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Aviation History
1957
1957 - 1047.PDF
26 July 1957 137 NORTH AMERICAN. North American Aviation, Inc., RocketdyneDivision, Canoga Park, Cal. Since 1946 this giant among the world's aircraft companies has been heavily engaged in the design, developmentand production of liquid-propellant rocket motors of very high thrust. The result of their work to date is summed up in a single sentencefrom the company's last annual report: "Rocket engines were produced ... for most of the nation's presently programmed intercontinentaland intermediate-range missiles." Rocketdyne, the division responsible for this work, has steadilyexpanded at Canoga Park, and its development and manufacturing strength, already considerable when we wrote our 1956 review ofengines, more than doubled during the 1956 fiscal year. Additional large test stands and supporting buildings were commissioned at thedivision's propulsion field laboratory in the Santa Susana mountains. Very soon Rocketdyne will occupy a $13m government-owned produc-tion plant nearing completion at Neosho, Missouri. Some 650 employees have been assigned to work at Neosho, and the number should reach1,500 in January. Total Rocketdyne employment on September 30, 1956, was 6,800. A licence was recently obtained for the production of IDIOT, orinstrumentation digital on-line transcriber, from Minneapolis-Honeywell. This equipment has been used by Rocketdyne for the simultaneousreduction and recording of up to 128 "bits" of data during test-firings, and its manufacture marks a broadening in scope of the division'soperations. Major programmes for which Rocketdyne holds propulsion respon-sibility include both the ICBMs, Convair's Atlas and Martin's Titan, as well as the two land-based IRBMs, the Army Redstone/Jupiter andthe Air Force Douglas Thor. For Titan, Rocketdyne are clearly either in competition or in partnership with Aerojet-General. For Atlas theB-2C powerplant was evolved, which, like nearly all the big Rocketdyne motors, operates on liquid oxygen and petrol. The missile has onesustainer of 135,000 1b thrust and two-self contained sustainer pods each rated at either 60,000 or 100,000 lb. Most important production unit, however, is the S-3 motor, rated at150,000 lb. This is the powerplant of both Jupiter and Thor, and until recently was the unit with the highest rating of any single-chamber motor. Three essentially similar chambers combine to provide from 405,000 to 450,000 1b thrust for 45 sec to accelerate the SM-64ANavaho up to the Mach-2.7 speed at which its ramjets will light up. Unfortunately flight experience with Navaho—now, in any case, can-celled—has been fraught with distressing, if instructive, mechanical failures. So also has that of Thor, which has four times reached thefiring pad and never yet achieved a successful flight. These are but temporary setbacks, and Rocketdyne have their finger in so many piesthat they cannot fail to be in at the finish. Under the terms of a ten-year mutual technical assistance agreementsigned in 1955 data are being exchanged with Rolls-Royce. The British company is also "licensed to manufacture large, liquid-propellant rocketengines designed and developed by North American." Several new rocket applications are being investigated, including manned aircraft. PRATT AND WHITNEY. Pratt and Whitney Aircraft, Divisionof United Aircraft Corpn., 400 Main Street, East Hartford, Conn. For many years Pratt and Whitney have been the largest aero-engine com-pany in the world. Several hundred thousand piston engines have been made to their design—these engines provided more than half thetotal horsepower of all the Allied aircraft used in World War 2— and the company have today unbalanced the entire American engineindustry by gaining more than 60 per cent of the total available business. This extraordinary position has come about through the company'sexcellent past record of sound engineering coupled with their inherent conservatism and extreme care in planning each new design. Thefirst advanced gas turbine of their own design (the J57, described below) appears on paper to be expensive and heavy in relation to itsoutput yet it has for several years been the only unit capable of doing several of the most important military propulsion jobs, and both theparent firm and the Ford Motor Company (q.v.) are working at high pressure to deliver engines at the required rate. It is the only Americanengine produced by a "second source". During the past year the company have begun the establishmentof a new plant at West Palm Beach, Florida. Situated 17 miles east of the town, the new facility will be an exceedingly large and well-equipped plant for the development and testing of advanced power- plants. It will fabricate and assemble new engines on a limited scale for use in experimental aircraft, but will not undertake production.The J58 will be its first major assignment. Earlier this month the U.S. Navy awarded a $28m contract for shop and test equipment, thewhole establishment being an investment of $40m. In the last twelve months the payroll at East Hartford has risen bymore than 3,500 to a total of over 40,000, the majority of the additional personnel being engaged in the production of the J57. Excludingdeliveries from Ford more than 6,000 of these fine two-spool turbo- jets have been delivered to the Air Force and Navy