NZ757889B2 - Satellite attitude control system using eigen vector, non-linear dynamic inversion, and feedforward control - Google Patents
Satellite attitude control system using eigen vector, non-linear dynamic inversion, and feedforward controlInfo
- Publication number
- NZ757889B2 NZ757889B2 NZ757832A NZ75783219A NZ757889B2 NZ 757889 B2 NZ757889 B2 NZ 757889B2 NZ 757832 A NZ757832 A NZ 757832A NZ 75783219 A NZ75783219 A NZ 75783219A NZ 757889 B2 NZ757889 B2 NZ 757889B2
- Authority
- NZ
- New Zealand
- Prior art keywords
- blade
- intake
- tip portion
- propeller
- root
- Prior art date
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- 238000005312 nonlinear dynamic Methods 0.000 title 1
- 238000000034 method Methods 0.000 claims abstract description 24
- 230000007704 transition Effects 0.000 claims description 23
- 230000007423 decrease Effects 0.000 claims description 10
- 230000001788 irregular Effects 0.000 claims description 5
- 238000004519 manufacturing process Methods 0.000 claims description 5
- 230000001746 atrial effect Effects 0.000 abstract 10
- 238000007789 sealing Methods 0.000 abstract 10
- 230000000747 cardiac effect Effects 0.000 abstract 3
- 210000003709 heart valve Anatomy 0.000 abstract 3
- 238000002513 implantation Methods 0.000 abstract 3
- 210000000591 tricuspid valve Anatomy 0.000 abstract 2
- 238000004873 anchoring Methods 0.000 abstract 1
- 239000012530 fluid Substances 0.000 description 30
- 238000005259 measurement Methods 0.000 description 6
- 238000001816 cooling Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000005672 electromagnetic field Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 230000002250 progressing effect Effects 0.000 description 1
Abstract
While, replacement of native cardiac valves is known, the anchoring of transcatheter valves is difficult and requires chest and cardiac cavity incisions. The present invention solves this problem by providing for the minimally invasively implantation of medical devices in the heart, including the replacement of native cardiac valves and especially replacement of tricuspid valves. A medical assembly implanting an atrial sealing skirt in the heart at an atrial sealing skirt deployment site and related methods of implantation and delivery. An anchor is endovascularly introduced into the heart and implanted to a cardiac wall with an anchor delivery system and delivery cable. A second delivery system introduces a tether which coupled to the implanted anchor and an atrial sealing skirt. The atrial sealing skirt includes a top brim which is positioned to conform to the atrial floor at the deployment site. The sealing skirt may be integrated with a valve or serve as a receptacle. eplacement of native cardiac valves and especially replacement of tricuspid valves. A medical assembly implanting an atrial sealing skirt in the heart at an atrial sealing skirt deployment site and related methods of implantation and delivery. An anchor is endovascularly introduced into the heart and implanted to a cardiac wall with an anchor delivery system and delivery cable. A second delivery system introduces a tether which coupled to the implanted anchor and an atrial sealing skirt. The atrial sealing skirt includes a top brim which is positioned to conform to the atrial floor at the deployment site. The sealing skirt may be integrated with a valve or serve as a receptacle.
Description
PROPELLER
TECHNICAL FIELD OF THE INVENTION
The invention relates to propellers that may be used, for example, for aircraft,
watercraft, turbines, unmanned aerial vehicles and air circulation devices.
[0001A] Also incorporated herein by reference, in its entirety, is
(published as ), filed on 25 May 2017.
[0001B] Reference to any prior art in the specification is not an acknowledgment or
suggestion that this prior art forms part of the common general knowledge in any jurisdiction
or that this prior art could reasonably be expected to be understood, regarded as relevant,
and/or combined with other pieces of prior art by a skilled person in the art.
SUMMARY
[0001C] As used herein, except where the context requires otherwise, the term "comprise"
and variations of the term, such as "comprising", "comprises" and "comprised", are not
intended to exclude further features, components, integers or steps.
[0001D] According to a first aspect of the invention there is provided a method of
manufacturing a propeller having a plurality of blades, each of the plurality of blades having an
intake portion, an exhaust portion, and a tip portion extending from the intake portion to the
exhaust portion, the method comprising: defining a plurality of parameter sections by selecting
parameters including skew angle, roll angle, rake, radius, pitch angle, vertical angle, wherein
the selected parameters redirect lift; defining a parameter section at the transition from the
intake portion to the tip portion having a roll angle between 40 to 50 degrees to cause an
amount of non-axial lift in the tip portion to be greater than the axial lift in the tip portion;
defining parameter sections to include a roll angle of 90 degrees in the tip portion; and
extrapolating between parameter sections to form smooth lines to form a blade configured to
form a loop when attached to a hub.
[0001E] According to a second aspect of the invention there is provided a propeller
comprising: a plurality of blades, each of the plurality of blades having an intake portion, an
exhaust portion, and a tip portion extending from the intake portion to the exhaust portion; a
hub; the plurality of blades extending outward from the hub and disposed around the hub; each
blade forming a loop; each blade comprising a plurality of parameter sections having selected
parameters including skew angle, roll angle, rake, radius, pitch angle, vertical angle, wherein
the selected parameters redirect lift; a parameter section at the transition from the intake
portion to the tip portion having a roll angle between 40 to 50 degrees to cause an amount of
non-axial lift in the tip portion to be greater than the axial lift in the tip portion; and a parameter
section or area between consecutive parameter sections in the tip portion having a roll angle of
90 degrees.
Embodiments of the invention provide a propeller that has a plurality of blades and
a means for generating non-axial lift, which creates non-axial fluid flow, and a means for
redirecting non-axial fluid flow to create axial fluid movement or thrust. The propeller may
include a hub or be of a rim or “hubless” form. The plurality of blades either extends outward
from the hub or inward from the rim. Each blade may form a loop-type structure that may be
open or closed, and having an intake portion, and exhaust portion and a tip portion extending
radially outward from to the hub or inward from a rim or “hubless” form. The means for
generating non-axial lift and non-axial fluid flow to create axial thrust may be a configuration
of the blades wherein in a cross-sectional-profile of each of the plurality of blades, the distance
from the rotational axis to the leading edge of the blade is greater than the distance from the
rotational axis to the trailing edge of the blade in at least part of the tip portion.
