U.S. patent application number 13/552290 was filed with the patent office on 2013-01-17 for adjusting rigid foil spar system.
The applicant listed for this patent is John Garrison Hoyt. Invention is credited to John Garrison Hoyt.
Application Number | 20130014683 13/552290 |
Document ID | / |
Family ID | 47518175 |
Filed Date | 2013-01-17 |
United States Patent
Application |
20130014683 |
Kind Code |
A1 |
Hoyt; John Garrison |
January 17, 2013 |
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 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. Further, a void within the foil
is filled with a lighter than air gas to assist in countering
heeling moment to allow the boat to be driven without the loss of
upwind pointing performance and without the loss of power and also
allowing the boat to be driven to windward more efficiently with a
minimum heel angle.
Inventors: |
Hoyt; John Garrison;
(Portsmouth, RI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hoyt; John Garrison |
Portsmouth |
RI |
US |
|
|
Family ID: |
47518175 |
Appl. No.: |
13/552290 |
Filed: |
July 18, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13180622 |
Jul 12, 2011 |
|
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13552290 |
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Current U.S.
Class: |
114/102.13 ;
114/102.18; 114/102.29 |
Current CPC
Class: |
B63H 9/0635 20200201;
B63B 2035/009 20130101; B63H 9/061 20200201 |
Class at
Publication: |
114/102.13 ;
114/102.29; 114/102.18 |
International
Class: |
B63H 9/06 20060101
B63H009/06; B63H 9/04 20060101 B63H009/04; B63H 9/10 20060101
B63H009/10 |
Claims
1. A rigid foil sail comprising: a free-standing rotatable mast; at
least one rigid foil affixed to said mast, said foil having a void
therein; and a lighter than air gas, disposed within and filling
said void within said rigid foil.
2. The rigid foil sail of claim 1, wherein said lighter than air
gas is helium.
3. A rigid foil sail comprising: a free-standing rotatable mast; a
leading edge having a symmetrical airfoil shape containing a void
therein and supported by said mast; a trailing edge flap also
containing a void therein rotatably supported adjacent a rear edge
of said leading edge; and a lighter than air gas, disposed within
and filling said void within said leading edge and said void within
said trailing edge flap.
4. The rigid foil sail of claim 3, wherein said lighter than air
gas is helium.
5. A rigid foil sail comprising: a free-standing rotatable mast; a
leading edge having a symmetrical airfoil shape containing a void
therein and 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 also containing a void therein rotatably supported between
said lower control tray and said at least one additional control
tray adjacent a rear edge of said leading edge; at least one upper
trailing edge flap also containing a void therein rotatably
supported above said additional control tray adjacent a rear edge
of said leading edge; and a lighter than air gas, disposed within
and filling said void within said leading edge, said void within
said upper trailing edge flap and said void within said upper
trailing edge flap.
6. The rigid foil sail of claim 5, wherein said lighter than air
gas is helium.
7. The rigid foil sail of claim 5, further comprising: a main sheet
for controlling rotation of said mast.
8. The rigid foil sail of claim 7, wherein said main sheet is
affixed to a bottom surface of said lower control tray proximate a
rear end thereof.
9. The rigid foil sail of claim 5, 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.
10. The rigid foil sail of claim 9 wherein said lower control and
upper control are operated independent of one another.
11. The rigid foil sail of claim 9, wherein said upper control and
lower control are run through fair leads to a single control
location.
12. The rigid foil sail of claim 5, 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.
13. The rigid foil sail of claim 5, wherein a portion of said
leading edge extends forward of said mast thereby creating a
semi-balanced sail.
14. The rigid foil sail of claim 5, 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.
15. The rigid foil sail of claim 5, wherein said leading edge,
lower trailing edge flap and at least one upper trailing edge flap
are formed of rigid material.
16. The rigid foil sail of claim 5, 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.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation in Part Application of
U.S. patent application Ser. No. 13/180,633, filed Jul. 11, 2011,
which is related to and claims priority from earlier filed U.S.
Provisional Patent Application No. 61/483,996, filed May 9, 2011,
the contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates generally to rigid foil sails
for boats. More specifically, the present invention relates to a
rigid foil sail system for boats that has independently
controllable sections that allow optimum control over the lift
force generated by the soil in varying wind conditions and
directions.
