Abstract:
A clip for attachment as an edge. The clip having two symmetric sides, each side composed of five arcs. A first arc of the side starting at the midpoint of the nose having a radius of 0.2476 inches and an arc length of 0.22395 inches. A second arc connected to the first arc having a radius of 0.5832 inches and an arc length of 0.0947 inches. A third arc connected to the second arc having a radius of 0.4636 inches and an arc length of 0.1682 inches. A fourth arc connected to the third arc having a radius of 0.3822 inches and an arc length of 0.2263 inches. A fifth arc connected to the fourth arc having an arc having a radius of 0.3291 inches and an arc length of 0.1917 inches. The fifth arc of each side forming the slot end on the clip.

Description:
This application claims the benefit of and incorporates by reference U.S. Provisional Application No. 61/820,887 filed May 8, 2013 and U.S. Provisional Application No. 61/916,357 filed Dec. 16, 2013. 
    
    
     BACKGROUND 
     The present invention generally relates to shapes used in fluid flow. More specifically, the present invention relates surface shapes and fluid flow over those shapes. 
     There are many shapes on the market to enhance fluid flow. Not much work has been done to simply add a device to a shape to enhance fluid flow over that shape. What would be useful is a shape that could be used as a leading edge or trailing edge to attach to a shape to enhance fluid flow over that shape. 
     It is an object of the present invention to provide a clip to add a leading edge or trailing edge to a shape to enhance fluid flow over that shape. 
     SUMMARY OF THE INVENTION 
     A clip for attachment as an edge. The clip having two symmetric sides, each side composed of five arcs. A first arc of the side starting at the midpoint of the nose having a radius of 0.2476 inches and an arc length of 0.22395 inches. A second arc connected to the first arc having a radius of 0.5832 inches and an arc length of 0.0947 inches. A third arc connected to the second arc having a radius of 0.4636 inches and an arc length of 0.1682 inches. A fourth arc connected to the third arc having a radius of 0.3822 inches and an arc length of 0.2263 inches. A fifth arc connected to the fourth arc having an arc having a radius of 0.3291 inches and an arc length of 0.1917 inches. The fifth arc of each side forming the slot end on the clip. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view of a wind turbine according to the present invention. 
         FIG. 2  is an exploded view of a wind turbine according to the present invention. 
         FIG. 3  is an exploded view of a wind turbine according to the present invention. 
         FIG. 4  is an end view of a vane according to the present invention. 
         FIG. 5  is a perspective view of a vane according to the present invention. 
         FIG. 6  is an end view of a turbine blade according to the present invention. 
         FIG. 7  is a perspective view of a turbine blade according to the present invention. 
         FIG. 8  is a top view of a wind turbine according to the present invention. 
         FIG. 9  is a profile view of a clip according to the present invention. 
         FIG. 10  is a segment view of a clip according to the present invention. 
         FIG. 11  is a top view of a flat blade assembly with clip according to the present invention. 
         FIG. 12  is a perspective view of a frame assembly according to the present invention. 
         FIG. 13  is an exploded view of a frame assembly according to the present invention. 
         FIG. 14  is a perspective view of a turbine assembly in a frame assembly according to the present invention. 
         FIG. 15  is a schematic view of a vane position according to the present invention. 
         FIG. 16  is a schematic view of a blade position according to the present invention. 
         FIG. 17  is a perspective view of a wind flow about a wind turbine according to the present invention. 
         FIG. 18  is a top view of a wind flow about a wind turbine according to the present invention. 
         FIG. 19  is a perspective view of a two flat blade assembly according to the present invention. 
         FIG. 20  is a perspective view of a Savonius scoop blade assembly according to the present invention. 
         FIG. 21  is a perspective view of a three curved blade assembly according to the present invention. 
         FIG. 22  is a perspective view of a two flat blade assembly without clip according to the present invention. 
         FIG. 23  is a perspective view of a two flat blade assembly with clip according to the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention is a wind turbine used to convert wind into rotational energy.  FIGS. 1-8  show a first embodiment.  FIG. 1  shows a perspective top and side view of the wind turbine  10  of the first embodiment.  FIG. 2  shows a side exploded view and  FIG. 3  shows a perspective exploded view of the wind turbine  10 .  FIGS. 1-3  show a frame assembly  12  and with a turbine assembly  14  within the frame assembly  12 . 
