Andrew Doyle/MUNICH

A study by DaimlerChrysler Aerospace (Dasa)has identified significant performance improvements that could be achieved with the Eurofighter by installing ITP-developed thrust-vectoring nozzles on the aircraft.

Meanwhile, Spanish engine company ITP is preparing to begin altitude testing of its Eurojet EJ200 nozzle at Stuttgart University in Germany next month and remains hopeful of launching flight trials by 2002.

The Dasa findings support ITP's recently refocused marketing strategy which places greater emphasis on the benefits of thrust vectoring for the Eurofighter throughout the aircraft's "normal" flight envelope, rather than simply for post-stall manoeuvres.

Daniel Ikaza, ITP project manager - nozzles, says Dasa's study shows that a Eurofighter flying at 30,000ft (9,150m) and a speed of M1.8 requires a 4° upward flaperon deflection to maintain level flight. A 5° upward nozzle deflection instead would enable the aircraft to fly "clean" and reduce the required engine thrust by 3%.

Under the same conditions, but in a sustained turn, where the pitch element of the control surface deflection was 6° up, this could be reduced to 2° combined with a 4° nozzle-up component. In this configuration lift coefficient would be increased by 14%, translating into a 9% improvement in turn rate. Take-off distance could be cut by at least 25%.

The figures include an adjustment for the extra weight of the two convergent/divergent axisymmetric nozzles, capable of multi-axis thrust-vectoring.

ITP is talking to the US Navy about a possible follow-on to the X-31 Vectoring Extremely short take-off and landing and Tailless Operational Research aircraft (VECTOR) programme to carry out nozzle flight tests.

"For money and other reasons we're not sure if it's going to happen or not," says VECTOR deputy programme manager William Voorhees.

ITP is optimistic it will have an opportunity to carry out trials on a Eurofighter. Ikaza says the system is being offered to existing and potential Eurofighter customers.

The initial phase of nozzle ground testing was performed at Ajalvir near Madrid at sea level conditions and comprised 80h of engine runs, including 15 with reheat, and was completed in February 1999.

Ikaza says budget constraints mean only 10-20h of testing will be performed in the Stuttgart altitude chamber next month. "This will be focused mainly on control and performance throughout the flight envelope," says Ikaza.

The tests will examine high altitude affects on the differential thermal expansion of nozzle components, structural deformations and gas pressure distributions. Studies are continuing into ways of reducing the weight of the nozzle, extending its life and designing in stealth capabilities.

Source: Flight International