Date: Thu, 25 Feb 1993 21:38:33 GMT From: sasaki@netop3 (Marty Sasaki) Message-ID: <1993Feb25.213932.17100@das.harvard.edu> Organization: Division of Applied Sciences, Harvard University Subject: FAQ, part 1 general questions This is part one of the FAQ. It will be posted periodically to rec.kites and sent to the kites mailing list maintained at Harvard. The FAQ is the result of many people working together. Please help to make it better by sending corrections and suggestions to "sasaki@noc.harvard.edu". This portion of the FAQ is divided into several sections. Section 1 - Questions about BBS and mailing lists dealing with kites. Section 2 - General questions about kites. Section 3 - Kite books. Section 4 - Kite terms. Section 5 - Materials Section 6 - Single line questions. Section 7 - Multi-line questions Section 8 - Safety Section 1: BBS, mailing lists and other things electronic ========================================================= 1Q1: What is rec.kites? 1A1: Rec.kites is a USENET news groups. It was created to encourage interest in kites and kite flying. The rec.kites charter was written by Ken Ritchie (lepcock@watsci.uwaterloo.ca) CHARTER The group rec.kites will, as its name implies, deal with discussions of kites and kiting. The discussion will deal with any and all aspects of kiting with no limitations as to specific types of kites. In general, possible lines of discussion could be about: 1)Plans and ideas as to how to build kites. 2)Information as to the best places to purchase materials. 3)Tips on flying different kites, and their pro's and con's. 4)Ratings of commercially available kites. 5)Safety and kite flying laws in effect. 6)Anything else to do with kites... This newsgroup will be of interest to anyone who is interested in kites and kiting, no matter how serious they are about it. The group is not to be limited to those who are already experienced in the sport. It will partially be set-up to introduce people to kiting. 1Q2: What is the "kites" mailing list? 1A2: The kites mailing list was originally set up by Irving Reid to for the same reasons that rec.kites was formed. Currently the kites mailing list is gatewayed to/from rec.kites, i.e., a message sent to the mailing list is posted to rec.kites, and messages posted to rec.kites are forwarded to the mailing list. The mailing list is maintained by Marty Sasaki. Send a note to: kites-request@das.harvard.edu to be added to the list. 1Q3: Can I get on the kites mailing list from my Compuserve account? 1A3: Yes. Since you can send and receive mail from the internet from Compuserve, you can be placed on the mailing list. Send a message to: >internet:kites-request@das.harvard.edu asking to be put on the list. 1Q4: What about Prodigy? 1A4: Currently there is no way to reliably send mail between the internet and prodigy, although this service will be available "soon". 1Q5: Are there any BBS that have kites discussions? Section 2: General Questions & Answers =============================== 2Q1: What is a kite? 2A1: A kite is a wind-powered, tethered flying object/device. They come in an incredible variety of shapes, colors, and sizes. The main division between kites has to do with the number of lines, with single and dual lines being the most common, and quad line kites gaining popularity. Many consider an airplane a kite without a flying line! 2Q2: Where can I get a good kite? 2A2: First, try your local yellow pages, or the European equivalent of yellow pages. Then, read the rec.kites address list which is posted periodically. 2Q3: Where can I get books on kites? 2A3: Most kite stores will have a selection of books. Mail order companies also sell books. Another source is the Kitelines Book Store (see the address FAQ for address and phone number?). 2Q4: Are there any magazines or other periodicals dealing with kites? 2A4: There are 3 U.S. magazines about kites, American Kite, Kite Lines, and Stunt Kite Quarterly. Section 3: Kite Books. ===================== When it was available, I have included publisher and author info, otherwise, just the titles are given. David Pelham, "The Penguin Book of Kites". Many kite flyers consider this to be the "Bible" of kite flying. Sections on kite history and flying and making kites. Large Section of kite plans in outline form. Margaret Greger, "Kites for Everyone" and "More Kites for Everyone". Kite patterns with good construction tips. Mark Cottrell, "The Kite Store Book of Kites." Single line designs and computer programs for kite CAD. Mark Cottrell, "Swept Wing Stunt Kites". Mark Cottrell's theory on stunt kites. Talks about how stunt kites fly and turn. Plans for a LiteFlite and a few other experimental kites. David Gomberg, "Stunt Kites!" A basic flight manual for dual line kites. This book is updated once a year, so if you haven't looked at it recently, it might be worth revisiting. The lastest edition just (2/93) went to the printers. Section 4: Basic Terms. ======================= Spars These are the framing members of a kite. There are several types of spars. Spine Main Spar Center Spar All of the above are names for the spar that runs from the nose to the tail of a kite. It is usually in the center of the kite. Vertical Spar(s) Longerons Spars that run from the top to the bottom of the kite. Leading Edge Spars These run along the front edge (called the leading edge) of the kite. Cross Spars Spreader Spars These run perpendicular to the center spar and keep the kite spread out. The number of cross spars varies from kite to kite. Whiskers Standoffs These are small thin spars that run between the trailing edges (back edge of the kite) and the spreader spars. Their purpose is to make