EP0259344B1 - Aerofoil - Google Patents
Aerofoil Download PDFInfo
- Publication number
- EP0259344B1 EP0259344B1 EP86904896A EP86904896A EP0259344B1 EP 0259344 B1 EP0259344 B1 EP 0259344B1 EP 86904896 A EP86904896 A EP 86904896A EP 86904896 A EP86904896 A EP 86904896A EP 0259344 B1 EP0259344 B1 EP 0259344B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- aerofoil
- leading
- chord
- trailing
- compound
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 150000001875 compounds Chemical class 0.000 claims abstract description 19
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
Images
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.
- European patent specification 61291 describes a compound wingsail assembly that comprises a plurality of symmetrical aerofoil sections which can be angled with respect to one another to give cambered and slotted configurations. In that specification a trailing aerofoil is mounted for pivoting movement about a point on the chord of a leading aerofoil so that it can pivot from a coplanar position to angularly displaced positions.
- the present invention relates to the particular profiles of aerofoil sections in a compound wingsail assembly of the type described in EP 61291.
- a compound wingsail assembly comprising a leading symmetrical aerofoil and a trailing symmetrical aerofoil mounted for pivoting movement about a point on the chord of the leading aerofoil from an aligned position coplanar with the leading aerofoil to positions angularly displaced from the aligned position, characterised in that the aerofoils have a thickness in the range of one to two fifths of their respective chord lengths, the leading aerofoil has a zone in which its thickness is at least 90% of its maximum thickness extending over substantially 30% of its chord length located in the range of 20% to 55% along its chord from its leading edge and the trailing aerofoil has a zone in which its thickness is at least 90% of its maximum thickness extending over substantially 20% of its chord length located in the range of 10% to 35% along the chord from its leading edge.
- 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 leading element 2 has a leading edge radius of 8.777% of its chord and a maximum thickness of 39.32% of its chord occurring at approximately 35% along the chord.
- the table of ordinates for this aerofoil shape is given in Table 2.
- 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.
- the trailing edge of the aerofoil 2 is provided with a slat 4 which acts to extend the trailing edge.
- the trailing edge of the leading section may be truncated for the pivot mounting of the slat.
- the curvatures of the leading parts of aerofoils 1 and 2 match, the positions of maximum thickness and leading edge radius in percentages deviate because of the differing lengths of the trailing sections.
- the trailing edge modification is shown in dotted outline.
- the trailing areofoil 3 of Figures 2 and 3 has a fatter leading edge portion, but from the point of maximum thickness matches with the trailing section of the aerofoil of Figure 1.
- the relatively rapid rise to maximum thickness makes the point of maximum thickness occur relatively sooner along the chord.
- Figure 4 the leading edge modification for a trailing aerofoil is shown in chain dot outline.
- 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 modifiy the curvature at the end that is adjacent another aerofoil, or to modify the overall curvature and compensate in the other aerofoil.
- 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 largerthickness) of .170 C TOT where C TOT 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 r or and the trailing section having a chord of .560C TOT with a space of .008C TOT between the aerofoils.
- the slat 4 has a length .076C TOT 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 is 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.
Landscapes
- 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)
Abstract
Description
- 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. European patent specification 61291 describes a compound wingsail assembly that comprises a plurality of symmetrical aerofoil sections which can be angled with respect to one another to give cambered and slotted configurations. In that specification a trailing aerofoil is mounted for pivoting movement about a point on the chord of a leading aerofoil so that it can pivot from a coplanar position to angularly displaced positions.
- The present invention relates to the particular profiles of aerofoil sections in a compound wingsail assembly of the type described in EP 61291.
- According to the invention there is provided a compound wingsail assembly comprising a leading symmetrical aerofoil and a trailing symmetrical aerofoil mounted for pivoting movement about a point on the chord of the leading aerofoil from an aligned position coplanar with the leading aerofoil to positions angularly displaced from the aligned position, characterised in that the aerofoils have a thickness in the range of one to two fifths of their respective chord lengths, the leading aerofoil has a zone in which its thickness is at least 90% of its maximum thickness extending over substantially 30% of its chord length located in the range of 20% to 55% along its chord from its leading edge and the trailing aerofoil has a zone in which its thickness is at least 90% of its maximum thickness extending over substantially 20% of its chord length located in the range of 10% to 35% along the chord from its leading edge.
