Arrow Vane

Description

CROSS REFERENCE

The present application claims the benefit of the filing date of U.S. Provisional Application No. 63/683,049 filed on Aug. 14, 2024, the entire contents of which is incorporated by reference.

FIELD

The present application is directed to the field of archery. More specifically, the present application is directed to an improved vane for attachment to an arrow shaft.

BACKGROUND

An arrow used for the sport of archery has evolved over the thousands of years archery has existed. In recent years, bows as well as arrow shafts have significantly improved in technology and construction methods leading to more consistent products. Now more focus is being given to the individual components and construction of complete arrow assemblies. These assemblies primarily consist of a point, an insert, an arrow shaft, vanes and a nock. Vanes, in particular, are aerodynamic elements operatively coupled in some way to the nock end (back) of an arrow shaft. Simply put, the vanes are used to increase the stability of an arrow in flight. Key to ensuring the optimal flight of an arrow is the design and alignment of the vanes and the specific broadhead or field point used. Acting as a guiding system, the fletching significantly influences accuracy, stability, drag, sound, and spin during flight.

One present issue for vanes currently available on the market is that the vanes that generate the most stability also cause a substantial amount of noise in both amplitude and high frequencies. The amplitude as well as higher frequency generated from current vane profiles leads to issues when (but not limited to) hunting. Animals will react to the noise and move (dodge, duck, dip or dive) before the arrow reaches its intended point of impact. This movement by the animal leads to missing shots or worse injuring or maiming the animal.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings form a part of this disclosure and are incorporated into the specification. The drawings illustrate example embodiments of the disclosure and, in conjunction with the description and claims, serve to explain various principles, features, or aspects of the disclosure. Certain embodiments of the disclosure are described more fully below with reference to the accompanying drawings. However, various aspects of the disclosure may be implemented in many different forms and should not be construed as being limited to the implementations set forth herein

FIG. 1 is a perspective view of an arrow, in an embodiment.

FIG. 2A is a perspective view of an arrow vane, in an embodiment.

FIG. 2A is a side view of an arrow vane, in an embodiment.

FIG. 2C is a front view of an arrow vane, in an embodiment.

FIG. 3 is a sideview of an arrow vane showing geometrical relationships of various sections of the arrow vane, in an embodiment.

FIG. 4 is a sideview of an arrow vane in another embodiment.

DETAILED DESCRIPTION

Provided herein is an arrow vane design (e.g., profile) with enhanced performance for bowhunting, meeting specific requirements: increasing accuracy/precision with a fixed broadhead on the front of the arrow for more precise flight, minimizing drag to maximize downrange velocity, reducing wind drift and applied moments or forces associated with crosswinds during arrow flight, minimizing sound in the 4-8 kHz range, and optimizing spin to quickly counteract any asymmetries. Both empirical testing and computational fluid dynamics (CFD) were used to develop the presented an arrow vane design.

Aspects of the present disclosure are based on the realization that there are competing interests in arrow vane design. For instance, it has been determined by the inventors that vanes that are shorter in height generate less sound and drag. However, shorter vanes also tend to produce less restoring force/torque. To fly accurately and repeatedly, arrows must be stable. To be stable, an arrow's center of pressure (CoP) must be behind the arrow's center of gravity (CoG). The CoG is the point where all the arrow's mass can be summed to, commonly known as the balance point. The CoP is the point where all the pressures/forces acting on the arrow can be summed to. This configuration is considered stable because the arrow will naturally align itself with the oncoming airflow whenever it gets angled away from the oncoming airflow. If the CoP was in front of or on top of the CoG the arrow will attempt to orient itself nock first into the airflow or simply tumble. To achieve a stable configuration, vanes are added to the rear of an arrow. When an arrow is not aligned with the oncoming airflow, a pressure differential develops between the windward (side of the vane which is facing towards the oncoming air) and leeward (side of the vane which is facing away from oncoming air) sides of the vanes which generates a lift force in the direction that would align the arrow back into the airflow. The lift force generated by the vanes is some distance away from the CoG, the point at which the arrow pivots about, which develops a restoring torque. The further behind (i.e., toward the rear of the arrow) the CoP the longer the lever arm for the restoring force.

