Ship with sail propulsion

Abstract

A double airfoil mounted on a structure controlled angularly around a generally vertical axis. The double airfoil includes a fore flap and an aft flap at least one of which has a fore-to-aft asymmetry. Each flap includes a series of shape members distributed in height, wherein the structure includes a fore mast and an aft mast connected by a boom member and a gaff member. The shape members of the fore flap are traversed by the fore mast while being able to turn around an axis defined thereby, while the shape members of the aft flap are traversed by the aft mast while being able to turn around an axis defined thereby. The aft mast is twistable, the shape members of the aft flap are rotationally locked to the aft mast, and the controller can act on the bottom and the top of the aft mast.

1 . An airfoil wind propeller, comprising at least one mast and a flap mounted on the mast and comprising a series of shape members distributed in height and each comprising an aperture, wherein the mast and the aperture of each shape member comprise rib and recess arrangements configured to cooperate to generate an angular freedom restriction of each shape member relative to the mast around an axis defined by the mast. 
     
     
         2 . An airfoil propeller according to  claim 1 , wherein the angular freedom restriction defines a limited angular freedom range of the shape members, and thus of the flap, relative to the mast. 
     
     
         3 . An airfoil propeller according to  claim 1 , wherein the angular freedom restriction defines an angular locking between the shape members, and thus of the flap, relative to the mast. 
     
     
         4 . An airfoil propeller according to  claim 1 , further comprising a second mast and a second flap mounted thereon. 
     
     
         5 . An airfoil propeller according to  claim 4 , wherein the second flap comprises a series of second shape members distributed in height and each comprising an aperture, wherein the second mast and the aperture of each second shape member comprise rib and recess arrangements configured to cooperate and generate a second angular freedom restriction of each second shape member relative to the second mast around an axis defined by the second mast. 
     
     
         6 . An airfoil propeller according to  claim 1 , wherein the second angular freedom restriction defines a limited angular freedom range of the shape members, and thus of the flap, relative to the mast. 
     
     
         7 . An airfoil propeller according to  claim 1 , wherein the second angular freedom restriction defines an angular locking between the shape members, and thus of the flap, relative to the mast. 
     
     
         8 . An airfoil propeller according to  claim 4 , wherein the first angular freedom restriction and the second angular freedom restriction define an angular freedom range and an angular locking, respectively. 
     
     
         9 . An airfoil propeller according to  claim 8 , wherein the first flap is a fore flap and the second flap is an aft flap relative to an incident air flow direction. 
     
     
         10 . An airfoil propeller according to  claim 4 , wherein the first mast and the second mast are connected at their ends by a boom member and a gaff member, respectively. 
     
     
         11 . An airfoil propeller according to  claim 10 , wherein the first angular freedom restriction defines a limited angular freedom range of the shape members, and thus of the flap, relative to the mast, and wherein said range is symmetrical relative to a median plane containing the axes of the two masts. 
     
     
         12 . An airfoil propeller according to  claim 11 , wherein said angular range is comprised between about ±1° and ±15°. 
     
     
         13 . An airfoil propeller according to  claim 9 , further comprising a controller for controlling the angulation of the aft flap relative to a median plane containing the axes of the two masts. 
     
     
         14 . An airfoil propeller according to  claim 1 , wherein the flap is defined by an envelope stretched on said shape members. 
     
     
         15 . An airfoil propeller according to  claim 1 , wherein the flap is formed by an assembly of generally rigid or semi-rigid boxes telescopically engaging with each other.