Patent ID: 7748950

Claim:
A turbofan engine comprising: (a) a core flow duct located at a center of the engine; (b) a bypass flow duct located at an outer periphery of the engine; (c) a fan first-stage moving blade for taking an air therein; and (d) a spinner rotationally driving the fan first-stage moving blade, wherein the spinner has a spiral blade extending spirally to an outer side in a radial direction from an axis of the spinner, sucking air from a front face of the spinner and supplying air to the fan first-stage moving blade, wherein the spiral blade and the fan first-stage moving blade are separated, wherein a separated region is formed between a rear edge end of the spiral blade and a front edge end of the fan first-stage moving blade, wherein the separated region extends toward the outer side in a radial direction from the axis of the spinner, in a direction inclined to a front side of the engine with respect to a plane perpendicular to a center line of the engine, and wherein a meridian plane shape at a position in a radially outer side rather than a root of the separated region in the spiral blade corresponds to a shape in which a chord length of the spiral blade is reduced toward a tip side of the spiral blade from a hub side of the spiral blade, and the chord length comes to zero without limit in the tip side of the spiral blade, wherein a tip is formed at a position of the rear edge end of the spiral blade, brought into contact with a diametrically outer end of the separated region, wherein a portion protruding toward the spiral blade side is formed at a position of the front edge end of the fan first-stage moving blade, brought into contact with the diametrical outer end of the separated region, and wherein the tip of the spiral blade and the protruding portion of the fan first-stage moving blade are formed in a curved shape.