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TEST PILOTS RATE EUROFIGHTER TYPHOON

Everything looks straightforward in the commercials: The hostile aircraft is visible on the multiple function screen, the Eurofighter pilot accelerates quickly from around 800km/h to Mach 1.6 and fires one of the guided missiles, which are attached below the fuselage. Seconds later a hit is signalled to the pilot, who has already changed course to tackle the next fight.

However, it will take a few more years until scenarios like these will become reality. At the moment the Eurofighter is going through a test program, which will take over 4,000 hours. Seven prototypes are involved in Germany, Great Britain, Italy and Spain. To date 29 pilots have flown this multi role fighter and were very impressed. Major Frode Andre Evensen, who tested the aircraft for the Norwegian Air Force spoke about the "climax of his career".

Wolfgang Schirdewahn, Dasa's Chief Test Pilot since 1995, has a more sober outlook, but is still very positive. "It is always amazing to find out how easy it is to fly the Eurofighter. Even after a longer break, one feels at home straight away". These are Schirdewahn's words in an exclusive interview with FLUG REVUE.

"In the squadron the pilots will do their flight preparation with the aid of a computer," Schirdewahn describes a typical mission. All data for the route, tactical information or the individual voice profile for voice activation of certain systems are loaded onto a small cassette, which will simply be inserted in the cockpit."

The pilot will certainly not do without a pre-flight walk-around, checking this aircraft just like checking any other model: Visual inspection of the air intake, a glance at the undercarriage, the control surfaces, the ECM pods, and the nozzles of the EJ200 engines. For the ground crew it is easy to find out whether the systems have any faults, they simply have to read off a small display once all self testing routines have been completed. This display is located at the side of the air intake.

Today pilots have to climb big external ladders to reach the cockpit, however, the series production EF2000 Typhoon's will be fitted with a retractable ladder like the F-15. After the short climb the pilot will sit down on his Mk.16 ejection seat made by Martin-Baker. Wolfgang Schirdewahn comments that this seat is "by far more comfortable than the Mk.10 in the Tornado. When compared with the F-16 it is only slightly tilted, which has ergonomic advantages and was asked for by customers. One can reach every control without stretching and does not have to crane one's neck.

Anti-g-trousers and jacket protect the pilot against high g-forces,. What remains is to fasten the five point belt and hook in the arm retrieval straps. The straps for leg retrieval in case of ejection are already integrated into the cockpit.

The starting procedure is mostly automated and much simpler when compared with today's models. "Seven or eight actions are needed and we're on our way," explains Wolfgang Schirdewahn. "After the battery has been switched on, the built in APU is started, and the systems are then powering up. You are now ready to start the first EJ200. This process is automatic thanks to the FA-DEC System, which controls the engine completely electronically. After 40 to 60 seconds constant revs are achieved, and everything is repeated for the second engine."

The pilot is informed of the correct start procedure on one of the three coloured multiple functions displays.

"The screens can indeed be used flexibly. The pilot can configure the displays the way it suits him,"explains Schirdewahn. They are, however, programmed to supply automatically the most relevant information according to the actual flight phase, e.g. take off, rolling and fighting.

Schirdewahn is convinced that, "All in all the cockpit concept is a quantum leap in crew visualisation and is by far superior to the workplaces in current models used by European air forces."

The Eurofighter is taxied at a speed of 30 to 40, sometimes even 50km/h. "We currently have to break more often, because the aircraft are not loaded and the idling engines produce more thrust. This situation is still being adjusted," is Schirdewahn's comment on one of the criticisms which came up during tests.

Apart from this all pilots are very satisfied with the EJ200 engines, which have a dry thrust of 60 kN, and max. 90 kN with full afterburners. Schirdewahn is pleased that "for the first time there is no call for more thrust". The acceleration is indeed impressive with a thrust/weight ratio of up to 1:1.15, depending on the payload. "I felt that the Tornado was a decent aircraft without an extra load, but the EF2000 is by far better", enthuses Schirdewahn.

The Dasa Chief Test Pilot explains, that "we start mostly with dry thrust during tests, which is sufficient. After a few hundred meters we have reached the take off speed of 250 to 300 km/h. With a slight tug on the joystick we lift the nosewheel off the ground, and the aircraft is airborne. We need not concern ourselves with flap positions, since they are activated fully automatically as integral part of the digital flight control system. The undercarriage simply needs to be retracted, the aircraft put into climb, and that is it".

The Eurofighter's ability to climb is, according to Schirdewahn, "about 25 per cent better than that of the F-16 Fighting Falcon. And one must also consider that not only two Sidewinders, but also four medium range missiles are fitted to the fuselage". According to the manufacturer the aircraft reaches a height of 35,000ft in less than two and a half minutes.