     The frame assembly  12  is a stationary circular frame that has a multiple of airfoil shaped vanes  16  that take advantage of the Coand{hacek over (a)} effect, Bernoulli&#39;s principle, viscous shear and a resulting creation of a low pressure area. The vanes  16  are vertically mounted and attached to the outer perimeter of frame assembly  12  at an angle. The vanes  16  include a round outer edge with a curved dip just in front of the curved outer semi-circle, to aid in using the Coand{hacek over (a)} effect, Bernoulli&#39;s principle, viscous shear and the resulting creation of a low pressure area. In the center of the frame assembly  12 , is the circular turbine assembly  14  that rotates within the frame assembly  12 . The turbine assembly  14  includes multiple angled airfoil shaped turbine blades  18  with a specific shape to compress and accelerate the air and direct the air to opposite turbine blades  18  in order to create lift and torque a second time within the turbine assembly  14  before the air exits wind turbine  10  during rotation. The turbine blades  18  can be angled at different angles depending on the number of turbine blades  18 , but ideally around 22.5 degrees is the best angle. The air entering into the turbine assembly  14  from the frame assembly  12  passes a turbine blade  18  by moving over the curved surface of the turbine blade  18  creating a low pressure area in front of the turbine blade  18  and creating lift that is imparted to the forward momentum of the turbine blade  18  to create rotation of the turbine assembly  14 . The turbine assembly  14  can be connected to a load shaft  20  that spins a load such as a generator. 
     The frame assembly  12  includes vanes  16 , a bottom vane retainer  22  and a top vane retainer  24 , as shown in  FIGS. 2-3 . The vanes  16  include a bottom vane end  26 , a top vane end  28 . The vanes  16  include an aerodynamic shape vane between the bottom vane end  26  and the top vane end  28 . The bottom vane retainer  22  and top vane retainer  24  include vane tabs  30  and weight reduction holes  32 . The bottom vane retainer  22  and top vane retainer  24  each have an area about the perimeter that forms a mounting ring  35  from mounting of the vanes  16 .  FIG. 3  shows a pair of vane tabs  30  on the ring  35  of the bottom vane retainer  22  for each vane  16 . Each pair of vane tabs  30  on the bottom vane retainer  22  are shaped to receive the bottom vane end  26  of the vane  16  between the pair of vane tabs  30 . The bottom vane end  26  is secured between the pair of vane tabs  30  and hence the bottom vane retainer  22 . The top vane retainer  24  is the same as the bottom vane retainer  22  as shown in  FIG. 2 , where the paired vane tabs  30  of top vane retainer  24  face the paired vane tabs  30  of the bottom vane retainer  22 . The top vane end  28  of the vane  16  is secured between a pair of vane tabs  30  of the top vane retainer  24  in the same manner as the vane  16  is secured to the bottom vane retainer  22 . A plurality of vanes  16  are secured between the top vane retainer  24  and the bottom vane retainer  22  to form the frame assembly  12 . 
     The turbine assembly  14  includes turbine blades  18 , a bottom blade retainer  34  and a top blade retainer  36 , as shown in  FIGS. 2-3 . The turbine blades  18  include a bottom blade end  38 , a top blade end  40 . The turbine blades  18  include a shaped blade between the bottom blade end  38  and the top blade end  40 . The bottom blade retainer  34  and top blade retainer  36  include blade tabs  42  and weight reduction holes  32 . The bottom blade retainer  34  and top blade retainer  36  each have an area about the perimeter that forms a mounting ring  44  from mounting of the turbine blades  18 .  FIG. 3  shows a pair of blade tabs  42  on the bottom blade retainer  34  for each turbine blade  18 . Each pair of blade tabs  42  on the bottom blade retainer  34  are shaped to receive the bottom blade end  38  of the turbine blade  18  between the pair of blade tabs  42 . The bottom blade end  38  is secured between the pair of blade tabs  42  and hence the bottom blade retainer  34 . The top blade retainer  36  is the same as the bottom blade retainer  34  as shown in  FIG. 2 , where the paired blade tabs  42  of top blade retainer  36  face the paired blade tabs  42  of the bottom blade retainer  34 . The top blade end  40  of the turbine blade  18  is secured between a pair of blade tabs  42  of the top blade retainer  36  in the same manner as the turbine blade  18  is secured to the bottom blade retainer  34 . A plurality of turbine blades  18  are secured between the top blade retainer  36  and the bottom blade retainer  34  to form the turbine assembly  14 . The top vane retainer  24 , bottom vane retainer  22 , top blade retainer  36  and bottom blade retainer  34  each have a shaft hole  46 .  FIG. 2  shows a load shaft  48  that mounts in the shaft holes  46 . The load shaft  48  is securely attached at the shaft holes  46  of top blade retainer  36  and bottom blade retainer  34  of turbine assembly  14 , such that rotation of the turbine assembly  14  rotates the load shaft  48 . Shaft bearings  50  are shown that attach to the top vane retainer  24  and bottom vane retainer  22  of the frame assembly  12 . The shaft bearings  50  receive the load shaft  48  and allow the load shaft  48  to rotate without the frame assembly  12  rotating. 
