My favorite variety is the delta wing. This kite also proves stable in moderate winds, and one measuring a dozen feet across (about $160) can deliver approximately 130 pounds (579 newtons) of pull in a stiff blow. That's enough to loft some 30 pounds. To lift heavier loads, KAPers sometimes connect two kites in tandem, spaced roughly 100 feet apart.
But be prepared. Even a single large kite in a strong wind exerts enough force to pull an adult over. So don't wrestle with a monster kite unless you have the right equipment to control it. Leather gloves are a must. And your line should be rated at least two and a half times the largest tug your kite is likely to deliver. Experienced flyers often wear leather tool belts to which they attach carabiners and other types of rock-climbing equipment to control the line. Another tip: I cut a notch to weaken the crossbar on each of my deltas to ensure that the kite will fail before my string does.
Getting a suitable kite up in the air should be straightforward, but doing photography with it is a bit tricky. Fortunately, one can learn from the experience of others: amateur scientists have been hoisting cameras with kites since the beginning of the 20th century. The earliest pioneers had only limited success because they lacked a platform that would remain level and stable no matter what. An ingenious Frenchman named Pierre Picavet solved that problem in 1912. His suspension system, which now bears his name, is shown above. The instrument package hangs below two perpendicular rods, which are each about one foot long. This large cross is attached to the kite string by threading approximately 50 feet of cord through eight small pulleys. The tiny pulleys sold at hobby stores for radio-controlled model sailboats are ideal (lacking a local source, you can try Proctor Enterprises; 503-678-1300). The Picavet assembly is free to slide about as the kite changes altitude, which keeps the instrument platform level.
To isolate the Picavet from the large side-to-side swaying that kites often execute in high winds, attach the assembly about 100 feet below the kite. Use a metal ring, such as a large key ring, and a lark's head knot [see inset at left] to attach the Picavet at two points on the kite string about six feet apart.
With the wind rushing over it, any taut kite string will develop high-frequency vibrations, which can propagate through the Picavet and blur your images. Large rubber O-rings attached to the kite line help reduce this annoyance [see illustration at left]. The rubber rings used to hang mufflers, available from your local auto supply store, are inexpensive and quite effective at damping vibration.
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ILLUSTRATION BY DANIELS & DANIELS OTHER KITE TYPES that might
be useful for lifting scientific payloads include the so-called parafoil design (left) and the ¿Rokkaku,¿ or Japanese fighting kite (right). | ¿ |
Other point-and-shoot cameras would work, too. But the more limited self-timers on most other models require you to reset them after each photo. Although it is tedious to have to reel in your kite that often, thousands of breathtaking aerial photos have been taken in this way. With any camera, use a film speed of at least ASA 400 and set the shutter to the shortest possible exposure for the light conditions to avoid motion blur.
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