| US 7,517,263 B1 | ||
| Advanced blade sections for high speed propellers | ||
| Young T. Shen, Potomac, Md. (US); Scott D. Black, Vienna, Va. (US); and Stuart D. Jessup, Arlington, Va. (US) | ||
| Assigned to The United States of America as represented by the Secretary of the Navy, Washington, D.C. (US) | ||
| Filed on Sep. 05, 2007, as Appl. No. 11/900,135. | ||
| Int. Cl. B63H 1/18 (2006.01) | ||
| U.S. Cl. 440—66 [416/223 R] | 19 Claims |
| 12. A propeller blade for rotatably mounting to a watercraft propulsion device for rotating at angular velocities defining
operation in a sub-cavitating mode and in a super-cavitating mode, the blade comprising:
an advanced blade section comprising:
an upper surface; and
a lower surface,
the upper surface and the lower surface intersecting at a leading end and at an trailing end, wherein the leading end has
a leading edge and a leading edge radius defining the leading edge, and the trailing end has a trailing edge,
the upper surface having an upper convex portion extending from the leading end to the trailing end, the upper surface defined
by a maximum half thickness of the upper convex portion and the chord-wise positioning of the maximum half thickness between
the leading edge and the trailing edge, and
the lower surface having a lower concave portion and a lower convex portion forming a transition region, the lower concave
portion defined by said leading edge radius, a super-cavitating contour height of the concave portion and the lower convex
portion defined by a bevel radius of the lower convex portion, a height of the lower convex portion, and chord-wise positioning
of the lower convex portion, wherein the lower concave portion and the lower convex portion intersect at a smooth continuous
central zone between the leading end and the trailing end.
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