AEROFOIL DESIGN BLADE WITH WINGLET FOR CEILING FAN
FIELD OF INVENTION:
[001] The present subject matter described herein, relates to ceiling fan, and, in
particular, to blade of ceiling fan with aerofoil shaped profile with winglet at top.
More particularly, the aerofoil shaped blade has variable twist angle along length
of the blade for higher air delivery.
BACKGROUND AND PRIOR ART:
[002] Generally, ceiling fans are powered by electric motors for circulating air.
The ceiling fan has a motor within housing, i.e., hub mounted to a down rod that
rotates a plurality of fan blades connected with the motor about the axis of the
down rod. Their blades have traditionally been flat and oriented at an incline or
pitch to present an angle of attack to the air mass in which they rotate. This causes
air to be driven downwardly.
[003] When a fan blade that extends generally radially from its axis of rotation is
rotated, its tip end travels in a far longer path of travel than does its root end for
any given time. Thus, its tip end travels much faster than its root end. To balance
the load of wind resistance along the blades, and the air flow generated by their
movement, fan blades have been designed with an angle of attack that diminishes
towards the tip.
[004] The ceiling fan or axial fan is suspended above the ground, the ceiling fan
sucks air radially. This means that the air flow is not fully perpendicular to the fan
blades. Also wind causes variations in the air flow direction relative to the fan
blade. This variation in air flow direction relative to the fan blades causes a non
optimal functioning of the fan. It is known to use twisted fan blades to optimize
the aerodynamic angle of attack of the fan blade. However, due to wind and to
other particular conditions that can create turbulence at the outboard edge of the
blade, only twisting of the fan blade does not provide an optimal solution for the
outboard edge zone of a fan blade. These conditions could cause such an air flow
direction relative to the tip of the fan blade, that stall can occur in the outboard

edge zone resulting in lower performance, lower efficiency of the fan blade and
causing extra noise.
[005] Technical problem in the conventional fan blade is that high air pressure is
developed near the tip of the blade which creates vortex and leads to noise
generation in the fan blade. Further, leading edge and trailing edge of the fan
blade are on same profile which creates less air pressure in down ward direction
for air delivery. Therefore, the conventional fan does not provide higher air
delivery at 250-300 RPM. Accordingly, the conventional fan has low efficiency.
[006] Existing conventional ceiling fans comes with metal blade or plastic blade
with bend or curved shape which gives optimum air delivery as per the shape of
blade. There are some plastic blades also available in ceiling fan with flat shape
and uniform thickness that also gives similar air delivery. There is need to develop
a ceiling fan which gives the maximum air delivery with less noise with very
variable thickness as compared to the conventional ceiling fan.
OBJECTS OF THE INVENTION:
[007] The principal objective of the present invention is to provide an aerofoil
shaped blade with winglet for ceiling fan.
[001] Another object of the present invention is to provide aerofoil shaped blade
with winglet for higher air spread with low noise.
[002] Another object of the present invention is to provide a ceiling fan with
higher air delivery in sweep size of 1350mm.
[008] Another object of the present invention is to provide a ceiling fan having
maximum air delivery about 300 CMM at 300RPM.
[009] Another object of the present invention is to provide blade having winglet
with variable thickness for increasing the air delivery.
[0010] Yet another object of present invention is to provide an aerofoil shaped
blade with optimized lift angle and variable twist angle for higher air delivery.
[0011] Yet another object of present invention is to develop an aerofoil shaped
blade with curved profile and with length in range 610-620 mm.

