Draw-wire sensors from Micro-Epsilon are being used in the testing of new wind turbine rotor blades at the Fraunhofer Institute IWES, Bremerhaven. The test rig is designed for rotor blades with a maximum length of 70m. The rotor blade distortion due to wind loads is simulated in this rig. The tip of the rotor blade can be distorted by up to 10m due to mechanical loads. The rotor blade is mounted horizontally in the test rig for this. Steel cables are routed to the rotor using guide pulleys and attached to the rotor blade at various positions, either directly or via mechanical clamps. Twelve draw-wire sensors from Micro-Epsilon are used for to measure the distortion. Mounted on the rails on the floor are two draw-wire sensors for each steel cable, which measure the movement and the distortion of the rotor blade. The sensors of the wireSENSOR P115 series have measuring ranges of between 3m and 10m and operate with a digital signal output. The sensors are particularly robust due to their aluminum housing.