The empirical testing and CFD analysis identified several trends and design choices in how to improve specific aspects of a vane's performance by making slight geometry changes. One finding was that when there are sharp changes in geometry, particularly around the transition from the leading to the trailing edge, the geometry causes an increase in drag thereby increasing sound. Another finding was that with geometry on the leading edge that induces a larger geometry change from the arrow body itself also increases the amount of drag that an arrow produces. That is, a rapid change in geometry causes flow around the arrow shaft to slow suddenly as it does not have time to react to the change in geometry. It was found that by smoothing the geometry to more slowly ‘ramp’ the air up reduced drag induced by the leading edge. Finally, it was determined that the more area a vane has in the trailing geometry section (e.g., rearward section) of the vane, when paired with a smooth transition from the leading edge to the trailing edge, the vane will increase the amount of restoring force and torque that the arrow experiences, imparted by the arrow vane. Having a smooth transition is important because of considerations like drag and sound as mentioned before, but also to increase flow attachment to the vane to let the air affect the vane as long as possible. That is, to reduce turbulence and provide a more laminar flow over the transition from the leading edge to the trailing edge. By moving a majority of the area of the vane to the trailing geometry section, there is an increased lever arm produced by the vane's reaction to the force from the air and allows for the arrow to have a stronger correcting force (e.g., to correct yaw of the arrow during flight).

FIG. 1 illustrates an exemplary arrow 10. The arrow 10 includes an elongated shaft 12 having a forward end 14 on which an arrowhead 16 (e.g., field point, etc.) is mounted and a rear end 18 on which a nock 20 is mounted. The arrow 10 includes three symmetrically spaced vanes 100 (only two shown) constructed in accordance with the present disclosure. Though described as having three vanes 100, it will be appreciated that the number and orientation of the vanes may vary.

FIGS. 2A, 2B and 2C illustrate a perspective, side and front-end view of the arrow vane 100, in an embodiment. The arrow vane 100 includes two main components, a vane fin 110 and a vane base 150. The vane fin 110 is a thin flat member, which may be made of any appropriate material. A straight bottom or base edge 116 of the vane fin 110 is fixedly attached to the vane base 150, which is configured for attachment to the shaft of an arrow. The edge profile of the vane fin 110 extending above the base 150 is defined by leading edge 120, 122, a trailing edge 140 and a rounded transition edge 142 connecting the leading and trailing edges. More specifically, the leading edge includes a steep front section 120 that extends between a forward end 112 of the vane fin 100 attached to the base 150 to a leading edge transition point 130 and a shallow sloping section 122 that extends between the leading edge transition point 130 and a highest edge point 132 of the vane fin (i.e., as measured from the base 150) The trailing edge 140 extends from the rearward end 114 of the vane fin attached to the base 150 upward toward the highest edge point 132 of the vane fin 110. The smooth arcuate or rounded transition edge 142 connects the trailing edge 140 to shallow sloping section 122 of the leading edge. The base 150 is substantially perpendicular to the vane fin 110 and has a top surface and a bottom surface. The top surface of the base 150 is attached, adhered, adjoined, integral with or otherwise meets or corresponds with the bottom-edge of the vane fin 110. The bottom surface of the base 150 is attachable to the surface of an arrow shaft.