The blades may have an intake portion, an exhaust portion, and a tip portion that
connects the intake and exhaust portions, but is not necessarily a discrete component. The
propeller has an intake root and an exhaust root, which are at either the rim or hub, for
example. The tip portion may include a roll angle of ninety degrees, wherein a roll angle of
zero is at the intake root. The tip portion vertical angle and pitch angle may be positive
throughout. In an exemplary embodiment the tip portion produces more non-axial lift than
either the intake or the exhaust portion.
In an illustrative embodiment the transition from the intake portion to the tip
portion occurs when the amount of non-axial lift produced by a given parameter section of the
blade is greater than the axial lift produced.
DESCRIPTION OF THE DRAWINGS
For further detail regarding illustrative embodiments of the disclosed propeller,
reference is made to the detailed description provided below, in conjunction with the following
illustrations: All figures are of illustrative embodiments of the disclosed propeller.
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FIGS. 1A-E depict various views of an illustrative propeller.
depicts a parameter sections defining a propeller blade.
depicts a blade parameter section geometry.
FIGS 4A-F depict measurements of rake for parameter sections in the intake
portion, tip portion and exhaust portion of a propeller blade.
FIGS. 5A-F depict measurements for skew angle and vertical angle of parameter
sections in the intake portion, tip portion and exhaust portion of a propeller blade.
depicts an example fluid flow around propeller blades.
FIGS. 7A-D depict examples of alpha and radius values for selected parameter
sections.
FIGS. 8A-H depict illustrative values or relative values of various parameters that
define a parameter section or a blade.
FIGS. 9A-F depict pitch angles for selected parameter sections of the blades.
FIGS. 10A-B depict views of a turbofan.
[0016] depicts an unmanned aerial vehicle.
FIGS. 12A-C depict roll angle for selected parameter sections.
FIGS. 13A-G depict a propeller without a hub and having a ring from which
propeller blades extend.
FIGS. 14A-B depict a two blade propeller and a cross-section thereof.
[0020] FIGS. 15A-B depict a three blade propeller and a cross-section thereof.
FIGS. 16A-B depict a five blade propeller and a cross-section thereof.
FIGS. 17A-B depict a seven blade propeller and a cross-section thereof.
FIGS. 18A-F depict an illustrative embodiment of a propeller with a high rake.
FIGS. 19A-F depict a further illustrative embodiment of a propeller with a high rake
for intake and exhaust.
FIGS. 20A-I depict an inboard propeller.
FIGS. 21A-F depict a propeller with a through hub exhaust.
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DETAILED DESCRIPTION OF THE INVENTION
FIGS. 1A-E depict propeller 100 according to an illustrative embodiment.
depicts a perspective view of propeller 100. depicts a side view of propeller 100, and
depicts the opposing side of propeller 100. FIGS. 1D and 1E depict a top (fore) view
and bottom (aft) view, respectively, of Propeller 100. Propeller 100 includes a plurality of
blades 102, 104, 106, each having, a tip portion 122, an intake portion 124 and an exhaust
portion 126. In this illustrative embodiment, blades 102, 104 and 106 extend from a hub 128.
Each of blades 102, 104, 106 has a median line 108, 110, 112, respectively. Blades 102, 104,
106 rotate about hub axis 103. For simplicity the term “hub” may be used to include any
rotational axis, even if there is no physical hub.
The blades have a means for generating non-axial lift and non-axial fluid flow and a
means for redirecting the non-axial fluid flow to axial fluid flow. In illustrative embodiments,
the means for generating non-axial lift and non-axial fluid flow is the configuration of the tip
portion of the blade, which will be described further below. In illustrative embodiments the
means for redirecting the non-axial fluid flow to axial fluid flow is the configuration of the tip
and intake portion, and may also include the exhaust portion, which will also be described in
more detail below.
The term “propeller” as used herein may include rotary blade devices that can be
used to displace fluid to propel an apparatus, or which are employed in a stationary device such
as, for example, a cooling or other air circulating fan, which moves fluid such as air through or
around it.
Propeller 100 has three blades 102, 104, 106 disposed at equal increments around
hub 128. Disclosed embodiments of the propeller may have for example, two, three, four, five,
six, seven or eight blades that rotate in the same plane. The number of blades will generally
depend on the application of the propeller. For example, additional blades may be beneficial
for increases in the weight of a boat or airplane in which the propeller is employed to increase
the area of the blades, thereby reducing the blade loading.
Blades 102, 104, 106 may be configured to rotate about an axis corresponding to
hub axis 103, but in an apparatus in which there is no hub, such as in a configuration in which
the blades extend inward from a rotating support. The rotation of the support may be generated
by an electromagnetic field. Hub 128 may also be hollow, and may have openings in its
surface, such as in a centrifugal fan.
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depicts a blade 200 having parameter sections 1-29, with parameter section 1
in the vicinity of the intake root 204, and parameter section 29 in the vicinity of exhaust root
206. Each parameter section represents a set of physical properties or measurements whose
values determine the characteristics of the blade area. The parameter sections as a group
determine the shape of blade 200 and its behavior. Parameter sections are equally spaced in an
exemplary embodiment but may be selected at unequal intervals. serves merely to
illustrate how blade parameter sections may be laid out to define the blade geometry.
Parameter sections represent the shape and orientation of blade 200 at a particular place along
the blade. A smooth transition is formed between parameter sections to create a blade. As used
herein “orientation” may include location. In the illustrative embodiment in blade
sections 1-29 are planar sections disposed along an irregular helical median line 202. “Irregular
helix” is used herein to mean varying from a mathematical helix-defining formula or as a spiral
in 3-D space wherein the angle between the tangent line at any point on the spiral and the
propeller axis is not constant. The blade may have an irregular, non-helical median line at least
in part, or the median line may be an irregular helix throughout.
Although 29 blade sections are shown in more or fewer sections can be used
to define a blade. Additionally, sections may exist within or partially within the hub that are
not shown or fully shown. Blades may be defined by planar or cylindrical parameter sections.
Parameter sections 1-29 are defined, for example, by orientation variables, such as
roll angle and vertical angle (alpha), and may include location variables; and shape variables,
such as chord length, thickness, and camber. Additional illustrative orientation or location
variable include rake, skew angle and radius. Some or more of the variables may change
through the blade or a blade portion and some may be constant throughout. Orientation
variables may be measured with respect to an X-Y-Z coordinate system. The X-Y-Z coordinate
system has the origin at the shaft centerline and a generating line normal to the shaft or hub axis
103. The X-Axis is along hub axis 103, positive downstream. The Y-Axis is up along the
generating line and the Z-Axis is positive to port for a right handed propeller. A left handed
propeller is created by switching the Z-Axis and making a left hand coordinate system.
