The Rolls-Royce RB211 is a British family of high-bypass turbofan engines made by Rolls-Royce. The engines are capable of generating of thrust. The RB211 engine was the first production three-spool engine.
Originally developed for the Lockheed L-1011 TriStar, it entered service in 1972 and was the exclusive engine to power the L-1011. Mismanagement of the initial development and consequent cost issues led to the company assets being transferred to a new government-owned company, Rolls-Royce (1971) Ltd.,The Magic of a Name The Rolls-Royce Story Part Two: The Power Behind the Jets 1945-1987, Peter Pugh 2001,,p.147 to save the workforce and the engine businesses important to the UK and many other aerospace and aircraft operating companies.
In the early 1970s, the engine was reckoned by the company to be capable of at least 50 years of continuous development.William Lazonick and Andrea Prencipe, "Dynamic Capabilities and Sustained Innovation: Strategic Control and Financial Commitment at Rolls-Royce plc," Industrial and Corporate Change, 14, 3, 2005: 1–42. The RB.211 was renamed, in 1989, to become the basis of the Rolls-Royce Trent family of engines when the RB211-524L was renamed to the Trent.The Development Of Jet And Turbine Aero Engines 4th Edition 2006, Bill Gunston,,p.196
History
Background
In 1966, American Airlines announced a requirement for a new short-medium range airliner with a focus on low-cost per-seat operations. While it was looking for a twin-engined plane, aircraft manufacturers needed more than one customer to justify developing a new airliner. Eastern Airlines had expressed interest, but required greater range and needed to operate long routes over water. At the time, this demanded three engines to provide redundancy. Other airlines also favored three engines. Lockheed and Douglas responded with designs, the L-1011 TriStar and DC-10 respectively. Both had three engines, transcontinental range and seated around 300 passengers in a widebody layout with two aisles.
The wide-body McDonnell-Douglas DC-10 was representative of the innovative aircraft and aero-engine technologies which were then being adopted by US and European airframe manufacturers to provide airlines with aircraft of very large carrying capacity and short/medium to long range. These very large capacity aircraft were needed to address the significant increases in passenger numbers and air traffic which were then being forecast by the industry. In Europe, large capacity airliner concept studies had been carried out by both private and government organisations since the late 1950s and early 1960s. Many of the studies conducted by the aviation companies were weighted towards a 200 to 300 seat aircraft, with a high cycle performance that was based on the usage of the game-changing new technology of the high by-pass ratio aero-engine.
Between 1964 and 1967, Hawker Siddeley's examination of British European Airways (BEA)'s requirements produced the 160-seat HS.132 and the 185-seat HS.134; both offered the prospect of a 25–30% reduction in seat mile costs over aircraft then in service. Both of the designs would have used two new-technology Rolls-Royce RB.178 aero-engines of to provide superior operating performance over the first generation three-engine jets.
According to Cownie, Gunston, Hayward and the UK Department of Trade & Industry (DTI), the roots of the advanced RB.178 go back to 1961 when Rolls-Royce officially initiated work on a high by-pass ratio aero-engine as a replacement for the Conway. The company went ahead with the project and under the leadership of Adrian Lombard built the twin-spool demonstrator. Overall development costs of the RB.178 was £2.6 million. As a comparison, the GE and P&W companies were awarded nearly $20 million by the US Department of Defense to develop and build the TF39 and STF200 technology demonstrators.
The RB.178 was built on the reliable and economic advantages inherent in the Conway and, given that engine's heritage, the new engine's performance looked certain. The RB.178 (designated the 16 series) appears to have been the engine proposed for the Vickers Superb DB.265 (VC10), with four engines powering the high capacity transatlantic airliner.
There are perhaps many reasons why the RB.178 failed. Chief among them was Boeing declining to offer the Rolls-Royce engine on the 747.
The RB.178 was cancelled in May 1966 and in June 1966 Rolls-Royce indicated it did not want to battle with P&W over the Boeing 747. In September 1966 Rolls-Royce revealed its decision to launch an Advanced Technology Engine (ATE) family covering thrusts ranging from the RB.203 through the RB.207. The ATE family introduced new technologies such as the triple-shaft architecture, an annular combustor and a structurally integrated power-plant (nacelle).
Both planes also required new engines. Engines were undergoing a period of rapid advance due to the introduction of the high bypass concept, which provided for greater thrust, improved fuel economy and less noise than the earlier low-bypass designs. Rolls-Royce had been working on an engine of the required 45,000 lbf (200 kN) thrust class for an abortive attempt to introduce an updated Hawker Siddeley Trident as the RB178. This work was later developed for the 47,500 lbf (211 kN) thrust RB207 to be used on the Airbus A300, before, with the withdrawal of the UK from the Airbus programme, it was cancelled in favour of the RB211 programme.Rolls-Royce Aero Engines, Bill Gunston 1989,, p.170
Rolls-Royce was also working on a series of triple-spoolSometimes called "three-spool". designs as replacements for the Conway, which promised to deliver higher efficiency. In this configuration, three groups of turbines spin three separate concentric shafts to power three sections of the compressor area running at different speeds. In addition to allowing each stage of the compressor to run at its optimal speed, the triple-spool design is more compact and rigid, although more complex to build and maintain. Several designs were being worked on at the time, including a 10,000 lbf (44 kN) thrust design known as the RB203 intended to replace the Spey. Work started on the Conway replacement engine in July 1961 and a twin-spool demonstrator engine to prove the HP compressor, combustor, and turbine system designs, had been run by 1966. Rolls-Royce chose the triple-spool system in 1965 as the simplest, lowest cost solution to the problem of obtaining lower fuel consumption and reduced noise levels at a constant power setting. Work on the RB211 as essentially a scaled-down RB207 began in 1966-7 with the first certificated engines being scheduled to be available by December 1970 at take-off thrust and at a price of $511,000 each.1967 | 2159 | Flight Archive. Flightglobal.com (9 November 1967). Retrieved on 16 August 2013.
