Christoph Maucher

Multidisciplinary Design and Optimization of Active Trailing Edge for Smart Helicopter Rotor Blade

A new concept is proposed for individual blade control: the Active Trailing Edge (ATE). The objective of this paper is to present the current status of design and optimization of the ATE. Due to the specific nature of the subject an inherently multi-disciplinary approach is taken. The aeroservoelastic optimization of the ATE actuator is based on evolutionary algorithm. The resulting optimal actuator design, the sensitivity of the optimal design to manufacturing and material constraints and some key performance characteristics like aeroservoelastic airfoil polars and Mach-number influence on aerodynamic effectiveness are presented. For the purpose of comprehensive rotor dynamics simulation including the dynamic and aeroservoelastic behaviour of the ATE actuator, a reduced-order model is developed. The paper concludes with a presentation of active helicopter benefit analysis.

Adaptive structures for fixed and rotary wing aircraft

Since more than 10 years EADS Innovation Works, which is the corporate research centre of EADS (European Aeronautic Defence and Space Company), is investigating smart materials and adaptive structures for aircraft in cooperation with EADS business units. Focus of research efforts are adaptive systems for shape control, noise reduction and vibration control of both fixed and rotary wing aircraft as well as for lift optimisation of fixed wing aircraft. Two outstanding adaptive systems which have been pushed ahead in cooperation with Airbus Germany and Eurocopter Germany are adaptive servo flaps for helicopter rotor blades and innovative high lift devices for fixed wing aircraft which both were tested in flight for the first time representing world premieres. In this paper various examples of adaptive systems are presented which were developed and realized by EADS in recent years.

Blade Deformation Measurements with IPCT on an EC 135 Helicopter Rotor

For the design of a helicopter rotor blade, it is crucial to predict the dynamic behavior and occurring forces and moments. For the validation of prediction tools, reliable flight test data is required. Furthermore, flight test measurements are necessary for the calculation of fatigue loads. Today, strain gauges are applied to a helicopter rotor blade to perform measurements in flight test. Locally, they allow a precise strain measurement for the complete rotor revolution. This instrumentation implies a high effort. Furthermore, wiring can imply difficulties due to its weight and its modification of the aerodynamic shape. An optical measurement technique may overcome some of the limitations of strain gauges. A precise measurement of the deformation of the complete surface of the rotor blade allows to locate high strains and to identify oscillatory modes. The exact blade position can be identified optically. One of these advanced optical measurement techniques is the Image Pattern Correlation Technique (IPCT). Today, IPCT is a state of the art measurement technique for static and dynamic deformations. In AIM, DLR and Eurocopter explore the feasibility of Quantitative Video Technique (QVT) together with the Image Pattern Correlation Technique (IPCT) on the rotating main rotor blades of a flying helicopter. Ground tests of the measurement system on a whirl tower and a tied down helicopter are performed to verify the feasibility and performance of the measurement system previous to flight testing.