Arrow shaft with an aerodynamic groove

An improved arrrow shaft is modified to include an aerodynamic groove longitudinally placed on the bottom of the shaft to improve accuracy, flatten trajectory and increase the flight distance of the arrow. The aerodynamics of the improved arrow shaft improve the flight characteristics of conventional fletched arrows and allow the use of fletchless arrows in combination with an archery bow or a crossbow.

BACKGROUND OF INVENTION 
1. Field of the Invention 
The present invention relates to the design of arrow shafts such as used in 
the field of archery. All such arrow shafts are round and straight, have 
points of various types, nocks and fletching. Points are essentially for 
penetration either into targets or game. The nock of the arrow functions 
to engage the bow string until the arrow is loosed. The flight 
characteristics of the arrow depend primarily on the fletching, either 
made from feathers or plastic. The fletching causes a measurable drag on 
the arrow and may also become partially or wholly torn from the shaft of 
the arrow during use, further impairing the aerodynamics of the flight of 
the arrow, necessitating the repair or replacement of the fletching. 
Fletching usually consists of three vanes, each attached to the rear of 
the arrow shaft at about 120.degree. from the others so that when the bow 
string is in the nock, one vane is horizontal at 90.degree. to the nock 
and the other two vanes are about 30.degree. from vertical. This necessary 
placement of the vanes has an inherent slightly detrimental effect on 
aerodynamics. It would be advantageous to modify the shape of the shaft to 
improve the aerodynamics and accuracy for the conventional arrow with 
fletching or to eliminate the necessity for fletching. 
2. Description of the Prior Art 
The basic arrow consists of point, shaft, fletching and nock. The points 
have been made from bone, flint, and metal and vary in shape, depending 
upon their use at targets, fish or various game. Nocks were simply carved 
into the shaft of the arrow, but are now predominately plastic and 
replaceable. One such nock (U.S. Pat. No. 5,306,019 to Guest and Eckert) 
is adjustable and holds the bow string within the nock until release. 
Fletching is usually made from feathers, such as turkey, or plastic. 
Shafts have been made from reed, wood dowels, carbon fiber and metal tubes 
and have always been round and straight. Aerodynamics of the shaft have 
been improved through the addition of an airfoil structure on top of the 
shaft (U.S. Pat. No. 4,182,513 to Henderson). 
There is a need for a more aerodynamic arrow shaft that will provide 
increased range, a flatter trajectory, improve accuracy and eliminate the 
need for fletching or airfoil structures. 
SUMMARY OF THE INVENTION 
The present invention is a more efficacious arrow shaft with an ease and 
simplicity of manufacture. More particularly the invention is concerned 
with an aerodynamic groove on the bottom of the shaft of the arrow to 
allow the shaft to capture air to fly further and more accurately. Much as 
the groove on the bottom of a snow ski helps it to track in a straight 
line, the groove on the bottom of the arrow shaft has a stabilizing action 
that helps the arrow to fly straight. This aerodynamic groove improves the 
flight characteristics of a conventional arrow with fletching and can 
eliminate the need for fletching or airfoil structures. 
These and other features and advantages of the present invention will 
become apparent to those skilled in the art upon a reading of the 
following detailed description when taken in conjunction with the drawings 
wherein there is shown and described an illustrative embodiment of the 
invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Prior to explaining the invention in detail, it is to be understood that 
the invention is not limited in its application to the details of 
construction and the arrangements of the components set forth in the 
following descriptions or illustrated in the drawings. The invention is 
capable of other embodiments and of being practiced and carried out in 
various ways. Also, it is to be understood that the phraseology and 
terminology employed herein is for the purposes of description and should 
not be regarded as limiting. 
FIG. 1 illustrates an arrow shaft (10) with point (12), fletching (14) and 
nock (16). The aerodynamic groove (18) is on the bottom of the shaft. FIG. 
2 illustrates a longer groove on a fletchless arrow shaft. FIG. 3 
illustrates the vertical nock orientation of a normally fletched arrow as 
it would engage the string of a vertically held bow. The orientation of 
the elongated aerodynamic groove is shown by the dotted line. FIG. 4 
illustrates the location and configuration of the preferred embodiment of 
the aerodynamic groove in a solid cross section and FIG. 5 illustrates 
this configuration in a tubular cross section. FIG. 6 is a perspective 
view of the preferred embodiment of the longitudinally located aerodynamic 
groove on the bottom of the arrow shaft. 
Although this invention has been described in detail with particular 
reference to the preferred embodiments thereof, it will be understood that 
variations and modifications can be effected within the spirit and scope 
of the invention as described and defined in the appended claims.