Once airborne the pilot spends far less time looking at the dials than he used to. "The Head-up-display (view angle 30 x 20 degrees), is the prime instrument to illustrate the flight status", explains Wolfgang Schirdewahn. "At that size more information can be displayed, and data can easily be assimilated. When presenting infrared images, the big space is also advantageous. One does no longer have the distinctive tunnel vision."

And how does the aircraft handle? "Unlike the F-16 we here have a central stick, which can be moved properly and does not just allow a few millimetres' play. Most pilots find this more natural and it isn't over sensitive, because the (artificially produced) effort gives the pilot a feel for the aircraft. Control forces around all axes are well harmonised, and the aircraft's reaction to any input can be predicted easily. There are no surprises in any corner of the flight envelope, in which forces suddenly rise dramatically or the rudder is even reversed. A pilot feels very much at home and feels he can trust this aircraft." Schirdewahn is certain.

The Eurofighter is very stable thanks to its Fly-by-Wire-System. "I can let go of the Stick for some time without having second thoughts, the aircraft will stay on course. This is an important difference to the MiG-29 for example, which is extremely agile, but at the same time reacts to every gust and every slight change in power and therefore needs to be controlled actively at all times."

It is not obvious to the pilot which of the nine control surfaces the Eurofigter uses to achieve the intended flight manoeuvre. They all work together according to the relevant flight situation. This is due to their complex programming. They furthermore make sure that the aerodynamic limits of the aircraft will not be surpassed and that the airframe will not be put under too much strain. "One should not mistake the carefree-handling characteristics with carelessness", claims Wolfgang Schiredwahn. The pilot does not have a license to fly recklessly, because nothing sinister can happen. "The aim is to free the pilot from routine tasks, so that he does not have to give more than ten to 15 per cent of his attention to flying and managing the systems. This will give him a chance to focus on tactical considerations and the deployment of weapons."

During aerial battles over great distances the colour displays are very useful. Schirdewahn emphasises, "Since all the buttons are labelled, we have more area for use at our disposal. The position in the air is easier to display in colour. Opponents are for example no longer just small rectangles, but are also colour coded in red. From the outset, all the symbols were developed by taking into account any feedback given by test pilots. In this way we were able to realise many wishes and optimise from a early stage."

This also applies for the HOTAS Concept, (Hands on Throttle and Stick), with its two dozen switches, i.e. functions on the thrust lever and stick.

"There seem to be a lot," admits Schirdewahn, "but when we will implement voice input for functions like frequency changes or other cockpit actions, it will become also obvious here that the pilot's workload will be eased considerably."

Back to long range air combat. This is where the ability to operate at supersonic speeds becomes important. "The Eurofighter has a lot of thrust and little drag. Acceleration from 800km/h to Mach 1.2 is therefore markedly faster than with all known models," Wolfgang Schirdewahn assures us. "We build up a lot of speed, which we then pass on to medium range guided weapons. And once were are travelling at supersonic speed, we can sustain it without using afterburners." Super Cruise will not be around Mach 1.6 as it is with the American F-22 Raptor, "but Super Cruise is a feature which was not required for the Eurofighter, and which the customer is supplied with more or less free of charge."

Schirdewahn sees the Eurofighter also well equipped for turning fights. "The aircraft had been designed to be aerodynamically unstable at any speed, which means that it is only controllable with the aid of the fly-by-wire system. This is why during manoeuvres very high acceleration forces are built up. Because of the abrupt increase of g-forces, care must be taken that the pilot does not black out. This is why we have a comprehensive anti-g-system to protect the pilot.

The Chief Test Pilot informs us that, "At the end of the test program, we will operate at an angle of attack of over 30 degrees. However, the deciding factor is not the exact number of degrees, but that it is still possible to manoeuvre under these conditions. As far as turning circles and rates are concerned, we are definitely better than the F-16. What is more, the pilot can make full use of the aircraft's agility without a second thought, since the fly-by-wire system will keep the aircraft within its aerodynamic limits in any situation. We won't lose energy quickly, or are able to build it up again thanks to powerful engines. It takes the EJ200 engines less than five seconds to accelerate from idle to full dry output. They also have a very soft and quick transition into the afterburner."

With these characteristics the Eurofighter should stand its ground against any opponent. After the mission, touch down should be child's play. Wolfgang Schirdewahn explains, "We have a comparatively low touch down speed. At an angle of between 12 and 14 degrees, visibility to the front is also good. With its big delta wing the Eurofighter builds up a distinctive ground effect and touches down very softly." A long landing strip is not needed. Even without a breaking parachute the effective carbon breaks with anti scid system provide short rolling distances. "If need may be, you really can put your foot down," claims Schirdewahn.

As soon as the aircraft has taxied into the parking position, and the ground crew has made contact, the engines can be stopped. "Turn off screens, head-up-display, battery, the whole procedure is normally completed within one or two minutes." While mechanics are seeing to the aircraft, the pilot has to take out the data cassette and may proceed to his debriefing.

From page 12 of FLUG REVUE 5/99