Kite types, kite mooring, and kite applications result in a variety of kite control systems. Contemporary manufacturers, kite athletes, kite pilots, scientists, and engineers are expanding the possibilities.
Kite control systems encompass a range of methods and technologies used for maneuvering and stabilizing kites in various applications. These systems have evolved from simple manual controls, to intricate automated and powered configurations, reflecting the spectrum of kite uses from recreational activities, to scientific research and energy generation. The development and refinement of these control systems have significantly expanded the capabilities and applications of kites, sometimes changing them from traditional leisure objects, into tools for modern-day purposes.
High-altitude kite control systems, especially notable in record-setting flights, incorporate advanced mechanisms such as on-board angle-of-attack adjusters. These systems are designed to manage kite line tension, often limiting it to a safe threshold to prevent breakage or loss of control. These high-altitude kites feature safety and tracking mechanisms like radio beacons for detection over long distances and strobe lights for enhanced visibility. The complexity of these systems shows the significant engineering and design efforts, aimed at maximizing the performance and safety of kites in challenging conditions.
In kite-fighting and recreational use, single-line control systems dominate, with the human operator mastering specific movements to control the kite. These movements include tugs, jerks, releases, and directional shifts, essential for maneuvering the kite in desired patterns or engaging in aerial combat. The evolution of control systems in this area highlights the blend of skill, tradition, and technological innovation in kite flying. Historical control systems, such as those developed by the Wright brothers and George A. Spratt, have played a key role in the broader field of aviation, illustrating the interconnectedness of kite technology with the development of flight.
Modern kite control systems extend into various specialized fields, including medium-length-tethered power kites and high-altitude electricity-generating wind-power kite systems. Power kites, controlled by multiple lines, are used for adjusting braking, and distorting the kite's shape for specific functionalities. These kites find applications in sports, renewable energy, and scientific research. The control systems are often complex, involving patented technologies to manage the forces at play. Kite aerial photography and governable gliding parachutes show the versatility of kite control systems, adapting traditional kite flying techniques for purposes like photography, payload delivery, and sport parachuting. There is ongoing innovation in kite control technology, including the exploration of solar sail and plasma kites for space applications.
Single-line kite control systems
High-altitude attempt single-line control systems On-board angle-of-attack mechanisms were used in the 2000 altitude record-making flight; the operators' designed adjuster limited kite line tension to not more than 100 pounds by altering the angle of attack of the kite's wing body. The kite's line had a control: a line payout meter that did not function in the record-setting flight. However, some special tether line lower end used bungee and pulley arrangements to lower the impact of gusts on the long tether. Control of a kite includes how other aircraft see the kite system; the team placed a radio beacon (using two-meter frequency detectable for 50 miles) on the kite; for sight visibility, strobe lights were hung from the kite's nose. Control via use of reels and pulleys become critical when tension is high; the team had to repair and replace parts during the flight session.
Auxiliary control Auxiliary devices have been invented and used for controlling single-line kites. Devices on board the kite's wing can react to the kite-line's tension or to the kite's angle of attack with the ambient stream in which the kite is flying. Special reel devices allow kite-line length and tension control. Moving the kite's line lower end left or right or windward or anti-windward forms part of the control system of single-line kites. Devices at the kite's bridle can be set to alter the relative lengths of sub-bridle lines in order to set the attitude of the kite so that the kite flies at a certain position of the potential positions; this can be done for one setting while the kite is readied for flight; but Kenneth C. Howard invited a device that can be operated on single-line kites during the flight session for variable settings:
Fighter-kite control systems The traditional fighter kiting with single-line control dominates kite fighting while multi-line kite fighting is yet a minor activity. The human operator of the single line aims to master movements (tugs, jerks, releases, directional movements) in order to have the unstable kite temporarily move in one direction or another. The intents of the controls are offensive and defensive; escape from an attack or position for an attack. The building of the kite so that motions by the kite's human operator or pilot allow a temporary limited stability takes special care.
