Adjusting rigid foil spar system

Abstract

A rigid foil sail having a full length vertical leading edge whose trim angle/angle of attack is controlled by the main sheet and at least two trailing edge flaps attached rearwardly of the leading edge, each of which can be independently trimmed from a convenient deck level control tray to achieve easily adjustable camber. The design of the rigid foil sail allows depowering of the sail without altering mainsheet trim by decreasing the camber of the upper trailing flap thus also decreasing the heeling force created by the power of the upper trailing flap. Such an arrangement allows the boat to be driven without the loss of upwind pointing performance and without the loss of power caused by luffing of the sail. Similarly, the boat can be better balanced by allowing the boat to be driven to windward more efficiently with a minimum heel angle.

1 . A rigid foil sail comprising:
 a free-standing rotatable mast;   a leading edge having a symmetrical airfoil shape supported by said mast;   a lower control tray affixed to said mast proximate a bottom edge of said leading edge;   at least one additional control tray affixed to said mast in spaced apart vertical relation to said lower control tray;   a lower trailing edge flap rotatably supported between said lower control tray and said at least one additional control tray adjacent a rear edge of said leading edge; and   at least one upper trailing edge flap rotatably supported above said additional control tray adjacent a rear edge of said leading edge.   
     
     
         2 . The rigid foil sail of  claim 1 , further comprising:
 a main sheet for controlling rotation of said mast.   
     
     
         3 . The rigid foil sail of  claim 2 , wherein said main sheet is affixed to a bottom surface of said lower control tray proximate a rear end thereof. 
     
     
         4 . The rigid foil sail of  claim 1 , further comprising:
 a lower control to control rotation of said lower trailing edge flap relative to said leading edge; and   an upper control to control rotation of said upper trailing edge flap relative to said leading edge.   
     
     
         5 . The rigid foil sail of  claim 4 , wherein said lower control and upper control are operated independent of one another. 
     
     
         6 . The rigid foil sail of  claim 4 , wherein said upper control and lower control are run through fair leads to a single control location. 
     
     
         7 . The rigid foil sail of  claim 1 , wherein said rear edge of said leading edge includes a recess therein to receive a forward edge of said lower and at least on upper trailing edge flaps. 
     
     
         8 . The rigid foil sail of  claim 1 , wherein a portion of said leading edge extends forward of said mast thereby creating a semi-balanced sail. 
     
     
         9 . The rigid foil sail of  claim 1 , further comprising:
 a winglet affixed to said mast in spaced apart vertical relation to said at least one additional control tray and adjacent said at least one upper trailing edge flap.   
     
     
         10 . The rigid foil sail of  claim 1 , wherein said leading edge, lower trailing edge flap and at least one upper trailing edge flap are formed of rigid material. 
     
     
         11 . The rigid foil sail of  claim 1 , wherein said lower trailing edge flap and said at least one upper trialing edge flap are rotatably adjustable independent of one another and relative to said leading edge to a range of negative camber, neutral and positive camber positions, wherein said negative camber positions generate a lift force to a windward direction relative to the sail and said positive camber positions generate a lift force to a leeward direction relative to the sail.