Date: Mon, 16 May 1994 06:07:01 -1000 From: salanne@convex.csc.FI (Simo Salanne) Message-Id: <2r85n5$cq0@pobox.csc.fi> Organization: Centre for Scintific Computing Subject: Kites & Computers (translation of an DRAma article) The following is an English translation of my article published in Drachen Magazin 2/94. I hope rec.kites readers will find it useful enough to justify the rather lengthy posting. The article was written to an ordinary kiter, please try to tolerate the "tutorial" tone:-) I have not included the pictures, but sent them to rec.kites archive, where you can get them in a few days. Smooth Winds Simo.Salanne@csc.fi ----------------------------------------------------------- Kites and Computers 1. Introduction Computers have become everyday tools on many areas of our life. Not only on professional or business matters, but also in passtime activities. In this article I describe some of the possibilities a kite enthusiast has in using computers for his favourite hobby. If you are in kite business you should be even more interested! The programs I use are either freeware or shareware (i.e. free or reasonably priced) and suit very well to private use. Most of them are available on bulletin board systems (BBS, "boxes") or evaluation copies can be ordered from vendors. The programs I mention by name are just few good choices and there are definitely others. All of them will run on ordinary PC with DOS and color display (EGA/VGA/SVGA), MS-Windows is not required. The application areas I will write about are: - kite design and building - kite flight simulation - competition management - communication. 2. Technical Kite CAD. Like any technical design work, kite design usually produces drawings to visualise the result. DraftChoice is simple 2- dimensional CAD (Computer Aided Design) software, with functionality to suit kite design very well. The features very common to CAD software and useful for kite designer, but usually not included in general purpose drawing programs are: - Layering. E.g. sail, frame and bridles can be drawn in different layers (and colors) on top of each other. Layers can be made visible or unvisible for viewing or printing. - Dimensioning. The program gets the dimensions directly from drawing. If the drawing is scaled, dimensions are updated automatically. Also the calculation of area by pointing the outline of sail is very convenient feature. - Exporting drawings to other programs: e.g. to a paint program to do the "artistic" design. An example of DraftChoice screen displaying a stunt kite design is in picture 1. Sail is drawn with dark green, [file: STUNTCAD.GIF] bridle light green, frame and frame diemensions are brown. DraftChoice will print the drawing on ordinary matrix, ink jet or laser printers. Very usefull companion to DraftChoice is program called PrintGL, which actually makes a printer to emulate a plotter. The real advantage of PrintGL is that it can print the sail plan on multiple A4 size sheets in 1:1 scale. A4 pages are easy to copy and when glued together you get templates of proper size! When selecting kite building materials, I use a spreadsheet program (any of them will do) to estimate the weight of the kite. My spreadsheet template has the unit weights of my standard materials: spars, fabrics, connectors, ferrules. Adding the amount of different materials needed the total weight is easy to find. E.g. when making a light wind stunt kite it's important to know if a kite having one square meter of sail will weight close to 200 g (OK) or close to 300 g (won't fly in 2 m/s!). 3. Graphics design Whether you are making a kite of your own design or making one published in books or magazines, it might be worth to draw the sail plan with DraftChoice and then import the sail layout into a paint program like Neopaint II. You can also draw a layout directly with Neopaint. Paint programs are made with coloring in mind. On computer screen you can very quickly paint sail panels with different colors, and change colors until you are satisfied. I like Neopaint's feature to allow me to adjust the colors to match rip-stop colors of different manufacturers. E.g. I have one palette of colors for Icarex and another for Carrington. Picture 2 shows [file: STUNTPNT.GIF] Neopaint screen with a stunt kite sail plan imported from DraftChoide and colored. DRAma 1/92 had an article "Tauschungsmanaver", which stimulated me to play with cubes. I used DraftChoice to draw the grid, which was colored on Neopaint, see picture 3. [file: CUBEROK.GIF] DraftChoice supports drawing of regular polygons, hexagons in this case, to make the grid took only a couple of minutes. When I built a Flowform from Jim Rowlands book "Soft Kites and Windsocks", I first scanned the drawing of the flying Flowform from the book into computer and then used paint program to try different coloring schemes on it, see picture [file: FLOWFORM.GIF] 4. (I didn't have a scanner, but used a fax machine in my office to send the picture to my home computer, which has fax send/receive funtionality.) 