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For the exploration and validation of the integration of efficient propulsion concepts and new technologies for future large passenger aircraft, it is necessary to establish suitable design, evaluation and measurement tools. Therefore, as one major activity of the Large Passenger Aircraft (LPA) Platform 1 of the Clean Sky 2 initiative, the so-called Cross-Capability Demonstrator (XDC), has been set up to develop and demonstrate powerful numerical and experimental methods for aerodynamic, aeroacoustics, and aeroelastic simulation and measurement tasks. The paper will give an overview of the activities to be performed within the XDC and present some of the latest achievements related to this demonstrator.

To integrate advanced propulsion systems and to assess and verify the related benefit (e.g. fuel burn, noise) suitable design, evaluation and measurement tools are required. For that reason, the so-called Cross-Capability-Demonstrator (XDC) has been set up as one major activity of the Large Passenger Aircraft (LPA) Platform 1 of the Clean Sky 2 initiative. The XDC is intended to demonstrate high-fidelity CFD-tools, further developed prediction tools for noise and aero-elastics as well as advanced testing tools for measuring e.g. the flow field, the deformation and the acoustics. The article will provide an update on activities within the XDC and presents some examples of recent accomplishments related to this demonstrator.

The integration of advanced propulsion systems into the aircraft, and the assessment of their benefits related to e.g. fuel burn, noise emission and potential further measures, is one of the major activities of the Large Passenger Aircraft (LPA) Platform 1 of the Clean Sky 2 initiative. In order to optimize and assess the potential of advanced propulsion integration, it is necessary to establish suitable design, evaluation, and measurement tools. The so-called Cross-Demonstrator-Capabilities (XDC-) activities have been set up to develop and demonstrate powerful numerical and experimental methods for aerodynamic, aeroacoustics and aeroelastic simulation and measurement tasks, supporting the dedicated demonstrators of LPA. The paper will give an overview of the XDC activities and some examples of the developments related to this demonstrator.

The knowledge of the movements and the deformation of rotor blades is of great importance for the performance and the safe operation of a rotor system, especially for blades with a high aspect ratio like on helicopters or wind turbines. To measure these parameters in the rotating system is not easy, because the number of sensors is limited due to their impact on the aerodynamics and the modification of the structure. Strain gauge measurements can furthermore directly be affected e.g. by the choice of the sensor location and temperature effects. To avoid those problems and in addition enable direct shape measurements contactless optical methods have still been applied to rotor and propeller deformation measurements in the past. These attempts have been done out of the rotating frame observing either only small rotors or the blade passing within the field of view. DLR and Hardsoft developed a rotating 3D image acquisition system for helicopter rotors and performed first tests on the whirltower of Airbus Helicopters in Donauwörth, Germany. The system is mounted on the hub and co-rotates with the rotor. It is able to record images of the whole blade at each azimuth angle. Later, those images are processed with an IPCT software tool and deliver the continuous 3D surface shape and location of the observed blade. From the comparison of the 3D surfaces for different recordings, the bending and torsion of the blade can be obtained. The paper will briefly describe the rotating camera system itself, the non-intrusive deformation measurement method IPCT and the measuring setup. The presentation of the recorded images, the obtained data and a discussion of the measurement results will conclude the paper. The lessons learned from the presented campaign will be helpful for manufacturers in the design and measurement of their future rotor systems.

The Newsletter gives same Information about the work performed within the first year of the European Project AIM – Advanced In-Flight Measurement Techniques, which was launched on November 1, 2006. This project intends to make advanced, non-intrusive measurement techniques applicable for time and cost effective industrial flight testing as well as in-flight testing for research. In the AIM consortium, ten Partners from aircraft industries, airport services and research organisations coming from 7 countries are working closely together. These partners are: Piaggio Aero Industries (I), Eurocopter France (F), Eurocopter Deutschland (D), Airbus France (F), DLR (D), ONERA (F), NLR (NL), EVEKTOR (CZ); Flughafen Braunschweig Wolfsburg GmbH (D), Cranfield University (GB), MPEI-Technical University (RUS). AIM is coordinated by DLR in Göttingen.

In the framework of the AIM project the near field of the blade tip vortex of a full-scale helicopter in simulated hover flight was investigated by combining three-component Particle Image Velocimetry and Background Oriented Schlieren measurements. The velocity field measurements in the range of wake ages of 1° to 30° in azimuth provided a reference for a quantitative analysis of the Schlieren results yielding vortex core density estimates. Ongoing vortex roll-up was observed at 1° while considerable aperiodicity was persistent thereafter. The vortex parameters for vortices older than 1° were consistent with the Scully vortex model. However, the particular challenges of full-scale, outdoor testing, especially the limited spatial resolution and aperiodicity effects, yielded a higher level of measurement uncertainty as compared to sub-scale experiments.