Abstract: An air supply system is provided that uses two sets of rotors on a common set of shafts to boost air in two stages. The air supply system includes a housing and a first and a second rotatable shaft at least partially within the housing. A first and a second pair of rotors are included. Each pair of rotors has a first rotor supported for rotation on the first shaft and a second rotor supported for rotation on the second shaft. The housing has an inlet at the first pair of rotors, an outlet at the second pair of rotors, and an internal chamber between the first and the second pairs of rotors. Air flow from the inlet to the outlet thereby has a first pressure boost from the inlet to the internal chamber and a second pressure boost from the inlet chamber to the outlet.

Abstract: An air supply system is provided that uses two sets of rotors on a common set of shafts to boost air in two stages. The air supply system includes a housing and a first and a second rotatable shaft at least partially within the housing. A first and a second pair of rotors are included. Each pair of rotors has a first rotor supported for rotation on the first shaft and a second rotor supported for rotation on the second shaft. The housing has an inlet at the first pair of rotors, an outlet at the second pair of rotors, and an internal chamber between the first and the second pairs of rotors. Air flow from the inlet to the outlet thereby has a first pressure boost from the inlet to the internal chamber and a second pressure boost from the inlet chamber to the outlet.

Abstract: A wingsail assembly comprises a main symmetrical aerofoil which is freely rotatable about an upright axis and a control vane which is settable about an upright axis spaced from the axis of the main aerofoil to cause the main aerofoil to adopt an angle of attack to the direction of the wind. A pivoted aerodynamic slot-forming vane assembly is rotatable in response to wind pressure to open and close respective slots, one on each side of the leading region of the main aerofoil. A linkage inhibits movement of the slot-forming vane assembly away from a neutral position when the control vane is set to a neutral position.

Abstract: A wingsail assembly comprises a main symmetrical aerofoil which is freely rotatable about an upright axis and a control vane which is settable about an upright axis spaced from the axis of the main aerofoil to cause the main aerofoil to adopt an angle of attack to the direction of the wind. A pivoted aerodynamic slot-forming vane assembly is rotatable in response to wind pressure to open and close respective slots, one on each side of the leading region of the main aerofoil. A linkage inhibits movement of the slot-forming vane assembly away from a neutral position when the control vane is set to a neutral position.

Abstract: A wingsail assembly in which at least one thrust wing is mounted for free rotation about an upright axis and defining by its free rotation a trimming circle. The assembly includes a first control airfoil freely pivoted on a first boom extended upstream of a thrust wing, the first boom being of a length such that the first auxiliary control airfoil is within the trimming circle and a second control airfoil mounted downstream of the first control airfoil within the trimming circle and settable for controlling the angle of attack of the first control airfoil to the wind which in turn provides a turning moment for controlling the angle of attack of the thrust wing to provide thrust levels required for all normal sailing conditions.

Abstract: A wingsail assembly comprising a thrust wing having a leading aerofoil (1) and a trailing aerofoil (2), the leading and trailing aerofoils being deflectable with respect to one another to adopt a cambered configuration, characterised in that the trailing aerofoil has a cross-sectional shape with a relatively flat leading edge interconnecting relatively strongly curved corners (5,6) on opposite sides of the aerofoil, such that for each direction of relative deflection between the leading and trailing aerofoils the corner more remote from the trailing edge of the leading section provides an aerodynamic leading edge for the trailing section and the corner more proximate the trailing edge of the leading section provides an inner wall for a convergent slot. The assembly is mounted on a vessel via a bearing having an axis passing through the trailing section. A tail aerofoil trims the assembly and is mounted on a boom extending from the trailing section.

Abstract: A clutch assembly for an accumulating roller conveyer such that torque transmission is accomplished by using clutch plates of deformable material which in association engage with the conveyer drive and conveyer rollers to allow the bearings to deform the surfaces of the clutch plates in transmitting the torque from the drive to the rollers.

Abstract: A deflection system for wingsail assemblies in which the deflection is performed by fluid operated cylinders that are inter connected in such a way that the wingsail element is moved by a co-operative push pull action from the annulus side of one cylinder and the full bore side of a second cylinder.

Abstract: A method of operating a multi-element self-trimming sailset to assist deflection of the trailing element of the main thrust wing to either side of the leading element. The sailset is first rotated to reduce the moment of wind on the flap opposing deflection, the flap is deflected, and then the sailset rotated to its operating angle of attack. Rotation of the sailset is achieved by a tail vane.

