Laboratory Tests of a Hybrid Metal-Composite Transport Helicopter Blade Segment

Experimental acquisition and verification of structural properties of an actual helicopter main rotor blade segment have been done with an aim to validate the capability of bonded joints of these structural elements to sustain the most dominant dynamic loads in forward flight, for the assigned blade's life time. It was also one of the qualitative tests of the newly applied rotor blade hybrid structure production technology, consisting of a metal spar and 21 plastic composite segments, bonded to it after the polymerization process. Because of the structural similarity of the segments, only the most highly loaded 21st segment and adjacent spar section were investigated, as representative in this particular sense. This has enabled remarkable reduction both in time and funds required for the design and construction of the test facility. This paper is focused on the demonstration of usage of fairly low-cost experimental infrastructure for that purpose, and also provides the designers and engineers with some examples and guidelines of how it is possible to conduct experimental verifications of the properties of similar, both aeronautical and non-aeronautical hybrid structures and joints, exposed to the long-lasting dynamic loads. Tests presented in this paper were only a part of a very wide test campaign, mostly undertaken on the entire new hybrid blade structures, both on the ground and in flight, before they have been put to operational service.