       FIG. 4  shows the profile of the vane  16 .  FIG. 5  shows a three dimensional view of the vane  16 . The profile includes a half circle leading edge  52 , where the radius of the half circle leading edge  52  depends on the size of the vane  16 . Extending from each end  54  of the half circle leading edge  52  are sides  56  of the vane  16  that come together to form a trailing edge  58 . The sides  56  are shown curving inward from ends  54  of the half circle leading edge  52  before making a straight run to form the trailing edge  58 . The sides  56  could also extend in a straight line from the ends  54  of the half circle leading edge  52  to form the trailing edge  58 .  FIG. 6  shows the profile of the turbine blade  18 .  FIG. 7  shows a three dimensional view of the turbine blade  18 . The profile includes a half circle leading edge  60 , where the radius of the half circle leading edge  60  depends on the size of the turbine blade  18 . The profile includes a half circle trailing edge  62 , where the radius of the half circle trailing edge  62  depends on the size of the turbine blade  18 . Extending from each end  54  of the leading edge  60  and the trailing edge  62  are a top side  64  and a bottom side  66  of the turbine blade  18 . The top side  64  is shown curving outward towards the middle of the top side  64  between the leading edge and the trailing edge. The bottom side  66  is shown curving inward towards the middle of the bottom side  66  between the leading edge  60  and the trailing edge  62  of the turbine blade  18 . The top side  64  and the bottom side  66  form an aerodynamic shape between the leading edge  60  and the trailing edge  62  of the turbine blade  18 . The top side  64  and the bottom side  66  could also extend in a straight line between the leading edge  60  and the trailing edge  62  of the turbine blade  18 . 
       FIG. 8  shows the airflow of the wind through the frame assembly  12  and the turbine assembly  14 . For discussion purposes, the top vane retainer  24  is removed from the frame assembly  12 .  FIG. 8  depicts what is believed to happen to airflow of wind as it hits the wind turbine  10  of  FIGS. 1-7  from any given direction. It is believed that Coand{hacek over (a)} effect and Bernoulli&#39;s principle pertaining to the acceleration of air are part of what causes the airflow depicted in  FIG. 8 .  FIG. 8  shows the wind turbine  10  in wind coming from direction A. The frame assembly  12  is a stationary circular frame with the fixed vertically mounted vanes  16  arranged around the outer perimeter of the frame assembly  12 . The vanes  16  are angled in the frame assembly  12  between 25-40 degrees, depending on diameter of frame assembly  12 . Purpose of the frame assembly  12  is to cause the wind coming from any direction to be directed to force forward motion of turbine blades  18  in the direction of rotation of the turbine assembly  14 . The frame assembly  12  captures air greater than the width of the frame assembly  12 , as shown in  FIG. 8 .  FIG. 8  shows capturing wind along the sides of the frame assembly  12  at points B and D. This happens because the air that is blowing outside the frame assembly  12  is literally sucked in between the vanes  16  on the sides and backside of the frame assembly  12 . The acceleration of air towards the vanes  16  in the frame assembly  12  cut through air on the return side B of the circular path. The air flow on side B is converted from being a point of drag on the rotation of the rotating turbine blades  18  of the turbine assembly  14  to a positive force of momentum that aides in creating rotation of the turbine assembly  14  instead of drag by the use of the above listed principals. The singular directional air flow at sections B, A, and D all combine to add to the speed of rotation of the turbine assembly  14 . This happens because the air that is blowing outside the frame assembly  12  is flowing in the opposite direction of the turbine blades  18  rotation and travels around the outer perimeter and is then sucked in between the vanes  16  nearest to the return path (junction of C and D) of the forward moving air due to the low pressure area created by accelerating air. This is due to areas of high pressure and low pressure being created by the turbine blades  18 . The angle and the placement in the vanes  16  in the frame assembly  12  does not allow for the wind to have a direct negative impact on the turbine blades  18  of the turbine assembly  14  since all air entering is in the direction of the forward rotation of the turbine assembly  14 . 
