An easily assembled, steerable two-string kite suitable for sailing in light or strong winds having self-adjusting wing members, a substantially delta-shaped frame made of lightweight material and covered with flexible sail material capable of in-flight maneuvers including maintaining constant speed over a wide angle relative to the ground, direct overhead flight, 90-degree turns relative to the center of the kite, and lift-off from the ground, all without need to adjust or alter the position of the strings affixed to the kite.

BACKGROUND OF THE INVENTION 
A variety of kites are presently commercially available for recreational 
purposes, or for use by the serious competitor aiming to excel at 
competition kite-sailing. Depending on the design of a particular kite and 
the materials used to construct it, it may be flown in light or moderate 
winds and maneuvered to exhibit aerial feats of different degrees of 
difficulty. 
Kites generally fall into two broad categories: those that are flown with a 
single string and those flown with two strings affixed to the kite. A 
variety of single-string kites are well-known, including the Chinese kite, 
barrel kite, Malay kite, Marconi-jib kite, and Indian-fighter kite. While 
there are significant differences in the wind speed single-string kites 
can be flown at, as well as the type of maneuvers each can perform, it is 
generally true that they perform best in low to moderate winds and are 
incapable of exhibiting radical aerial maneuvers such as direct overhead 
flight and dramatic turns accompanied by nearly parallel flight to the 
ground. Because of the limited weather conditions and limited 
maneuverability in which single-string kites can be flown, two-string 
kites that exhibit a wide range of desirable properties have been accepted 
among kite enthusiasts. 
As is apparent from the name, a primary feature of two-string kites is the 
attachment of two strings of equal length to the kite, one to the right 
and left sides of the kite, respectively. By pulling on either of the 
strings, the kite enthusiast can put a two-string kite through exceptional 
maneuvers. Indeed, the maneuverability of two-string kites is due to 
constant adjustment of the tension on the string. When tension is applied 
to either the right or left string, the kite responds by moving in the 
corresponding direction. If tension is continuously applied evenly on one 
string, the kite turns continuously in that direction. For example, a 
clockwise spin is imparted to the kite by pulling in on the right string 
and stopped by sequentially pulling in on the left string. By exerting 
even tension on both lines after a particular line of flight is 
established, the direction of flight can be conserved. Thus, a variety of 
aerial maneuvers can be performed by sequentially pulling on either the 
right or left strings. 
A feature that distinguishes single-string from dual-string kites is the 
flight angle of attack. Single-string kites fly at a near fixed angle of 
attack to the ground, whereas dual-string kites exhibit a variable angle 
of attack. When the angle of attack is great, a dual-string kite is 
capable of obtaining high speeds and performing rapid turns. The maximum 
angle of attack occurs when the kite is nearly parallel to the ground and 
the wind is at the back of the person controlling the strings. 
Several dual-string kites are presently commercially available with names 
that adequately describe their raucous aerial maneuverability, such as Sky 
Cat, Sky-Ro-Gyro, and Super Stuntor. Regardless of the type of kite, 
however, they all share several undesirable features that limit the 
conditions under which they can be flown or the types of maneuvers that 
they are capable of performing, even in the hands of an experienced kite 
flier. First, all the kites require that they be launched by hand, or, 
alternatively, that the flier be highly experienced to launch it alone. 
Thus, most of the two-string kites necessarily require that two people be 
present initially to fly the kite, one to launch it and another to control 
the strings. Second, most two-string kites presently available can not be 
flown efficaciously in variable wind speeds of between 10-25 miles per 
hour without adjusting the point of attachment of the string s to the 
kite. In kite flying competition, it is highly advantageous to have a kite 
that can perform different maneuvers without having to make such 
adjustments so as to avoid grounding the kite and losing competition time 
needed to make the necessary changes. 
Third, most two-string kites cannot readily perform direct overhead 
360-degree turns. Last, two-string kites are, for the most part, limited 
to being flown in winds of up to 25 miles per hour and not higher. 
SUMMARY OF THE INVENTION 
A two-string kite is described that is easily assembled and highly 
maneuverable in both low and high winds. The kite exhibits a substantially 
delta-shaped frame made of lightweight material with a central support 
member fixed aft and running forward connecting at the midpoint of the 
nose. Additionally, the frame contains a pair of lateral members situated 
on either side of the central support member, and a pair of middle 
members, one member of each pair being situated between the central 
support and lateral members. Further, there are two parallel horizontal 
crossbars spaced rearward from the nose of the kite. The central support 
member connects aft of the nose to the rearmost horizontal crossbar, while 
the lateral and middle members are enclosed and connect to sail material 
at the rear. The frame of the kite is covered with lightweight sail 
material, and a bridle is used to attach two strings to the kite.

DETAILED DESCRIPTION OF THE INVENTION 
Referring now to FIG. 1, the kite is shown to comprise a cover of flexible 
material 10 that is arranged below a supporting substantially flexible 
delta-shaped frame comprising a fore and aft central support member 12 
connected with the foremost and rearmost edge portions of the cover to 
limit the upward movement of the longitudinally central portion of the 
cover, and lateral frame members 14 connected respectively with the 
lateral edge portions of the cover and so arranged with relation to the 
central fore and aft frame member so as to permit the lateral portions of 
the cover between the lateral frame member and the central support member 
of the cover to move upwardly between these members when the kite is in 
flight. Additionally, the frame has two parallel horizontal crossbars 16 
and 18 placed at different distances from the nose of the frame and that 
are connected at points 20 and 22 on the lateral members. The rearmost 
horizontal member 18, in addition to being connected to the lateral 
members, is also connected to a fitting 24 to the central support member 
at about the midpoint of the horizontal member. Last, the frame has two 
further members, or middle members 26, that connect to the nose of the 
kite and extend rearward with each being situated between a lateral member 
and the central support member. The nose of the kite 28 receives the 
central support member, lateral members, and the middle members and is 
substantially flat at its end. Two strings are affixed to the kite by a 
bridle 30. In flight the nose curls inward catching the wind and provides 
or increases the maneuverability of the kite. 
