F. Boden, A. Torres, C. Maucher

The performance of a helicopter mainly depends on the design of the main rotor. They have to endure strong centrifugal and bending forces and should be able to transmit these loads to the rotor hub and therefore to the airframe. To design rotor blades which could fulfil these requirements, the loads occurring under flight conditions and the resultant behaviour of the rotor blades (flapping, lead-lag bending and twisting motion) have to be known. The in-flight investigation of the deformation of the fast spinning rotor is a demanding task. It is evident, that conventional methods such as strain gauges and accelerometers are difficult to use because of problems with their installation, wiring, the data transmission, and the balancing of the rotor. Additionally, such sensors provide data only at the location where they have been installed. Consequently, a non-intrusive and planar measurement of the rotor blade deformation in flight is of high interest. This need for advanced, non-intrusive e.g. optical measurement techniques has been identified. Within the EC-funded specific targeted research project "AIM - Advanced In-flight Measurement Techniques" DLR and Eurocopter are applying the Quantitative Video Technique (QVT) together with the Image Pattern Correlation Technique (IPCT) to obtain the in-flight deformation of the main rotor blades of an EC-135. These advanced measurement techniques deliver 3D shape and deformation results by using stereoscopic camera pictures of the investigated objects, in this case, the EC-135 main rotor blades. To check the usability of the QVT and the accuracy of the IPCT for industrial in-flight measurements, a test with an instrumented rotor blade has been performed. The present paper will give a short introduction to the challenging task and some basics of the used measurement techniques. The measuring system will be described and the performed tests will be presented. To conclude, some example results and a short outlook concerning future activities will be given.

35th European Rotorcraft Forum 2009,

Conference Paper

englisch

21,0 x 29,7 cm, 10 Seiten

DGLR-Bericht, 2009, 2009-03, 35th European Rotorcraft Forum 2009 - Conference Proceedings; S.1-10; 2009; Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V., Bonn

NA

in getr. Zählung;

rotor blades, ec135 helicopter, loads measurement, rotorcrafts

Bestellbar

2009