Rolls Readies Demonstrator Engine For European Fighter Aircraft
JUNE 23 1986
Rolls Readies Demonstrator Engine For European Fighter Aircraft
ADVANCED FIGHTER TECHNOLOGY
Bristol, England—Rolls-Royce XG-40 demonstrator engine, the core high pressure spool of which has been running on a test rig here since March, is expected to prove its ability to meet the requirements laid down for the European fighter aircraft powerplant in a series of tests that will continue into early 1987.
This would permit the four partner companies in the new Eurofighter engine consortium to begin full-scale development of an engine based primarily on the XG-40 design later this year, in order to have it flying in 1990 and ready to power the EFA development aircraft during at least the latter stages of flight testing of the airframe in about 1992.
Partner Companies
The four partner companies are RollsRoyce, Motorenund Turbinen-Union of West Germany, Fiat of Italy and Sener of Spain.
EFA specifications call for an engine rated at 20,232 lb. minimum takeoff thrust with afterburner.
In addition to EFA, Rolls-Royce sees the Eurofighter engine as a possible powerplant or technology base for:
■ Advanced Panavia Tornado air defense versions, if operational requirements call for improved aircraft performance.
■ A new single-engine light combat aircraft with capabilities beyond current light strike aircraft.
■ The basis of a new powerplant for an advanced short takeoff-vertical landing aircraft.
■ Basic component technology for an advanced small turboprop engine, with a power rating of less than 10,000 shp.
Rolls-Royce believes there will be little alternative to using the XG-40 as the basis for the Eurofighter engine, since no other engine company in the four cooperating nations has begun development work on any other concept.
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The EFA project was not yet in existence when Rolls-Royce sized the engine according to its own judgment of what would be required, emphasizing a high specific thrust capability and a high compressor ratio.
The XG-40 was funded 85% by the British Ministry of Defense and 15% by Rolls-Royce. It was sized at 20,232 lb. thrust (90 kilonewtons) and was designed to have a 10:1 thrust-to-weight ratio.
Three basic test phases are planned. Component testing is nearing completion and test running of the full engine is planned for October, 1986. It will include an electronic fuel control system and an advanced afterburner.
A five-stage high-pressure compressor driven by a single-stage turbine has been tested and an alternate three-stage highpressure compressor has been designed. The five-stage compressor, with a pressure ratio of 6.5:1, has completed 50 hr. of testing without problems. It incorporates tip clearance control and uses low-aspect ratio blades to gain beneficial surge characteristics without adding to the compressor weight.
Afterburner Tests
The afterburner module began tests at the British Royal Aircraft Establishment’s Pyestock, England, facility late in 1985. High inlet temperatures have increased the difficulty of developing a satisfactory unit.
The complete XG-40 engine is scheduled to begin running in October, with a second unit to be delivered for test in 1987.
Current planning calls for the four companies to perform collaborative detail design definition work on the EFA engine concurrent with the XG-40 demonstrator testing and with complementary advanced technology work by the other three companies in the program.
Rolls-Royce officials note that the XG40 “lends itself to more advanced materials, including composites and reinforced ceramics,” and said that the components that would benefit markedly from the adoption of technologically advanced materials will be redesigned to incorporate them, if necessary.
Latest decision concerning the EFA engine concept has been to select convergent/divergent nozzle technology, as opposed to a more common convergent nozzle.
The Eurofighter engine will be expected to operate at extremely high temperatures, with the high-pressure turbine running at 200C more than that in the existing Turbo-Union RB. 199, according to officials in the Eurofighter program.
Data derived from the XG-40 development program can be progressively fed into the EFA engine design, along with specific technology developed by the other partners, Gordon Lewis, Rolls-Royce corporate technical director, said. This will enable collaborative pre-development engines to be specified and tested before hardware is committed to production.
The EFA engine will be broken down into modules, which can be developed and produced by the four partner companies.
Still to be settled is whether the initial test versions of the EFA will be powered by the new EFA engine, or by an existing engine, such as the RB. 199 or the General Electric F404.