Parameter sections may be located by their chord (nose-to-tail) midpoint, such as by
using radius, rake and skew. Parameter sections may be oriented using the angles Phi, Psi and
Alfa, as will be described further below.
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depicts blade parameter section geometry by reference to a cross-sectional
profile of a blade, which could be a parameter section. An illustrative parameter section 300.
Parameter section 300 is in the form of an asymmetrical airfoil. The airfoil is bounded by a
curved blade surface line 302 and a generally flat blade surface line 304, with a rounded nose
306 at the leading edge 310 of the parameter section and a pointed or less rounded tail 308 at
the trailing edge 312 of parameter section 300. Parameter sections may also be in the shape of a
symmetrical airfoil. Additional parameter section shapes include, for example, a shape having
parallel blade surface lines 302, 304. Blade surface lines 302, 304 may also be linear and at an
angle to one another. The nose and tail edges may both be rounded, both be flat (perpendicular
to one or both blade surface lines 302, 304) or one of either the nose or tail may be rounded and
the other of the two flat. A blade formed of a sheet material, for example, would generally
exhibit parallel blade surface lines 302, 304. In an illustrative example of a blade formed of a
sheet, the leading edge of the blade is rounded and the trailing edge is flat or less rounded,
though both intake and trailing edges could be rounded.
[0037] Illustrative shape variables for parameter sections are defined as follows;
Radius: The term radius is used to define both the shape of a parameter section and
its orientation with respect to the X-Y-Z coordinate system. With regard to the parameter
section shape, radius may refer to the curvature of the nose 306 of parameter section 300, for
example, and thus will be referred to as a “nose radius.” Other points on parameter section 300
may be used to calculate a radius. By way of example, parameter section leading edge radius
may be calculated based on maximum thickness 316 and the length of chord 314.
Chord: The chord is the nose-to-tail line 314 of the parameter section.
Thickness: Various thickness measurements may define a parameter section such
as, for example, the maximum thickness 316. A further illustrative example is the trailing edge
thickness, which may be calculated as a percentage of maximum thickness 316. For example,
the trailing edge thickness may be 8% of maximum thickness 316 of parameter section 300.
Camber: Camber 318 defines the curvature of a parameter section.
Illustrative orientation variables include:
Rake: Rake is the axial location of a parameter section chord midpoint.
[0044] By “axial location” it is meant in this instance, along the X-axis, which is coincident
with the propeller rotational axis. Illustrative rake measurements are shown in FIGS. 4A-F for
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various parameter sections. Each of FIGS. 4A-F show coordinates X, Y and Z, wherein the X-
axis is coincident with the propeller rotational axis, and the Y-axis and Z-axis are perpendicular
to the X-axis, and the three axes are mutually perpendicular. Parameters are measured from the
origin of the coordinate system. In an illustrative embodiment, the zero point of the coordinate
system is along the propeller rotational axis, and is closer to the intake root than the exhaust
root. Illustratively, values along the X-axis toward the intake root are negative and toward the
exhaust root are positive. In general a coordinate system is located as desired and all
parameters or geometry are measured from the origin of the selected coordinate system.
FIGS. 4A and 4B depict Rake for parameter sections 412, 414 on the intake portion
402 of blade 400. Parameter section 412 in is toward tip portion 404 of blade 400.
Parameter section 414 is toward intake root 406. Rake is measured along the propeller
rotational axis or along a line parallel to the rotational axis. In the illustrative examples of
FIGS. 4A, 4B, Rake is the distance from point A at X equals zero to the X coordinate value of
point B, wherein point B is at the midpoint 410 of the chord of parameter sections 412, 414.
The X-coordinate value of point B is represented by Bx in FIGS. 4A-F. .
FIGS. 4C and 4D depict Rake for parameter sections 418, 420 on the tip portion
404 of blade 400. Parameter section 418 in is at a first position in tip portion 404 of
blade 400 wherein the roll value (described further below) is greater than zero and less than 90
degrees. Parameter section 420 in is at a second position in tip portion 404 where the
roll value is equal to or greater than 90 degrees. In the illustrative examples of FIGS. 4C, 4D,
Rake is the distance from point A at X equals zero to the X coordinate value, Bx, of point B,
wherein point B is at the midpoint 410 of the chord of parameter sections 418, 420. FIGS. 4E
and 4F depict Rake for parameter sections 422, 424 on the exhaust portion 426 of blade 400.
Parameter section 422 in is toward tip portion 404 of blade 400. Parameter section 424
is toward exhaust root 428. In the illustrative examples of FIGS. 4E, 4F, Rake is the distance
from point A at X equals zero to the X coordinate value of point B, wherein point B is at the
midpoint 410 of the chord of parameter sections 422, 424.
Pitch Angle: Pitch Angle is the angle between the chord line of a parameter section
and a plane perpendicular to the X-axis. Pitch angle may be calculated based on pitch distance
and blade radius. Examples of pitch angle of parameter sections is provided in FIGS. 9A to9F.
Radius: The orientation radius is the distance from the hub center 208 to the
midpoint 320 of chord 314 of a parameter section. Chord 314 may also be referred to as the
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nose-to-tail line. The radius described in this paragraph will be referred to as the parameter
section orientation radius to differentiate it from the nose radius or other parameter section
shape radii, which are not measured with respect to the X-Y-Z coordinate system. Midpoint
320 of chord 314 is the point on the parameter section chord line through which the median line
202 would pass. This is illustrated in by line R which extends from hub center 208 to
the midpoint of the chord of parameter section 5. Note that the chord of parameter section 5 and
its midpoint are not specifically shown in
FIGS. 5A-F depict blade 400 viewed along the blade rotational axis X. FIGS. 5A-F
identify representative parameter section radii and skew angle. depicts the radius of
parameter section 412 in the intake portion 402 of blade 400. shows the radius of
parameter section 414, a parameter section in intake portion 402 of blade 400 further from
intake root 406 than parameter section 412. FIGS. 5C and 5D depict radii for parameter section
418 and 420, respectively, wherein parameter section 418, 420 are in tip portion 404. FIGS. 5E
and 5F depict radii for exhaust parameter section 422 and 424, respectively, both within exhaust
portion 426. The position of parameter sections 412, 414, 418, 420, 422 and 424 as being in
intake portion 402, tip portion 404, or exhaust portion 426 are provided only for ease of
discussion. The actual parameter values and resulting fluid flow may define the positions of the
sections otherwise.
