Boeing, Rolls-Royce, RUAG Aerospace, and Deharde Maschinenbau entered into a collaborative research agreement to explore the potential of fuel-efficient open-fan (open-rotor) propulsion technology for future commercial airplanes. Tests of a model concept airplane with open-fan engines are planned for early in 2010 at the RUAG low-speed wind tunnel in Emmen, Switzerland. A unique propulsion and measurement system is to be integrated into the model. Rolls-Royce is providing propulsion design expertise from facilities in the U.K. and Germany, while Boeing is designing the integrated wind-tunnel model airframe. The wind-tunnel model will be manufactured by Deharde Maschinenbau of Varel, Germany. The model will use RUAG expertise in counter-rotating open-rotor engine simulation.