[0003] Although the appearance of the conventional sail is quite
different from that of an aircraft wing, its function in generating
a positive force is based on the same aerodynamic principles as
those applied to a wing. The sail, however, is considerably the
less efficient foil of the two partly because the sail utilizes a
single surface air foil as opposed to the more efficient double
surface air foil of the wing. Another factor that reduces the
efficiency of a conventional sail is that its external bracing,
mast and rigging disturb the flow of air around its surface,
resulting in an energy loss to turbulence and drag.
[0004] Despite its much greater efficiency, a standard wing does
not make a good sail when mounted in a vertical position so that
the lift that it generates can be used as thrust to drive a boat or
vehicle. This is because of the shape of the wing and the fact that
in use wind is directed against both sides of the wing at various
angles. In this regard, it should be appreciated as the wind
approaches a conventional wing at a positive angle of attack from
what was its bottom surface, the wing will produce good results and
significantly improve the efficiency over the conventional sail.
But when the wind is directed from a direction where the same
impinges on the upper surface of a conventional wing, its
efficiency drops well below that of the sail.
[0005] Consequently, it follows that in order to provide an all
around efficient wing for "sailing purposes", it would be desirable
to design the same to have a changeable air foil, or variable
camber. This would enable the wing to have the high efficiency
referred to with the wind approaching the same from either side. It
should be noted that the provision of a variable camber wing for a
vessel has been provided in the past. A close review of the prior
art in this area reveals that the design and construction of such
variable camber wings have been complex and in fact impractical
when considered on a commercial production basis. However, because
of the increases in efficiency achieved by such a variable camber
wing, it is highly desirable that a relatively simple and easy to
use design be provided that lends itself to commercial
production.
[0006] Such rigid sail designs have been created for use on
specialty boats usually intended for racing events as is known,
with rigid sails commonly called wing sails on account of their
sectional profile duplicating basically that of an airplane wing.
It has been observed that this type of sail can improve the
aerodynamic qualities of a sailboat and afford higher cruising
speeds to be attained and maintained. It has, however, a fault in
that it is difficult to handle and troublesome to lower.
[0007] This prior approach, while substantially achieving its
objective, still has some shortcomings as pointed out below. In the
first place, sail area cannot be reduced, or the sail be reefed
down, in a continuous fashion. Further, the airfoil shape of the
sail can only be achieved effectively with the various segments
fully extended vertically. Further shortcomings originate from the
excessively complicated construction of the sail, which is also the
cause for high cost and low reliability. Finally, such sail
arrangements are generally heavy. Should the vessel overturn the
prior art rigid sails risk filling with water, compromising both
the floatation of the sail and the boat.
[0008] There is therefore a need for a rigid foil sail that has
adjustable camber that is also capable of being detuned to allow
its use in heavier wind conditions. There is a further need for a
self-supporting rigid foil sail that includes adjustable camber to
increase or decrease the power generated by the foil shape. The is
still a further need for a rigid foil sail that includes at least
two adjustable trailing sections to allow independent adjustment of
the sail camber.
BRIEF SUMMARY OF THE INVENTION
[0009] In this regard, the present invention provides for a three
dimensional rigid foil sail design. As such, the general purpose of
the present invention, which will be described subsequently in
greater detail, is to provide at least a three part 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.
[0010] The design of the rigid foil sail of the present invention
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 trimming the lower trailing flap for
optimum performance and simultaneously trimming the upper trailing
flap neutral or even to leeward to create an opposing force that
will counter the heeling moment of the sail allowing the boat to be
driven to windward more efficiently with a minimum heel angle.
[0011] Therefore, it is an object of the present invention to
provide a rigid foil sail that has adjustable camber that is also
capable of being detuned to allow its use in heavier wind
conditions. It is a further object of the present invention to
provide a self-supporting rigid foil sail that includes adjustable
camber to increase or decrease the power generated by the foil
shape. It is still a further object of the present invention to
provide a rigid foil sail that includes at least two adjustable
trailing sections to allow independent adjustment of the sail
camber in a manner that better balances the boat without
compromising upwind pointing performance.