- The invention is now described by way of example with reference to the accompanying drawings in which:
- 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; and
- Figure 4 is a schematic outline superimposing the aerofoil sections of Figures 1, 2 and 3.
-
- It will be seen from Table 1 that the maximum thickness occurs at approximately 30% along the total chord.
-
-
- 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. In the drawing 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 theaerofoil 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. Although the curvatures of the leading parts ofaerofoils - The trailing
areofoil 3 of Figures 2 and 3 has a fatter leading edge portion, but from the point of maximum thickness matches with the trailing section of the aerofoil of Figure 1. The relatively rapid rise to maximum thickness makes the point of maximum thickness occur relatively sooner along the chord. In Figure 4 the leading edge modification for a trailing aerofoil is shown in chain dot outline. - For a single aerofoil, 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%.
- In compound wings 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.
-
- 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 leadingelement 2. Each of themain aerofoils - 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. As the 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.
Claims (10)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB8521085 | 1985-08-22 | ||
GB858521085A GB8521085D0 (en) | 1985-08-22 | 1985-08-22 | Aerofoil |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0259344A1 EP0259344A1 (en) | 1988-03-16 |
EP0259344B1 true EP0259344B1 (en) | 1990-12-27 |
Family
ID=10584188
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP86904896A Expired - Lifetime EP0259344B1 (en) | 1985-08-22 | 1986-08-22 | Aerofoil |
Country Status (8)
Country | Link |
---|---|
EP (1) | EP0259344B1 (en) |
JP (1) | JPS63501355A (en) |
AU (1) | AU597904B2 (en) |
DE (1) | DE3676702D1 (en) |
DK (1) | DK202087A (en) |
FI (1) | FI880826A0 (en) |
GB (1) | GB8521085D0 (en) |
WO (1) | WO1987001088A1 (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR940000045B1 (en) * | 1985-05-02 | 1994-01-05 | 쟝 마가렛 워커 | Wingsail system |
GB9401744D0 (en) * | 1994-01-31 | 1994-03-23 | Walker John G | Monoplane wingsail |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU554405B2 (en) * | 1981-03-19 | 1986-08-21 | Walker Wingsail Systems Ltd. | Sail of hinged aerofoil sections |
US4519746A (en) * | 1981-07-24 | 1985-05-28 | United Technologies Corporation | Airfoil blade |
US4432298A (en) * | 1981-10-01 | 1984-02-21 | Cudmore Patrick J | Hydrofoil sailing craft |
JPS59184096A (en) * | 1983-03-31 | 1984-10-19 | Mitsui Eng & Shipbuild Co Ltd | Composite sail |
-
1985
- 1985-08-22 GB GB858521085A patent/GB8521085D0/en active Pending
-
1986
- 1986-08-22 JP JP61504504A patent/JPS63501355A/en 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/en 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/en not_active Application Discontinuation
-
1988
- 1988-02-22 FI FI880826A patent/FI880826A0/en not_active IP Right Cessation
Non-Patent Citations (1)
Title |
---|
Abbott, Von Doenhoff: "Theory of wing sections ", Dover Publications, New York (US), pages 326, 327 see page 326, Naca 0021, columns 1,2 page 327, NACA 0024, columns 1,2, last but one line * |
Also Published As
Publication number | Publication date |
---|---|
JPS63501355A (en) | 1988-05-26 |
GB8521085D0 (en) | 1985-09-25 |
AU597904B2 (en) | 1990-06-14 |
DE3676702D1 (en) | 1991-02-07 |
AU6280886A (en) | 1987-03-10 |
DK202087D0 (en) | 1987-04-21 |
WO1987001088A1 (en) | 1987-02-26 |
FI880826A (en) | 1988-02-22 |
DK202087A (en) | 1987-05-20 |
EP0259344A1 (en) | 1988-03-16 |
FI880826A0 (en) | 1988-02-22 |
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