Ian Sheppard/LONDON
Initial production-standard Eurojet EJ200 engines installed on the Italian DA3 Eurofighter EF2000 prototype have been fitted with a new full-authority digital engine-control (FADEC) system after the original unit was found to be overweight and unreliable.
The engines are undergoing ground runs in Turin before being flown by the end of the month, says Eurojet, the Rolls-Royce, FiatAvio, ITP and MTU consortium.
The 03A standard engine's new FADEC has been developed by Daimler-Benz Aerospace's (Dasa) aero-engine unit at MTU Munich. Vice-president of electronic systems Klaus Fuchs confirms that the original C1 FADEC it developed was "too heavy and unreliable". Fuchs admits that, at one stage, R-R was sceptical about Dasa's ability to develop the C2 version and considered a Lucas design instead.
Each of the five EF2000s being flown with EJ200s is equipped with two dual-redundant units. Richter says that, thanks to simulation and engine test-rig work, "-we have virtually 100% confidence in the final design".
Because of workshare arrangements, the engine-monitoring unit (EMU), which "supervises" sensors and actuators, has been developed as a separate unit. Richter admits that not having the EMU integrated is "crazy", but says that the next-generation unit being developed for the Future Large Aircraft is integrated, with more data correlated in real time, allowing the engines to be operated safely, "closer to their physical limits".
The EMU also monitors life usage, based on a simplified thermodynamic model, which combines factors such as temperature and stress histories into a fatigue-damage-accumulation index. Incident monitoring is also incorporated for occurrences such as "buzz, screech, high vibrations, start abort, flame-out, surge and stall of the engine", says Richter.
One item new to the C2 is FiatAvio's oil-debris magnetic sensor (ODMS), which is "-close to being operational". The ODMS not only detects the size and number of ferrous particles, but it also removes 70-90% of them in conjunction with a centrifuge.
When a particle build-up is detected, the EMU is able to check for signs of vibration and can pinpoint the problem, such as impending bearing failure, by searching the WEM simulated-failure database using pattern-recognition techniques . "The maintenance benefit is very high," says Richter.
Source: Flight International