[0012] These together with other objects of the invention, along
with various features of novelty which characterize the invention,
are pointed out with particularity in the claims annexed hereto and
forming a part of this disclosure. For a better understanding of
the invention, its operating advantages and the specific objects
attained by its uses, reference should be had to the accompanying
drawings and descriptive matter in which there is illustrated a
preferred embodiment of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] In the drawings which illustrate the best mode presently
contemplated for carrying out the present invention:
[0014] FIG. 1 is a perspective view of a boat with a rigid foil
sail in accordance with the present disclosure;
[0015] FIG. 2 is an exploded view of the rigid foil sail of the
present disclosure;
[0016] FIG. 3 is a diagrammatic plan view of the rigid foil sail
depicting the various positions of the trailing flaps;
[0017] FIG. 4 depicts the relative position of the rigid foil sail
when sailing up wind and the forces that result;
[0018] FIG. 5 depicts the rigid foil sail in a downwind sailing
configuration;
[0019] FIG. 6 depicts the rigid foil sail in an upwind sailing
configuration;
[0020] FIG. 7 is a perspective view of an alternate boat
arrangement with a rigid foil sail in accordance with the present
disclosure; and
[0021] FIG. 8 is a perspective view of a second alternate boat
arrangement with a rigid foil sail in accordance with the present
disclosure
DETAILED DESCRIPTION OF THE INVENTION
[0022] Now referring to the drawings, the three dimensional rigid
foil sail design is generally shown and illustrated at 10. As can
be seen at FIG. 1, the present invention generally provides at
least a three part rigid foil sail 10 having a full length vertical
leading edge 12 whose trim angle/angle of attack is controlled by
the main sheet and at least two trailing edge flaps 14, 16 attached
rearwardly of the leading edge 12, each of which can be
independently trimmed from a convenient deck level control tray to
achieve easily adjustable camber. Further, the rigid foil sail 10
can be seen to include control trays 18 at the bottom of each of
the trailing edge flaps 14 and 16 that allow independent adjustment
of the camber for each section of the rigid foil sail 10
independently of one another.
[0023] It can be seen from FIG. 1 that the rigid foil sad 10
provides a squared geometry as compared to the prior art sails.
Such squared geometry can be achieved due to the rigid nature of
the construction of the rigid foil sail. Such a squared geometry is
more efficient in that the sail does not need to be triangular to
get the necessary support in order to maintain trim. As can best be
seen at FIG. 2, the entire rigid foil sail is received and
supported by a rotating mast 20. It should be noted that the mast
20 may be rigidly affixed to the leading edge 12 such that they
rotate as a single unit or the leading edge 12 may rotate about the
mast 20. The mast 20 serves to support the entire rigid foil sail
10 in a freestanding, aerodynamically clean manner. The
freestanding mast 20 arrangement eliminates the needs for side,
fore and aft stays as were required in the prior art thereby
reducing the aerodynamic drag typically generated in such
conventional sailing rigs. To further increase the efficiency of
the rigid foil sail, a top winglet 28 can be seen. Such a winglet
28 prevents the formation of a wing tip vortex as the high pressure
(windward) air spills across the top of the foil to the lower
pressure (leeward) side of the rigid foil. In this manner, the
winglet serves to increase the efficiency of the upper portion of
the rig thereby allowing a reduction in overall size of the rigid
foil sail 10.
[0024] The mast 20 can be seen to support the leading edge 12 of
the rigid foil sail.
[0025] The leading edge 12 is preferably a symmetrical two sided
airfoil. The mast 20 can be seen positioned slightly aft of the
leading edge 12. This creates a semi-balanced rig arrangement that
allows a forward positioning of the rigid foil rig 10 as well as a
reduction in the dynamic forces generated when the sail changes
sides of the boat during a maneuver such as a tack or jibe. This
forward position of the rig means that jibing can be accomplished
with no danger of the boom hitting the skipper during the jibe as
was a risk in the prior art with full extension booms over the
length of the cockpit. Still further, due to the shortened overall
length of the rig and its balanced nature, the rig automatically
weathercocks (turns its leading edge into the wind) when at rest
allowing the boat to be docked and stored with the rig remaining in
the boat. This is to be contrasted with prior art rigid foil
arrangements that require removal of the rig each time the boat is
docked.