FIGS. 5A-F further show skew angle of parameter sections 412, 414, 418, 420, 422,
424. Skew angle is the projected angle from a line through midpoint 410 of chord 314 to the
generating line, in this illustrative embodiment the Y-axis looking along hub axis 103 (X-axis).
FIGS. 7A-D, in addition to depicting skew angle and radius, depict parameter
section vertical angle, Alpha, labeled on each of FIGS. 7A-D. Vertical angle may also be
referred to as “lift angle.” Alpha is the angle that the parameter section is rotated relative to a
line perpendicular to the skew line, which is identified in FIGS. 6A-D and described below.
The aforementioned skew line refers to the line together with the zero skew line that forms the
skew angle. Depending on the value of Alpha, the nose of the parameter section will either be
“lifted” or will “droop” from a line perpendicular to the skew line that forms the skew angle
with respect to the zero skew line, wherein the zero skew line is coincident with the Y-axis of
the coordinate system identified on FIGS. 7A-D.
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It is noted that FIGS. 5A-F do not identify Alpha, because Alpha equals zero.
When Alpha is zero, the chord line of the parameter section is perpendicular to the zero skew
line. This can be seen by a comparison of FIGS. 5A-F with FIGS. 7A-D.
Roll: Roll is the angle that a parameter section is rotated about its chord line. As
described herein, a zero roll value is in a plane parallel to the hub axis. In an illustrative
embodiment, roll at intake root 132 is zero, roll at exhaust root 134 is 180 degrees and a roll of
90 degrees is at a location within tip portion 122.
Various illustrative embodiments will be described by combinations of
characteristics. The disclosed propeller includes different combinations of the characteristics,
equivalents of the elements and may also include embodiments wherein not all characteristics
are included.
In an illustrative embodiment of a propeller, the propeller includes a plurality of
blades in a loop form, generally as shown in FIGS. 1A-E. The propeller in is referred
to only as a general reference to equate particulars with propeller regions. The actual form of
the propeller blades will vary according to the parameters and within the ranges specified.
Each blade 102, 104, 106 of propeller 100 includes a tip portion 122, an intake
portion 124 and an exhaust portion 126. In an illustrative embodiment, the intake portion is 0-
45% of the blade, the tip portion is 30%-75% of the blade and the exhaust portion is 50 percent
to 90 percent of the blade.
[0057] Propeller 100 may have various number of blades, each preferably with the same
characteristics and parameters, although variations between blades is within the scope of the
embodiments. An illustrative number of blades is between two and twelve, although more
blades may be included in a single propeller. In particular embodiments a propeller may have
three, four, five, seven or eleven blades. In a propeller embodiment having looped blades, the
blades have an intake root 132 at hub 128 and an exhaust root134 at hub 128. Intake portion
124, tip portion 122 and exhaust portion 126 together may form a closed loop or the loop may
be opened at the intake “root” or exhaust “root.”
Roll: The roll angle (Psi) is the orientation angle about chord 314, for example.
Referring back to FIGS. 1A-F, intake portion 124 extends from hub 128 generally outward for a
propeller with a hub 128. Intake portion 124 may have a roll of zero at intake root 132. Intake
portion 124 is configured to create axial lift only or more axial lift than non-axial lift. The roll
value for all parameter sections in intake portion 124 may be zero. Illustrative roll value ranges
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for parameter sections in intake portion 124 include zero at intake root 132 progressing to
between about 1 degree to 35 degrees where intake portion 124 transitions to tip portion 122.
Additional ranges of roll value for intake portion 124 from intake root 132 to tip portion 122
include: from zero to between about 5 degrees to 25 degrees, and from zero to between about
10 degrees to 20 degrees.
Tip portion 122 may also be defined by a tip portion intake end that begins at the
first deviation from zero of roll value and extends to a tip portion exhaust end that begins at a
roll value of 90 degrees or just greater than 90 degrees.
Tip portion 122 is configured to generate non-axial lift only, more non-axial lift
than axial lift, or more non-axial lift than intake portion 124. The roll value of parameter
sections in tip portion 122 will transition from less than 90 degrees to greater than 90 degrees.
Illustrative roll value ranges of tip portion 122 include between 1 degree and 46 degrees at the
transition from intake portion 124 through between 91 and 150 degrees where tip portion
transitions to exhaust portion 126. Additional illustrative roll value ranges of tip portion 122
include beginning at the transition from intake portion 124, between 5 degrees and 25 degrees
and transitioning to a roll of between 110-135 degrees.
In an illustrative embodiment the transition from intake portion 124 to tip portion
122 occurs when the amount of non-axial lift produced by a given parameter section is greater
than the axial lift. In a particular embodiment of the invention this transition takes place when
roll is 45 degrees, or when roll is in a range of 40 degrees to 50 degrees.
Exhaust portion 126 is configured to generate less non-axial lift than tip portion
122. In an illustrative embodiment of the invention, the blade is configured so the average non-
axial lift is the greatest in tip portion 122 as compared to either intake portion 124 or exhaust
portion 126. In an illustrative embodiment the blade is configured so the average non-axial lift,
if any, is greater in exhaust portion 126 than in intake portion 124. Illustrative roll value ranges
of exhaust portion 126 include between 91 degrees and 150 degrees at the transition from tip
portion 122 to exhaust portion 126 through 180 degrees at exhaust root 134. Additional
illustrative ranges include beginning at the transition from tip portion 122, between 91 degrees
and 135 degrees and transitioning to a roll of 180 degrees at exhaust root 134.
[0063] FIGS. 8A-H depict illustrative values or relative values of various parameters that
define a parameter section or a blade. depicts illustrative roll values from an intake
root of a blade to exhaust root. In an illustrative embodiment, beginning at intake root 132
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through exhaust root 134, parameter section roll transitions from about zero to 5 degrees over
the first 25 percent of the blade, from about 5 degrees to about 162 degrees over the next 50
percent of the blade, and from about 165 degrees to about 180 degrees over the last 25 percent
of the blade.
