Patent Description:
<CIT> discloses a propeller with closed loop blades. <CIT> discloses a propeller comprising a plurality of blades wherein a section side of the blade unit of a blade at the downstream side is located in a position closer to the pressure side of the blade units at the upstream rather than the suction side of the blade units at the upstream. <NPL>, presents a compendium on maritime bionics including information on propellers used for ships.

It 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 some of the parameters including skew angle, roll angle, rake, radius, pitch angle, vertical angle values, defining a parameter section at the transition from the intake portion to the tip portion by parameters to cause the 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 value of <NUM> 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.

For further detail regarding illustrative examples of propellers that can be manufactured by the herein disclosed methods of manufacturing propellers, reference is made to the detailed description provided below, in conjunction with the following illustrations.

<FIG>depict propeller <NUM> that can be manufactured by a method according to an illustrative embodiment. <FIG> depicts a perspective view of propeller <NUM>. <FIG> depicts a side view of propeller <NUM>, and <FIG> depicts the opposing side of propeller <NUM>. <FIG> and <FIG> depict a top (fore) view and bottom (aft) view, respectively, of Propeller <NUM>. Propeller <NUM> includes a plurality of blades <NUM>, <NUM>, <NUM>, each having, an tip portion <NUM>, an intake portion <NUM> and an exhaust portion <NUM>. In this illustrative example, blades <NUM>, <NUM> and <NUM> extend from a hub <NUM>. Each of blades <NUM>, <NUM>, <NUM> has a median line <NUM>, <NUM>, <NUM>, respectively. Blades <NUM>, <NUM>, <NUM> rotate about hub axis <NUM>. 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 examples, 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 examples 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 <NUM> has three blades <NUM>, <NUM>, <NUM> disposed at equal increments around hub <NUM>. Disclosed examples 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 <NUM>, <NUM>, <NUM> may be configured to rotate about an axis corresponding to hub axis <NUM>, 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 <NUM> may also be hollow, and may have openings in its surface, such as in a centrifugal fan.

<FIG> depicts a blade <NUM> having parameter sections <NUM>-<NUM>, with parameter section <NUM> in the vicinity of the intake root <NUM>, and parameter section <NUM> in the vicinity of exhaust root <NUM>. 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 <NUM> and its behavior. Parameter sections are equally spaced in an exemplary example but may be selected at unequal intervals. <FIG> 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 <NUM> 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 example in <FIG>, blade sections <NUM>-<NUM> are planar sections disposed along an irregular helical median line <NUM>. "Irregular helix" is used herein to mean varying from a mathematical helix-defining formula or as a spiral in <NUM>-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 <NUM> blade sections are shown in <FIG>, 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 <NUM>-<NUM> 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 <NUM>. The X-Axis is along hub axis <NUM>, 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.

<FIG> 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 <NUM>. Parameter section <NUM> is in the form of an asymmetrical airfoil. The airfoil is bounded by a curved blade surface line <NUM> and a generally flat blade surface line <NUM>, with a rounded nose <NUM> at the leading edge <NUM> of the parameter section and a pointed or less rounded tail <NUM> at the trailing edge <NUM> of parameter section <NUM>. 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 <NUM>, <NUM>. Blade surface lines <NUM>, <NUM> 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 <NUM>, <NUM>) 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 <NUM>, <NUM>. 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.

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 <NUM> of parameter section <NUM>, for example, and thus will be referred to as a "nose radius. Other points on parameter section <NUM> may be used to calculate a radius. By way of example, parameter section leading edge radius may be calculated based on maximum thickness <NUM> and the length of chord <NUM>.

Chord: The chord is the nose-to-tail line <NUM> of the parameter section.

Thickness: Various thickness measurements may define a parameter section such as, for example, the maximum thickness <NUM>. A further illustrative example is the trailing edge thickness, which may be calculated as a percentage of maximum thickness <NUM>. For example, the trailing edge thickness may be <NUM>% of maximum thickness <NUM> of parameter section <NUM>.

Camber: Camber <NUM> defines the curvature of a parameter section.

Rake: Rake is the axial location of a parameter section chord midpoint.

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 <FIG> for various parameter sections. Each of <FIG> 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 example, 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.

