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Aviation History
1967
1967 - 2211.PDF
806 FLIGHT International, 16 November SPEYS INTERNATIONAL . . . nacelles of a modified Hawker Siddeley Vulcan started on October 12, 1961. This occupied only 88 flying hours over a four-week pdriod when the new all-speed engine control system was checked in flight. All other testing was performed on ground test beds and rigs, and in R-R's altitude test facility. The Trident 1 first flew on January 9, 1962, and in July of that year ARB special-category approval was obtained for the Spey-1 only 18 months after the engine first ran. A Certificate of Airworthiness was awarded to the Trident in February 1964, and in the following month the aircraft entered service with BEA with the Spey-1 Mk 505-5. This engine /airframe combination represented the first of a new generation of jet- powered short/medium-haul airlines offering an economy of operation comparable with that of propeller-driven transports. Rated at 9,8501b, the Spey Mk 505-5 has since completed a third of a million operating hours and has an officially approved t.b.o. (time between overhauls) of 3,3OOhr, with engines being sampled at 3,600hr. The Trident 1 and 1C have been the sole applications of the Spey-1. Spey RB.163-2 In May 1961, when BAC decided to proceed with the One-Eleven short/medium-haul airliner powered by two Speys, a higher rating was requested. This led to the 10,4101b Spey-2, similar to the Spey-1 but with a revised design of turbine of higher efficiency and operating at a higher gas entry temperature. Design of the engine started in June 1961, followed by development testing a year after; on August 20, 1963, the One-Eleven made its first flight powered by two Spey-2s. The One-Eleven 200 series entered service with BUA and Braniff International Airways in April 1965 with the Spey-2 Mk 506-14, and has subsequently established a notable reputa- tion for reliability and low operating costs. With Braniff, in the 12 months following September 1966, the FAA-authorised t.b.o. rose from 3,000hr to 5,000hr. On the policy that the fleet is allowed to extend its life with sample engines being pulled, some Mk 506s have already exceeded 5,400hr. The One-Eleven 200 series is the sole application of the Spey-2. RB.163-25 With the emergence of American turbofan- powered short/medium-haul transports in the early 1960s it was clear that both the Trident and One-Eleven would need to grow in size to remain competitive. There was a requirement, therefore, to provide a more powerful version of the Spey for both these applications but without changing its major airframe matching features, i.e., air mass flow and external dimensions. This was achieved by increasing the airflow through the h-p system, accompanied by some downward adjustment of the by-pass ratio. As R-R also sought to retain the same turbine entry temperatures as before, the overall pressure ratio was raised to minimise the effect on the six. Design work on this derivative of the Spey-2 started at the beginning of 1962 and development testing was initiated in April "the following year. Major change to the component configuration was the addition of a fifth stage to the rear of 1-p compressor. This elevated the pressure ratio from its pre- vious value of 16.9:1 to 19.1:1, and the revised internal division of the flow raised the basic thrust to 11,4001b. Two versions of the engine were initially made available, both physically the same—namely, the de-rated Mk 510 of 11,0001b and the fully rated Mk 511. Both can incorporate a water injection system to provide a flat rating to 90°F (ISA+20°C). Three applications of the Spey-25 in these variations have flown. These are, first, the Trident IE (with Mk 511-5 engines) which flew on November 2, 1964, and first entered service with Iraqi Airways a year later; secondly, the One-Eleven Series 300/400 (with either Mk 510-14 or Mk 511-14 engines) which flew on July 13, 1965, and first entered service with American Airlines in March 1966 (with Mk 510-14 engines—this operator was the only one to use this type—later modified to Mk 511-14 standard); and, thirdly, the Grumman Gulfstream II (with Mk 511-8 engines), which flew on October 2, 1966, and is about to enter service with corporate operators. A fourth type, the high-capacity Trident 1E-140 for Channel Airways, will be delivered in March next year. Maximum t.b.o. at present is 2,800hr for the Mk 