Abstract: Wingsail configurations for multi element wingsails for maintaining full stall for maximum speed in running downwind in which the trailing edges of at least a pair of flap elements of a multi element structure are maintained in the convergent configuration so that in the deflected position of the flap there is a leeward progression to deeper stalling.

Abstract: A wingsail arrangement comprises a thrust wing having an upright leading airfoil having a leading edge and a trailing edge and an upright trailing airfoil having a leading edge and a trailing edge. The leading edge of the trailing airfoil is positioned closely behind the trailing edge of the leading airfoil. The trailing airfoil is mounted for pivoting movement about an upright axis relative to the leading airfoil from an aligned position in which the trailing airfoil is aligned with the leading airfoil to positions to each side of and angularly displaced from that aligned position. A slat has a leading edge and a trailing edge and is pivoted at its leading edge to the trailing edge of the leading airfoil and connected to the leading edge of the trailing airfoil by at least one cable so as to be moved in response to pivoting movement of the trailing airfoil to form a linear nozzle when the trailing airfoil is angularly displaced from the aligned position.

Abstract: A tie gun for applying a flexible tie around a roll or bundle, said tie having an apertured head through which the tail of the tie, after looping around the roll or bundle, is threaded, tensioned and locked in position, the gun incorporating an indexing means in the form of a rotary drum which advances successive ties, tail forward, into the path of a push rod driven by a trigger actuated, pneumatically operated piston so that said push rod performs a rearward stroke during the second part of an operating cycle and in so doing indexes the tie feed drum and simultaneously turns the buckle of an advanced tie into a tail receiving position, thus completing loading of the gun in readiness for the next operating cycle during the first part of which the push rod moves forwardly to push the tail around the roll or bundle to be tied back through the pre-orientated buckle ready for tensioning and locking.

Abstract: Pressure tapping for rigid sails, the tappings (10, 11, 12, 15, 16) being located to either provide a stall warning or to enable tuning of the sailset to the desired operating angles. A particular flow-state sensitive stall warning device is also described.

Abstract: A sailset comprising a leading aerofoil and a trailing aerofoil that pivots about an axis passing through the leading aerofoil. A third comparatively small aerofoil is retractable within the leading aerofoil and extendable downwind of the trailing edge of the leading aerofoil to provide a surface overlapping the leading edge of the trailing aerofoil.Guides for the third aerofoil are preferably provided for both its leading and trailing edges, the guides comprising roller and roller tracks and/or sliding pivots.

Abstract: A principal sail (1) rotates about an erect axis (2) and an auxiliary sail or vane (3) is mounted downstream of the principal sail (1). The vane (3) is mounted on a boom (4) that extends from the principal sail (1) so that the principal sail (1) is trimmed as the tail vane (3) moves to its position of minimum drag. A second auxiliary vane (5) is mounted forwards of the leading edge of the principal sail (1) and is capable of opposing the moment of the principal sail (1) about its own axis as the principal sail is moved towards a stalling position.

Abstract: A tie gun for applying a flexible tie around a roll or bundle, the tie having an apertured head through which the tail of the tie, after looping around the roll or bundle, is threaded, tensioned and locked in position, the gun incorporating an indexing means in the form of a rotary drum which advances successive ties, tail forward, into the path of a push rod driven by a trigger actuated, pneumatically operated piston so that the push rod performs a rearward stroke during the second part of an operating cycle and in so doing indexes the tie feed drum and simultaneously turns the buckle of an advanced tie into a tail receiving position, thus completing loading of the gun in readiness for the next operating cycle during the first part of which the push rod moves forwardly to push the tail around the roll or bundle to be tied back through the pre-oriented buckle ready for tensioning and locking.

Abstract: A wingsail assembly in which the pivoting mounting is situated in line with a strengthened portion of the sail assembly such as a strengthened leading edge of a sail element while still retaining the alignment of the axis of pivoting and the center of pressure. A sail assembly is also described in which a locating mechanism, typically in the form of wire stays, a mechanical linkage or a hydraulic system, is arranged to act on opposite sides of a balancing mass, carried by a boom attached to the wingsail assembly and arranged to locate the mass in an approximately horizontal plane. Where the wing or wing section is constructed from spars and ribs where the latter define the aerofoil section of the wing and lie in the direction of air flow, the ribs are conveniently formed from moulded GRP material and include flanges which in selected regions of the periphery of the rib subtend an angle of greater than 90.degree.

Abstract: A wingsail has two rigid symmetrical aerofoil section sail sections (10, 12) which are mounted one downstream of the other, the trailing sail section (12) being freely pivotally mounted to the center line of the leading sail section (10) so that its leading edge just clears the trailing edge of leading sail section.