Historical kite control systems Wing warping A quad-line two-handled kite control system to warp the wing shape used by the Wright brothers and other aviation pioneers. The brothers asserted the control system as their own invention, although several contemporaries claimed prior art including European patents issued in 1868 (before the brothers were born), culminating in a series of lawsuits was called the Wright brothers patent war. This control system is quite similar to the quad line sport kites used today. George A. Spratt triangle control frame
Triangle control frame for any towed or free-flight kite system.George Spratt Paresev
A mass-shifting via pulley-routed cables from a control stick while kite pilot hung from the kite from a single tensional point. Blue-Hill Observatory A piano-wire based kite control system. Barry Hill Palmer Of seven to eight experiments, Barry Hill Palmer found several control systems for his foot-launch hang glider in 1960–1962. He finally came upon what inventor George A. Spratt had already found in aviation and regarding any hang glider: a triangle control frame or A-frame in front of the pilot while the pilot hung from a tether either in a seat or harness for various positions; the mechanical arrangement precluded the later invention of the same. Many others would find the same mechanical arrangement for mass-shifting for Rogallo hang gliders and derivatives; these free-flying manned kites or hang gliders used the wing for the kites from the Fleep or Paresev or derivatives of that branch of stiffened flexible wings.
Medium-length-tethered power kites Power kites are controlled by two to five lines. The simplest systems provide steering by pulling either end of the kite. More lines can provide different functions. These are:
adjusting the angle of attack: Pulling on lines attached to the front edge of the kite will reduce the angle of attack and thereby reduce the pull of the kite. braking: A line pulling the trailing edge down causes a braking effect that can be used either to make the kite turn quickly if applied to only one side, or to bring the kite down if applied symmetrically. distorting the kite: Useful when the kite is lying on the surface of the water. A fifth line is occasionally used to do this and thereby makes relaunching much quicker and easier.
The lines attach to different controllers:
Rings or wrist loops These are commonly found on smaller foils. Two-line bars These are found on LEIs, target kites, and other recreational, and special-application kite systems. They almost always have a wrist leash attached to one of the lines so that the kite will come down if the bar is released. Three-line bars These are found on some foils. Lines from the ends of the bar attach to either side of the kite and the third line attaches to the rear edge of the foil. This line passes through the bar and is attached to a wrist leash via a cleat to lock the brake off until the bar is dropped. This bar design was never developed by the major manufacturers due to the complexity of the design; however an advanced model is now commercially available from K-trac. Four-line bars These are found on LEIs, Bows and some foils. This system provides angle-of-attack adjustment. There is usually a semi-permanent attachment, known as the chicken loop, fastened to the kiter's harness via the front lines. Releasing the bar while still attached to the chicken loop causes the kite to assume its minimum angle of attack and therefore minimizes the pull generated. There is usually a safety mechanism so that the kite can be totally depowered by detaching from the chicken loop whilst still hanging on to the kite by a leash attached to one of the lines. There are many variants on this system. Five-line bars These are essentially a four-line system plus a fifth line attached to either the leading edge or trailing edge of the kite. A trailing edge system causes the kite to travel to the center of the power zone and thus re-launch with a lot of power. A leading edge system is used both as a depower and a relaunch device. It can be used to lower the angle of attack for depowering. For relaunch it can be used to assist rolling the kite into the proper position. Handles These are commonly found on four-line foils. Each handle is a bar with a line attached at each end and each handle controls either the left or right side of the kite. They are held at the top where the power lines attach. Brake lines attach to the bottom of each bar and go to the rear edge of each side of the kite. These provide a braking function not an angle of attack function
Control of high-altitude electricity-generating wind-power kite systems
Human control of high altitude wind power systems is typically accomplished through servo mechanisms, as the tether tensions are too great for direct manual operation.KiteGen project: control as key technology for a quantum leap in wind energy generators by M. Canale, L. Fagiano, M. Milanese, and M. Ippolito.
There are a number of patents in this area: Kite control systems by John D. Bellacera Several patents by Dominique and Bruno LegaignouxPatents by Dominique and Bruno Legaignoux In 1984 a fundamental first patent gave them impetus to later bring forward several other key kite control patents.
Other concepts include: Pulling the lines using winches Rotating the line attachment points around a central pivot.Kite test 2 of the Sussex University kite control project. Shifting the line attachment points back and forth (or up and down) using linear motors
Control of kite rigs
Kite rigs are systems for propelling a vehicle, such as a boat, buggy, or a vehicle with snow and ice runners. They may be as simple as a person flying a kite while standing on a specialized skateboard, or be complex systems fixed to the vehicle with powered and automated controls. They differ from conventional sails in that they are flown from lines, not supported by masts.
Commercial transport propulsion Ship-pulling kites run to hundreds of square meters of area and require a special attachment points, a launch and recovery system, and fly-by-wire controls.
The SkySails ship propulsion system consists of a large foil kite, an electronic control system for the kite, and an automatic system to retract the kite.