<FIG> and <FIG> depict Rake for parameter sections <NUM>, <NUM> on the intake portion <NUM> of blade <NUM>. Parameter section <NUM> in <FIG> is toward tip portion <NUM> of blade <NUM>. Parameter section <NUM> is toward intake root <NUM>. Rake is measured along the propeller rotational axis or along a line parallel to the rotational axis. In the illustrative examples of <FIG>, <FIG>, 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 <NUM> of the chord of parameter sections <NUM>, <NUM>. The X-coordinate value of point B is represented by Bx in <FIG>.

<FIG> and <FIG> depict Rake for parameter sections <NUM>, <NUM> on the tip portion <NUM> of blade <NUM>. Parameter section <NUM> in <FIG> is at a first position in tip portion <NUM> of blade <NUM> wherein the roll value (described further below) is greater than zero and less than <NUM> degrees. Parameter section <NUM> in <FIG> is at a second position in tip portion <NUM> where the roll value is equal to or greater than <NUM> degrees. In the illustrative examples of <FIG>, <FIG>, 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 <NUM> of the chord of parameter sections <NUM>, <NUM>. <FIG> and <FIG> depict Rake for parameter sections <NUM>, <NUM> on the exhaust portion <NUM> of blade <NUM>. Parameter section <NUM> in <FIG> is toward tip portion <NUM> of blade <NUM>. Parameter section <NUM> is toward exhaust root <NUM>. In the illustrative examples of <FIG>, <FIG>, 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 <NUM> of the chord of parameter sections <NUM>, <NUM>.

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 <FIG> and <FIG>. <FIG> and <FIG> show pitch angle for parameter sections <NUM> and <NUM>, respectively.

Radius: The orientation radius is the distance from the hub center <NUM> to the midpoint <NUM> of chord <NUM> of a parameter section. Chord <NUM> may also be referred to as the 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 <NUM> of chord <NUM> is the point on the parameter section chord line through which the median line <NUM> would pass. This is illustrated in <FIG> by line R which extends from hub center <NUM> to the midpoint of the chord of parameter section <NUM>. Note that the chord of parameter section <NUM> and its midpoint are not specifically shown in <FIG>.

<FIG> depict blade <NUM> viewed along the blade rotational axis X. <FIG> identify representative parameter section radii and skew angle. <FIG> depicts the radius of parameter section <NUM> in the intake portion <NUM> of blade <NUM>. <FIG> shows the radius of parameter section <NUM>, a parameter section in intake portion <NUM> of blade <NUM> further from intake root <NUM> than parameter section <NUM>. <FIG> and <FIG> depict radii for parameter section <NUM> and <NUM>, respectively, wherein parameter section <NUM>, <NUM> are in tip portion <NUM>. <FIG> and <FIG> depict radii for exhaust parameter section <NUM> and <NUM>, respectively, both within exhaust portion <NUM>. The position of parameter sections <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM> as being in intake portion <NUM>, tip portion <NUM>, or exhaust portion <NUM> are provided only for ease of discussion. The actual parameter values and resulting fluid flow may define the positions of the sections otherwise.

<FIG>further show skew angle of parameter sections <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. Skew angle is the projected angle from a line through midpoint <NUM> of chord <NUM> to the generating line, in this illustrative example the Y-axis looking along hub axis <NUM> (X-axis).

<FIG>, in addition to depicting skew angle and radius, depict parameter section vertical angle, Alpha, labeled on each of <FIG>. 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 <FIG>.

It is noted that <FIG> 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 <FIG> with <FIG>.

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 example, roll at intake root <NUM> is zero, roll at exhaust root <NUM> is <NUM> degrees and a roll of <NUM> degrees is at a location within tip portion <NUM>.

Various illustrative examples will be described by combinations of characteristics. The disclosed propeller includes different combinations of the characteristics, equivalents of the elements and may also include examples wherein not all characteristics are included.

In an illustrative example of a propeller, the propeller includes a plurality of blades in a loop form, generally as shown in <FIG>. The propeller in <FIG> 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 <NUM>, <NUM>, <NUM> of propeller <NUM> includes a tip portion <NUM>, an intake portion <NUM> and an exhaust portion <NUM>. In an illustrative example, the intake portion is <NUM>-<NUM>% of the blade, the tip portion is <NUM>%-<NUM>% of the blade and the exhaust portion is <NUM> percent to <NUM> percent of the blade.