4. Flight Simulation - KiteFlight Computer flight simulators are well known entertainment in computer games, but KiteFlight is not a toy. It is a design and animation tool to create sport kite flying figures and routines. It will also create diagrams to be printed on paper. Have a look at picture 5. [file: KITEFLIT.GIF] In a magazine I cannot represent the animation, but try to imagine the small kite triangle moving on the computer screen, with a speed which feels the same as if you were flying your favourite kite in a gentle breeze. The speed can be changed to adapt the simulation to different kites and wind speed conditions. You can optionally make the kite to draw a trail of it's flying path on the screeen, and make "snapshots" of kite's positions. And, it's not only one kite, but you can simulate the whole team! That's the real power of KiteFlight. KiteFlight originates from Dutch, six person team Dike Hoppers, which has successfully used it to design and learn their amazing routines. KiteFlight can be used for: - teaching stunts to flyers - training judges - informing event audience about compulsory routines - designing routines for individuals, pairs and teams - printing stunt diagrams An example of KiteFlight simulation program (KF1-program) for a compulsory figure called "Hairpin" and the diagram are in picture 6. [files: I17.KF1 & I17.PS ] The author of KiteFlight is Peter van den Hamer from Holland. KiteFlight will be published in May 1994 together with the new stunt kite book by Servaas van der Horst & Nop Velthuizen. A demo version of KiteFlight and simulations for the rule book compulsory figures can be found on rec.kites archives (see next chapter). 5. Electronic mail & rec.kites Electronic mail and conferencing systems offer fast and international communication opportunities to kiters. The best forum is usenet/Internet newsgroup called rec.kites, which has some tens of regular contributors and estimated 15000 readers world wide! Internet is probably the largest computer network in the world, with millions of computers connected (nobody knows all the time increasing number of them). Universities, research organisations, companies have access to Internet. Many commercial companies offer services to access Internet. Many new things are discussed in rec.kites months before they appear in any kite magazines; e.g. the stunt called "Axel" or "Axle" (see DRAma 4/93, World Cup), were discussed and a detailed history how it evolved, how to do the stunt and which kites are especially suitable for it, were presented in summer 1993. Kite traction (i.e. buggying ) discussions have been very active in winter 93/94. New products introduced in KTA show were reported to rec.kites next week after the show. Typical topics discussed in rec.kites are: Designs, building, tuning, sewing, materials, reviews, flying, competitions, rules, power kiting, indoors flying, aerial photography, etc. Usually there are 5-20 new articles daily. Best of all with rec.kites is the interactive nature: you can ask questions and there are experts from all over the world to help you (Ron Reich, Marty Sasaki, Bob Hanson, Dean Jordan, Jeff Burka, Darrin Skinner, Kevin Mayeshiro, Steve Thomas, Bert Tanaka, Andrew Beattie, Patrick Prosser, Anne Rock, Bernhard Malle, Esben Collstrup, Peter Ulfheden, Stein Hjelland, etc.) Even if you don't ask anything yourself, you can learn a lot from problems and solutions presented by others. To avoid repeating same discussions again and again rec.kites contributors have created four articles, which are updated and posted regularly. They are called FAQs - Frequently Asked Questions. The topics of four FAQs are: 1. General 2. Stunt Kite Reviews 3. Stunt Kite Plans Bibliography 4. Addresses Their total volume exeeds 100 pages of vital kiting information. There's a lot of people, who have first "met" each other on kiting matters on a computer network, and then face-to- face on a kite festival. Like the five person group now called "n@r.k", which was born sometimes in 1992 and got together first time on Fano 1993. n@r.k has one member from