The aircraft will be guided by the motor impulse

2000/06/01 Kortabarria Olabarria, Beñardo - Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Garraioak
• Aeronautika

The EF-2000 hunting programme is the largest military cooperation project that has been launched and almost completed in Europe to date. More than 400 companies from Germany, the United Kingdom, Italy and Spain work live in the Eurofighter consortium (British Aerospace (United Kingdom), DASA (Germany), Alenia (Italy) and CASA (Spain). The first aircraft in the EF-2000 series, 148 and 363 engines, will be produced in 2001 and will fly in 2002.

The EJ-200 engine will drive the EF-2000 fighter aircraft and its development is the responsibility of the Eurojet consortium, Rolls Royce (UK), MTU (Germany), Fiat Avio (Italy) and Zamudio Turbo Propulsion Industry (ITP). The construction of the engine is distributed and the company of Zamudio is manufacturing the convergente-divergent hopper, the leak diffuser of the turbine, the deflection pipe housing, the rear burner housing and the outer tubes and cables of the engine.

It is clear that the most powerful companies in the aviation sector in Europe have decided to follow the path of collaboration. They have had no choice but to face the competition. European companies have to compete with US companies and for this they will have to build engines with low environmental impact and good price without failures.

Experts anticipate growth in the aviation sector in the next twenty years and it is detected that the current intercontinental competition will be replaced by cooperation between continents, including Asia. For this future, ITP has worked and works with the world's leading motor producers: EJ-200 (Rolls Royce, MTU, Fiat Avio); Trent (Rolls Royce); 501K and 601K (Allison); Atar 9K50 Plus (Snecma); BR710 and BR715 (BMW-RR); General Fiat.

All this experience and, above all, the path traveled in the development of the EJ-200 engine nozzle project, have allowed ITP to start a new project that has practically culminated: Vector hopper for the EJ-200 engine. This project has been considered as R&D work and is not part of the current EJ-200 engine program.

New hopper New hopper

The hopper is the final part of the jet engine of the aircraft. In conventional hoppers, gas from the turbine expands into the hopper, so as the pressure decreases, the speed of the exhaust gases increases. Therefore, the air leaves at a speed higher than the entrance. Thus arises the thrust that moves the plane forward. Vector nozzles have the same function: increase the speed of the gas coming out of the turbine to increase the thrust of the engine, but they can also drive the gas direction.

Therefore, the plane can use the same thrust to control and maneuver the flight. The use of the impulse to control the flight is not a new idea, but so far it has not been possible to carry out due to the lack of suitable technology and materials. Today in Europe there are no planes that use the vector nozzle, while in other places there are. According to the movement, two types of vector hoppers are distinguished: 1) 2D vector nozzles: capable of moving from left to right. 2) 3D vector nozzles: those that allow movement from left to right and from top to bottom up. In general, the technology of vector hoppers can be used with any turbojet or turbofan. However, the existing vector nozzles are currently used in postcombustion military reaction aircraft. In the future, this technology is also expected to be used in aircraft with another reaction engine.

One of the most serious problems of the vector nozzles that have been designed so far has been to find a drive capable of deploying and closing the convergent and divergent part of the nozzle and, at the same time, directing the hopper towards different directions. Therefore, all existing vector nozzles use a system of actuators for each function, two therefore. In addition to finding a system of good weight, price and size to fulfill the role of the vector nozzle, so far it has been a big problem. The largest technological innovation of the nozzle designed in ITP is found in the actuator system. Precisely because it has a single drive system, in this case hydraulic, to perform all the tasks of the vector nozzle. With the same drive, both the convergent section of the nozzle is controlled, which is the place where the gas inlet is decided, as well as the divergent, which is the point where the gas is sent. It is clear that this can have a great influence on the weight, cost and efficiency of the engine in general. To improve this aspect of research, ITP is currently working with new materials, in addition to flight tests and launch tasks of the hopper.

Tour 10 years

As said, one can think that the project of the vector nozzle is finished, but it is not so, although it has traveled a long way, still remains to be done. The project itself began in 1990. During the first five years of the project the idea was patented, the conceptual design was realized and the model was built. ITP counted in those years with the collaboration of the German company DASA in the field of the consultancy, that it is a powerful promoter of the technology associated to the vectorial nozzle.

Once this was done, we proceeded to the aerodynamic design. At the same time, until finding the most suitable one, we proceeded to the selection of light materials necessary to make reality the project of the vector hopper. In general, most parts of the hopper are made up of titanium and nickel alloys.

In the first months of 1997, the design of the prototype of vector hopper for trials was launched. And they wanted to start testing next year.

Before starting the tests, however, there was something to do. They were intended for the manufacture of components of the vector nozzle, as well as actuators that gave movement to the hopper. Under the orders of ITP they were carried out by the Madrid company CESA. Not only that, but in addition to the manufacture of components and actuators, its correct response was also verified, as several tests were conducted.

The year 1998 was an important year for the project of the vector nozzle, since in that year several works already started were finished. Initially, the electronic control system of the vector hopper was developed. Subsequently, the vector hopper was integrated into the EJ-200 engine. Finally, the control systems were tested in a virtual flight simulator. The work was carried out by the German company MTU, the only partner of ITP in this project. MTU is also responsible for electronic engine control in the Eurojet consortium for the execution of the original EJ-200 engine. Once the components, actuators and control system were developed, the assembly and instrumentation of the hopper was carried out.

In addition to the simulators, before the tests carried out on flights before going on the market, it is necessary to perform ground tests in the workshop. Although these tests are performed in pre-prepared test benches, because the vector hopper project is special, the test bench had to be adapted. Once the test bench was prepared, tests were carried out on the ground, placing the hopper in different situations that it would have in a real flight. In these tests, data were obtained that proved the proper functioning of the nozzle.

After more than a year since performing ground tests, the next step will be to perform tests on real flights, since before starting with production it is essential to test the technology flying. Finally, logically, the product should be marketed. At the moment it seems that the market will be unique, the military. If it responds correctly in military planes, there is no doubt that in the future this technology can also be used in civil society.

At the start of the project, ITP's main goal, logically, was to do business, but it was not the only one. The steps that have been taken so far have allowed us to demonstrate at ITP that the technology of vector nozzles can have a future, which has allowed potential customers of the future. From a technical point of view, the work carried out has allowed ITP to expand its knowledge on vector nozzles, to calibrate its systems of calculation and to work with hydraulic systems for actuations -in the original project EJ-200 the nozzle is the responsibility of the ITP, but the hydraulic system and actuators are the responsibility of Fiat Avio, while in the project of vector nozzle, the hydraulic system and actuator are responsible.

The prediction can be too dangerous, but if you advance on the road of the vector nozzles, it is possible that the control of future planes and the ability to maneuver have little to do with the current ones.