[0012] Yet another object of the present invention is to provide an aerofoil shaped
blade with a winglet at tip end to reduce vortex.
[0013] Yet another object of the present invention is to provide a simple and cost
effective ceiling fan with aerofoil shaped blade for higher air delivery and less
noise.
SUMMARY OF THE INVENTION:
[0014] The present subject matter relates to a ceiling fan with aerofoil shaped
blade with winglet for higher air delivery at fan sweep size 1350mm with less
noise. The present aerofoil shaped blade with winglet has curved profile and
variable thickness to provide higher air delivery and less noise. The aerofoil
shaped blade with winglet has twist angle is in range of 26o to 4o which decreases
non-uniformly from rotor end to tip end of the blade. Further, a winglet is
provided at the tip end to reduce formation of vortex due to high air pressure at tip
end. The winglet is provided in upward direction from the horizontal axis of the
fan blade. The winglet guides smooth passage of the high pressure air in upward
direction to reduce air cutting noise. The aerofoil shaped blade has leading edge
and trailing edge. The leading edge has thickness in range 11.2mm to 6.2mm from
rotor end to the tip end. On the other side of the aerofoil shaped blade, the trailing
edge has thickness in the range 2.5mm to 1.8mm. Variation in the thickness of the
edges permits formation of high air pressure under the fan blade. The aerofoil
shaped blade has lift angle of 3o with reference to horizontal axis of the blade.
Due to the curved profile, aerofoil shaped profile, and variable thickness with
non-uniform optimized twist angle provides higher air delivery at fan sweep size
of 1350mm.
[0015] In order to further understand the characteristics and technical contents of
the present subject matter, a description relating thereto will be made with
reference to the accompanying drawings. However, the drawings are illustrative
only but not used to limit scope of the present subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS

[0016] It is to be noted, however, that the appended drawings illustrate only
typical embodiments of the present subject matter and are therefore not to be
considered for limiting of its scope, for the invention may admit to other equally
effective embodiments. The detailed description is described with reference to the
accompanying figures. In the figures, the left-most digit(s) of a reference number
identifies the figure in which the reference number first appears. The same
numbers are used throughout the figures to reference like features and
components. Some embodiments of system or methods in accordance with
embodiments of the present subject matter are now described, by way of example,
and with reference to the accompanying figures, in which:
[0017] Fig. 1 illustrates ceiling fan with aerofoil shaped blade, in accordance with
an embodiment of the present subject matter;
[0018] Fig. 2 illustrates lift angle of the aerofoil shaped blade with winglet, in
accordance with the present subject matter;
[0019] Fig. 3 illustrates variable twist angle, variable thickness, variable depth
along length of the of the aerofoil shaped blade with winglet, in accordance with
an embodiment of the present subject matter;
[0020] Fig. 4 illustrates twist angle with various cross section of the aerofoil
shaped blade as shown in the figure 3, in accordance with an embodiment of the
present subject matter; and
[0021] Fig. 5 illustrates shape and structure of the aerofoil shaped blade with
winglet, in accordance with an embodiment of the present subject matter.
[0022] The figures depict embodiments of the present subject matter for the
purposes of illustration only. A person skilled in the art will easily recognize from
the following description that alternative embodiments of the structures and
methods illustrated herein may be employed without departing from the principles
of the disclosure described herein.
DESCRIPTION OF THE PREFERRED EMBODIMENTS:

[0023] The present subject matter relates to a ceiling fan with aerofoil shaped
blade with winglet for higher air delivery at fan sweep size 1350mm with less
noise. The present aerofoil shaped blade with winglet has curved profile and
variable thickness to provide higher air delivery and less noise. The aerofoil
shaped blade with winglet has twist angle is in range of 26o to 4o which decreases
non-uniformly from rotor end to tip end of the blade. Further, a winglet is
provided at the tip end to reduce formation of vortex due to high air pressure at tip
end. The winglet is provided in upward direction from the horizontal axis of the
fan blade. The winglet guides smooth passage of the high pressure air in upward
direction to reduce air cutting noise. The aerofoil shaped blade has leading edge
and trailing edge. The leading edge has thickness in range 11.2mm to 6.2mm from
rotor end to the tip end. On the other side of the aerofoil shaped blade, the trailing
edge has thickness in the range 2.5mm to 1.8mm. Variation in the thickness of the
edges permits formation of high air pressure under the fan blade. The aerofoil
shaped blade has lift angle of 3o with reference to horizontal axis of the blade.
Due to the curved profile, aerofoil shaped profile, and variable thickness with
non-uniform optimized twist angle provides higher air delivery at fan sweep size
of 1350mm.
[0024] It should be noted that the description and figures merely illustrate the
principles of the present subject matter. It should be appreciated by those skilled
in the art that conception and specific embodiment disclosed may be readily
utilized as a basis for modifying or designing other structures for carrying out the
same purposes of the present subject matter. It should also be appreciated by those
skilled in the art that by devising various arrangements that, although not
explicitly described or shown herein, embody the principles of the present subject
matter and are included within its spirit and scope. Furthermore, all examples
recited herein are principally intended expressly to be for pedagogical purposes to
aid the reader in understanding the principles of the present subject matter and the
concepts contributed by the inventor(s) to furthering the art, and are to be
constructed as being without limitation to such specifically recited examples and
conditions. The novel features which are believed to be characteristic of the