     The acceleration and change of direction of existing wind to operate the wind turbine  10  is achieved with this design. The wind is redirected toward the forward motion of the turbine assembly  14  with the use of a special aerodynamic shape leading edge creating a positive force in place of the drag created by turbine blades  18  of the turbine assembly  14  spinning into the direction of the wind. The use of this special aerodynamic shape of the half circle leading edge allows for smooth flow of air into and out of the wind turbine  10 . As described above, the air flow on the left side of  FIG. 8  is converted from a point of drag on the rotation to a positive force of momentum creating rotation instead of drag by the use of the above principals. The entire width and height of the air flow from the wind all combine to add to the forward rotation of the turbine assembly  14 . The purpose of the frame assembly  12  is to cause the wind coming from any direction to be directed toward forward motion of turbine blades  18  and eliminate drag and creating a positive force in its place using the Coand{hacek over (a)} effect, Bernoulli&#39;s principle, viscous shear and the resulting creation of a low pressure area. The frame assembly  12  captures air greater than the width of itself using viscous shear. This happens because the air of the wind that is blowing outside the frame assembly  12  is redirected toward the rotation of the turbine blades  18  inside frame assembly  12  and the pulling adjacent air along that would not normally enter prior vertical wind turbine designs. The angle and the placement of the vanes  16  in the frame assembly  12  does not allow for the wind to have a direct negative impact on the spinning turbine blades  18  but instead creates a positive force in place of the drag, since all air entering is in the direction of rotation of the turbine blades  18 . It is believed that a prime number of turbine blades  18  is the most effective configuration of turbine blades  18  in the turbine assembly  14 . 
     For a second embodiment, a clip of a special fluid dynamic shape was developed to replace the semi-circle leading edges and trailing edges of the first embodiment. The clip is shown in  FIG. 9  and has proven to be useful as a leading edge and trailing edge for many devices that employ fluid dynamics. In experiments, the clip was used as an aerodynamic edge on aerodynamic shapes such as airfoils. In the experiments, the clip has proven to increase lift on the shape at lower air velocities, but the clip can also be used to improve any fluid flow over a shape. The clip can be added to a blade that has a flat bar shape to almost any shaped blade that employs techniques to enhance fluid flow over a shape.  FIG. 9  shows the dimensions of the outside surface of a clip for use with a wind turbine having a frame assembly diameter in the range of 12 inches to 48 inches and turbine assembly diameter in the range of 8 inches to 36 inches. The clip is symmetric about a line through points A and B and is shown to be made up of five arcs.  FIG. 10  shows an enlarged view between points D and G. Between points A and G, is an arc having a radius of 0.2476 inches and an arc length of 0.23895. Between points G and F, is an arc having a radius of 0.5832 inches and an arc length of 0.0948 inches. Between points F and E, is an arc having a radius of 0.4636 inches and an arc length of 0.1691 inches. Between points E and D, is an arc having a radius of 0.3822 inches and an arc length of 0.2298 inches. Between points D and C, is an arc having a radius of 0.3291 inches and an arc length of 0.1945 inches.  FIG. 9  also shows distance between points from a datum at point A and distance between points G with A as the midpoint.  FIG. 10  shows the distance between points G, F, E and D. The arc between G and A for both sides forms a nose end. The outside surface of the clip can be enlarged or reduced in size by scaling the size of the arc radius and arc length of each arc between the points by applying the same percentage of change to each arc. 
