Scale model of the General Electric Unducted Fan (UDF) concept undergoing dynamic testing in a supersonic wind tunnel at the NASA Lewis Research Center. A laser is used to measure the deflection of the blades during operation, rather than at rest, to provide more precise data for the design and evaluation teams. The properties of lasers allow extremely accurate measurements to be made of the very small deflections of the blade at this model scale, not detectable by more conventional optical methods. The UDF uses two sets of blades rotating in opposite directions for propulsion, powered by a small jet engine.