The central support member is connected to the nose of the kite 28 by 
contact with a fitting formed from reinforced flight material, 
particularly useful are synthetic polyester textile materials, an example 
being Dacron.RTM.. At the rear, the central support member is connected by 
contact with a fitting 24 formed particularly vinyl tubing and aluminum or 
other suitable material. In addition to receiving the central support 
member, the rear fitting receives connections from the rearmost horizontal 
support member 18 and thereby supports the central support member. 
The parallel horizontal crossbars 16 and 18 provide support to the frame 
and can be made of lightweight materials such as hollow fiberglass, 
particularly useful in Arrowshaft.RTM. fiberglass. The horizontal crossbar 
closest to the nose 16 attaches to the lateral members by any of several 
commonly used fittings that yieldably resist the movement of the fitting 
in the rod and retains the same in adjusting positions thereon. As shown 
in FIG. 2, it is convenient to employ plastic tubing or material made of 
soft rubber 32 with a hole of an approximate diameter the size of the 
crossbar and capable of receiving the same. Whereas the fitting can be 
attached to the lateral members in several ways, it is preferable to 
effect a longitudinal bore through the plastic fitting and slide it down 
the latter member to the desired distance from the front of the kite. 
The horizontal crossbar farthest from the nose of the kite 18 in its 
preferred embodiment is disassemblable into two sections, and allows for 
the kite to be readily folded and transported. Each section is connected 
to the lateral member independent of the other using fittings as described 
in the crossbar closest to the nose. Additionally, each section connects 
to the central support, as shown in FIG. 3, member by sliding into affixed 
fittings 24 attached to the central support member by way of a piece of 
tubing 25. This crossbar is also made of lightweight material such as 
hollow fiberglass, particularly Arrowshaft.RTM.. 
A property of the rearmost horizontal crossbar that contributes 
substantially to the kite's in-flight maneuverability is the capacity of 
the crossbar to flex opposite the direction of the wind to different 
degrees depending on the force of the wind. FIG. 4 depicts the degree of 
flex when the kite is stationary (34), flown in low winds about 5 knots 
(36) or stronger winds of 10 knots (37), 20 knots (38), or 30 knots (39). 
In strong winds the bar is at its greatest flex 39 while in low winds it 
may assume little or no flex 36. The self-adjusting property of the bar in 
strong winds which exerts a downward pull on the lateral regions of the 
kite forcing them to curl down resulting in more efficient use of the wind 
much akin to outriggers on boats or planes. 
It is important to note that a feature associated with the use of fittings 
that allow either crossbar to be easily inserted and removed permits the 
kite to be folded and easily packaged for transport. This procedure is 
rapid and enables the user to launch a kite literally within a minute of 
removing the kite from its protective sheath. 
The middle members are attached to the nose of the kite between the central 
support and lateral members and are also attached at the rear by contacts 
with kite sail material. Such contact can be effected by string, elastic 
bands, grommets, or other suitable means attached to the kite sail 
material and the middle members. As shown in FIGS. 5 and 6, it is 
particularly desirable to fit this contact into a slot 40 in the rod. 
In order to restrain the central support lateral members and middle members 
to maintain a set position while the kite is in flight, as depicted in 
FIG. 7, they are situated inside a tunnel 42 made of two layers 44 and 46 
of kite material. This can be accomplished by stitching or gluing the two 
layers together to form a tunnel of a diameter equal to that of the 
members that occupy it. 
The length of the central support lateral members and middle members, the 
angles that separate them, and the distance of the parallel horizontal 
crossbar from the nose establish the limits of the kites aerial 
maneuverability. Generally, it is anticipated that the most used version 
of the kite will have central support and lateral members of 28"-34" and 
63"-69" long, respectively, with the middle member being 49"-55" long. The 
horizontal cross bars will generally be spaced 11"-17" and 42"-48" from 
the nose and will generally be 20"-26" and 62"-69" long, respectively. It 
will be understood to one skilled in the art that kites of any size can be 
constructed provided the dimensions are scaled up or down accordingly. 
In the assembly of the kite preparatory to flight, the parallel horizontal 
crossbars are inserted in to the fittings situated on the lateral members. 
The horizontal crossbar nearest the nose is inserted in a single step 
requiring insertion only into fittings on the lateral members. The 
crossbar farthest from the nose, being in two parts, requires that each 
part be inserted into fittings on both the lateral members and on the 
central support member. A bridle is attached to the kite at the region 
where the horizontal crossbars contact the lateral members and the rear of 
the central support member. Next, two strings or other suitable material 
of sufficient strength to hold the kite aloft are attached at points on 
the bridle. FIG. 8 shows that the kite can be launched directly from the 
ground, without the aid of a person to hand-launch it, by standing it on 
the tips of the outer frame members. When supported by the air, the upper 
pressure of the air on the cover moves the lateral portions thereof 
upwardly between the fore and aft frame members forcing the cover a 
minimum distance of 6"-9" near the midpoint of the two middle members.