Patent ID: 8221086
Filing Date: 2012-07-17
Classification: B63H,F04D

Abstract:
1. A propeller comprising a hub ( 1 ) having a plurality of blades ( 3 ) extending therefrom, each blade ( 3 ) having a root, a tip, a first blade portion ( 10 a ) extending between said root and said tip and a second blade portion ( 10 b ) extending between said root and said tip adjacent and substantially parallel to said first blade portion ( 10 a ), said first and second blade portions ( 10 a , 10 b ) each having an arcuate concave face ( 11 a , 11 b ), the radius of curvature of each concave face ( 11 a , 11 b ) being constant between the root and tip of the blade ( 3 ) such that each concave face ( 11 a , 11 b ) is defined by a curved surface of a segment of a circle between the root and the tip of the blade ( 3 ), wherein said concave faces ( 11 a , 11 b ) of said first and second portions ( 10 a , 10 b ) faces in substantially opposite directions such that, in use, said concave face ( 11 a ) of said first blade portion ( 10 a ) faces rearwards and said concave face ( 11 b ) of the second blade portion ( 10 b ) faces forwards, wherein said first blade portion (