Germany, Denmark, Norway, Sweden and Finland. It's planned to meet again on Fano in June 1994. If you see there a banner with "n@r.k" sign or a stunt kite like in CAD example, come to say hello to us! WARNING: Next two paragraphs contain tricky computer jargon, skip them unless you are familiar with computer networks. The material presented in rec.kites is archived on a computer in Hawaii (ftp.hawaii.edu). Hawaii archive is mirrored on two sites in Europe: Bremen (ftp.uni-bremen.de), and Helsinki (ftp.funet.fi). If you have access to Internet and ftp service you can access any of these archive sites via anonymous ftp. Bremen offers also "ftp-by-email" service. If you don't have access to Usenet news system, but have access to Internet electronic mail, you can send a message to kites-request@das.harvard.edu to join rec.kites mailing list and start receiving rec.kites articles in your mailbox. Be patient to wait for FAQs, which are posted about once a month. 6. Competition management The scoring system in sport kite competitions needs so many calculations that a pocket calculator with a pen and paper is not very attractive solution. A general purpose spreadsheet program is good and feasible solution for score calculations, especially if you manage to get spreadsheet templates somewhere. E.g. European Cup 93 results were processed by a spreadsheet. World Cup 93 used a special purpose kite competition software called KiteFest, which not only calculates the results but: - Helps to plan the time schedule of events. - Keeps track on contestants, judges and event officials. - Scores can be entered as the event progresses and results are ready in a minute after last performance. - Prints variety of reports. (Flight order generation is missing!). KiteFest is made in U.S. and has some peculiarities like 12 hours clock, two characters for "State" in addresses, which doesn't work well in Europe. 7. Other Mark Cottrell's The Kite Store Book of Kites contains some BASIC programs to calculate e.g. - Dimensions of single line Delta - An estimate how high a kite can fly - An estimate of the size of single line kite needed to lift a load. Dave Lord's Stunt Kite Design software is available on rec.kites archive and can be used to dimension many popular types of controllable kites: Spinoff, Hawaiian Team, Fire Dart, Double Spined Kite, Speedwing, Revolution and Double Diamond. The program lets you select some main dimensions like leading edge length and nose angle. Then it calculates: - sail, spar and bridle dimensions - estimates the weight - calculates the wing area - calculates the wing loading The program also helps to select proper spars for the kite. Last year I flew my ballet routine to the music, which was recorded directly from computer sound card to tape. It sounded like a real orchestra, with the advantage of small cost - compared to real orchestra - and easy way to change the tempo to match different wind conditions. But that story is outside of DRAma's scope... The author can be contacted by email (in English, please): Simo.Salanne@csc.fi If you need further information in German e.g. about rec.kites please contact Bernhard Malle: malle%fuzi.uucp@germany.eu.net The English version of this article will be available on rec.kites archives after the publication in DRAma. ----------------------------------------------------------- Software products mentioned in the article are available >From the following sources: --------------------------------------------------- DraftChoice V2.0 TRIUS, Inc. P.O. Box 249 N. Andover, MA 01845-0249 Tel. (508) 794-9377 Fax. (508) 688-6312 BBS (508) 794-0762 69.90 USD + Shipping & Handling 12.50 USD Evaluation copy 5.00 USD. (Cheaper than downloading via long distance phone call!) --------------------------------------------------- PrintGL V1.40 Ravitz Software Inc. P.O. Box 25068 Lexington, KY 40524-5068 USA BBS/FAX 606-268-0577 registered copy 50.00 USD. --------------------------------------------------- NeoPaint - Version 2.0 OSCS Software Development, Inc. Customer Support 354 NE Greenwood Avenue, Suite 108 Bend, OR 97701-4631 U.S.A. Sales (503) 389-5489 BBS (503) 383-7195. FAX (503) 388-8221. NeoPaint $45 + $21 (shipping and handling) --------------------------------------------------- KiteFest Albany Hill Software 643 Jackson STreet Albany, CA 94706 USA phone (510) 527-3547 --------------------------------------------------- KiteFlight >From your local kite shop or from Vlieger-Op, Holland. --------------------------------------------------- -- Simo.Salanne@csc.fi STACK Finland