Propeller <NUM> may have various number of blades, each preferably with the same characteristics and parameters, although variations between blades is within the scope of the examples. An illustrative number of blades is between two and twelve, although more blades may be included in a single propeller. In particular examples a propeller may have three, four, five, seven or eleven blades. In a propeller example having looped blades, the blades have an intake root <NUM> at hub <NUM> and an exhaust root134 at hub <NUM>. Intake portion <NUM>, tip portion <NUM> and exhaust portion <NUM> 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 <NUM>, for example. Referring back to FIGS. 1A-F, intake portion <NUM> extends from hub <NUM> generally outward for a propeller with a hub <NUM>. Intake portion <NUM> may have a roll of zero at intake root <NUM>. Intake portion <NUM> 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 <NUM> may be zero. Illustrative roll value ranges for parameter sections in intake portion <NUM> include zero at intake root <NUM> progressing to between about <NUM> degree to <NUM> degrees where intake portion <NUM> transitions to tip portion <NUM>. Additional ranges of roll value for intake portion <NUM> from intake root <NUM> to tip portion <NUM> include: from zero to between about <NUM> degrees to <NUM> degrees, and from zero to between about <NUM> degrees to <NUM> degrees.

Tip portion <NUM> 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 <NUM> degrees or just greater than <NUM> degrees.

Tip portion <NUM> is configured to generate non-axial lift only, more non-axial lift than axial lift, or more non-axial lift than intake portion <NUM>. The roll value of parameter sections in tip portion <NUM> will transition from less than <NUM> degrees to greater than <NUM> degrees. Illustrative roll value ranges of tip portion <NUM> include between <NUM> degree and <NUM> degrees at the transition from intake portion <NUM> through between <NUM> and <NUM> degrees where tip portion transitions to exhaust portion <NUM>. Additional illustrative roll value ranges of tip portion <NUM> include beginning at the transition from intake portion <NUM>, between <NUM> degrees and <NUM> degrees and transitioning to a roll of between <NUM>-<NUM> degrees.

In an illustrative example the transition from intake portion <NUM> to tip portion <NUM> occurs when the amount of non-axial lift produced by a given parameter section is greater than the axial lift. In a particular example this transition takes place when roll is <NUM> degrees, or when roll is in a range of <NUM> degrees to <NUM> degrees.

Exhaust portion <NUM> is configured to generate less non-axial lift than tip portion <NUM>. In an illustrative example, the blade is configured so the average non-axial lift is the greatest in tip portion <NUM> as compared to either intake portion <NUM> or exhaust portion <NUM>. In an illustrative example the blade is configured so the average non-axial lift, if any, is greater in exhaust portion <NUM> than in intake portion <NUM>. Illustrative roll value ranges of exhaust portion <NUM> include between <NUM> degrees and <NUM> degrees at the transition from tip portion <NUM> to exhaust portion <NUM> through <NUM> degrees at exhaust root <NUM>. Additional illustrative ranges include beginning at the transition from tip portion <NUM>, between <NUM> degrees and <NUM> degrees and transitioning to a roll of <NUM> degrees at exhaust root <NUM>.

<FIG> depict illustrative values or relative values of various parameters that define a parameter section or a blade. <FIG> depicts illustrative roll values from an intake root of a blade to exhaust root. In an illustrative example, beginning at intake root <NUM> through exhaust root <NUM>, parameter section roll transitions from about zero to <NUM> degrees over the first <NUM> percent of the blade, from about <NUM> degrees to about <NUM> degrees over the next <NUM> percent of the blade, and from about <NUM> degrees to about <NUM> degrees over the last <NUM> percent of the blade.

In an illustrative example non-axial lift is created by <NUM> percent to <NUM> percent of the blade. Further illustrative ranges include <NUM> percent to <NUM> percent and <NUM> percent to <NUM> percent.

<FIG> depicts an illustrative example of a propeller <NUM> showing fluid flow around blades <NUM>, <NUM>. Intake portions <NUM>, <NUM> show fluid flow in an axial direction at the intake portions <NUM>, <NUM> of blades <NUM>, <NUM>, respectively. Fluid flow remains axial as the propeller moves forward or fluid moves through blades <NUM>, <NUM>. Fluid flow is still axial as it departs from the exhaust portions <NUM>, <NUM> of blades <NUM>, <NUM>, respectively.

Within the tip portion of blades <NUM>, <NUM> 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 <NUM>, <NUM> non-axially. As fluid is pulled in by the tip portions <NUM>, <NUM> it is redirected into toward an axial direction within the loops of blades <NUM>, <NUM>. The non-axial lift may cause drag, which is created by the tip portion. As fluid passes the trailing edge of blades <NUM>, <NUM>, in tip portions <NUM>, <NUM> it is in an axial direction or more toward an axial direction than when it entered the interior of the loops of blades <NUM>, <NUM>.

