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Aviation History
1973
1973 - 0028.PDF
22 TURBINE ENGINES OF THE WORLD to start in March next year. Later versions of the A300B are to be powered by the 51,0001b CF6-50C, which is planned to be available in May 1974, with uprating kits for -50A engines. Also on offer are the 51,0001b CF6-50D and 52,5001b CF6-50F. In August 1972 Boeing and GE announced their intention to develop and flight-test a 747 with the CF6-50 for a growth version of the aircraft. In its military version the CF6-50 is designated F103. Flight-testing is scheduled to start in July and to be complete by the end of 1973. CF6-50A Single-stage fan plus three-stage "booster" 1-p com pressor, 14-stage h-p compressor, annular combustor, two- stage h-p turbine, four-stage 1-p turbine. Take-off 49,0001b; bypass ratio 4-4:1; mass flow l,4511b/sec; pressure ratio 29-9:1; length 190in; diameter 93-7in; weight 8,2251b. Pratt & Whitney JT9D (USA) Two-shaft turbofan. It ran in December 1966 as the world's first large civil turbofan and, after initial flight-testing in a modified B-52, powered the Boeing 747 (its prime application) when the aircraft flew in February 1969. Certification of the 43,5001b JT9D-3 was completed in May of that year and the 747 entered service in January 1970. Following introductory problems with the turbofan, all engines were modified to -3A standard by the end of 1970. The improved and uprated 45,5001b JT9D-7 for the 747 was introduced in October 1971. In February 1972 P&W's parent company, United Aircraft Corp, announced a net trading loss for 1971 largely as a result of writing-off $137 million (£57 million) to cover existing and future costs associated with the JT9D development programme (which had been entirely company-financed). This provision also in cluded the cost of certificating the 45,5001b JT9D-15 in the DC-10-20, for which only Northwest Airlines has placed orders (for 22). First flight of the DC-10-20 with the JT9D-15 took place in February last year; by the time the aircraft entered service in November it had been re-designated DC-10-40, reflecting its use of the JT9D-20 of 48,5001b wet rating com pared with the -15's water-injection thrust of 47,0001b. In June this year the JT9D-25 is planned to be certificated for later DC-10-40s, giving dry and wet ratings of 47,0001b and 50,0001b respectively. Only other potential application of the JT9D is as an alternative power unit to the GE CF6-50A for Boeing's entry in the TJSAF's AMST competition. Total order book for the JT9D is about 1,300 units, and engines in service have accumulated well over 3 million flying hours; ten million hours are expected to be reached by 1975. JT9D-7 Single-stage fan plus three-stage 1-p compressor, 11-stage h-p compressor, annular combustor, two-stage h-p turbine, four-stage 1-p turbine. Take-off 45,5001b dry up to 80°F (or 84°F for JT9D-7A), 47,0001b wet; bypass ratio approxi mately 5:1; length 128-2in; diameter 95-6in; weight 8,7701b. Pratt & Whitney JT9D-X (USA) Two-shaft turbofan. The first growth version of the JT9D, it was tested as an h-p core demonstrator in early 1971. Its rating in initial form is 55,0001b, with later growth to a basic rating of 60,0001b, and a demon strator has already attained 62,0001b. The JT9D-X attains its higher thrust by increased core-engine mass flow and im proved turbine cooling. The engine, which is intended to power future twin-jet wide-body transports and growth ver sions of the 747 and DC-10, has the same maximum diameter as the JT9D-7 and fits existing pods with minimum changes. The JT9D-X is to be offered for service in about 1974/75. Rolls-Royce RB.211-22 (UK) Three-shaft turbofan. Bench running of the BB.211 to power the Lockheed TriStar started in August 1968, being followed by flight testing in March 1970 in a modified VC10; first flight of the TriStar was in Novem ber 1970. Escalating development costs with the engine led to the receivership of Rolls-Royce in February 1971, with the subsequent formation of the Government-owned Rolls-Royce (1971) Ltd to continue the RB.211 programme. The engine received FAA certification in March 1972 as production deliveries started, and the TriStar entered airline service in April. By mid-1972, 50 RB.211s had been delivered, rising to 100 by November. First- and second-purchase orders have been placed for a total of 184 TriStars, requiring 552 installed engines. On the basis of an extra 25 per cent for spare engines, this gives a total existing requirement of nearly 700 units, worth about £350 million. The engine currently in service, the RB.211-22C of 42,0001b up to 66°F, has completed more than 55,000hr of development and service running. The RB.211-22B of 42,0001b up to 84°F is planned for FAA certification in April this year, and modification kits are being produced to enable -22C engines to be upgraded to -22B standard. RB.211-22B Single-stage fan, seven-stage i-p compressor, six- FLIGHT International, 4 January 1973 Two modern turbofans from GE: the CF6-50 (in background) and the TF34. The former powers the McDonnell Douglas DC-10-30 and the A300B stage 1-p compressor, annular combustor, single-stage h-p and i-p turbines, three-stage 1-p turbine. Take-off 42,0001b; bypass ratio 5:1; pressure ratio 27:1; length 119-4in; diameter 88-2in; weight 7,2031b. Rolls-Royce RB.211-24 (UK) Three-shaft turbofan. Based closely on the RB.211-22, it is entering development for the longer-range TriStar L.1011-2 at a projected programme cost of £31 million. Changes from the RB.211-22B standard include a new fan of the same diameter but increased pressure ratio, modified blading and increased mass flow for i-p and h-p compressors, bigger jet pipe, re-optimised afterbody and a modest increase in temperature. All components are now scheduled to be on test, and the complete engine should run in September. Completion of certification testing, at a rating of 45,0001b up to 84°F, is planned for early 1975. Other poten tial applications include a twin-jet version of the TriStar, the QStol projects of Boeing/Aeritalia and Europlane, an HS.148 version of the A300B for BEA and a re-engined VC10 version for China. Growth versions of the RB.211-24 are expected to produce 48,0001b at 84°F, and thence up to 55,0001b. - Most evident among the trends emerging with the big three turbofans is the increasing success of the 50,0001b CF6-50 series. The engine is currently entering service in the DC-10-30, has recently flown on schedule in the A300B, will fly in the re-engined prototype 747 later this year and has been chosen for the twin-engined version of the DC-10. Lockheed may select it for its projected BiStar twin-jet derivative of the TriStar. As the F103, the CF6-50 has already been chosen to power any future military 747. Leapfrogging the low-50,0001b bracket dominated by the CF6-50 is the JT9D-X, now running in demonstrator form and designed to straddle the 55,0001b-60,0001b sector. Belatedly chasing up behind is the RB.211-24, with initial and growth ratings in the 45,0001b-50,0001b bracket. While the JT9D has expensively bought its way in to the DC-10-40, and the CF6-50 is now edging into the 747, the growth programme for the R-R engine is primarily intended to maintain the viability of its sole application in the TriStar. The chances seem to be improving that each of the basic engine/airframe combinations will reach its individual break even points in terms of orders. For the turbofan manufac turers the additional business from spare engines, spare parts and overhaul work brings additional increments with, in the long term, sales of spare parts accounting for anything up to 50 per cent of total programme income. There is heightening competition among the three big- engine firms to show the best reliability statistics. Here the CF6-6 series, with the considerable development and service background of its gas generator in the military TF39, has a unique advantage.
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