Automatic attitude adjuster for kite

An automatic attitude adjuster for a kite made from a strip of flexible material having a memory. A preferred material is plastic such as polypropylene. The strip when connected between the kite and the kite bridle changes the position of the tow point and the attitude of the kite automatically in response to variations in wind strength.

BACKGROUND OF THE INVENTION 
The invention is directed to a simple and inexpensive means to 
automatically change the effective position of the string or bridle 
attachment on a kite. The word kite as used in this disclosure refers to 
any airfoil which is lifted by the wind and tethered by a string. 
One of the inherent problems with kites is that for the kite to perform 
well the string or bridle must be attached at a particular point relative 
to the center of the airfoil surface. The ideal point of attachment varies 
depending on the wind velocity. Attempts to change the position of the 
string attachment and thereby alter the attitude of the craft for 
different wind velocities have been made in the past. The most usual of 
these adjustments is the provision of a plurality of notches on the string 
attachment member. However this adjustment must be made manually, requires 
knowledge of the wind velocity, and is not easily changed to compensate 
for shifting winds without retrieving the kite. 
One prior art patent which controls the attitude of a kite by moving its 
bridle point is U.S. Pat. No. 4,280,675. This kite is controlled in two 
discrete steps in response to both release of tension on the cord and the 
wind. It requires a mechanism using springs and cams and is not completely 
automatic. 
The acrobatic kites can change their attitude in response to motions of the 
kite handler. The success of these motions depends on the skill of the 
kite handler. 
There still exists a need for a kite attitude adjustment which is dependent 
on wind strength and is continuous, automatic, and reversible. 
SUMMARY OF THE INVENTION 
The object of the invention is to provide a superior means for changing the 
attitude of a kite automatically in response to changes in the wind 
velocity. 
A further object of the invention is to cushion a kite against the shock of 
a sudden gust of wind. 
These objects are achieved by connecting an adjusting member between the 
kite bridle and the kite. 
The word bridle is used throughout the specification and claims in its 
broadest sense to refer to the cord or arrangement of cords attaching a 
kite to its line or string. In cases where the bridle is a single cord, 
the cord is also the kite string or is connected to the kite string in 
such a way as to make a continuous line from the kite. 
Where the bridle has two or more cords, the string is connected to the 
point where all of the bridle cords are connected together. This point is 
referred to as the tow point. The tow point on a single bridle kite is the 
point on the kite to which the bridle, or string, is attached. 
Because the invention automatically changes the attitude of the kite by 
shifting the tow point, the invention is called an Auto Tow. 
The adjustment member of the invention is a strip of flexible material 
having a memory and an attaching means at each end of the strip. 
The flexible strip has one end attached to the kite and the other end is 
attached to the bridle. The end attached to the kite must be firmly 
attached to the kite in a position which is rearward of the end to be 
attached to the kite bridle so that when the kite is in flight, the force 
produced by the wind and the holding force of the kite operator will bend 
the strip downward which has the effect of moving the tow point both 
rearward and downward thus changing the attitude of the kite. As the force 
of the wind increases, the bending of the strip increases; and if the wind 
velocity decreases, the strip will tend to return to its original 
position, again changing the attitude of the kite. Because the response is 
automatic, continuous, and reversible, it can compensate for changes in 
wind velocity more quickly than can be done by any system which depends on 
the skill of the kite operator.

DETAILED DESCRIPTION OF THE DRAWINGS 
The attitude adjuster shown in FIGS. 1 thru 4 is a strip of flexible 
material which has a memory such as plastic, rubber, fiberglass, etc. The 
length and thickness of the strip is chosen to suit the type of size of 
kite. The exact dimensions are not critical. Good results have been 
obtained using a six inch strip of 1/8 inch polypropylene on a keel kite 
with a 35 inch wingspread. 
FIGS. 1 thru 4 show some examples of the shapes which the strip may have. 
The shape of the upper end of the strip, as shown in the drawings, and the 
type of attachment used can vary with the type of kite. Any known 
attachment means can be used if it provides a firm attachment to the kite 
assembly. 
The firm attachment should be such that when the kite is in flight, the 
adjustment member will bend in response to force but will not pivot around 
a single point of attachment. The attachment can be made either to a rigid 
portion of the kite, such as a stiffening member, or to a portion of the 
kite which maintains its position relative to other parts of the kite when 
the kite is flown. If the kite is symmetrical about a fore-to-aft center 
line, the center line of the kite should be in the same plane as the 
center line of the flexible strip. In the case of a box kite, the center 
line of the strip should be in the same plane as the support member to 
which it is attached. The hole at the lower end of the strips in FIGS. 1 
thru 4 is used for attaching to the bridle. 
FIG. 1 shows an embodiment of the invention which has been used with a 
Styrofoam keel kite. The dotted lines in FIG. 1 represent fold lines. The 
strip is folded along these lines and then attached to the keel of the 
kite by a rivet which passes through the keel and the two holes. This is 
shown attached in FIG. 5. The size of the strip and the keel are not shown 
to scale. In operation, as the wind increases, the strip bends downward 
assuming positions as shown by the dotted lines in FIG. 5. The bending is 
a smooth transition and is reversed any time that the wind velocity 
lessens. This immediate and smooth response also prevents the kite from 
getting out of control in gusty winds. 
The attaching point of the invention can be slightly rearward of the point 
where the bridle would be attached without the invention because the 
bridle itself is connected farther forward because of the extension of the 
flexible strip. 
The embodiment of FIG. 2 can be attached to a stiffening member by 
stapling, clamping, or other means. This embodiment could be used with the 
box kite of FIG. 8. 
In each of FIGS. 5 thru 8, the numeral 1 refers to the strip of the 
invention, 2 is the tow point and 3 is the bridle. 
FIGS. 3, A and B show mating members, B is the flexible strip and A is a 
fastening member. The circles in the flexible strip represent snap members 
and the circles in A represent mating snap members. These can be snaps of 
the type used as garment fasteners. The strip of B is placed in the 
desired position under a kite airfoil made of fabric such as nylon and the 
mating member A is placed over the airfoil and snapped to the strip with 
the fabric of the kite held between the two mating parts in a firm 
attachment. This type of attachment can be used with the diamond kite 
shown in FIG. 7. The kite in FIG. 7 uses a two cord bridle 3,3. The kite 
string is attached at tow point 2. When the flexible strip 1 is bent 
downward, the tow point 2 assumes a new position which is both downward 
and rearward of its initial position. 
When attaching the flexible strip to a kite with more than one cord to its 
bridle, the strip is attached at, or near, the point at which the most 
forward of the bridle lines is normally attached. 
The embodiment of FIG. 4 was made from a plastic strip with integral 
attachment wings 5. The strip was bent at the fold lines and attached to a 
light weight plastic keel of a kite which is on the market. The stiffness 
of the wings 5 and the tautness of the keel in flight made a firm 
attachment through rivets 5--5 and 6--6. 
The flexible strip of the invention can either be attached to existing 
kites or built into kites as they are being made. Modifications of a kite 
to accommodate the invention such as adding a stiffener to be used as an 
attaching point can be made if desired, but are usually not necessary. 
The forms of the invention described are illustrative. Modifications may be 
made without departing from the spirit of the invention.