Abstract:
Since the installation on Gazelle in 1968, great experience has been acquired by Airbus Helicopters on Fenestron™ technology. The experience gained after 18.5 million flight hours during the past decades allowed defining clear guidelines for the enhancement of design and substantiation principles applied on this technology. This is a progression which automatically serves as a safety improvement and contributes strongly in reduction of the number of accidents caused by conventional tail rotors. This paper summarizes the evolution of design technologies applied for the Fenestron™ tail rotors in Airbus Helicopters and specifies the results of recent research and development work conducted in this area. First part of the paper mainly focuses on operational safety improvement by the Fenestron™ concept and makes comparisons with aircrafts equipped with a conventional tail rotor. The second part gives detailed information about the design features and strength substantiation of the EC145 T2 Fenestron™ rotor. The composite Fenestron™ blade with the newest technology is chosen as an exemplary part to describe the design improvements and to show the application of the new substantiation rules. The development and certification logic is presented mainly from the perspective of strength substantiation. The development approach followed by Airbus Helicopters which primarily bases on mixture of analysis and tests by taking into account the previous in-service experience is described subsequently.