Several actuation concepts for deforming helicopter blades have been presented with focus on active twist and camber variation. In the case of blade twist, placement of active material layers has significant effect on achievable twist preformance, additional mass and blade cross-section properties like location of center of gravity. Further detailed full-scale studies are necessary to optimize the blade layout and actuator integration. In the case of airfoil camber variation, the Active Trailing Edge concept has been proposed based on the successfully flight-tested trailing edge servo flap. Aero-servo-elastic optimization studies have been executed to analyze the trade-off between aerodynamic effectiveness in terms of direct lift or servo effect and additional mass while maintaining the center of gravity at 25 % chord. Advantages of the Active Trailing Edge concept are a smoothly deflected airfoil contour in chordwise direction and no gaps at the ends of the arodynamically active surfaces in spanwise direction. Due to the modular design of the Active Trailing Edge actuator, maintenance is simplified and the actuator may be easily detached from the host blade structure for replacement. Piezoceramics have been proven to be suitable actuation technology for morphing helicopter rotor blades. Main advantages are electrical power supply, robustness concerning hostile environmental conditions, especially vibration, and high bandwith. Focus on recent developments has been on d33-mode actuation where significant improvement has been achieved. Worldwide, several adaptive helicopter rotor concepts have been proven from a scientific or technological point of view. However, the proof of their commercial benefit for the helicopter market including cost, reliability and maintenance issues is still pending. For this reason, future development efforts will increasingly focus on reliability (e.g. redundancy), integration as well as manufacturing issues and cost.
Actuation concepts for morphing helicopter rotor blades
Stellkonzepte für Hubschrauberrotorblätter mit veränderlicher Profilform
2006
10 Seiten, 12 Bilder, 10 Quellen
Conference paper
English
ACTUATION CONCEPTS FOR MORPHING HELICOPTER ROTOR BLADES
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