511-5 in the Trident lEs of Pakistan Inter- national Airlines (where engines are sampled at 3,100hr) and 3,5OOhr for the Mk 511-14 in American Airlines' One-Eleven 400s (where the sampling period is 4,000hr). Third version of the Spey-25, and most powerful of the civil Speys so far, is the Mk 512, which embodies detailed aerodynamic, mechanical and material changes to permit operation at slightly higher air mass flows, r.p.m. and tempera- tures. As the Mk 512-5 for the longer-range Trident 2E and 3B, this is rated at 11,9601b, while as the Mk 512-14 for the One-Eleven 300,400 and "stretched" 500 series the engine is rated at 12,0001b. Both versions are again available with water injection for operators using hot, high airfields. Design started in June 1965, followed by testing in July 1966, and the basic Mk 512 has just completed its officially declared 150hr type- test. The engine should enter service with BEA in spring 1968 in the Trident 2E (first flight of which was on July 27 this year), followed by the One-Eleven 500 series, also for BEA, in the winter of 1968-69 (first flight of the aerodynamic prototype took place on June 30 this year). Spey Junior RB.183-1 First announced in July 1962, the Spey Junior was initially a lighter, simplified version of the Spey-1, de-rated to 8,6501b. Introduced to power the Fokker F.28 Fellowship short-haul airliner, the engine has been subse- quently re-rated at Fokker's request to the full Spey-1 thrust of 9,8501b and at a comparable weight. This enables the Fellow- ship to use a reduced length of runway at maximum take-off and landing weights in meeting the ISA+10°C requirement, Differences between the Spey Junior and Spey-1 include the use of a plastic glass-fibre reinforced by-pass duct. The Fellowship flew on May 9, 1967, and first deliveries to Lufttransport- Unternehmen, with the Spey Junior Mk 555-15, are scheduled for November 1968. ..; —- Further Civil Development. If an adequate market emerged to support development of a Spey of significantly greater thrust than 12,0001b, the most likely proposal would be for a higher- b.p.r. configuration giving a total flow comparable with that of later military variants but with a lower s.f.c. This could elevate the thrust to between 13,5001b and 14,0001b. Military Spey Variants Spey RB.168-1 Design of a military counterpart to the Spey RB.163-1 under the designation RB.168-1, was started by R-R in November 1960. This led to the award the following year of a government developmment contract for the RB.168-1 to power the Hawker Siddeley Buccaneer S.2. This was a higher- performance version of the Royal Navy's strike aircraft designed to take advantage of the greater thrust and lower s.f.c. of the Spey compared with that of the Bristol Siddelev Gyron Junior Mk 101 of 7,100lb thrust in the S.I. To optimise the Spey's parameters for this military role, some trading oi economy for performance was introduced. Thus by operating at a higher turbine entry temperature, a valuable gain in thrust over the Spey RB.163-1 rating was achieved while still retaining a differential in s.f.c. To combat the more rigorous intake conditions of the transonic Buccaneer and its higher-g flight envelope, changes were made in the materials and stressing of the rotating and structural components. Material change; were also introduced to provide corrosion resistance agains! the salt-laden atmosphere inherent in the carrier-borne, low- level strike role. A major feature of the Buccaneer is its use of boundary layer control by blowing air over the wings and tailpi"11' With the Spey installed, use was made of the h-p compressor seventh-stage bleed to supply the necessary air. Although take- off and landing with the b.l.c. system operative results :n 15 per cent reduction in engine thrust, 70 per cent of this los; is regained through the b.l.c. slits, giving a net loss of iota' thrust of only 5 per cent—an insignificant amount in view <>! the considerably greater rating of the Spey in comparison wit' that of the Gyron Junior. Testing of the RB.168-1 started in December 1961, and the Buccaneer S.2 flew on May 17, 1963. As a result of the close derivation of the military engine from the civil, considerable benefit was gained from Spey RB.163-1 flight testing and airline operation in the development of the RB.168. The increase" thrust of the military Spey also provided background ex peri-
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