[0026] The rear of the leading edge 12 includes recesses 22 that in
turn receive the forward ends of the trailing edge flaps 14,16 in a
smooth and aerodynamically efficient manner while also allowing the
trailing edge flaps 14,16 the freedom to rotate as will be further
discussed below. The trailing edge flaps are received and supported
about a pivot or shaft 14 that firmly retains the trailing edge
flaps 14, 16 yet allows them rotational movement.
[0027] As can best be seen in FIG. 3, the trailing edge flaps 14,
16 have a rotational range of motion that allows the trailing edge
flaps 14, 16 to be adjusted relative to the leading edge 12 from a
neutral position as depicted at 26a to a positive camber position
26b relative to the prevailing wind direction and a negative camber
direction 26c relative to the wind direction. This allows the lift
force of the rigid foil sail to be fully adjusted from a maximum
power position having a high positive camber to a neutral power
position to still further a negative lift position having negative
camber. Further, the sail components are formed from a rigid,
moldable material that is highly durable creating a permanent sail
that never needs replacement. The components may be formed from any
molded material known in the boat building art. Most preferably the
components are formed from a carbon fiber composite material. These
molded components also are hollow thereby trapping air pockets
therein which in turn provides positive floatation should the boat
capsize. This positive flotation in turn prevents the rig from
fully inverting in the water in the event of capsize. Further the
interior volume created by the wing sections also opens up the
possibility of inflating each foil with helium or other lighter
than air gas. This arrangement provides an automatic righting
moment that is in constant operation because the intrinsic upward
force of the gas inflation is constantly try to return the rig to
the favorable vertical position.
[0028] By employing helium (or any other suitable lighter than air
gas) to fill the volume created by the shape of a wing sail, the
interior volume can establish an automatic righting moment to
resist heeling since the helium filled sail is constantly trying to
lift the sail back up to the vertical. The recent developments in
rigid foil sails open up new possibilities in this regard. Instead
of being a one dimensional cloth sail, the rigid foil sail adds the
dimension of depth, which opens up the possibility of filling the
interior volume of the rigid foil sail with helium or lighter than
air gas, thereby gaining an automatic righting moment without the
penalty of extra ballast weight. In fact, the lift of a helium
filled rigid foil sail actually reduces the overall weight of the
sail craft, while simultaneously adding heel resistant stability.
The benefits can be summarized as follows: The lighter than air
quality of helium reduces the overall weight of the wing, and
thereby reduces the overall weight of the sail craft, which means
it will float higher with less drag resistance. The Reduced weight
of the helium filled rigid foil sail makes the rig lighter thereby
making easier the stepping and unstepping of the rig. The upward
lift created by a helium filled rigid foil sail counters the
negative effects of heeling, thus creating a more stable craft. The
lighter than air quality of the helium filled sail will remove the
dangerous possibility of rig inversion in the case of capsize.
Finally, should the mast break, the helium filled wing becomes a
separate floating unit that adds safety.
[0029] Returning now to FIG. 1, the rigid foil sail 10 can be
easily controlled using only three lines that are routed through
fairleads to a convenient position that is accessible by the
skipper of the boat. The first line is the traditional main sheet
30. The main sheet 30 controls the overall rotation of the entire
rigid foil sail 10 relative to the boat as it rotates around the
mast 20. Adjustment of the main sheet 30 serves to adjust the angle
of attack of the entire rigid foil sail 10 relative to the wind
direction. An upper control line 32 serves to control the camber of
the upper trailing flap 14 relative to the leading edge 12 as
between a neutral position 26a, a positive camber position 26b and
a negative camber position 26c to increase, decrease or generate
negative lift respectively. The upper control line preferably runs
from both the port and starboard sides of the upper trailing flap
14, through the upper control tray 18 and then through fairleads to
allow symmetrical control of the upper trailing flap depending on
which jibe or tack the boat is travelling. Similarly, a lower
control line 34 serves to control the camber of the lower trailing
flap 16 relative to the leading edge 12 as between a neutral
position 26a, a positive camber position 26b and a negative camber
position 26c to increase, decrease or generate negative lift
respectively. The lower control line 34 preferably runs from both
the port and starboard sides of the lower trailing flap 16, to the
lower control tray 18 and then through fairleads to allow
symmetrical control of the upper trailing flap depending on which
jibe or tack the boat is travelling.
