초록 ▼

An airfoil assembly having a blade with a leading edge, a trailing edge, a root and a tip. The assembly rotates about a first axis. The blade has a planar windward surface parallel to a second axis which is orthogonal to the first axis. A third axis orthogonal with the first and second axes defines

An airfoil assembly having a blade with a leading edge, a trailing edge, a root and a tip. The assembly rotates about a first axis. The blade has a planar windward surface parallel to a second axis which is orthogonal to the first axis. A third axis orthogonal with the first and second axes defines the general orientation of the blade viewed along the first axis; however, the blade is pitched at an angle relative to the third axis. The convex leading edge, convex tip, and concave trailing edge have similar radii, and the leading and trailing edges converge as they approach the tip.

대표청구항 ▼

1. An airfoil assembly with mutually orthogonal first, second and third axes, the assembly comprising:a shaft rotatable about the first axis; an arm extending outwardly from the shaft; and a blade connected to the arm; the blade having a leeward surface, a planar windward surface, a leading edge, a

1. An airfoil assembly with mutually orthogonal first, second and third axes, the assembly comprising:a shaft rotatable about the first axis; an arm extending outwardly from the shaft; and a blade connected to the arm; the blade having a leeward surface, a planar windward surface, a leading edge, a trailing edge, a root attached to the arm and a tip spaced from the root, the leading edge and the trailing edge converging as they extend from the root towards the tip, the plane of the windward surface being parallel to the second axis, a projection of the windward surface onto a plane defined by the first axis and the third axis having a pitch angle relative to the third axis.2. The airfoil assembly of claim 1, the pitch angle being in the range 12-22°.3. The airfoil assembly of claim 1, the pitch angle being in the range 14-18°.4. The airfoil assembly of claim 1, the leading edge, the trailing edge and the tip being curved.5. The airfoil assembly of claim 1, the leading edge and the tip being convex, the trailing edge being concave.6. The airfoil assembly of claim 5, the leading edge, the trailing edge and the tip having identical radii of curvature.7. The airfoil assembly of claim 1, the root having between 1.7 and 2.7 times the length of the tip.8. The airfoil assembly of claim 1, the root having between 2.1 and 2.3 times the length of the tip.9. The airfoil assembly of claim 1, having a rounded transition region between the trailing edge and the tip.10. The airfoil assembly of claim 1, the leeward surface being contoured.11. The airfoil assembly of claim 1, the arm being contoured.12. The airfoil assembly of claim 1 having a plurality of blades equally spaced about the shaft, each blade having the same pitch angle.13. The airfoil assembly of claim 1, an outer portion of the blade capable of flexing as the airfoil assembly rotates.14. The airfoil assembly of claim 13, the outer portion limited to 50% of the blade length.15. The airfoil assembly of claim 13, the outer portion limited to 25% of the blade length.16. The airfoil assembly of claim 13, the outer portion limited to 10% of the blade length.17. The airfoil assembly of claim 1, further comprising an energizing device coupled to the shaft.18. An airfoil assembly with mutually orthogonal first, second and third axes, the assembly comprising:a shaft rotatable about the first axis; and a blade connected to the shaft; the blade having a leeward surface, a planar windward surface, a leading edge, a trailing edge, a root attached to the shaft and a tip spaced from the root, the leading edge and the trailing edge converging as they extend from the root towards the tip, the plane of the windward surface being parallel to the second axis, a projection of the windward surface onto a plane defined by the first axis and the third axis having a pitch angle relative to the third axis.19. The airfoil assembly of claim 18, the pitch angle being in the range 12-22°.20. The airfoil assembly of claim 18, the pitch angle being in the range 14-15°.21. The airfoil assembly of claim 18, the leading edge, the trailing edge and the tip being curved.22. The airfoil assembly of claim 18, the leading edge and the tip being convex, the trailing edge being concave.23. The airfoil assembly of claim 22, the leading edge, the trailing edge and the tip having identical radii of curvature.24. The airfoil assembly of claim 18, the root having between 1.7 and 2.7 times the length of the tip.25. The airfoil assembly of claim 18, the root having between 2.1 and 2.3 times the length of the tip.26. The airfoil assembly of claim 18, having a rounded transition region between the trailing edge and the tip.27. The airfoil assembly of claim 18, the leeward surface being contoured.28. The airfoil assembly of claim 18 having a plurality of blades equally spaced about the shaft, each blade having the same pitch angle.29. The airfoil assembly of claim 18, an outer portion of the blade capable of flexing as the airfoil assembly rotates.30. The airfoil assembly of claim 29, the outer portion limited to 50% of the blade length.31. The airfoil assembly of claim 29, the outer portion limited to 25% of the blade length.32. The airfoil assembly of claim 29, the outer portion limited to 10% of the blade length.33. The airfoil assembly of claim 18, further comprising an energizing device coupled to the shaft.