Active Twist Rotor for Wind Tunnel Investigations

This paper describes the design and manufacturing of active twist rotor blades for the use as secundary control of a helicopter main rotor. These blades have been developed at the DLR in Braunschweig, Germany over the last years. Special features of the blade are the capability to twist individual sections of the blade. It is planned to equip the blade so that the following test methods can be applied: strain gauges and SPR for deformations, optical measurements as a reference of the blade tip twist and pressure sensors in certain sections. I order to reduce the complexity of the blade/rotor shaft interface, blade integrated amplifiers for the strain gauge bridges have been developed and teste. Right now a set of six instrumented blades is being built, in order to test a four bladed rotor in a wind tunnel in 2012.