The Eurojet team is ready to begin the full development of the Thrust Vectoring Nozzle (TVN) to be installed on its EJ200 engine, and forecasts a 24-month period from the green light to the first flight of an aircraft equipped with the TVN. The go-ahead awaits however a launch customer,Eurojet currently being busy
in talks with the four Eurofighter core nations on the benefits of the TVN. In the past, performance benefits were mostly considered, while the change in the overall political and economical situation brought a change in focus, life cycle costs reductions are now at the forefront. According to Eurojet officials, the adoption of the TVN should decrease fuel consumption on a standard mission by about three per cent, while in the afterburner mode the hot section temperature could be lowered, 10° K less during take-off and 10 to 20° K less at high altitude, with beneficial effects on the engine life. As for performances, a seven per cent increase in supercruise mode has been realised during simulations. The TVN would also become a third attitude control system besides the forward canard surfaces and the wing mobile surfaces, thus increasing redundancy and survivability in combat. The TVN also allows better aircraft behaviour when asym metric payloads are carried, avoiding the need to use mobile surfaces to trim the aircraft, something that considerably increases drag and therefore fuel consumption. The engine manufacturer underlined that the TVN can be installed with minimal adaptations to the EJ200 on Eurofighter Tranche 2 aircraft: the modifications include updating the software for the Digital Engine Control and Monitoring Unit (Decmu), an upgrading of the Hydraulic Power Generating Unit and hydraulic piping and of course the installation of the TVN. The balance beam part of the jet helps in reducing the forces needed to move the nozzle, thus reducing the power of the actuators and their weight. The Eurojet TVN uses only three to four actuators compared to the six to nine found on others, and has a weight of only 40 kg. The balance beam also improves safety as it allows the nozzle to close and set itself at 0° deflection in the maximum dry thrust position should the hydraulic system fail. The TVN design responsibility falls on the Spanish partner within Eurojet, ITP partners, Avio being responsible for the hydraulic modifications, while MTU will provide software modification to the Decmu. Eurojet already tested a mechanical prototype of its TVN, which reached a 23° deflection, however designers estimate that the system can reach angles of 30 to 35°.
Read more in armada International's issue 1/2010
