The EC 725 is the latest member of the Cougar family. This aircraft has benefited both from the experience and proven long-term operability of its predecessors of the Puma/Super Puma family. Being equipped with numerous considerable technical improvements, the EC 725 is designed to perform tactical transport missions, SAR (Search and Rescue), Combat SAR, but also medical transport and logistical services. The helicopter can also be equipped for antisurface and anti-submarine naval missions.
The French Air Force, being the EC 725’s launching customer, ordered 18 aircraft. Among
those, fourteen aircraft are planned to be used for Combat SAR missions. The French Military is operating the EC 725 since 2004 according to scheduled operational needs. Meanwhile, the Cougar/Super Puma family has completed more than 3 million flying hours, proving the helicopter’s excellent multi-mission capability. While offering moderate operating costs, the helicopter is unrestrictedly serviceable in very hot climate as well as under extremely severe icing conditions.
Performance and payload increase
The EC 725 is a medium-class twin-engine helicopter (in the 11 metric ton class), whose
performance capabilities have been noticeably increased with regard to long range as well as hot/high missions compared to the Cougar AS532 AL version as it is currently operated by the Turkish armed forces (in total, the Turkish Armed Forces operate 49 COUGAR AS532 UL or AS532 AL helicopters).
The military payload of this new version has also been substantially increased to 5,000 kg. Notable new features of the EC 725 include an entirely new main rotor head, a reinforced main gearbox, new engines, and a new integrated piloting and display system. Eurocopter selected the Cougar fuselage structure for the EC 725 because of its tremendous operational qualities already proven in service and its large selection of available options and equipment.
New Five-bladed Main Rotor
The EC 725 will continue to use the proven capabilities of the Spheriflex® technology for the main and tail rotor heads. This technology also cuts costs for operations and maintenance.
The main rotor diameter is 16.2 meters. With five blades, the main rotor benefits from the most recent advances in airfoil section development and aerodynamic performance. Their design is based on a spar made from composite materials. The blades also make use of multiple box-structures in their construction. With five blades, the aircraft has an especially low vibration level.
State-of-the-art de-icing system
The rotors and the horizontal stabilizer can be equipped with a de-icing/anti-icing system that enables EC 725 crews to fly under extremely severe icing conditions. For that purpose, the helicopter is fitted with a duplex-architecture protection system that satisfies the highest level of safety requirements ever demonstrated. The 5 main rotor blades are de-iced cyclically by mats heated by metal resistors. With this system, the blades can be folded manually. The anti-icing system for the 4 tail rotor blades operates continuously. The blades incorporate 4 anti-icing carbon resistors.
New Main Gearbox
The main gear box of the EC 725 has been reinforced in order to account for the aircraft’s increased turbine power and gross weight. The drive chain of the Mk2 has been kept, and the spiral bevel gears feature deep nitration technology and the latest optimisation of tooth profiles. The lubrication circuit includes a back-up spraying system that makes it possible to operate without oil for 30 minutes.
The EC 725 is equipped with two MAKILA 2A Turbo engine units. This new engine, developed by the company Turbomeca, includes a new-generation compressor and can operate at a higher temperature than its predecessor, the MAKILA 1A2. It is thus capable of generating 1,800 kW (2,448 ch, 2,413 shp) of contingency power, an increase of 14% over the previous version.
The dual channel FADEC (Full Authority Digital Electronic Control) system ensures optimal performance, safety and fuel efficiency in any phase of flight. The "blade shedding"
architecture of the free turbine also contributes to modern, reliable, and safe operating capacities. Each engine is a self-contained assembly with all the necessary systems, equipment, and accessories for its operations. The fact that the engines are modular makes maintenance and inspection much easier.
New Integrated Display System
The EC 725 is equipped with new avionics, the result of Eurocopter’s extensive experience in pilot-helicopter interface technology and the development of ergonomic features.
The Flight Display System makes use of LCD with four multi-function screens (6" x 8") and two additional screens (4“x 5“) for the helicopter parameters. These screens provide the operator with a simultaneous display for piloting, navigation, and mission parameters. Their modular design makes many different configurations possible. Computers integrate all flight, navigation, and tactical parameters. With this integrated system, the pilot and co-pilot can concentrate on external mission features instead of on the aircraft functioning, which means their mission has a much higher probability of success.
Author: Christopher Bach
Picture provided and copyrighted by Eurocopter
For further information about Eurocopter, click here