Ham Television htm fare, so he reeled in the fine as fast as he could, narrowly missing the train. This episode convinced him he needed a much larger kite, capable of lifting ar least four pounds. Raw materials were gathered up from the kite store to put together a massive 16-toot delta wing. (Jon's new kite was mentioned briefly in the February 1990 "ATV" column.)
Figure T. ,4 TU paytoad configuration.
Photo 8. The ATV payload ready for lift-off. (Photo by Jennifer Pifer,)
After a summer of experimentation, he sent us construction details for his ATV kite with a radio-controlled TV camera. Through use of a two-channel R/C system, he now has control of both the azimuth and elevation of the camera for some spectacular aerial views from as high as 600 feet.
The fatest system consists of a Uniden B/W camera, t wan P C. Electronics ATV transmitter, two-channel R/C receiver and servos, a i pound gel cell battery and a little wheel antenna (see Figure 1). The "Little Wheel" worked well in the flight tests and is a very lightweight omrii-hoii-zontal antenna, it was obtained from Otde Antenna Lab. 4725 W. Quincy #1014, Denver CO $0236.
Eric Vermillion, one of the local R/C enthusiasts, fabricated a camera mount out of nylon for Ihe two servos such that one se rvo i s att ache d d irectly to the othc r (P h o* to C), This provides a very lightweight method of independent Az-El control of the TV camera. The azimuth control has better than 90 degrees of movement, while the elevation servo allows you to view the horizon or to pan smoothly down to point at the crowd directly below the kite (Whenever you fly a kite this size there usually is a crowd 1) The little wheel antenna is mounted on three 12* long plasticor nylon rods to help keep RF out of the camera and the R/C receiver. Using a 1.2 Ah lead acid battery, the payload operates for about 45 minutes.
For best stability, attach four strings about two feet long to the corners of the payload. Tie two of these strings together at each end of the payload. This forms your mounting harness to the flight line. Make two loops about iftree feet apart in the kite's flight line about 50 feet beiowthe kite itself. Attach each pair of payload mounting strings to these [oops. This provides a very stable mount, although you sometimes may experience a gentle swinging motion depending on wind conditions.
You can construct your very own monster delta wing kite using the dimensions shown in Figure 2 (The heavy black tines are the support spars). Choose the design width (example: 16 feet). This is your 200% value. This will make the height of your kite exactly eight feet (100% scale). Atl other dimensions are scaied from this value. It's a good idea to make a paper version of the kite just to be sure of your
calculations. The actual kite is constructed from 1,5-ounce nylon material. Aliow enough overlap (3"} on the edges of the kite and the centerline to make sleeves for the spar supports. The Va" diameter spars are made out of a high strength carbon fiber They are lightweight and hollow, but can really take a lol of heavy lifting and abuse. The spars can be purchased at kite stores and come in 55" lengths. It will probably be necessary to connect two sections together with a ferrule to achieve the proper size spar. It's a good idea to double stitch those areas of highest stress, such as the horizontal back spar attachment points. The mounting hole on the keel consists of three nylon layers stitched together to provide additional support for flight
Photo D. The ATV package heads for the skies.
line attachment The horizontal spar mounts in pockets sewed into the back of the kite and helps to form the kite into the proper airfoil shape. All materials are available from stores that specialize in larger kites. While at the kite store, it's a good ideas to take a close look at a commercially built delta wing kite before building yours.
It's best to use 220-pound kite string. The forces on this large a surface area can be quite strong in a moderate wind. It sometimes takes three people just to bring the thing back in!
A good source of information about kite flying [as well as listings for kite store locations nationwide) is available from a magazine called American Kite. They can be reached at American Kite Company, 480 Clementina St, San Francisco, OA 94103; (415)896-0830.
Jon plans to add a 100 milliwatt 10 meter beacon on 28.235 MHz which will be mounted directly on the kite itself. The 10 meter inverted-V antenna will fit nicely inside of ihe spars. The beacon will be operational during each flight and should prove to be an interesting experiment.
The ATV kite has been a big hit at ham-tests and other special happenings. Not only is it a crowd stopper, it's an inexpensive way 1o provide a bird s-eye view of any event, For more detailed information on the kite system, you may send an SASE to Jon Pifer WM8W, P.O. Box 574. Arlington OH 45814.
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