The length ‘L’ of the arrow vane 100 is the distance between the forward end 112 and rearward end 114 of the vane fin 110 (e.g., measured along the straight bottom edge). Typically, the base 150 is the same length as the van fin 110 though in some instances the length of the base may exceed the length of the vane fin 110. In some embodiments, the length L of the arrow vane is between about 1.75 inches and about 3.5 inches. In other embodiments, the length L of the arrow vane is between about 2.0 inches and about 3.0 inches. In other embodiments, the length L of the arrow vane is between about 2.2 inches and about 2.75 inches. As shown, the height ‘H’ of the vane fin 110 is measured from the straight bottom edge 116 of the vane fin, which forms a reference axis, perpendicular to its upward edge. The height H varies over the length of the vane fin 110. In any embodiment, the vane fin will have a highest point extending the greatest distance from the bottom edge 116 of the vane fin. In some embodiments, the height H of the highest point of the arrow vane is between about 0.3 inches and about 1.0 inches. In other embodiments, the height H of the highest point of the arrow vane is between about 0.4 inches and about 0.7 inches. In other embodiments, the height H of the highest point of the arrow vane is between about 0.45 inches and about 0.6 inches.

FIG. 3 illustrates the arrow vane 100 of FIG. 2B with various reference lines to illustrate the various different sections and geometric relationships of the various edge surfaces of the arrow vane. As illustrated, the arrow vane is divided into four sections associated with the edge sections 120, 122, 140 and 142 discussed in relation to FIG. 2B. A ramp or forward section has a length LF that corresponds to the distance measured along the base edge 116 between the forward end 112 of the vane fin 110 and the leading-edge transition point 130. A sloping section has a length LS that corresponds to the distance measured along the base edge 116 between the leading-edge transition point 130 and the highest edge point 132 of the vane fin 110. A transition section has a length LT that corresponds to the distance measured along the base edge 116 between the highest edge point 132 of the vane fin 110 and the intersection of the with the trailing edge 140. A trailing or end section has a has a length LE that corresponds to the distance measured along the base edge 116 between the rearward end 114 of the vane fin and the intersection of the rounded transition edge 142 and the trailing edge 140 of the vane fin 110. In an embodiment, the forward section length LF forms between 15-25% of the overall length L of the vane fin 110, the sloping section length LS forms between 55-70% of the overall length L of the vane fin 110, the transition section length LT forms between 3-10% of the overall length L of the vane fin 110, and the end section length LE forms between 8-17% of the overall length L of the vane fin 110. In another embodiment, the forward section length LF forms between 18-22% of the overall length L of the vane fin 110, the sloping section length LS forms between 60-65% of the overall length L of the vane fin 110, the transition section length LT forms between 5-8% of the overall length L of the vane fin 110, and the end section length LE forms between 10-14% of the overall length L of the vane fin 110. In an embodiment, the highest edge point has a height H (see FIG. 2B) that is between about 15-30% of the overall length L of the vane fin 110. In another embodiment, the highest edge point has a height H that is between about 18-25% of the overall length L of the vane fin 110.

The chord angles of the leading edge sections 120, 122 and the angle of the substantially straight trailing edge 140 are also of importance for the presented design. As illustrated in FIGS. 2B and 3, the leading edge sections 120, 122 are relatively straight sections though not necessarily straight lines. In an embodiment, these sections 120, 122 are arcs having a large radius of curvature. In an embodiment, the radius of curvature for the forward leading edge section 120 is about 3 inches and a radius of curvature for the sloping section is about 14 inches (i.e., both for vanes between about 1.75 and about 3.5 inches long). However, a line segment that connects two points on these arcuate edge sections illustrate the primary angle at which these sections are disposed to the bottom edge 116 of the vane fin 110. In the embodiment of FIG. 3, a forward section chord 220 (shown as a ray for purposes of illustration) extending between the between the forward end 112 of the vane fin 110 and the leading edge transition point 130 has an included angle Θ relative to the bottom edge 116 of the vane fin 110 of between about 22° and about 31°. In another embodiment, the included angle Θ is between about 25° and about 29°. A sloping section chord 222 extending between the between the leading edge transition point 130 and the highest edge point 132 has an included angle β relative to the bottom edge 116 of the vane fin 110 of between about 7° and about 17°. In another embodiment, the included angle β is between about 10° and about 14°. This configuration results in the shorter forward section being relatively steeper than the longer sloping section.