[0064] In an illustrative embodiment non-axial lift is created by 10 percent to 90 percent of
the blade. Further illustrative ranges include 10 percent to 75 percent and 25 percent to 50
percent.
depicts an illustrative example of a propeller 600 showing fluid flow around
blades 602, 604. Intake portions 606, 608 show fluid flow in an axial direction at the intake
portions 606, 608 of blades 602, 604, respectively. Fluid flow remains axial as the propeller
moves forward or fluid moves through blades 602, 604. Fluid flow is still axial as it departs
from the exhaust portions 610, 612 of blades 602, 604, respectively.
Within the tip portion of blades 602, 604 axial thrust is generated from the non-
axial lift. Non-axial lift results in a fluid flow into the propeller blade, such as within the
interior of the loop. Fluid encounters the leading edge of tip portions 610, 612 non-axially. As
fluid is pulled in by the tip portions 610, 612 it is redirected into toward an axial direction
within the loops of blades 602, 604. The non-axial lift may cause drag, which is created by the
tip portion. As fluid passes the trailing edge of blades 602, 604, in tip portions 610, 612 it is in
an axial direction or more toward an axial direction than when it entered the interior of the
loops of blades 602, 604.
In an illustrative embodiment, propeller 600 is configured to create mixture of the
free stream and jet stream of fluid flow aft of the propeller, wherein the mixing area is greater
than the diameter of the propeller, wherein the propeller diameter in this instance is the
measurement of the largest span of the propeller through the hub axis.
[0068] Referring back to FIGS. 1A-F, tip portions 122, intake portions 124 and exhaust
portions 126 do not necessarily extend equal distances, such as along median lines 108, 110,
112. In an illustrative embodiment, intake portions 124 encompass a shorter distance than
exhaust portions 126. Therefore, the distance along median line 108, 110, 112 wherein the
blade is configured to redirect axial lift to non-axial lift extends a greater distance from exhaust
root 134 than from intake root 132. In an illustrative embodiment, intake portion 124 extends a
distance in a range of 10 percent to 50 percent of the median line length, exhaust portion 126
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extends a distance in a range of 10 percent to 60 percent of the median line length; and tip
portion 122 extends a distance of 5 percent to 60 percent of the median line length.
depicts illustrative relative pitch angle values from an intake root of a blade
to exhaust root. In an illustrative embodiment, beginning at intake root 132 through exhaust
root 134, parameter section pitch angle transitions from about 70 degrees to about 35 degrees,
over the next 50 percent of the blade pitch angle transitions from about 35 degrees to about 25
degrees, and over the last 25 percent of the blade, pitch angle transitions from about 25 degrees
to about 75 degrees. In an illustrative embodiment of the invention, tip portion 122 has a non-
zero pitch angle throughout. In an exemplary embodiment of the invention tip portion 122 is
defined as and is configured to have non-zero pitch and redirect non-axial lift to create axial
thrust.
depicts the vertical angle, Alpha, from an intake root of a blade to exhaust
root according to an illustrative embodiment. The vertical angle orients parameter sections
away from being perpendicular to skew. In an illustrative embodiment the vertical angle is zero
for all parameter sections. In a further embodiment the vertical angle for the intake and tip
portions is positive for all parameter sections and the vertical angle for the exhaust portion is
negative for all parameter sections. In yet a further embodiment tip portion 122 may have at
least one parameter section with a non-zero vertical angle. In other embodiments, the average
vertical angle for the tip and intake portions is greater than the average vertical angle of the
exhaust portion.
In an illustrative embodiment the average vertical angle for parameter sections in
exhaust portion 126 is greater than the average vertical angle for parameter sections in intake
portion 124.
Illustrative ranges of the vertical angle of tip portion 122 includes, 0 to 1 degree, 1
degree to 10 degrees; 4 degrees to six degrees; zero to 5 degrees; 1 degree to 4 degrees; and 2
degrees to 3 degrees. The vertical angle may also be zero throughout the entire blade. The
vertical angle at the tip may cause fluid to be drawn in to the interior of the blade “loop” and
may thereby cause drag. The vertical angle at the tip may also create fluid flow that is off-axis
from the direction of travel which is redirected to axial fluid flow within the loop. The greater
the vertical angle in the tip region, the greater the amount of non-axial lift and as a result the
greater the amount of non-axial fluid flow into the propeller. The vertical angle of parameter
sections in tip portion 122 may create non-axial lift and drag in the vicinity. In illustrative
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embodiments, the vertical angle is between -45 degrees and 45 degrees throughout the blade;
between -25 degrees and 25 degrees or between -15 degrees and 15 degrees throughout the
blade.
depicts illustrative relative radius values from an intake root of a blade to
exhaust root. In an illustrative embodiment the radius of parameter sections increases
throughout the first 60 percent to 80 percent of the blade beginning at intake root 132 and then
decreases through parameter sections through to exhaust root 134. As used in this paragraph
and elsewhere, parameters transitions over parameter sections correspond to transitions through
the blade.
[0074] depicts illustrative rake values from an intake root of a blade to exhaust
root. Rake in an exemplary embodiment may be increasingly negative from intake root 132
through the first 30 percent to 40 percent of the blade. Rake may then increase for the next 10
percent to 15 percent of the blade until it reaches positive values. Rake may then continue to
increase for an additional 20 percent to 40 percent of the blade and then level off for the
remainder of the blade or decrease. Rake may also be linear from the intake root of position of
zero to a positive exhaust root value.
depicts illustrative relative skew values from an intake root of a blade to
exhaust root. In an illustrative embodiment the skew value continually increases from intake
root 132 through exhaust root 134. In another illustrative embodiment the skew value may
continually decrease so the exhaust portion is forward of the intake and tip portion on its
rotational plane. Parameter section chord 314 may be normal to the skew line throughout the
blade or in a portion of the blade, wherein the skew line to which chord 314 is perpendicular is
the skew line that forms the skew angle with the zero skew line.
depicts illustrative relative camber values from an intake root of a blade to
exhaust root. In an illustrative embodiment the camber of parameter sections transitions from a
positive value at the intake root 132 to a negative value at the exhaust root 134, wherein the
suction side of the blade changes to the pressure side of the blade near the transition from the
tip portion to the exhaust portion at the interface of positive camber to negative camber.
depicts illustrative relative chord values from an intake root of a blade to
exhaust root. In an illustrative embodiment chord decreases from intake root 132 and then
begins to increase toward exhaust portion 126 and continues to increase to exhaust root 134. . In
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other illustrative embodiments, chord increases from intake root 132 and then decreases toward
exhaust portion 126 and continues to decrease to exhaust root 134.
