 Within the next ten years, manufacturers of high-output wind turbines for offshore wind farms plan to produce blades up to 90 m long. The prototypes of these new blades have to be tested and certified before they can go into production, and that requires equally large testing facilities. This year the Fraunhofer Institute for Wind Energy and Energy System Technology (IWES), Bremerhaven, Germany, is inaugurating a new facility with the capability of testing rotor blades up to 90 m long. The central feature of the facility will be a tiltable 1000 metric tons steel and reinforced concrete mounting block. Hydraulic cylinders used to tilt the block and additional cylinders to load the blade will allow the IWES engineers to bend a rotor blade as easily as a finger to a blade of grass. This unique testing setup allows for the blade tip of a 90 m blade to be bent through a distance of 25 m. “The big advantage of the hydraulic tiltable mounting block is that it allows us to set up the ideal configuration for conducting tests with high precision in a minimum amount of time,” says Falko Bürkner, who leads the rotor-blade testing team at IWES. This is especially important when testing the blades under extreme conditions, which involves subjecting the blades to the maximum theoretical loading they have been designed to withstand, that is, 100% of the design load.