present subject matter, both as to its organization and method of operation,
together with further objects and advantages will be better understood from the
following description when considered in connection with the accompanying
figures.
[0025] These and other advantages of the present subject matter would be
described in greater detail with reference to the following figures. It should be
noted that the description merely illustrates the principles of the present subject
matter. It will thus be appreciated that those skilled in the art will be able to devise
various arrangements that, although not explicitly described herein, embody the
principles of the present subject matter and are included within its scope.
[0026] Fig. 1 illustrates structure of ceiling fan with the fan blade, in accordance
with the present subject matter. The ceiling fan 100 has a plurality of ceiling fan
blade 101, motor 102, hanging rod 104, and canopies 103. The canopies 103 of
the fan and hanging rod 104 are designed for matching with motor profile to make
fan more attractive. Further, the plurality of ceiling fan blade 101 is three in
number. It can be more and less as per the requirement. The plurality of ceiling
fan blade 101 is mounted on hub of the motor 102 which is a rotor. The mounting
can be done by screw. The plurality of ceiling fan blade 101 is mounted in such a
manner that is looks smooth circumference at the hub.
[0027] Fig. 2 illustrates lift angle of the aerofoil shaped blade, in accordance with
the present subject matter. The ceiling fan blade 101 (hereinafter it can be referred
as fan blade 101) has aerofoil shaped profile with a winglet 105 at tip end 101a.
The ceiling fan blade 101 has a tip end 101a and a rotor end 101b. The winglet
105 is lifted in upward direction from the fan blade 101 to reduce formation of
vortex at the tip end 101a of the ceiling fan blade 101. The winglet 105 reduces
the air pressure and guides the high pressure air under the aerofoil shaped ceiling
fan blade 101 in upward direction for smooth release. The winglet 105 allows
smooth release of the high air pressure instead of immediate release of high air
pressure from the surface of the fan blade 101, due to which the fan blade 101 has
less air cutting noise. The winglet 105 at the tip end 101a has lift angle in range

35o to 40o, preferably 37o with respect to the horizontal surface of the tip end 101a
to reduce vortex. In the figure 2, arrow X indicates horizontal direction or plane
and arrow Y indicates vertical direction or plane. The ceiling fan blade 101 is
mounted at the rotor of the motor 102 at the rotor end 101b. The tip end 101a
rotates about central axis (Y axis) of the motor 102 during movement of the rotor.
The aerofoil shaped ceiling fan blade 101 is thicker at the rotor end 101b tapering
down to a thinner at the tip end 101a for providing high lift and low drag. As
shown in the figure 2, aerofoil shaped fan blade 101 has lift angle 201 in range 2o
to 5o, preferably 3o with reference to horizontal axis X of the fan for higher air
delivery. The lift angle 201 increases spread of air in the ceiling fan 100.
[0028] Fig. 3 illustrates variable twist angle, variable thickness, and variable
depth of the aerofoil shaped blade with winglet at different cross section points, in
accordance with an embodiment of the present subject matter. The aerofoil shaped
fan blade 101 has twist angle in range of 26o to 4o along length of the ceiling fan
blade from the rotor end 101b to the tip end 101a. The twist angle decreases non-
uniformly from the rotor end 101b to the tip end 101a of the aerofoil shaped fan
blade 101. The aerofoil shaped fan blade 101 has curved profile along with length
instead of flat profile as in existing fan blades. The curved profile of the aerofoil
shaped fan blade 101 has a leading edge 101c and a trailing edge 101d. The
ceiling fan blade 101 has a bottom concave curved surface and a top convex
curved surface in between leading edge 101c and trailing edge 101d. The bottom
concave curved surface between the leading edge 101c and the trailing edge 101d
defines depth of the ceiling fan blade 101. The depth of the ceiling fan blade
increases the air pressure in ceiling fan.
[0029] Fig. 4 illustrates variable twist angle, variable thickness, variable depth
along length of the aerofoil shaped blade, in accordance with an embodiment of
the present subject matter. The aerofoil shaped fan blade 101 has a leading edge
101c and a trailing edge 101d. The thickness of the leading edge 101c is greater
than thickness of the trailing edge 101d. The leading edge 101c is the edge where
the fan blade starts compressing the air till the trailing edge 101d. The present

