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EUROCOPTER MODERNISES COUGAR FAMILY

81 customers in 48 countries have to date ordered around 580 of Eurocopter's biggest helicopter yet. But the company would be ill advised to rest on its laurels. With the EH101 up and flying, the S-92 the subject of an aggressive marketing campaign by Sikorsky, and Eurocopter's own alternative, the NH90, jostling with it for sales, the competition has become distinctly tougher.

Against this background Eurocopter has in recent years been examining a number of options for ensuring that the Cougar/Super Puma family remains attractive to prospective customers. For example, the company considered developing a Mk3 version with a significantly larger cabin. However, the associated development costs would have been too great, explained programme director Alain Rolland during a visit from FLUG REVUE in Marignane. Instead, a decision was made initially to go for a Cougar Mk2+, which would offer significantly improved capability but with the same size of airframe. This now goes under the type designation EC 725 (military version) or EC 225 (civilian version).

Eurocopter EC 725

There was another reason as well for adopting this course. The French armed forces had ordered the Recherche et Sauvetage au COmbat (RESCO) version of the AS 532A2 search and rescue helicopter back in May 1995. But even while the helicopter was still under development, the customer came up with some additional requirements as regards equipment and capability. Together they were so far-reaching that it became increasingly difficult to satisfy them with the Cougar Mk2. Evidently this was also confirmed in trials on the first RESCO aircraft (F-ZVMC), which was officially handed over to the Armée de l'Air on 9 September 1999.

The result was the evolution of the Mk2+ alias EC 725 on the computers of the engineers. To give this new version greater capability, at the outset they asked Turboméca for a more powerful version of the Makila engine. Version 1A4 now has almost 14% more take-off power, at 1566 kW, and its emergency power has been correspondingly increased as well. As well as higher operating temperatures, it also required development of a new compressor. The Makila has two-channel full-authority digital engine controls (FADEC).

To make use of the extra engine power, the main transmission has been modified. The basic configuration is unchanged, but optimised tooth forms and hardening techniques have been used for the individual bevel gears. An independent spraying system ensures that operations can continue for 30 minutes after a complete loss of oil.

An extra fifth blade has been added to the main rotor of the EC 725, and the diameter has been increased. As a result, it now provides more lift, helped also by the new asymmetric profiles developed in collaboration with Onera, which are based on the ones in the NH90. The blades are made entirely from composite materials. The Spheriflex rotor head has an unchanged design while incorporating components such as dampers from the Mk2. All in all, the new rotor produces significantly less vibration so that is possible to dispense with vibration dampers. It is now possible to install a de-icer system, the lack of which considerably hindered sales of the Cougar Mk2.

As well as the dynamic system, the engineers have put a lot of work into the avionics fit. The instrument panel is now dominated by four large colour LCDs (15cm x 20cm), with two additional displays in the centre (10cm x 15cm) for presentation of engine and system data.

In the case of the RESCO version for the French Armée de l'Air this is of course only the start of a very comprehensive equipment list which includes amongst other items:

• High-precision navigation system with a combined inertial platform/12-channel GPS receiver from Sagem plus Doppler system.
• Radio equipment which covers a wide frequency spectrum (30 to 400MHz) and includes two Saturn sets from Thales, an ARC-210 HF set from Rockwell Collins and another set for satellite communications. Naturally the data is encrypted.
• Personal locator system from Cubic, which enables the emergency transmitter of a downed crew to be located.
• Elbit digital map system, identical to the one fitted in the V-22 Osprey
• Electronic self-protection suite comprising radar warning receiver (the EWR-99 from Thales), laser warning receiver and missile-approach warner (Damien millimetre wave radar from Thales), and chaff and flare dispensers (ELIPS from Alkan with a total of 72 cartridges).
• Chlio thermal imager from Thales in the nose
• Health and Usage Monitoring System (HUMS)

To suppress enemy fire, a 20mm GIAT cannon can be mounted on the EC 725. On top of this, 7.62mm Herstal machine guns are fitted in the front side windows (1000 rounds each!) Various Kevlar mats are provided in the cockpit and cabin to protect the crew. In addition there is a rescue hoist which can handle 275kg, plus a spare hoist and a search light. The tanks are self-sealing, and emergency floats provide security over water.

When it comes to choosing the equipment configuration, the customer is spoilt for choice. "Because we have used the Mk2 airframe, all the options that have already been certified are available," says programme manager Alain Rolland. This fact that the equipment fit can be tailored to meet specific customer requirements he sees as a major advantage compared, for example, with the UH-60 Black Hawk.

A new addition to the option list is an in-flight refuelling probe - the first time that this has been offered on a European helicopter. When extended, it has a length of around 7m, permitting secure docking to hoses trailed out behind a C-130 Hercules. Whether the French army will take up this option is not yet clear. It requires a suitable tanker.

In any case four EC 725's will enter service with the Armée de l'Air by the middle of 2004. This means that the first fully fitted aircraft must be delivered in September 2003. Three new EC 725's are to be built, to be joined by an upgraded Cougar Mk2.

There is still plenty of work for the test crew to do. The remaining prototype still with Eurocopter (F-ZVLR) has been flying since 27 November of last year. By the summer the flight envelope limits and performance figures should have been established. The first customer aircraft ("Air 007") is expected to fly in September. This will be fitted with the more powerful Makila engines. Its main task will be to test the power plant, but it will also be used to check out the autopilot.

A third EC 725 ("Air 006") is to be available from October. The de-icing system is to be installed and tested on this helicopter, which will also be used for trials of other equipment. Certification of the civilian version is expected to be achieved by the end of 2002, with certification of the military version to follow in the spring of 2003, all being well.

The EC 725's will also be flown with EH 1/67 "Pyrénées", which up to now has had to make do with three old Pumas. The RESCO upgrade, quite modest compared with American specifications, does not come cheap. Apparently the four EC 725's will cost the Armée de l'Air 1.05 billion francs ($144 million). But that is only the beginning. By 2015 the fleet will have been increased to 14 aircraft.

No other customers for the EC 725 have as yet been announced by Eurocopter. However, it is clear that the new version of the Cougar is being aggressively marketed. "Our price is more competitive than Sikorsky's (S-92)," says Alain Rolland. In the civilian market the company plans to offer operating cost guarantees, he told FLUG REVUE in Marignane. It currently has its sights set on the forthcoming Canadian competition for 28 naval helicopters, and it has not yet given up hope of a Portuguese sale. Eurocopter's big cats are rising to the challenge.

From page 70 of FLUG REVUE 6/2001