In illustrative embodiments tip portion 122 from the tip portion intake end to the tip
portion exhaust end exhibits one or more of the following characteristics:
average non-axial greater than average axial lift;.
non-axial lift from the tip portion intake end to the tip portion exhaust end;
zero alpha value throughout;
positive pitch angle throughout;
positive pitch distance throughout
positive pitch angle throughout a portion between 70% and 95% of tip portion 122
a maximum blade radius value within the tip portion extending from a parameter
section having a roll value of 80 degrees to a parameter section having a roll value of 95
degrees.
The chart below provides illustrative values for selected parameter sections. The
parameter sections are 2, 6, 11, 19, 25 and 29 from a blade defined by 30 parameter sections.
Parameter section 2 is the closest of the selected parameter sections to intake root 132.
Parameter section 29 is the closest of the selected parameter section to exhaust root 134.
Section &
Radius Pitch
Figure Pitch Angle
Numbers (inches) (inches) Ske w˚ (Phi) Roll (Psi)
SECT. 2
0.860 9.899 3.139 61.38 0.57
SECT. 6
2.000 9.396 12.615 36.79 3.34
SECT. 11
3.278 9.366 25.043 24.45 11.98
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Section &
Radius Pitch
Figure Pitch Angle
Numbers (inches) (inches) Ske w˚ (Phi) Roll (Psi)
SECT. 19
4.335 10.248 46.069 20.62 91.38
SECT. 25
2.674 11.197 62.206 33.68 172.24
SECT. 29
0.941 12.035 73.241 63.85 178.62
FIGS. 5A-F provide a schematic representation of parameter sections 2, 6, 11, 19,
and 29, respectively. As noted above, FIGS. 5A-F depict parameter sections having an
Alpha value of zero. In an illustrative embodiment these parameter sections may be part of a
group of parameter section all having a zero alpha value that form a propeller blade.
Referring to FIGS. 5A-F, it can be seen that the radius increases from parameter
section 2 through parameter section 19 and then is decreasing at parameter section 25 through
parameter section 29. Pitch, skew and roll increase throughout parameter sections 2, 6, 11, 19,
and 29. Pitch angle decreases from parameter section 2 through parameter section 25 and
then shows an increase at parameter section 29.
FIGS. 9A-F provide a schematic representation of pitch angle for parameter
sections 2, 6, 11, 19, 25 and 29, respectively. Pitch angle varies throughout the blade with the
largest values occurring at the intake and exhaust roots.
FIGS. 7A-D depict representations of parameter sections 6, 11, 19 and 25 of 30
parameter sections defining a blade shown in the table below. These parameters include varying
Alpha values. The chart below provides illustrative values for the selected parameter sections.
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Section & Vertical
Radius Pitch
Figure Pitch Angle Angle
Numbers (inches) (inches) Ske w˚ (Phi) Roll (Psi) (Alpha)
SECT. 6
2.000 9.396 12.615 36.79 3.34 16.74
SECT. 11
3.278 9.366 25.043 24.45 11.98 16.34
SECT. 19
4.335 10.248 46.069 20.62 91.38 11.75
SECT. 25
2.674 11.197 62.206 33.68 172.24 -14.80
Radius, Pitch, Skew, Pitch Angle and Roll are given the same values as the
illustrative example having Alpha equal to zero. In the embodiment represented by FIGS. 7A-
D Alpha decreases through parameter sections 6 through 19 and then becomes negative at a
location on the blade between parameter section 19 and 25. This change is illustrated in FIGS.
7A-D.
It is noted that throughout where values are associated with section parameters, the
values may define blade portions as each of the intake, tip and exhaust portions are defined
herein.
[0086] Illustrative embodiments of the propeller may have one or more of the following
characteristics and any characteristics described herein:
throughout at least a portion of tip portion 122 on the intake side 90 degree roll, the
distance (N) to the nose of a parameter section as measured perpendicularly from hub axis 103
is greater than the distance (T) to the tail of the parameter section as measured perpendicularly
from the hub axis;
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80% of the tip portion has a roll value of less than 90 degrees and N>T for the same
80% of the tip portion;
average pitch angle of exhaust portion 126 is greater than the average pitch of
intake portion 124;
pitch angle varies as roll varies;
pitch angle is positive throughout the blade;
length of entire leading edge of propeller blade is greater than the length of the
entire trailing edge as measure perpendicularly from the propeller axis;
first rake position (intake root) is less than the last (exhaust root) rake position thus
there is a resulting gap between the intake root and the exhaust root with the exhaust root aft of
the intake root;
skew increases from intake root 132 to exhaust root 134;
intake root is forward of exhaust root and skew begins at zero and ends at a positive
value;
intake root is aft of exhaust root and skew starts at zero and ends at a negative
value;
the entire intake portion is forward of the exhaust portion except for tip region.
the greatest thickness of the blade cross-section is between the midpoint of the
chord and the leading edge of the cross-section;
the pressure face continues to turn toward the tip on the intake portion and then
becomes suction face on the exhaust portion;
intake root 132 is in-line with exhaust root 134 so skew is zero;
substantial mixing of jet stream and free stream downstream of the exhaust blade
compared to traditional propellers;
blades are configured to “effectively increase” the diameter of the propeller by
increasing mixture of free stream and jet stream;
pitch angle of the exhaust blade at its root end is greater than the pitch angle of the
intake blade at its root end;
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the tip portion has a 90 degree roll angle closer to the exhaust portion than to the
intake portion;
a gap between the intake portion root and the exhaust portion root;
chord length of parameter sections varying throughout the blades;
parameter sections defining the blade are planar and perpendicular to the median
line;
Some or all of the parameter sections defining the blade are non-planar, cylindrical
to the median line.
negative rake in the exhaust portion;
positive rake in the exhaust portion and
blades of different configuration are incorporated into a single propeller.
