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Aviation History
1995
1995 - 1253.PDF
MIL! The EJ200 should be airborne soon ments", the M88-3 "will definitely be needed one day", pointing out that 80% of the devel opment funding for the engine will come from the French Government. The M88-3 thrust increase comes from a new, increased-flow, low-pressure compressor now being developed, on which tests began in Snecma's Villaroche plant, near Paris, on 17 February. Technology for the compressor comes from the French CENTOR pro gramme, which incorporates research from the Onera research agency, French universi ties, and Snecma itself. "The aim is to widen the range of operability," says Masson, "so that the engine is more efficient in intermedi ate and low-power regimes." The three stages of the development com pressor now in test each feature integrally b laded discs and compressor-discs, known as "blisks". These are lighter than the current units (in which the blades are inserted individu ally into each disc), while the three-dimension al blade design contributes to the significantly improved performance, namely a higher pres sure ratio (4.3 versus 3.8 on the M88-2), and extra airflow (72kg/s versus 65kg/s). "We don't know at this stage if we will be using blisks throughout the low-pressure compressor", says Massot. "Although we've done a lot of mechanical tests, we have only just begun aerodynamic testing". Much depends on finding the right solution to the blade vibration which can affect LP compres sor blisks in which the blades are relatively long, and there is no natural damping through the movement of the blades in the root. "The trick is to compromise between mechanical strength and aerodynamic perfor mance", says Massot. The M88-3 will also feature a new nozzle developed under the DRAG programme, which aims to reduce exhaust signature. Massot declines to describe the system, saying only that it will be "very efficient in reheat, with a shorter reheat pipe, and will have a considerably reduced infrared signature". Rig tests of the new nozzle are now under way. "It will be ready at the same time as the rest of the engine...at the end of 1996", says Massot. If Snecma and Rolls-Royce are competing on the JAS39 requirement, tben, on the next - generation combat-aircraft engine project their futures are intimately linked. Anglo-French cooperation on combat air craft is back in vogue, in part propelled by gal loping consolidation amongst US airframe competitors. British Aerospace and Dassault are tenta tively examining a future strike aircraft to meet their respective air force's emerging future requirements. Rolls-Royce and Snecma are looking to a next-generation powerplant for this aircraft under the Advanced Military Engine Technology (AMET) initiative. An initial agreement on collaboration was signed as far back as November 1990. While hardly a fast-moving programme, its goals are ambitious: to develop jointly core technology for an engine that would have a 15:1 thrust- to-weight ratio by the year 2001, with a possi ble increase to 18:1 further ahead. "We're still at the paper study stage", says advanced designs programme manager Jacques Maunand. "We had a kickoff meeting last November, and discussed how we would work together". The two teams will not have any par ticular responsibility for specific areas of the core demonstrator. "There is no division of dis cipline", says Maunand. "We will work in paral lel, and choose the best approach for the design of die most efficient components". Acquisition of technologies for core parts is under way, and Snecma and R-R are evaluat ing metal matrix composites for the high pressure compressor, with some funding from the European Commission's EUCLID pro- 26 FLIGHT INTERNATIONAL 3 - 9 May 1995
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