aerofoil shaped fan blade 101 has four sections BB, CC, DD, and EE at distance
82mm, 282mm, 482mm, and 582mm from the center of the ceiling fan,
respectively. The sections BB, CC, and DD are at a distance of 200 mm from each
other. Further, the section BB is at 82mm from the center of the ceiling fan. The
aerofoil shaped fan blade 101 is curved along the length as shown in the figures 1
and 5. The aerofoil shaped blade 101 has continued twist angle running from the
rotor end 101b to the tip end 101a in Y axis. The twist angle decreases non-
uniformly from the rotor end 101b to the tip end 101a of the aerofoil shaped fan
blade 101. The twist angle is in range 26o to 4o from the rotor end 101b to the tip
end 101a.
[0030] The leading edge 101c of the fan blade 101 has thickness in range 11.2mm
to 6.2mm from the rotor end 101b to the tip end 101a. The trailing edge 101d has
thickness in range of 2.5mm to 1.8mm from the rotor end 101b to the tip end
101a. The depth of the fan blade 101 is in range 4.8mm to 2.7mm from the rotor
end 101b to the tip end 101a.
[0031] As shown in the figure 4, the section BB which is closer to the rotor end
101b has highest twist angle of approximately 26o. The section BB shows highest
thickness of the leading edge 101c is 11.2mm and the highest thickness of the
trailing edge 101d is 2.5mm. At the section BB, the depth which is a concave
shaped profile in between the leading edge 101c and the trailing edge 101d is
4.2mm which is highest along length of the blade. The thickness of the fan blade
101 decreases from the leading edge 101c to trailing edge 101d. In the present
section BB, the leading edge 101c has 11.2mm thickness and trailing edge 101d
has 2.5mm thickness.
[0032] The section CC has twist angle of approximately 14o. The section CC
illustrates thickness of the leading edge 101c is 9.8mm and the thickness of the
trailing edge 101d is 1.8mm. At the section CC, the depth in between the leading
edge 101c and the trailing edge 101d is 3.8mm.
[0033] The section DD illustrates twist angle of approximately 9o. The section
DD illustrates thickness of the leading edge 101c is 8.4mm and the thickness of

the trailing edge 101d is 1.8mm. At the section DD, the depth in between the
leading edge 101c and the trailing edge 101d is 2.9mm.
[0034] The section EE illustrates twist angle of approximately 4o. The section EE
illustrates thickness of the leading edge 101c is 6.2mm and the thickness of the
trailing edge 101d is 5.2mm. At the section EE, the depth in between the leading
edge 101c and the trailing edge 101d is 2.7mm. The section EE illustrates section
of the winglet 105. The winglet 105 has approximately equal thickness at the
leading edge 101c as well as the trailing edge 101d. Approximate equal thickness
is provided in the winglet to avoid breaking of the winglet due to high air pressure
at the tip end 101a.
[0035] As shown in the figure 4, the aerofoil shaped fan blade 101 has variable
thickness which decreases from the rotor end 101b to the tip end 101a. Similarly,
the aerofoil shaped fan blade 101 is wider at the rotor end 101b and narrow down
towards the tip end 101a. The thickness at rotor end is designed to give higher air
delivery and to allow blade fitment with the motor 102 and to withstand the blade
in static as well as dynamic load without sagging/ breaking.
[0036] The aerofoil shaped fan blade with winglet 101 has blade length in range
610mm to 620mm, preferably 616mm and fan sweep size is 1350mm. The
aerofoil shaped fan blade 101 is compounded polymer blade which is made from
single mold. Further, the aerofoil shaped fan blade 101 is painted with
Polyurethane (PU) to increase shine and aesthetic appearance of the ceiling fan.
[0037] The present ceiling fan 100 with the aerofoil shaped fan blade with winglet
101 provides higher air delivery of 300 CMM at full speed, i.e., at 300 RPM.
Further, the present ceiling fan 100 has improved noise performance with
56dB(A) at distance of one meter from the center axis of the fan. The present
ceiling fan 100 has service value of 4 at power of 75watt. The present ceiling fan
100 has air spread of approximately 1000mm from the center of the ceiling fan.
The present ceiling fan 100 has peak air velocity of 225meter/minute at 280mm
from the center.