Propeller variations can have the same median line but vary in other parameters. A
series of propellers according to illustrative embodiments of the invention can be based on a
common median line with varying parameter section pitch, angle of attack, angle, rake, surface
area, area ratio, spline form, cross-sectional profile, chord length, vertical angle, roll and other
blade parameters.
FIGS. 14A-B, 15A-B, 16A-B and 17A-B depict side views and cross-sectional
views of propellers with two blades, three blades, four blades and seven blades, respectively.
Cross-sections are taken viewed from the propeller fore location along the rotational axis. The
cross-sections are generally in tip portion 122 of the blade. As can been seen in each of the
cross-sectional drawings, for each cross-sectional profile of the blade, the distance A from the
rotational axis to the leading edge of the blade cross section is greater than the distance B from
the rotational axis to the trailing edge of the blade cross section in these particular areas of tip
portion 122. In an illustrative embodiment of the invention A is greater than B for all of tip
portion 122. In further illustrative embodiments of the invention A is greater than B for 50
percent to 100 percent of tip portion 122. In a further embodiments the percent of tip portion
122 that has A greater than B is in the range of 85 percent to 90 percent. In general, the greater
the difference between the length of A band B the more fluid will be pulled in from a non-axial
direction. Similarly, the greater the percent of the blade that has A greater than B, the more
fluid will be pulled in from a non-axial directions.
1002737816
Illustrative embodiments have been depicted or described as a propeller having a
hub. The blades described herein may also be used in a hubless propeller device such as shown
in FIGS. 13A-G. A is a perspective view of a “hubless” propeller 800. In this
embodiment there are seven blades 804, each having their intake root 132 and exhaust root 134
extending from a rim 802, with tip portion 122 toward the center of the propeller. FIGS. 13B-G
show views from the top, bottom, “front,” “back,” “left,” and “right,” respectively. The terms
“left,” “right,” “front” and “back” are used for description purposes only to distinguish views
from 90 degree intervals around the propeller, but as a circular device, have no literal meaning.
The blades follow the same or similar characteristics as propellers with hubs, with some varied
air flow due to the rim.
Further disclosed is a method for creating a propeller according to any of the
embodiments described herein. In an exemplary embodiment a plurality of independently
modifiable orientation and shape variables are provided to define the orientation and shape of a
plurality of parameter sections forming a propeller blade. The shape and orientation variables
can be any combination of those disclosed herein. The parameter sections may be planar or
cylindrical. In an illustrative embodiment the variables are modified to direct and redirect lift as
desired, such as described herein. The configured parameter sections are then used to form a
blade by extrapolating between parameter sections to form smooth lines. The method may be
used to form any blade as described herein.
[0091] The invention includes several different devices having the disclosed propeller
incorporated therein. For example, the invention includes the following illustrative devices:,
propulsors, shrouded propellers, encased propellers, impellers, aircraft, watercraft, turbines,
including wind turbines, cooling devices, heating devices, automobile engines, unmanned aerial
vehicles, turbofans (hydrojets), air circulation devices, compressors, pump jets, centrifugal fans,
jet engines and the like. The invention also includes methods of manufacturing and designing a
propeller, including any of the above-listed devices, according to any of the embodiments
described, pictured or claimed herein; a method of manufacturing a device comprising any of
the aforementioned propellers; a method of manufacturing a product wherein the method
includes installing a device containing any of the aforementioned propellers.
[0092] The ratio of the roll to distance along the median line may be a factor in whether a
particular propeller is suitable for an application. For example, a greater roll per given distance
1002737816
creates a more squat blade profile and thus may be more suitable for application as a fan for a
cooling or ventilating device.
In an illustrative embodiment, a propeller as described herein is incorporated into a
turbofan as shown, for example, in FIGS. 10A and 10B. The turbofan may have, for example,
between eight and twelve blades. It is noted that the blades depicted in FIGS. 10A-B are not
necessarily of a type described herein. The figures are merely provided to indicate the type of
device.
In a further illustrative embodiment of the invention a propeller as described herein
is incorporated into an unmanned aerial vehicle or device such as shown for example, in 11. It is noted that the blades depicted in are not necessarily of a type described herein.
The figures are merely provided to indicate the type of device.
Various embodiments and view of illustrative propellers are provided in FIGS.
18A-F, FIGS. 19A-F, FIGS. 20A-I and FIGS. 21A-F. Views including from the top, bottom,
“front,” “back,” “left,” “right,” and perspective views are provided and labeled on the drawings.
The terms “left,” “right,” “front” and “back” are used for description purposes only to
distinguish views from 90 degree intervals around the propeller, but as a circular device, the
terms have no significance. FIGS. 18A-F depict an illustrative embodiment of a propeller with a
high rake value for intake portion of the blade. FIGS. 19A-F depict a further illustrative
embodiment of a propeller with a high rake value for intake and exhaust. FIGS. 20A-I depict an
inboard propeller. FIGS. 21A-F depict a propeller with a through hub exhaust for an outboard
motor.
Various embodiments of the invention have been described, each having a different
combination of elements. The invention is not limited to the specific embodiments disclosed,
and may include different combinations of the elements disclosed or omission of some elements
and the equivalents of such structures.
While the invention has been described by illustrative embodiments, additional
advantages and modifications will occur to those skilled in the art. Therefore, the invention in
its broader aspects is not limited to specific details shown and described herein. Modifications,
for example, the number of blades and curvature of the blades, may be made without departing
from the spirit and scope of the invention. Accordingly, it is intended that the invention not be
limited to the specific illustrative embodiments, but be interpreted within the full scope of the
appended claims and their equivalents.
Claims (33)
1. A method of manufacturing a propeller having a plurality of blades, each of the plurality of blades having an intake portion, an exhaust portion, and a tip portion extending from the intake portion to the exhaust portion, the method comprising: defining a plurality of parameter sections by selecting parameters including skew angle, roll angle, rake, radius, pitch angle, vertical angle, wherein the selected parameters redirect lift; defining a parameter section at the transition from the intake portion to the tip portion having a roll angle between 40 to 50 degrees to cause an amount of non-axial lift in the tip portion to be greater than an axial lift in the tip portion; defining parameter sections to include a roll angle of 90 degrees in the tip portion; extrapolating between parameter sections to form smooth lines to form a blade configured to form a loop when attached to a hub.