In an illustrative example, propeller <NUM> 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.

Referring back to FIGS. 1A-F, tip portions <NUM>, intake portions <NUM> and exhaust portions <NUM> do not necessarily extend equal distances, such as along median lines <NUM>, <NUM>, <NUM>. In an illustrative example, intake portions <NUM> encompass a shorter distance than exhaust portions <NUM>. Therefore, the distance along median line <NUM>, <NUM>, <NUM> wherein the blade is configured to redirect axial lift to non-axial lift extends a greater distance from exhaust root <NUM> than from intake root <NUM>. In an illustrative example, intake portion <NUM> extends a distance in a range of <NUM> percent to <NUM> percent of the median line length, exhaust portion <NUM> extends a distance in a range of <NUM> percent to <NUM> percent of the median line length; and tip portion <NUM> extends a distance of <NUM> percent to <NUM> percent of the median line length.

<FIG> depicts illustrative relative pitch angle values from an intake root of a blade to exhaust root. In an illustrative example, beginning at intake root <NUM> through exhaust root <NUM>, parameter section pitch angle transitions from about <NUM> degrees to about <NUM> degrees, over the next <NUM> percent of the blade pitch angle transitions from about <NUM> degrees to about <NUM> degrees, and over the last <NUM> percent of the blade, pitch angle transitions from about <NUM> degrees to about <NUM> degrees. In an illustrative example, tip portion <NUM> has a non-zero pitch angle throughout. In an exemplary example tip portion <NUM> is defined as and is configured to have non-zero pitch and redirect non-axial lift to create axial thrust.

<FIG> depicts the vertical angle, Alpha, from an intake root of a blade to exhaust root according to an illustrative example. The vertical angle orients parameter sections away from being perpendicular to skew. In an illustrative example the vertical angle is zero for all parameter sections. In a further example 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 example tip portion <NUM> may have at least one parameter section with a non-zero vertical angle. In other examples, the average vertical angle for the tip and intake portions is greater than the average vertical angle of the exhaust portion.

In an illustrative example the average vertical angle for parameter sections in exhaust portion <NUM> is greater than the average vertical angle for parameter sections in intake portion <NUM>.

Illustrative ranges of the vertical angle of tip portion <NUM> includes, <NUM> to <NUM> degree, <NUM> degree to <NUM> degrees; <NUM> degrees to six degrees; zero to <NUM> degrees; <NUM> degree to <NUM> degrees; and <NUM> degrees to <NUM> 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 <NUM> may create non-axial lift and drag in the vicinity. In illustrative examples, the vertical angle is between -<NUM> degrees and <NUM> degrees throughout the blade; between -<NUM> degrees and <NUM> degrees or between -<NUM> degrees and <NUM> degrees throughout the blade.

<FIG> depicts illustrative relative radius values from an intake root of a blade to exhaust root. In an illustrative example the radius of parameter sections increases throughout the first <NUM> percent to <NUM> percent of the blade beginning at intake root <NUM> and then decreases through parameter sections through to exhaust root <NUM>. As used in this paragraph and elsewhere, parameters transitions over parameter sections correspond to transitions through the blade.

<FIG> depicts illustrative rake values from an intake root of a blade to exhaust root. Rake in an exemplary example may be increasingly negative from intake root <NUM> through the first <NUM> percent to <NUM> percent of the blade. Rake may then increase for the next <NUM> percent to <NUM> percent of the blade until it reaches positive values. Rake may then continue to increase for an additional <NUM> percent to <NUM> 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.

<FIG> depicts illustrative relative skew values from an intake root of a blade to exhaust root. In an illustrative example the skew value continually increases from intake root <NUM> through exhaust root <NUM>. In another illustrative example 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 <NUM> may be normal to the skew line throughout the blade or in a portion of the blade, wherein the skew line to which chord <NUM> is perpendicular is the skew line that forms the skew angle with the zero skew line.

<FIG> depicts illustrative relative camber values from an intake root of a blade to exhaust root. In an illustrative example the camber of parameter sections transitions from a positive value at the intake root <NUM> to a negative value at the exhaust root <NUM>, 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.