[0038] Although embodiments for the present subject matter have been described
in language specific to structural features, it is to be understood that the present
subject matter is not necessarily limited to the specific features described. Rather,
the specific features and methods are disclosed as embodiments for the present
subject matter. Numerous modifications and adaptations of the system/component
of the present invention will be apparent to those skilled in the art, and thus it is
intended by the appended claims to cover all such modifications and adaptations
which fall within the scope of the present subject matter.

We claim:
1. A ceiling fan blade (101) for high air delivery in ceiling fan system (100),
the ceiling fan blade (101) comprising:
a rotor end (101b) towards rotor of the ceiling fan (100) for
connecting the ceiling fan blade (101) with the rotor;
a tip end (101a) at distal end of the ceiling fan blade (100);
wherein the ceiling fan blade (101) has an aerofoil shaped profile
which is thicker at the rotor end (101b) tapering down to a thinner at the tip
end (101a);
wherein the ceiling fan blade (101) has continue twist angle running
from the root end (101b) to the tip end (101a) in Y axis, wherein the twist
angle is in range 26o to 4o from the rotor end (101b) to the tip end (101a);
wherein the ceiling fan blade (101) has a winglet (105) at the tip end
(101a) to remove vortex formation.
2. The ceiling fan blade (101) as claimed in claim 1, wherein the winglet (105)
is lifted in upward direction in plane (Y), wherein lift angle (202) of the
winglet (105) is in range 35o to 40o, preferably 37o with reference to
horizontal plane (X).
3. The ceiling fan blade (101) as claimed in claim 1, wherein the ceiling fan
blade (101) has leading edge (101c) and trailing edge (101d), wherein
thickness of the leading edge (101c) is greater than thickness of the trailing
edge (101d).
4. The ceiling fan blade (101) as claimed in claim 3, wherein the thickness of
the leading edge (101c) is in range 11.2mm to 6.2mm from the rotor end
(101b) to the tip end (101a).

5. The ceiling fan blade (101) as claimed in claim 3, wherein the thickness of
the trailing edge (101d) is in range 2.5mm to 1.8mm from the rotor end
(101b) to the tip end (101a).
6. The ceiling fan blade (101) as claimed in claim 1, wherein thickness of the
winglet (105) at leading edge (101c) is 6.2mm and thickness of the winglet
at trailing edge (101d) is 5.2mm.
7. The ceiling fan blade (101) as claimed in claim 1, wherein the ceiling fan
blade (101) has a bottom concave curved surface and a top convex curved
surface in between leading edge (101c) and trailing edge (101d), wherein
the bottom concave curved surface defines depth of the ceiling blade (101).
8. The ceiling fan blade (101) as claimed in claim 7, wherein the depth of the
ceiling fan blade (101) is in range 4.8mm to 2.7mm from the rotor end
(101b) to the tip end (101a).
9. The ceiling fan blade (101) as claimed in claim 1, wherein the ceiling fan
blade (101) has lift angle is in range 2o to 5o, preferably 3o.
10. The ceiling fan blade (101) as claimed in claim 1, wherein length of ceiling
fan blade (101) is in range 610mm to 620mm, preferably 616mm.
11. The ceiling fan blade (101) as claimed in claim 1, wherein the ceiling fan
blade (101) is aerofoil compounded polymer blade.
12. The ceiling fan blade (101) as claimed in claim 1, wherein the ceiling fan
blade (101) is Polyurethane (PU) painted.
13. The ceiling fan blade (101) as claimed in claim 1, wherein the ceiling fan
(100) has a sweep size is 1350mm.