FAIRING AND AIRFOIL APPARATUS AND METHOD

• US 20090321572A1
• Filed: 05/28/2008
• Published: 12/31/2009
• Est. Priority Date: 01/16/2004
• Status: Active Grant

• Current Assignee: CardioInsight Technologies Inc. (Medtronic Plc), The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Herling, William W., Ferguson, Stanley D., Treiber, David A.
• Granted Patent: US 7,967,252 B2
• Time in Patent Office: Days
• US Class Current: 244/130
• CPC Class Codes: B64C 7/00 Structures or fairings not otherwise provided for

Abstract

An airfoil for use on a high speed, jet powered airborne mobile platform and secured to an exterior surface of said mobile platform at a location so as to be disposed within a boundary layer during flight of the mobile platform. The airfoil produces a peak Mach number for airflow over a longitudinal centerline of said airfoil that is no greater than about Mach 1.2 when said mobile platform is moving at a speed of about Mach 0.85 with a relative constant Mach number flow over a region defined as at least an approximate 20% length of maximum thickness of said airfoil. The airfoil also has a pressure distribution (Cp) that is positive at a trailing edge thereof.

Claims

1. An airfoil for use on a high speed, jet powered airborne mobile platform, and secured to an exterior surface of said mobile platform at a location so as to be disposed within a boundary layer during flight of the mobile platform, the airfoil comprising:

a chord length designated by X;

a chord thickness at a local center line representing a thickness designated by Z;

wherein one-half of a thickness (Z) of said chord forms a ratio (Z/X) approximately within a range of about 11-13%; and

said airfoil producing a peak Mach number for airflow over a longitudinal centerline of said airfoil that is no greater than about Mach 1.2 when said mobile platform is moving at a speed of about Mach 0.85 with a relative constant Mach number flow over a region defined as at least an approximate 20% length of maximum thickness of said airfoil;

said airfoil further having a drag coefficient that is relatively constant and less than a value of about 0.10 up to an airspeed of about Mach 0.9;

said airfoil further having a pressure distribution (Cp) that is positive at a trailing edge; and

said airfoil further having a frontal portion forming an angle at a half height point thereof of between about 20 degrees to about 32 degrees relative to the exterior surface of the mobile platform.

2. The airfoil of claim 1, wherein said ratio comprises a ratio of about 12%.

3. The airfoil of claim 1, wherein said frontal portion comprises a frontal area of at least approximately three square feet.

4. The airfoil of claim 1, wherein the airfoil comprises a top portion and a tapering rear portion, and wherein said top portion and said tapering rear portion have a radius of curvature of about 130 inches.

5. The airfoil of claim 4, wherein a maximum angle for the tapering rear portion is less than about 23 degrees.

6. The airfoil of claim 1, wherein said airfoil includes upper corner portions each having a radius of curvature of about 6 inches.

7. The airfoil of claim 1, wherein the airfoil produces an aerodynamic drag of no more than about 50 pounds when said mobile platform is traveling at an airspeed of about 0.80-0.90 mach.

8. The airfoil of claim 1, wherein the airfoil generates no more than about 50 pounds of drag at about 0.85 Mach.

9. The airfoil of claim 1, wherein said chord length comprises a length of between about 90-100 inches (228.6-254 cm).

10. The airfoil of claim 1, wherein said chord thickness (Z) comprises a maximum half thickness at said local centerline of about 12 inches (30.48 cm).

11. The airfoil of claim 1, wherein said frontal portion includes a fillet.

12. The airfoil of claim 1, wherein said frontal portion generally comprises a bull nose shape.

13. An airfoil on a high speed jet aircraft, secured to an exterior surface of said aircraft at a location so as to be within a boundary layer while the aircraft is in flight, the airfoil comprising:

a chord length designated by X;

a chord thickness at a local center line representing a thickness designated by Z; and

wherein one-half of a thickness (Z) of said chord forms a ratio (Z/X) approximately within a range of about 11-13%;

wherein said airfoil includes a frontal portion, said frontal portion including a fillet and a generally bull nose shape;

said airfoil producing a peak Mach number for airflow over a longitudinal centerline of said airfoil of no more than about 1.2 over an operating speed of about Mach 0.41-Mach 0.85, with a relatively constant Mach number for airflow over a region defining the thickest 20% of said airfoil, and with no abrupt change from supersonic to subsonic flow that would result in formation of a shock wave;

said airfoil further having a drag coefficient that is relatively constant and less than a value of about 0.10 up to an airspeed of about Mach 0.9;

said airfoil further having a tapering rear portion and a pressure distribution (Cp) that is positive at said tapering rear portion;

said frontal portion forming a leading edge surface for the airfoil, said frontal portion forming an angle at a half height point thereof between about 30 degrees to about 31 degrees; and

said top portion and said tapering rear portion forming a radius of curvature that is between about 125 inches-135 inches.

14. The airfoil of claim 13, wherein said frontal portion includes a pair of fillets on opposite sides of a longitudinal centerline extending through a midpoint of said chord thickness.

15. The airfoil of claim 13, wherein said airfoil generates peak local Mach numbers of no more than about 1.2 over its entire surface while said aircraft travels at a speed between about Mach 0.41-Mach 0.85.

16. The aerodynamic fairing of claim 13, wherein the airfoil produces no more than about 50 pounds of drag at an airspeed of about 0.85 Mach.

17. An airfoil on a high speed jet aircraft, secured to an exterior surface of said aircraft at a location so as to be within a boundary layer while the aircraft is in flight, the airfoil comprising:

a chord length designated by X;

a chord thickness at a local center line representing a thickness designated by Z; and

wherein one-half of a thickness (Z) of said chord forms a ratio (Z/X) approximately within a range of about 11-13%;

wherein said airfoil includes a frontal portion, said frontal portion including a fillet and a generally bull nose shape;

said airfoil producing a peak Mach number for airflow over a longitudinal centerline of said airflow of no more than about 1.2 over an operating speed of about Mach 0.41-Mach 0.85, with a relatively constant Mach number for airflow over a region defining the thickest 20% of said airfoil, and with no abrupt change from supersonic to subsonic flow that would result in formation of a shock wave;

said airfoil further having a drag coefficient that is relatively constant and less than a value of about 0.10 up to an airspeed of about Mach 0.9;

said airfoil further having a tapering rear portion and a pressure distribution (Cp) that is positive at said tapering rear portion;

said frontal portion forming a leading edge surface for the airfoil, said frontal portion forming an angle at a half height point thereof between about 30 degrees to about 31 degrees; and

said top portion and said tapering rear portion forming a radius of curvature that is between about 125 inches-135 inches.

18. The method of claim 17, further forming the airfoil with said chord length (X) comprising a length of between about 90-100 inches (228.6-254 cm).

19. The method of claim 17, further forming the airfoil with said chord half thickness (Z) comprising a thickness of about 12 inches (60.96 cm).