A kite leading edge has a tubular structure having a first curve in a span-wise direction and a second curve a chord-wise direction. The tubular structure is formed by a plurality of panels joined together at seams including at least a first longitudinal seam running in the span-wise direction of the tubular structure. At least a portion of the first longitudinal seam defines a first partial helical path about the circumference of the tubular structure.

Methods and devices taught in the present disclosure address the need for improving stability and performance of delta wing kites. Delta wing kites as disclosed include a delta wing shaped sail reinforced with rigid or semi-rigid wing spars and a center spar, the wing spars and central spar being housed and secured within corresponding sleeves. A combination of various elements such as fuselage and corresponding through-holes, front and back pods, keel and top pockets provides improved stability and performance for the disclosed devices.

An airtight bladder for kites and method of sealing an airtight bladder for kites. The bladder body has longitudinal edges sealed with a lap seam and ends sealed by a combination of deforming bladder material and applying an end seam. The deforming of the bladder materials is done by folding, rolling, accordion folding, knotting, or twisting the ends. The deforming of the bladder material in this matter shelters and protects the end seals.

An aircraft can include a wing. The wing can include a tip. A winglet can be pivotably connected to the wing proximate the tip. A connecting member can be operatively connected to the wing and the winglet. The connecting member can include a flexible material with a super elastic material member operatively connected to the flexible material. Thus, the connecting member can allow passive movement of the winglet responsive to real-time operational forces acting upon the aircraft. In some arrangements, the flexible material can be a fabric, and the super elastic material member can be a wire. In some arrangements, the super elastic material member can be configured to exhibit a non-linear stiffness profile. The non-linear stiffness profile can include a region of quasi-zero stiffness. The stiffness profile of the super elastic material member can be selectively varied, such as by controlling a temperature of the super elastic material member.

A kite includes a frame including a leading edge support and a plurality of struts extending rearward from the leading edge support, a flexible main canopy attached to the frame and at least one flexible kite sizing section adjustably attached to the flexible main canopy. The at least one flexible kite sizing section is adjustable to change an area of the kite, including an area of at least a first wing tip section of the kite.

A kite includes a frame including a leading edge support and a plurality of struts extending rearward from the leading edge support, a flexible main canopy attached to the frame and at least one flexible kite sizing section adjustably attached to the flexible main canopy. The at least one flexible kite sizing section is adjustable to change an area of the kite, including an area of at least a first wing tip section of the kite.

Methods and devices taught in the present disclosure address the need for improving stability and performance of delta wing kites. Delta wing kites as disclosed include a delta wing shaped sail reinforced with rigid or semi-rigid wing spars and a center spar, the wing spars and central spar being housed and secured within corresponding sleeves. A combination of various elements such as fuselage and corresponding through-holes, front and back pods, keel and top pockets provides improved stability and performance for the disclosed devices.

A kite leading edge has a tubular structure having a first curve in a span-wise direction and a second curve a chord-wise direction. The tubular structure is formed by a plurality of panels joined together at seams including at least a first longitudinal seam running in the span-wise direction of the tubular structure. At least a portion of the first longitudinal seam defines a first partial helical path about the circumference of the tubular structure.

A wind-powered unmanned underwater vehicle (UUV) system can include a kite subsystem configured to be powered by wind energy, a control pod coupled with the kite sub-system and configured to control the kite sub-system, a payload platform configured to provide a mechanical structure on which at least one module may be mounted, a submersible UUV, and a coupling device configured to physically couple between the kite sub-system and the submersible UUV.

A method for monitoring air pressure in a kite when kite boarding is described. The method involves a first step of connecting an air pressure sensor to one or more bladders of the kite. The method involves a second step of positioning a visual display for the air pressure sensor where it will be visible to a user conducting a visual inspection of the kite to display a pressure reading as sensed by the pressure sensor.