The bridle and the control line help the kite flyer control the kite. In flight, the kite is connected to the kite flyer by the control line, which is connected to the kite by the bridle. The kite pivots and dives about the point where the bridle connects to the control line. The four forces of flight i. Lift, Weight, Drag, and Thrust affect kites in the same way they affect airplanes, and anything else that flies.
Lift is the upward force that pushes a kite into the air. Lift is generated by differences in air pressure, which are created by air in motion over the body of the kite.
Kites are shaped and angled so that the air moving over the top moves faster than the air moving over the bottom. Daniel Bernoulli, an 18th century Swiss mathematician, discovered that the pressure of a fluid like air decreases as the fluid speeds up.
Since the speed of the air above the kite is greater than the speed of air below, the pressure above is less than the pressure below and the kite is pushed into the air and — Tada — lift! Weight is the downward force generated by the gravitational attraction of the Earth on the kite.
The force of weight pulls the kite toward the center of the Earth. Thrust is the forward force that propels a kite in the direction of motion. An airplane generates thrust with its engines, but a kite must rely on tension from the string and moving air created by the wind or the forward motion of the kite flyer to generate thrust.
Naturally, the kite must be constructed properly and maintained in perfect balance. Assuming these prerequisites are fulfilled, obtaining the correct lift-to-drag ratio depends on angling the kite to the wind properly, a task which is accomplished by a carefully constructed bridle. The bridle, which is connected to the kite at the bridle point or points, helps the kite obtain the most suitable flight angle called the angle of attack or attitude into the wind. Moving the tow point up or down on the bridle can change the flight angle at which the kite faces the oncoming wind, allowing the kite to fly in a wide variety of winds.
Particularly evident with maneuverable kites dual-line, quad-line, fighter, or power kites , the wind window is an important aspect of kite flying — the angle of wind on your kite changes as you fly around the wind window, decreasing or increasing the power and control depending on a number of other factors such as the weight of your kite or lines.
Images below by reeddesign. The two small areas at the top of the kite are called pilot sails , while the two larger segments are known as driving sails.
The pilot sails partly control the direction in which the kite moves and the driving sails provide most of the lift. The tail of a kite refers to the strips of paper, plastic or fabric which are attached to the bottom of the kite in order to increase the drag of the kite. Tails can be made in a number of different ways, and can also be added to the wingtips of kites. Kites can be bowed , or bent, in order to give the cross-spar a dihedral angle. When this happens the cross-spar is bent so that the wingtips are at a slight backwards angle to the spine.
This helps make the kite stable. If the kite starts to roll to one side the wing on that side presents a greater surface area to the wind and the wing on the opposite side appears to reduce in surface area. The greater pressure being exerted on the wing with more surface area being exposed to the wind forces it to return to a normal attitude again.
Flat kites include all kites that are not bowed in some way. They don't have to be any particular shape, as long as they are flat, or planar. All flat kites need tails in order to fly. Bowed kites are those kites that have a dihedral angle. Because they are bowed they do not need tails. Parafoils are special sort of kites which are shaped very much like an aeroplane wing. They rely on the wind to hold them open as they generally have no spars.
These kites normally do not need tails. Box kites are also called cellular kites. They have many surfaces, some of which normally lie vertically, while others lie horizontally. Because of these surfaces, which act in a similar way to the dihedral angle on bowed kites, this sort of kite does not need a tail.
They are normally a strong wind kite. Compound box kites are basically box kites with wings attached to them. They fly in lighter winds than normal box kites and can pull much harder because of the increased surface area being presented to the wind. Delta wings are the best kites for very light winds. They tend to be pushed up and forward so that they lie nearly parallel to the wind.
Because of this they have a very low angle of attack. Consequently they don't pull very hard at all. The sail forms a billow, and this, combined with a keel in place of a bridle, allows deltas to fly without a tail. This kite was named the delta because it looked like the letter "delta" in the Greek alphabet, which corresponds to our letter "d".
The sled is similar to the parafoil in that it relies on the wind to hold it open. It has several spines running the length of the kite, but no cross-spars. Sleds often have vents cut in the sail, near the bottom of the kite, instead of using a tail.
They pull very hard and fly with a high angle of attack. Never fly a kite in a thunderstorm or while it is raining. The kite, or the flying line, might be hit by lightning.
Never fly a kite with wire, or anything that could conduct electricity through the flying line to you, and don't use a wet flying line. Never fly a kite near power lines, antennae or transmission towers. If your kite does get caught in power lines, do not attempt to retrieve it. Call the S. Never fly a kite above crowds, near public streets, highways, airports or helicopter pads, or other areas where your kite might be a hazard to other people.
In Australia kites are legally allowed to be flown up to three hundred feet above ground level, and may not be flown within five kilometers of an airport. Don't climb trees, buildings or power poles to retrieve your kite.
Ask for help from an adult, or make another kite. If your kite pulls strongly, wear gloves while flying it, to prevent the line cutting into your hands or causing a friction burn. Don't use monofilament fishing line to fly your kite.
It is hard to see, and it can cut into skin very easily when it is pulled taut by a flying kite.
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