2. The method of claim 1 comprising aligning the parameter sections along a non- helical median line.
3. The method of claim 1 further comprising forming the hub having a plurality of the blades extending outward from the hub and disposed around the hub.
4. The method of claim 1 comprising defining one or more parameters for parameter sections in the intake portion to cause the amount of non-axial lift in the intake portion to be less than the non-axial lift in tip portion.
5. The method of claim 1 comprising defining one or more parameters for parameter sections in the exhaust portion to cause the amount of non-axial lift in the exhaust portion to be less than the non-axial lift in the tip portion.
6. The method of claim 1 comprising selecting parameters including average pitch angle of the exhaust portion of the blade greater than average pitch angle of the intake portion.
7. The method of claim 1 comprising selecting parameters so a root of the intake portion is forward of a root of the exhaust portion when extending outward from the hub, and skew begins at zero and ends at a positive value.
8. The method of claim 1 comprising selecting parameters including pitch angle of the exhaust portion at its root greater than pitch angle of the intake portion at its root.
9. The method of claim 1 comprising selecting parameters for parameter sections such that the tip portion has a 90 degree roll angle closer to the exhaust portion than to the intake portion.
10. The method of claim 1 comprising selecting parameters including a zero vertical angle throughout the tip portion.
11. The method of claim 1 comprising selecting parameters including a pitch angle of the exhaust portion at its root less than a pitch angle of the intake portion at its root.
12. The method of claim 1 wherein the parameter sections are planar.
13. The method of claim 1 comprising selecting parameters to form a blade having an average non-axial lift greatest in the tip portion as compared to either in the intake portion or the exhaust portion, and the intake portion is 0-45% of the blade, the tip portion is 30%-75% of the blade and the exhaust portion is 50 % to 90 % of the blade.
14. The method of claim 1 comprising selecting parameters so in at least a portion of the tip portion of the blade before a 90 degree roll angle and toward the intake end of the tip portion, the distance (N) to a parameter cross-section nose as would be measured perpendicularly from a rotational axis to which the blade extends outward is greater than distance (T) to a parameter cross-section tail as measured perpendicularly from the rotational axis; and wherein 80% of the tip portion has a roll angle of less than 90 degrees and N is greater than T for the same 80% of the tip portion.
15. The method of claim 1 comprising selecting parameters including a non-zero pitch angle throughout the tip portion.
16. The method of claim 1 comprising selecting parameters including an average vertical angle for parameter sections in the exhaust portion greater than an average vertical angle for parameter sections in the intake portion.
17. The method of claim 1 comprising selecting parameters including rake of parameter sections being increasingly negative from a root of the intake portion root through the first 30% to 40% of the blade, then increasing for the next 10% to 15% of the blade until it reaches positive values and continues to increase for an additional 20% to 40% of the blade and then level off for the remainder of the blade or decrease.
18. A propeller comprising: a plurality of blades, each of the plurality of blades having an intake portion, an exhaust portion, and a tip portion extending from the intake portion to the exhaust portion; a hub; the plurality of blades extending outward from the hub and disposed around the hub; each blade forming a loop; each blade comprising a plurality of parameter sections having selected parameters including skew angle, roll angle, rake, radius, pitch angle, vertical angle, wherein the selected parameters redirect lift; a parameter section at the transition from the intake portion to the tip portion having a roll angle between 40 to 50 degrees to cause an amount of non-axial lift in the tip portion to be greater than an axial lift in the tip portion; and a parameter section or area between consecutive parameter sections in the tip portion having a roll angle of 90 degrees.
19. The propeller of claim 18 comprising the plurality of blades each having an irregular helical median line
20. The propeller of claim 18 wherein the plurality of blades are configured so non-axial lift in the intake portion is less than the non-axial lift in the tip portion.
21. The propeller of claim 18 wherein the plurality of blades are configured so an amount of non-axial lift in the exhaust portion is less than the non-axial lift in the tip portion.
22 The propeller of claim 18 wherein the average pitch angle of the exhaust portion of the blade is greater than the average pitch angle of the intake portion.
23. The propeller of claim 18 wherein a root of the intake portion is forward of a root of the exhaust portion when extending outward from the hub, and skew begins at zero and ends at a positive value.
24. The propeller of claim 18 wherein pitch angle of the exhaust portion at its root is greater than pitch angle of the intake portion at its root.
25. The propeller of claim 18 wherein the tip portion has a 90 degree roll angle closer to the exhaust portion than to the intake portion.
26. The propeller of claim 18 wherein the tip portion has a zero vertical angle throughout.
27. The propeller of claim 18 wherein a pitch angle of the exhaust portion at its root is less than a pitch angle of the intake portion at its root.
28. The propeller of claim 18 wherein the parameter sections are planar.
29. The propeller of claim 18 wherein the blades are configured so average non-axial lift is greatest in the tip portion as compared to either in the intake portion or the exhaust portion, and the intake portion is 0-45% of the blade, the tip portion is 30%-75% of the blade and the exhaust portion is 50% to 90% of the blade.
30. The propeller of claim 18 wherein in at least a portion of the tip portion of the blade before a 90 degree roll angle and toward the intake end of the tip portion, distance (N) to a parameter cross-section nose as would be measured perpendicularly from a rotational axis to which the blade extends outward is greater than distance (T) to a parameter cross-section tail as measured perpendicularly from the rotational axis; and wherein 80% of the tip portion has a roll angle of less than 90 degrees and N is greater than T for the same 80% of the tip portion.
31. The propeller of claim 18 comprising a non-zero pitch angle throughout the tip portion.
32. The propeller of claim 18 wherein an average vertical angle for parameter sections in the exhaust portion is greater than an average vertical angle for parameter sections in the intake portion.
33. The propeller of claim 18 wherein the plurality of blades are configured so rake of parameter sections is increasingly negative from a root of the intake portion root through the first 30% to 40% of the blade, then increasing for the next 10% to 15% of the blade until rake reaches positive values and continues to increase for an additional 20% to 40% of the blade and then level off for the remainder of the blade or decrease.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US16/170,157 US11279501B2 (en) | 2018-10-25 | 2018-10-25 | Satellite attitude control system using eigen vector, non-linear dynamic inversion, and feedforward control |
| US16/170,157 | 2018-10-25 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| NZ757832A NZ757832A (en) | 2021-05-28 |
| NZ757889B2 true NZ757889B2 (en) | 2021-08-31 |
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