     The opening at the blade end  67  of the clip between points C in  FIG. 9  is for receiving a blade or other fluid dynamic shape.  FIG. 11  shows a flat blade assembly  68  of two clips  70  on each end of a flat blade  72 . The flat blade includes side  74 , side  76  and thickness  78 . A blade used with the clip can be of any thickness, but there is a requirement that point C of  FIG. 9  connects to the sides of the blade in a way such that there is no opening between points C and the sides of the blade. This requirement is for keeping the flow off of the clip separated from other airflow, which causes the air to be drawn around the one side more than the other of the clip and hence the flat blade assembly  68 . This requirement is not only subject to flat blades, but all blade profiles that incorporate the use of the clip. Therefore, the distance between points C of the clip will vary depending on the thickness of the flat blade. If it is desired to use a blade of a thickness that is less than the opening of the blade end  67  of any particular sized clip, a gap filler can be used between points C and the sides of the blade. An example of a gap filler is a straight wall of material between points C and the sides of the blade. The clip can be applied to many applications that involve fluid dynamics, where the second embodiment will be one example of the application of the clip. Each clip includes a blade channel  80  inside the clip to hold the blade  72  and clip  70  in position together, as shown in  FIG. 11 .  FIG. 11  shows the behavior of fluid flow from the wind, where the air directed at almost 90 degrees from the nose  82  of the clip  70  at point  84  versus wind that has direct impingement on the nose  82 . The air flow from the wind is directed about side  86  and nose  82  of the clip  70  and then flows about the other side  88  of the clip  70 . The airflow then follows side  74  of the flat blade  72  towards the other clip  70  for exiting pass the flat blade assembly  68 . The unique feature of the flat blade assembly  68  using the clip  70  is how the air is captured in the area about the side  86  and nose  82  of the clip  70  and then forced along the flat blade assembly  68 . 
       FIGS. 12-13  shows a frame assembly  90  of the second embodiment with a top vane retainer  92 , bottom vane retainer  94  and using the flat blade assembly  68  of  FIG. 11  for the vanes  96 .  FIG. 14  shows a turbine assembly  98  within the frame assembly  90  of  FIGS. 12-13 . The turbine assembly  98  is shown with a top blade retainer  100 , bottom blade retainer  102  and using the flat blade assembly  68  of  FIG. 11  for the turbine blades  104 .  FIGS. 13-14  also show a load shaft  106  for connecting to a load.  FIG. 14  shows shaft mounts  108  attached to the top blade retainer  100  and bottom blade retainer  102  to secure the load shaft  106  so that the load shaft  106  rotates with the turbine assembly  98  during turbine assembly  98  rotation.  FIG. 14  shows a shaft bearing  110  which mounts to the outside surface of the top vane retainer  92  to receive the load shaft  106 . The outside surface of the bottom vane retainer  94  would also have a shaft bearing  110 , but is not shown. The top vane retainer  92 , bottom vane retainer  94 , top blade retainer  100  and bottom blade retainer  102  all have a shaft hole  112  similar to the first embodiment to allow passage of the load shaft  106 . The shaft bearings  110  allow the load shaft  106  to rotate within the frame assembly  90 , as the frame assembly  90  is stationary. The vanes  96  and turbine blades  104  can be mounted in various ways, including using the modern technology of printing the frame assembly  90  and turbine assembly  98  each as one piece with a 3-D printing device. 
       FIG. 15  shows how to define positioning of the vanes which can be applied to both embodiments.  FIG. 15  shows an imagery line drawn  114  from the center of the frame assembly to the leading edge clip  116  of the flat blade assembly  118  used for the vanes. An angle of 45 degrees is formed between the flat blade assembly  118  and the imagery line  114  due to the position of the trailing edge clip  120  of the flat blade assembly  118 . A counter clockwise rotation of the trailing edge clip  120  from the imagery line  114  is considered positive angle and a clockwise rotation (not shown) from the imagery line  114  is considered a negative angle. A flat blade assembly position of a vane that has a positive angle produces the turbine assembly rotation in the clockwise direction and a position of a vane that has a negative angle produces the turbine assembly rotation in the counter clockwise direction. A flat blade assembly position for the vanes of 35 to 50 degrees of angle in the positive or negative direction works well and an angle of +/−45 degrees appears to be optimal in limited testing.  FIG. 16  shows how to define positioning of the turbine blades.  FIG. 16  shows an imagery line  122  drawn from the center of the turbine assembly to the leading edge clip  124  of the flat blade assembly  126  used for the turbine blades. A positive angle of 25 degrees formed between the flat blade assembly  126  and the imagery line  122  due to the position of the trailing edge clip  128  of the flat blade assembly  126  used as a turbine blade is shown in  FIG. 16 . A counter clockwise rotation of the trailing edge clip  128  from the imagery line  122  is considered positive angle and a clockwise rotation is considered a negative angle.  FIG. 16 , also shows a negative angle of 10 degrees formed between the flat blade assembly  126  and the imagery line  122  due to the position of the trailing edge clip  128  of the flat blade assembly  126  used as a turbine blade. A flat blade assembly position for the turbine blades of −20 degrees to +25 degrees of angle works well. An angle of −10 degrees appears to be optimal in limited testing. The angles show are for a turbine assembly that rotates in the clockwise direction. The angles would be reversed for a turbine assembly designed to rotate in the counter clockwise direction, where +20 degrees to −25 degrees of angle would work well and +10 degrees of angle would be optimal. 
