Rotating Camera for non-intrusive Measurements of Propeller Blades Deformation in Flight

Abstract

The Image Pattern Correlation Technique (IPCT), an optical method based on photogrammetry in combination with cross correlation algorithms, is a powerful tool for non-intrusive measurements of the surface shape and deformation of aircraft structures, e.g. wings, propeller or rotor blades. The latest development of this technique is its application to 360° propeller deformation measurements. Therefore a special stereo camera system rotating with the propeller at its full rotational speed was designed, whereby the system was exposed to extreme vibration and centrifugal forces. Within the last years, this novel measurement system was intensively developed by a team of researchers, technicians and engineers from Avia Propeller, DLR, EVEKTOR and HARDsoft. By beginning of 2014 the whole system had been successfully tested on an EVEKTOR VUT 100 COBRA airplane in Kunovice (CZ). The presented paper will partly demonstrate the hard and valuable work performed by all team members from drawing the first sketch of the system up to performing an successful flight test. Beside the description of the measurement hardware and the applied IPCT method, the paper will give some impressions of the flight test activities and some of the first results.