Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63H—MARINE PROPULSION OR STEERING
  • B63H9/00—Marine propulsion provided directly by wind power
  • B63H9/04—Marine propulsion provided directly by wind power using sails or like wind-catching surfaces
  • B63H9/06—Types of sail; Constructional features of sails; Arrangements thereof on vessels
  • B63H9/061—Rigid sails; Aerofoil sails

Definitions

• This invention relates to aerofoils for wingsails.
• Wingsails used to propel marine or terrestrial vessels, generally require to be capable of operation on port or starboard tack. This may be achieved by having complex folding arrangements of asymmetrical aerofoils the camber of which can be reversed by extension and folding of separate sections.
• the present invention is preferably utilised in wingsail systems that comprise a plurality of symmetrical aerofoil sections which can be angled with respect to one another to give cambered and slotted configurations and also self-setting configurations.
• Figure 1 is a schematic outline of an aerofoil according to the invention.
• Figure 2 is a schematic outline of a slotted wing assembly according to the invention.
• Figure 3 is a schematic outline of the wing of Figure 2 in a cambered configuration
• Figure 4 is a schematic outline superimposing the aerofoil sections of Figures 1, 2 and 3.
• the aerofoil shown has a chord length C and a maximum thickness of 0.291 C- with a leading edge radius of 6.489% of C.
• the overall shape follows that of the table of ordinates Table 1.
• the trailing element 3 shown in Figure 2 has a leading edge radius of 10.625% of its chord with a maximum thickness of 30.42% of its chord occurring at approximately 25% along the chord from the leading edge.
• the table of ordinates for the profile is given in Table 3.
• the aerofoil of Figure 1 may be regarded as a basic member of the preferred family of wingsail profiles. It comprises a relatively high leading edge radius when compared with aerofoils for aircraft, and thickens relatively rapidly to reach a 90% thickness zone that commences at about 20% of the chord and continues to about 40% of the chord, the aerofoil then narrowing into the trailing portion and curvature undergoing an inflexion.
• the second member of the family, aerofoil 2 of Figure 2 has a leading edge curvature that matches with the leading edge of the aerofoil of Figure 1, but is modified into a more abrupt trailing edge with almost no curvature from about two thirds of the way along the chord.
• the trailing edges are flat, in a more general case they may only be substantially flat and may have a slight curve or a slight inflexion. If reference is made to Figure 3 it will be observed that the trailing edge of the aerofoil 2 is provided with a slat 4 which acts to extend the trailing edge. In practice the trailing edge of the leading section may be truncated for the pivot mounting of the slat.
• the 90% thickness zone extends over a range of approximately 17% to 33% of the chord, most preferably in the range of 23% to 27% of the chord.
• the 90% thickness zone may commence in the range of 10% to 25% of the chord and be contained within the range of 10% to 55% of the chord from the leading edge, most preferably being within the range 17% to 45%.
• the maximum thickness may lie in the range of 20% to 40% but preferably is in the range of 25% to 30% of the chord.
• the leading edge radius is preferably in the range of 5.5% to 7.5% of the chord, but may be in the range 5.5% to 12%.
• the leading section (disregarding any flaps or slats) preferably has a shortened tail section with no inflexion so that the 90% thickness zone starts at about 19% to 23% of the chord.
• the trailing section of compound wings preferably has a leading edge radius that lies in the upper end of the range as defined for single aerofoils. Table 4 gives the approximate preferred ranges in terms of chord % for the three wingsail aerofoils described above. In compound wingsails it is possible to modify the curvature at the end that is adjacent another aerofoil, or to modify the overall curvature and compensate in the other aerofoil.
• Thickness Max. Thickness LE range length position % radius
• Figures 2 and 3 represent an especially preferred compound wingsail according to the invention.
• the trailing element 3 is mounted on a boom or booms pivotable about an axis 5 on the chord of the leading element 2.
• Each of the main aerofoils 2 and 3 preferably have the same maximum thickness (although differing thickness is possible, the trailing section preferably having the larger thickness) of .170 C TQT where C TO ⁇ is the total chord defined from the leading edge of the leading section to the trailing edge of the trailing section with the aerofoils aligned as in Figure 2.
• the leading element is shorter having a chord of .432C TO ⁇ an ⁇ the trailing section having a chord of .560C Q r.
• the slat 4 has a length .076C TQT and in the fully cambered position shown in Figure 3 is deflected through 25° with an adjustment facility of 5.5°.
• the preferred fully cambered configuration deflects the trailing section through 42° with the pivot of the trailing section positioned about 2/3 of the way along the leading section: in Figure 3 it is .278c TOT from the leading edge.
• a main upright pivot axis for the compound wing passes through the zone of the centre of pressure of the leading element 2 and the wing is trimmed to the wind by an auxiliary aerofoil, normally a tail vane, which also has an aerofoil section in accordance with the invention.
• a tail vane is usually a single aerofoil and does not have slats or an adjacent aerofoil it preferably has the leading and trailing profiles shown in Figure 1.

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• Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Sustainable Development (AREA)
• Sustainable Energy (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• Ocean & Marine Engineering (AREA)
• Wind Motors (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=10584188

Family Applications (1)

Country Status (8)

Cited By (1)

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Citations (2)

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• 1985
  • 1985-08-22 GB GB858521085A patent/GB8521085D0/en active Pending
• 1986
  • 1986-08-22 JP JP61504504A patent/JPS63501355A/ja active Pending
  • 1986-08-22 WO PCT/GB1986/000502 patent/WO1987001088A1/en active IP Right Grant
  • 1986-08-22 EP EP86904896A patent/EP0259344B1/en not_active Expired - Lifetime
  • 1986-08-22 DE DE8686904896T patent/DE3676702D1/de not_active Expired - Fee Related
  • 1986-08-22 AU AU62808/86A patent/AU597904B2/en not_active Ceased
• 1987
  • 1987-04-21 DK DK202087A patent/DK202087A/da not_active Application Discontinuation
• 1988
  • 1988-02-22 FI FI880826A patent/FI880826A0/fi not_active IP Right Cessation

Patent Citations (2)

Non-Patent Citations (1)

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