and from the endof this year the company are to deliver the fully certificated JT3C commercial derivative. Backing up the J57 is the rather larger andmuch more powerful J75, which is already in production to meet the requirements of several important programmes of the Air Force andNavy. From early 1959 a commercial variant of this engine, also, is scheduled to be delivered against heavy orders placed by airlines allover the world. Pratt and Whitney have also had limited success with two engines originally financed by the U.S. Navy, the T34 turbopropand the J52 turbojet, and they are pressing ahead with advanced engines such as the J58 and J91. The latter is a turbojet drawing its heat energy from a nuclear reactor,and Pratt and Whitney remain one of the largest workers in the nuclear- propulsion field. This activity is likely to provide the company withbusiness of a very long-term nature. The company are also retaining an interest in other forms of propulsion, and are in addition finding thatthe reciprocating engine is dying a slow death. J48. Ultimate development of the Rolls-Royce Tay centrifugal turbo-jet, the J48 has been licence-built at East Hartford since 1951. Owing to the continued production of the Grumman F9F-8 and F9F-8T theengine has remained in production much longer than was originally anticipated, but the total contracts have now been fulfilled. In its finalform the J48 was rated at 8,500 lb-thrust with water injection. J52. Development of this medium-thrust turbojet began with thereceipt of a Navy contract about four years ago, funds having been transferred from the defunct T52 turboprop. In its essentials the unitis a scaled-down J57, and it introduces few novel features. Until last year the engine had no firm application and seemed likelyto die a natural death. It was, however, an obvious basis from which a commercial engine suitable for an important medium-range trans-port market might be developed, and the manufacturer may have brought some pressure to bear on the Navy to hasten its development.In any event, the Navy decided to purchase an afterburning version as the powerplant of the Douglas A4D-3 Skyhawk carrier-based attackbomber. Compared with earlier versions of the Skyhawk the A4D-3 promised to have substantially improved performance in all respects,since, although the Pratt and Whitney engine is larger and heavier than the powerplant for which the aircraft was designed, it has con-siderably greater maximum thrust and improved specific fuel consump- tion. The order for the J52 amounted to several hundred engineswhen it was cancelled earlier this month. It is unlikely that the engine will find other applications. JS7. Maintaining its position established in 1953, this high-pressuretwo-spool turbojet can be assessed as the most important American engine in current operation. It was Pratt and Whitney's first attemptto design a modern gas turbine and, although one could today make such a unit much lighter, simpler and cheaper, the J57 was soonestablished as being without any peer. It was the first turbojet in the 10,000 lb-ihrust class to become available for use in the U.S.A., andthis fact, coupled with its outstanding economy and reliability ensured its immediate acceptance by six major airframe manufacturers for thepropulsion of the most important American bombers, fighters, attack aircraft, tankers and transports of their generation. It is also usedby two more manufacturers for the propulsion of a high-altitude research aircraft and a cruise-type strategic missile. On July 1 total deliveriesfrom Pratt and Whitney and Ford were in excess of 9,500. When design began in 1948 the project was the only two-spool, orsplit-compressor, gas turbine in the world. The prototype first ran in June 1949. From that date the engine has been exhaustively developed;it has been run in the company's Willgoos laboratory under conditions appropriate to flight at 70,000ft, and has been air-tested in a widerange of aircraft. Initial flight trials took place with units slung under a B-45 and a B-50, and in April 1952 eight development enginespowered the Boeing YB-52 on its maiden flight, when the engine had a special-category flight clearance rating of 8,800 lb. Curiously, the work-split between the two compressors is such thatthe low-pressure front spool requires a two-stage turbine to drive it. Pratt and Whitney J52-P-2. Turbojet with afterburner.Split-compressor (two-spool) turbojet with can-annular combustion chamber fed by 12 injectors, mechanicallyindependent high- and low-pressure turbines and after- burner with multiple injectors and variable-area nozzle.No data on this engine are available except for the dry thrust rating of 7,500 Ib and the corresponding s.f.c. of 0.8. Pratt and Whitney J57-P-19 or -31 (JT3 is essentiallysimilar). Split-compressor turbojet. Nine-stage low- pressure compressor, seven-stage high-pressure com-pressor, can-annular combustion chamber with eight flame tubes, single-stage high-pressure turbine and two-stagelow-pressure turbine. Basic diameter, 40in; overall length as depicted, 180in; dry weight, 4,1001b; mass flow, 181Ib/sec; pressure ratio, 12.5:1; maximum thrust, 13,0001b with water injection at 8,000 low-pressure r.p.m. with s.f.c.of 0.82 With afterburner this engine can give up to 17,500 Ib (s.f.c., 2.0) and weighs 5.200/5,600 Ib.
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