BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to kites used in the sport of kite boarding and more particularly an inflatable kite having vents.
2. Discussion of Prior Art
Kite boarding is a sport where an individual is pulled along the top of the water, snow or land while standing on a small board (approx. 48″×16″×½″) by a kite (approx. 5-20 sq. meters). Kite boarding is a fast growing sport worldwide. Very high speeds can be reached on these boards and they can jump many meters into the air even off a small wave due to the power generated by the kites. Kites now have the ability to have their angle of attack controlled by the rider but this can at times result in the kite stalling because the kite wing is set at too high of an angle of attack to the wind.
Therefore there is a need to improve the aerodynamic stability of the kite at high angles of attack so that the kite does not stall and crash.
SUMMARY OF THE INVENTION
To solve the problem with unstable airflow over the top surface of the kite wing membrane at high angles of attack, vents have been introduced on an inflatable kite. When vents are placed in a predetermined location on the wing membrane they can delay the onset of stalling by allowing higher pressure air on the underside of the wing membrane to be released onto the top surface of the wing membrane, near the region where the air flow is separating from the top surface of the membrane, and hence keep the air flow attached. This increases the kite's overall wind range as well as making it easier for the rider to fly.
One embodiment of my invention comprises an aerodynamic body comprising a generally elliptical wing formed by a flexible low porosity membrane having a top surface, a bottom surface, a left tip, a right tip and a plurality of vents for venting air from the wing bottom surface to the wing top surface. The wing has a leading edge comprising an inflatable tubular member. The wing also has a trailing edge; and, a plurality of ribs disposed between the leading edge and the trailing edge for supporting a desired geometry of the wing.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view of a kite body of one embodiment of the invention.
FIG. 2 is a cross-sectional view of a kite body of another embodiment of the invention.
FIG. 3 is a view of the same embodiment of FIG. 1.
FIG. 4 is two views of vent mesh of embodiments of the invention.
FIG. 5 is a view of a kite body including fabric covers on the vents.
DETAILED DESCRIPTION
Referring to FIG. 1, my invention is a kite 10 of the type used in kite boarding and related sports. A person familiar with the sport will realize that the drawings accompanying this submission are of the kite only. Additional equipment, not illustrated in this submission, would include kite rigging, a kite board, a control bar and a harness for the user. The kite 10 of my invention comprises an aerodynamic body 12. The aerodynamic body 12 comprises a generally elliptical wing 14 comprising a low porosity membrane having a top surface 16, a bottom surface 18, a left tip 20, a right tip 22 and a plurality of vents 24 for venting 25 high pressure air 26 from underneath the wing bottom surface 18 to the wing top surface 16. The body of my invention further comprises a leading edge 28 comprising an inflatable tubular member 30. There is also a trailing edge 34 opposite the leading edge 28. To provide a desired geometric form and structural support to the wing there is included in my invention a plurality of parallel ribs 36 disposed between the leading edge 28 and the trailing edge 34 of the wing 14.
The inflatable tubular member has a radial length as shown by dashed line 38 connecting said left tip 20 and the right tip 22.
Refer now to FIG. 2 and FIG. 5. FIG. 5 is the same embodiment as FIG. 1 with flap members 106 and 108. As shown in FIG. 2, which is a cross-section of the wing of one embodiment of the invention shown in FIG. 5 at A-A, the generally elliptical wing 14 is fixed to the leading edge 28 at a wing fixing point 56 that is on the front 42 of the outer surface 40 of the inflatable tubular member.
Referring to FIG. 3, which is the same embodiment as in FIG. 1, kite wing 14 has two generally rectangular vents 80 and 82 disposed parallel to the inflatable tubular member 30 from approximately midway to two thirds the distance between the leading edge 28 and the trailing edge 34. In other embodiments of the invention there can be more or fewer vents depending on the desired aerodynamic properties of the wing. In the embodiment illustrated in FIG. 3, the wing has a first opening 80 disposed within the upper left segment 72 of the wing and a second opening 82 disposed within the upper right segment of the wing 74. The first and second vents comprise a leading edge 86 and a trailing edge 88 generally parallel to the inflatable tubular member 30 and a left side edge 90 and right side edge 92 generally parallel to the left 20 and right tips 22 respectively. The vents are covered with a fabric having a large geometric porosity that permits pressurized air 26 flow from the bottom of the wing to the top of the wing 25.
Referring now to FIG. 4, in one embodiment of the invention shown in FIG. 4A the fabric is a mesh fabric 96 having a large geometric porosity. In another embodiment as shown in FIG. 4B the fabric is a perforated fabric 98 with circular perforations 100. In yet another embodiment of the invention, the first and second vents comprise a portion of wing fabric that have been suitably reinforced and perforated for air flow. Alternatively, the vents may be vents without any fabric across them with edges reinforced.
Referring back to FIG. 2, during flight the first opening 80 and the second opening 82 permit high pressure air 26 under the wing 14 to escape to the upper surface 16 of the wing and flow rear-ward 104 along the upper surface as near laminar flow thereby improving aerodynamic performance of the wing at low speeds.
In the embodiment depicted in FIG. 2 and in FIG. 5, the first 80 and second 82 vents are located about two-thirds the distance between the leading edge and the trailing edge and include flap members 106 and 108 fixed to their respective opening leading edges 86, left tips 90 and right tips 92 thereby forming a nozzle 110 as shown in FIG. 2 having an open end 112 for directing air from the lower surface of the wing to the upper surface of the wing and rearward at a velocity sufficient to extend near laminar flow on the upper surface of the wing rearward for improved aerodynamic performance.
Although the description above contains much specificity, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. Thus the scope of the invention should be determined by the appended claims and their legal equivalents.
Patent Application
20090045291
