Andrew Doyle/MUNICH

Spain, Germany and the USA are finalising an inter-governmental agreement clearing the way for a thrust vectoring nozzle (TVN)-equipped Eurojet EJ200 Eurofighter engine to be test flown on the US Navy's X-31 experimental aircraft.

The programme, due to get underway in late-2002, will boost efforts by the Eurofighter and Eurojet industrial partners to persuade the UK, Germany, Italy and Spain to equip the third Eurofighter production batch with the ITP-developed TVN from 2010.

Spanish company ITP has carried out extensive bench-testing of its EJ200 nozzle but has been unable to flight test the device, due to the lack of a Eurofighter prototype. However, the X-31 emerged as a candidate after a Swedish consortium shelved plans to test a TVN on the General ElectricF404-powered US aircraft.

Re-engining the X-31 with the EJ200 and completing the flight test programme is projected to cost $60 million, says ITP. Most funding will come from the Spanish Government, the rest coming from the Eurojet partners.

The NATO Eurofighter and Tornado Management Agency (NETMA) has agreed to provide engines, although Spain may have to loan them from its delivery quota.

The US Navy will not provide funding but will manage the flight test programme, taking responsibility for flight clearances. Still to be resolved are European sensitivities over the level of proprietary EJ200 technical data that will have to be disclosed to the US Navy.

The industrial partners have yet to agree on specific proposals to NETMA for implementing the TVN on production Eurofighters. ITP project manager nozzles, Daniel Ikaza, says one option could be to offer a phased solution starting with the use of pitch-only vectoring to enhance performance in the normal operating envelope, followed by progression to full post-stall manouevring capability which would require major changes to flight control software.

NETMA director of operations and engineering Yago Fernandez de Bobadilla says the Eurofighter nations are "firm believers in the potential of thrust-vectoring technology" and that it is a "credible candidate for the third production tranche and beyond".

In conventional flight, thrust vectoring has the potential to improve cruise performance by reducing control surface deflections, and to increase sustained turn rates and cut take-off distances by more than 25%.

The X-31 is now being readied for the US Navy's Vectoring Extremely short take-off and landing and Tailless Operational Research programme.

Source: Flight International