초록 ▼

An aerodynamic blunt aft body (10) of a helicopter fuselage with two strakes (7, 8) along an aft surface (9) and/or respective left hand and right hand side fuselage surfaces (5, 6). Each strake (7, 8) is defined by first and second intersection lines (3, 4) resulting from intersections of horizonta

An aerodynamic blunt aft body (10) of a helicopter fuselage with two strakes (7, 8) along an aft surface (9) and/or respective left hand and right hand side fuselage surfaces (5, 6). Each strake (7, 8) is defined by first and second intersection lines (3, 4) resulting from intersections of horizontal planes (z) with the surface of the aft surface (9) or the respective left hand and right hand side fuselage surfaces (7, 8). The strakes are defined by a two or three dimensional spline (12) from the surface (2) towards the aft surface (9) inside said first and second intersection lines (3, 4) and inside the bounding box (15).

대표청구항 ▼

1. An aerodynamic blunt aft body of a helicopter fuselage with a longitudinal middle plane, the helicopter fuselage comprising left hand and right hand side fuselage surfaces essentially parallel to the longitudinal middle plane, an aft surface between the left hand and right hand fuselage surfaces

1. An aerodynamic blunt aft body of a helicopter fuselage with a longitudinal middle plane, the helicopter fuselage comprising left hand and right hand side fuselage surfaces essentially parallel to the longitudinal middle plane, an aft surface between the left hand and right hand fuselage surfaces with an essentially normal alignment of the aft surface to the longitudinal middle plane, andat least two stakes provided along the aft surface and/or the respective left hand and right hand side fuselage surfaces as an essentially mirrored image of each other with respect to the longitudinal middle plane, wherein each respective strake is defined by: an upper plane normal to the longitudinal middle plane and passing through a junction between the aft surface and a tail boom,a lower plane normal to the longitudinal middle plane and being placed at 10% of the helicopter width above the lowest horizontal station of the fuselage,a first intersection line defined by a respective first set of points between the upper plane and the lower plane, wherein at the respective first set of points, local tangents to the respective surface lying in a horizontal plane are inclined at an angle of 15° relative to the central plane; anda second intersection line defined by a respective second set of points between the upper plane and the lower plane, wherein at the respective second set of points, local tangents to the respective surface lying in a horizontal plane are inclined at an angle of 60° relative to the central plane;each respective strake being defined within a respective bounding box with a height of 13% (+/−7%) offset relative to the fuselage widthwith a two or three dimensional spline towards the aft surface inside the first and second intersection lines. 2. The aerodynamic blunt aft body according to claim 1, wherein the strake has a contour corresponding to the fuselage geometry without the strakes. 3. The aerodynamic blunt aft body according to claim 2, wherein every intersection curve of the strake with the respective horizontal planes lies within the bounding box. 4. The aerodynamic blunt aft body according to claim 1, wherein the tail boom has a transition to the strakes. 5. The aerodynamic blunt aft body according to claim 1, wherein the aft surface is provided with a rear loading capability. 6. The aerodynamic blunt aft body according to claim 1, wherein the two or three dimensional spline from the strake surface to the first and second intersection lines is blended through a variable fillet for a smooth transition to the aft surface. 7. The aerodynamic blunt aft body of claim 1, wherein a maximum upsweep angle associated with an aft portion of the fuselage is greater than 25 degrees. 8. A helicopter comprising: a fuselage having a fore portion, an aft portion, a port portion with a port surface, and a starboard portion with a starboard surface, the aft portion being blunt, the fuselage additionally having a central plane extending from the fore portion to the aft portion, the central plane dividing the fuselage into the port portion and starboard portion, the fuselage further having a fuselage width and a lowest horizontal station;a tail boom coupled to and extending from the fuselage;a port strake coupled to the port surface by a first spline, the first spline extending to a region defined by: an upper plane extending normal to the central plane and passing through a connection point between the tail boom and the fuselage;a lower plane extending normal to the central plane and being positioned at 10% of the helicopter width above the lowest horizontal station;a port inner intersection line defined by a first set of points between the upper plane and the lower plane, wherein at the first set of points, local tangents to the port surface lying in a horizontal plane are inclined at an angle of 15° relative to the central plane; anda port outer intersection line defined by a second set of points between the upper plane and the lower plane, wherein at the second set of points, local tangents to the port surface lying in a horizontal plane are inclined at an angle of 60° relative to the central plane; anda starboard strake coupled to the starboard surface by a second spline, the second spline extending to a region defined by: the upper plane;the lower plane;a starboard inner intersection line defined by a third set of points between the upper plane and the lower plane, wherein at the third set of points, local tangents to the port surface lying in a horizontal plane are inclined at an angle of 15° relative to the central plane; anda starboard outer intersection line defined by a fourth set of points between the upper plane and the lower plane, wherein at the fourth set of points, local tangents to the starboard surface lying in a horizontal plane are inclined at an angle of 60° relative to the central plane. 9. The helicopter of claim 8, wherein the port strake extends from the port surface to a height of 13% (+/−7%) relative to the fuselage width and the starboard strake extends from the starboard surface to a height of 13% (+/−7%) relative to the fuselage width. 10. The helicopter of claim 8, wherein the port strake and the starboard strake are coupled to the aft portion of the fuselage. 11. The helicopter of claim 8, wherein the first spline and the second spline are two- or three-dimensional splines. 12. The helicopter of claim 8, wherein the first spline is blended to the port surface by a first variable fillet and the second spline is blended to the starboard surface by a second variable fillet. 13. The helicopter of claim 8, wherein the aft portion includes a back loading door or back hatch for rear loading of the helicopter. 14. A helicopter fuselage having a fore portion, an aft portion, a central plane extending from the fore portion to the aft portion and dividing the fuselage into a port portion and a starboard portion, the fuselage comprising: a port surface on the port portion of the fuselage;a starboard surface on the starboard portion of the fuselage; andfirst and second strakes coupled to the fuselage at corresponding locations on opposite sides of the central plane, the first strake being provided on the port surface and the second strake being provided on the starboard surface, each respective strake of the first strake and second strake being defined by: an upper plane extending normal to the central plane and passing through a connection point between a tail boom and the fuselage;a lower plane extending normal to the central plane and being positioned at 10% of the helicopter width above the lowest horizontal station;a respective inner intersection line defined by a respective first set of points between the upper plane and the lower plane, wherein at the respective first set of points, local tangents to the respective surface lying in a horizontal plane are inclined at an angle of 15° relative to the central plane; anda respective outer intersection line defined by a respective second set of points between the upper plane and the lower plane, wherein at the respective second set of points, local tangents to the respective surface lying in a horizontal plane are inclined at an angle of 60° relative to the central plane;each respective strake projecting from the fuselage at a height of 13% (+/−7%) relative to the fuselage width, each respective strake being joined to the respective inner intersection line and the respective outer intersection line by a respective two- or three-dimensional spline. 15. The fuselage of claim 14, wherein the first strake and the second strake are coupled to the aft portion. 16. The fuselage of claim 4, wherein each respective spline is blended to the fuselage by a respective variable fillet. 17. The fuselage of claim 14, wherein the aft portion includes a back loading door or back hatch for rear loading of the helicopter.