In February 1968, American Airlines had chosen the Rolls-Royce RB211 to power its order for up to 50 McDonnell-Douglas DC-10s. On 7 March 1968, the Washington correspondent of The Times wrote of an attempt being made by Congress to block Rolls-Royce's bid to supply engines for the projected United States airbus. Representative Robert Taft Jr. of Ohio had marshalled opposition because of a report that Rolls-Royce had won approval for the engine. On 9 March 1968, The Times reported that President Lyndon Johnson had received written protests from six senators and five representatives, from Ohio and New Mexico – states that would benefit if a US manufacturer was selected. Their complaint was that 'not adequately balanced information was given during talks between representatives of airlines and the British Government concerning the American Government's position on buying foreign engines'. The US Congress was concerned that the import of foreign engines would result in a US payments deficit of $3,800 million and the loss of 18,000 to 20,000 jobs.
Finalisation of design
On 23 June 1967, Rolls-Royce offered Lockheed the RB211-06 for the L-1011. The new engine was to be rated at thrust and combined features of several engines then under development: the large high-power, high-bypass design from the RB207 and the triple-spool design of the RB203. To this was added one new piece of technology, a fan stage built of a new carbon fibre material called Hyfil developed at the RAE Farnborough. The weight saving was considerable over a similar fan made of titanium, and gave the RB211 an advantage over its competitors in terms of power-to-weight ratio. Despite knowing that the timetable was challenging for an engine incorporating these new features, Rolls-Royce committed to putting the RB211 into service in 1971.
Lockheed felt that the new engine enabled the L-1011 to offer a distinct advantage over the otherwise similar DC-10 product. However, Douglas had also requested proposals from Rolls-Royce for an engine to power its DC-10, and in October 1967 the response was a thrust version of the RB211 designated RB211-10. There followed a period of intense negotiation between airframe manufacturers Lockheed and Douglas, engine suppliers Rolls-Royce, General Electric and Pratt & Whitney, and the major US airlines. During this time prices were negotiated downwards and the required thrust ratings were increased. By early 1968, Rolls-Royce was offering a thrust engine designated RB211-18. On 29 March 1968 Lockheed announced that it had received orders for 94 TriStars, and placed an order with Rolls-Royce for 150 sets of engines designated RB211-22.Douglas and its DC-10 launch customers American Airlines and United Airlines selected the General Electric CF6 engine for the DC-10. The Pratt & Whitney JT9D was fitted to later variants.
RB211-22 series
Development and testing
The RB211's complexity required a lengthy development and testing period. By Autumn 1969 Rolls-Royce was struggling to meet the performance guarantees to which it had committed: the engine had insufficient thrust, was over weight and its fuel consumption was excessive. The situation deteriorated further when in May 1970 the new Hyfil (a carbon fibre composite) fan stage, after passing other tests, shattered when a chicken carcass was fired into it at high speed as part of the bird ingestion test.Bird ingestion testing was, and still is, a FAA requirement for aircraft engines. The company had been developing a titanium blade as an insurance against difficulties with Hyfil, but this meant extra cost and more weight. It also brought its own technical problems when it was discovered that only one side of the titanium billet was of the right metallurgical quality for blade fabrication.
In addition, the project suffered a setback with the death of Chief Engineer Adrian "Lom" Lombard in July 1967, a loss that was described as Rolls-Royce having been "deprived of one of the finest trouble-shooting engineers in the industry".
"It was all too obvious that the Derby engineers, normally proud and self-confident to the point of arrogance, had slid from bad to worse when their great leader, Lombard, had been so suddenly plucked from them in 1967. His death had left a vacuum which nobody could fill ... " – Stanley Hooker
In September 1970, Rolls-Royce reported to the government that development costs for the RB211 had risen to £170.3 million – nearly double the original estimate. The estimated production costs now exceeded the £230,375 selling price of each engine. The project was in crisis.
Insolvency and aftermath By January 1971 Rolls-Royce had become insolvent, and on 4 February 1971 was placed into receivership,Rolls-Royce is commonly said to have become bankrupt in 1971. Strictly speaking only individuals and partnerships can go into bankruptcy in the UK. seriously jeopardising the L-1011 TriStar programme. Because of its strategic importance, the company was nationalised by the Conservative government of Edward Heath, allowing development of the RB211 to be completed.