While it has been determined that more slowly ramping the air up the vane reduces drag and noise induced by the leading edge of the vane, it has also been determined by CFD modeling that the forward section 120 of the leading edge can ramp up more quickly as the air contacting the forward end 112 of the forward section 120 is coming almost directly off of the arrow shaft as the arrow passes through the air. Air near the surface of the arrow shaft is subject to the boundary layer effect where air flowing over the shaft surface creates a thin layer near the shaft surface where the air's velocity changes from zero at the surface (due to the no-slip condition) to the free stream velocity further away. Stated otherwise, the air contacting the shorter steeper forward section 120 of the leading edge is at lower velocity and therefore results in less drag and noise. Further, the steeper shorter forward section 120 reduces the overall length of the arrow vane reducing material needed for construction. The shorter overall length also allows for easier application/bonding to the arrow shaft.

The sloping section 122 of the leading edge is disposed further from the arrow shaft and is therefore subjected to higher air velocities. Accordingly, ramping air over the sloping section 122 at a reduced angle is desirable to reduce drag and noise. Along these lines, the sloping section 122 of the leading edge typically has an angle β relative to the bottom edge 116 of the vane fin that is approximately one-half of the angle Θ of the forward section 120 of the leading edge relative to the bottom edge 116 of the vane fin. Further, due to the length and shallow angle of the sloping section 122, which forms the majority of the length of the vane fin 110, the center of area of the vane fin is disposed further back. This moves the CoP further toward the rear of the arrow providing a longer the lever arm for the restoring force generated on the arrow vane when the arrow is in flight.

Through CFD modeling and empirical testing, it has also been determined that use of a straight or nearly straight rearward edge 140, in conjunction with the rounded transition edge 142 reduces drag and noise while the arrow is in flight. That is, this combination allows air to maintain contact with the trailing edge 140 reducing turbulence. Further using a high included angle Ω between the trailing edge and the bottom edge of the fin vane shortens this section of the fin vane again allowing the center of area to be moved further back. In an embodiment, the included angle Ω is between about 50° and about 65°. In another embodiment, the included angle Ω is between about 50° and about 60°.

Though illustrated in FIGS. 2A, 2B and 3 as having leading-edge sections 120, 122 that are arcuate, it will be appreciated that these leading-edge sections 120, 122 could be straight edge sections as illustrated in FIG. 4, which utilizes like reference numerals to identify like elements with FIG. 3.

All directional references (e.g., plus, minus, upper, lower, upward, downward, left, right, leftward, rightward, top, bottom, above, below, vertical, horizontal, clockwise, and counterclockwise) are only used for identification purposes to aid the reader's understanding of the present disclosure, and do not create limitations, particularly as to the position, orientation, or use of the any aspect of the disclosure. As used herein, the phrased “configured to,” “configured for,” and similar phrases indicate that the subject device, apparatus, or system is designed and/or constructed (e.g., through appropriate hardware, software, and/or components) to fulfill one or more specific object purposes, not that the subject device, apparatus, or system is merely capable of performing the object purpose. Joinder references (e.g., attached, coupled, connected, and the like) are to be construed broadly and may include intermediate members between a connection of elements and relative movement between elements. As such, joinder references do not necessarily infer that two elements are directly connected and in fixed relation to each other. It is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative only and not limiting. Changes in detail or structure may be made without departing from the spirit of the invention as defined in the appended claims.

Any patent, publication, or other disclosure material, in whole or in part, which is said to be incorporated by reference herein is incorporated herein only to the extent that the incorporated materials does not conflict with existing definitions, statements, or other disclosure material set forth in this disclosure. As such, and to the extent necessary, the disclosure as explicitly set forth herein supersedes any conflicting material incorporated herein by reference. Any material, or portion thereof, that is said to be incorporated by reference herein, but which conflicts with existing definitions, statements, or other disclosure material set forth herein will only be incorporated to the extent that no conflict arises between that incorporated material and the existing disclosure material.