost 14 months and was a 2|-year-old model. MA-2 Under this designation Rocketdynehave produced the comolete propulsion system for the SM-65 Atlas ICBM developed by Con-vair for the U.S.A.F. Strategic Air Command. As described in our issue of December 5 last,this huge missile is powered by a centrally mounted sustainer engine and twin laterallydisposed booster motors. All three engines draw liquid oxygen and RP-1 from the sametanks; all chambers are fired on the ground and the booster package is jettisoned afteroperating for its programmed duration. Both chambers of the booster package aremounted on gimbals to provide coarse control of the trajectory during the launching phase.The boost engines are designated LR89-NA-3. Like the chambers used in the engines of theJupiter and Thor IRBMs (which are of very similar design), the chamber of the LR89incorporates an entirely new form of construc- tion which significantly reduces weight andeases gimballing and flight-performance re- quirements considerably. This design ofchamber was evolved during the original development of the rocket booster packagefor the Navaho cruise-ramjet missile. The original Navaho engine was rated at75,000 lb and was designed in 1951. Origin- ally this powerplant embodied thick double-wall chambers regeneratively cooled by fuel circulated between the two shells. Engineering advances led to a completely new form ofchamber, fabricated entirely from longitudin- ally disposed tubes (just as a barrel is built upfrom longitudinal staves). The production LR89 chamber is fabricated from approxi-mately 300 nickel-alloy tubes, originally with an external diameter of 0.45in. These arepressure formed until their section becomes basically rectangular, varying in area from amaximum at the end of the tube near the nozzle of the chamber to a minimum at thethroat. The tubes are positioned around a vertical jig, brazed together with silver solderand finally secured by welded circumferential steel bands to give the chamber burstingstrength adequate for the very high internal pressure. The first engine incorporatingtubular chambers was fired at Santa Susana in April 1953. Work on the MA propulsion system for theAtlas began in March 1954, the original design being based on the experience gained withthe Navaho package. The first flyable system was delivered to Convair in June 1956. Thecomplete propulsion system, including the sustainer, was subsequently extensively groundtested by both Rocketdyne and Convair. The initial flight test was made in June 1957, usingbooster and vernier power only, and the first fully powered flight by an Atlas B, utilizingthe centrally mounted sustainer in addition, took place on August 2 last year. Both of theLR89 chambers are gimballed to a common frame, and they are pivoted by a controlsystem actuated by the guidance equipment. In the latest versions integrated tankage andturbopump systems are employed for all three chambers, and the boost package is enclosedin a chemically milled assembly of much reduced weight. The single LR1O5-NA-3sustainer is designed to an expansion ratio appropriate to space flight, and supplies theslightly lower thrust necessary to sustain powered flight and keep the Arias on course.It is similarly mounted on gimbals and is flanked by the multiple exhausts from theturbopump, and numerous venting and dump- ing systems. At the time of writing 22 Atlastest vehicles have been fired, including the Atlas Score satellite. S-3 All the S-3 series are engines forthe Jupiter IRBM, developed by the U.S. Army Ballistic Missile Agency at Huntsvilleand manufactured by the Chrysler Corporation
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