US Patent 7963094 Fragmentor for bird ingestible gas turbine engine

In an aircraft turbofan or turbojet engine including a fan blade assembly mounted thereon rotating about the central axis of the engine, there are provided aerodynamically profiled rotating cutting rings arranged concentrically to the engine axis upstream of the fan blade assembly on which a bird traveling toward the engine will fragment to extravasations and evisceration to produce bird debris of a sufficiently low density to be safely ingested by the engine.