Experimental and numerical investigations on a counterrotating propfan (CRISP') have been carried out to study unsteady flow phenomena generated by the interaction of the two rotors. This paper focuses mainly on the downstream effects of rotor 1 on rotor 2. Therefore unsteady Laser-2-Focus, unsteady total pressure measurements and an unsteady simulation have been carried out. The total pressure measurements behind the rotors show variations of the absolute total pressure outside the wake

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... up to 30 percent of the average total pressure rise. Some of these are caused by the interaction of the rotor 1-generated wakes with the leading edge of rotor 2. The others may result from the pressure waves generated by the reflection of the rotor 2-shockwaves by the blades of rotor 1.