<FIG> depicts illustrative relative chord values from an intake root of a blade to exhaust root. In an illustrative example chord decreases from intake root <NUM> and then begins to increase toward exhaust portion <NUM> and continues to increase to exhaust root <NUM>. In other illustrative examples, chord increases from intake root <NUM> and then decreases toward exhaust portion <NUM> and continues to decrease to exhaust root <NUM>.

In illustrative examples tip portion <NUM> from the tip portion intake end to the tip portion exhaust end exhibits one or more of the following characteristics:.

The chart below provides illustrative values for selected parameter sections. The parameter sections are <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM> from a blade defined by <NUM> parameter sections. Parameter section <NUM> is the closest of the selected parameter sections to intake root <NUM>. Parameter section <NUM> is the closest of the selected parameter section to exhaust root <NUM>.

<FIG> provide a schematic representation of parameter sections <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM>, respectively. As noted above, <FIG> depict parameter sections having an Alpha value of zero. In an illustrative example 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 <FIG>, it can be seen that the radius increases from parameter section <NUM> through parameter section <NUM> and then is decreasing at parameter section <NUM> through parameter section <NUM>. Pitch, skew and roll increase throughout parameter sections <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM>. Pitch angle decreases from parameter section <NUM> through parameter section <NUM> and then shows an increase at parameter section <NUM>.

<FIG>provide a schematic representation of pitch angle for parameter sections <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM>, respectively. Pitch angle varies throughout the blade with the largest values occurring at the intake and exhaust roots.

<FIG> depict representations of parameter sections <NUM>, <NUM>, <NUM> and <NUM> of <NUM> 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.

Radius, Pitch, Skew, Pitch Angle and Roll are given the same values as the illustrative example having Alpha equal to zero. In the example represented by <FIG> Alpha decreases through parameter sections <NUM> through <NUM> and then becomes negative at a location on the blade between parameter section <NUM> and <NUM>. This change is illustrated in <FIG>.

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.

Illustrative examples of the propeller may have one or more of the following characteristics and any characteristics described herein:.

Propeller variations can have the same median line but vary in other parameters. A series of propellers according to illustrative examples 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.

<FIG>, <FIG> 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 <NUM> 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 <NUM>. In an illustrative example A is greater than B for all of tip portion <NUM>. In further illustrative examples A is greater than B for <NUM> percent to <NUM> percent of tip portion <NUM>. In a further examples the percent of tip portion <NUM> that has A greater than B is in the range of <NUM> percent to <NUM> 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.

Illustrative examples 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 <FIG>. <FIG> is a perspective view of a "hubless" propeller <NUM>. In this example there are seven blades <NUM>, each having their intake root <NUM> and exhaust root <NUM> extending from a rim <NUM>, with tip portion <NUM> toward the center of the propeller. <FIG>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 <NUM> 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.

It is disclosed is a method for creating a propeller according to any of the examples described herein. In an exemplary example 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 example 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.

Several different devices can be obtained by the inventive method, for example: 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 includes methods of manufacturing a propeller, including any of the above-listed devices, according to any of the examples described, pictured or claimed herein.

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 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 example, a propeller as described herein is incorporated into a turbofan as shown, for example, in <FIG>. The turbofan may have, for example, between eight and twelve blades. It is noted that the blades depicted in <FIG> are not necessarily of a type described herein. The figures are merely provided to indicate the type of device.

In a further illustrative example a propeller as described herein is incorporated into an unmanned aerial vehicle or device such as shown for example, in <FIG>. It is noted that the blades depicted in <FIG> are not necessarily of a type described herein. The figures are merely provided to indicate the type of device.

Claim 1:
A method of manufacturing a propeller (<NUM>) having a plurality of blades (<NUM>), each of the plurality of blades (<NUM>) having an intake portion (<NUM>), an exhaust portion (<NUM>), and a tip portion (<NUM>) extending from the intake portion (<NUM>) to the exhaust portion (<NUM>), the method comprising:
defining a plurality of parameter sections by selecting some of the parameters including skew angle, roll angle, rake, radius, pitch angle, vertical angle values;
defining a parameter section at the transition from the intake portion (<NUM>) to the tip portion (<NUM>) by parameters to cause the amount of non-axial lift in the tip portion (<NUM>) to be greater than the axial lift in the tip portion (<NUM>);
defining parameter sections to include a roll value of <NUM> degrees in the tip portion (<NUM>); and
extrapolating between parameter sections to form smooth lines to form a blade configured to form a loop when attached to a hub (<NUM>).