[0030] Turning to FIG. 4 the arrangement of the rigid foil sail 10
of the present invention allows a great deal of flexibility over
the power generated by the sail. This allows the skipper of the
boat to effectively reef the boat by depowering the sail without
ever leaving his seated position at the helm. As can be
appreciated, the power of the sail can be adjusted without ever
adjusting the main sheet 30 or changing the angle of attack of the
sail. In FIG. 4, the foil is shown with the same angle of attack
relative to the wind direction. However, position 26a depicts a
neutral camber generating little to no lift, position 26b shows
positive camber resulting in greater positive lift forces and in
turn heeling moments applied to the boat and position 26c shows
negative camber with a resulting negative lift and a reduction in
heeling forces. In this manner, a skipper can balance the
positioning of the upper and lower trailing flaps 14, 16 to balance
the pointing ability of the boat, the power generated by the rigid
foil sail 10 and the overall heeling force on the boat. In this
manner, the rigid foil sail 10 can be de-powered without altering
the trim of the mainsheet 30. Simply easing the control line 32 of
the upper flap removes the camber and thus the heeling force of the
upper flap. This means that the lower rear flap can continue to
provide drive and pointing ability without the loss of power
incurred by the normal process of luffing the sail to counter
heeling. Similarly, the camber created by trimming the lower flap
to windward provides forward drive plus a substantial heeling
force. By trimming the upper flap to the opposite side of the upper
tray control pan& an opposing lift force is created that will
have the effect of countering the heeling moment created by the
camber of the lower flap. This means a sailboat can be driven to
windward more efficiently-with minimum heeling. One skilled in the
art will also appreciate that more precise "twist" control is
obtained by completely separating upper sail camber from lower sail
camber, enabling adjustment for greater wind velocity aloft.
Previously these adjustments required the adjustment of a boom
yang, a Cunningham, a down haul, an outhaul and backstay tension.
Notably, the present invention eliminates the need for all of the
above noted controls as well as halyards, running rigging and
battens.
[0031] FIGS. 5 and 6 are provided to show additional context for
the present invention wherein FIG. 5 depicts the rigid foil sail
positioned for downwind sailing of the boat and FIG. 6 depicts a
reaching configuration.
[0032] FIGS. 7 and 8 depict the present invention in the context of
a multi hulled sailing vessel such as a catamaran. In such an
arrangement there may be employed a single rigid foil sail
arrangement stepped on a forward structural element spanning the
hulls or may be duplicated such that there are two rigid foil sails
positioned and supported above each of the two hulls of the
boat.
[0033] One skilled in the art should appreciate that the structures
shown herein can be duplicated in a vertical fashion to employ two,
three or more trailing edge flaps and respective controls arranged
in a vertical fashion. Further, such a rigid foil sail may be
placed in duplication forward and rear of one another or side to
side relative to one another without departing from the spirit and
scope of the invention.
[0034] It can therefore be seen that the present invention provides
a rigid foil sail that has adjustable camber that is also capable
of being detuned to allow its use in heavier wind conditions.
Further the present invention provides a self-supporting rigid foil
sail that includes adjustable camber to increase or decrease the
power generated by the foil shape and includes at least two
adjustable trailing sections to allow independent adjustment of the
sail camber in a manner that better balances the boat without
compromising upwind pointing performance. For these reasons, the
instant invention is believed to represent a significant
advancement in the art, which has substantial commercial merit.
[0035] While there is shown and described herein certain specific
structure embodying the invention, it will be manifest to those
skilled in the art that various modifications and rearrangements of
the parts may be made without departing from the spirit and scope
of the underlying inventive concept and that the same is not
limited to the particular forms herein shown and described except
insofar as indicated by the scope of the appended claims.
* * * * *