       FIGS. 17-18  show airflow from a wind direction W flowing about and through the wind turbine of the second embodiment. For the wind turbine of  FIGS. 17-18 , the turbine assembly  98  rotates in a clockwise direction when viewed from the top vane retainer  92 . The clockwise rotation is due the positioning of the vanes  96  in the frame assembly  90 , as described for  FIGS. 15-16 .  FIGS. 17-18  show the collection of wind thru the frame assembly  90  from not only direct impingement from the wind at point W, but collection of wind on the sides of the frame assembly  90  by the wind turbine for used to turn the turbine blades  104 . The capture and use of the wind in the second embodiment is the same theory as described above in  FIG. 8  for the first embodiment. 
     Tests were performed on a wind turbine of the second embodiment. The wind turbine had a frame assembly with a 48 inch diameter and a height of 28 inches. The vanes were 5 inches wide and there were 20 vanes on the frame assembly. The turbine assembly had a 36 inch diameter and 13 turbine blades that were 8 inches wide. Measured at the shaft was a production of 21 lb ft of torque at 91 rpm for a 6.5 m/s wind speed. This model was designed to produce a high torque for a low rpm generator. It was found that a reduction in vanes in the frame assembly will increase rpm but lower torque at the load shaft for the same size frame assembly and turbine assembly and an increase in vanes has the opposite effect on torque and rpm at the shaft. Using scale models 6 inches high and a 12 inch frame assembly diameter the following results were achieved. Testing was done with a two flat blade assembly  130  that was 5.5 inches wide and 6 inches high and affixed to a center shaft straight across from each other, as shown in  FIG. 19 . A wind speed was 10 mph was used and there was no movement attained. The next test with the same blade assembly  130  was to place them inside the frame assembly of second embodiment and use the same 10 mph wind, where the blades spun 430 rpm. This shows the positive effect of the frame assembly to turn the air flow and create a one way flow of air inside the frame assembly and eliminate the drag on the blade spinning into the direction of the wind. A second test was done the same way using a Savonius two scoop design blade assembly  132  with 5.5 inch diameter and 6 inches high shown in  FIG. 20  without the frame assembly, where the blade assembly  132  achieved 392 rpm in the 10 mph wind. When the blade assembly  132  was placed inside the frame assembly, the blade assembly  132  achieved 507 rpm in the 10 mph wind.  FIG. 21  shows a three curved blade assembly  134  of 5.5 inches in diameter and 6 inches high. Without the frame assembly, the blade assembly  134  achieved 128 rpm in the 10 mph wind. When the blade assembly  134  was placed inside the frame assembly, a 328 rpm was achieved in the 10 mph wind. These tests show that the frame assembly with the design of the clip enhances the rotation of blades inside the frame assembly by the collection of more wind about the frame assembly versus only allowing direct impingement of the wind on such blade designs.  FIG. 22  shows a two flat blade assembly  136 , which includes two flat blades  138  and a spindle  140 . The flat blade assembly  136  was 5.5 inches in diameter and 6 inches high. When a 10 mph wind speed was applied, there was no movement caused by the simulated wind.  FIG. 23  shows the clip  142  in scale added to each flat blade  138  of  FIG. 22 . When a 10 mph wind speed was applied, the spindle  140  rotated at 370 rpm. This shows that the addition of the clip  142  can cause rotation and lift due the aerodynamic shape of the clip  142 . 
     While different embodiments of the invention have been described in detail herein, it will be appreciated by those skilled in the art that various modifications and alternatives to the embodiments could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements are illustrative only and are not limiting as to the scope of the invention that is to be given the full breadth of any and all equivalents thereof.