sure the sail keeps theright shape in light winds. These are found most often on delta (triangular shaped) stunt kites. Sail Skin The sail of a kite is the material that covers the spars. Sails are made from many different materials (see section on materials). Bridle Lines The bridle of a kite is a set of lines that distribute the attachment of the flying line(s) to the kite. Changing the length of the bridle lines changes the way a kite flys. Kite Line The term "string" doesn't really apply to flying line when you consider the strengths and the materials used for flying line. Modern kite line can be made out of Dacron or Nylon, or high-tech materials such as Spectra, or Kevlar. Some flyers still use cotton or linen string! Section 5: Materials. ===================== 5.1 Sail Material ----------------- Ripstop Nylon This is the most common material used for stunt kites as well as many single line kites. Because of it's strength and light weight, ripstop nylon is a good material for making kites. Ripstop Polyester Ripstop polyester (or ripstop Dacron) is becomming more common in the kite world. It's main advantage is higher strength than Nylon for a given weight. It also stretches less than nylon. Nylon Taffeta Nylon taffeta is often used in single line kites. Taffeta usually isn't coated and the porosity of the fabric adds stability to many kite designs. Tyvek Looks and feels like paper, this is technically a non-woven spun olefin fabric. It is inexpensive, difficult to tear, and is easy to decorate with paint and markers. Tyvek is often glued or taped, and can be sewn. Paper The Japanese and other Asians make strong lightweight paper that is often used for making kites. Don't be fooled by "rice paper" which is made for it's looks. Japanese paper is often called "washi". Construction paper, paper bags, wrapping paper, newspapaer, and tissue paper have all been used to make successful kites. In general look for paper that is made out of long fibers. Tear a piece of it to see how strong it is (ask before you tear it though). Plastic Garbage Bags These are inexpensive, can be found in many colors, and are easy to work with. Plastic garbage bags are often used for simpler kites (sleds, deltas, and diamonds), but some people have made complex box kites and stunt kites out of them. Mylar Mylar is usually found as a thin sheet. It can be used in much the same way that paper is used, but it is lighter and stronger than most papers. It's main disadvantage is that once it is torn or cut, it tears very easily. Mylar kites are usually stuck together using tape since mylar is difficult to glue and sewing reduces the strength. 5.2. Spar Material ------------------ Solid Fiberglass Rods These are flexible, very strong, and inexpensive. They are also fairly heavy. These are often used when flexibility is an asset, such as in dragon kites. Solid fiberglass is also used in many small fighter kites in the cross spar. Fiberglass tubing Flexible, fairly strong, moderately expensive. A typical fiberglass tube with outer diameter of 6 mm weights 30 g/m. Withstands "unintentional ground contact" better than carbon. For a given radius, these are stiffer than solid fiberglass rods. Carbon/Graphite Fiber tubing and rods. Graphite is lighter and stiffer than fiberglass. It is more expensive, sometimes much more expensive than fiberglass. A typical carbon tube with an outer diameter of 6 mm weights 20 g/m and has stiffness ("a measure of the ability to resist deflection by a load") 2.5 times that of fiberglass. Aluminum Between fiberglass and graphite for flexibility, and less expensive than most graphite. Dowels Hardwood dowels are inexpensive and fairly strong for their weight. Arrow shafts Most of the fiberglass and graphite tubes are arrow shafts. 5.3. Line Material ------------------ Kite lines can be made out of a variety of materials using different construnction techniques. The two predominant types of line are twisted and braided. Twisted line is often less expensive. Braided line is generally easier to handle, especially when left on the ground. Kevlar Kevlar is strong (much stronger than Dacron), light in weight and has little stretch, which makes it an almost ideal stunt kite line. On the down side, Kevlar deteriorates with exposure to UV-light fairly easily. Kevlar is also highly abrasive and will cut through most other kite line. Kevlar fibers stretch less than 50f their length. Spectra Spectra has very similar characteristics as Kevlar, but is less sensitive to UV than Kevlar and is not as abrasive. Spectra has a low melting point which makes it much more vulnerable to being cut than other kite lines. Dacron/Polyester Dacron is the line of choice for many single line kites. It is strong (stronger than Nylon), and fairly light in weight. Typical stretch is about 15 Nylon Nylon is inexpensive and is quite usable for flying kites. It's high stretch makes it difficult to handle at times. Please do not fly kites on monofilament nylon. Mono is often hard to see, tangles and snarls easily, and will cut through other kite line. One small child running around a field with mono line can ground every other kite on the field. Cotton Not very strong, but light weight and perfect for small kites. Cotton line is often preferred for single line fighter kites. In larger diameters, cotton line can be great for flying larger kites. It is easy on the hands, and is easy to tie. Linen Linen line is often the line of choice for fighter kites. It's low stretch allows good control of a fighter kite. Section 6: Single line questions ================================ 6Q1: I'm a beginner, what sorts of kites should I look for? 6A1: The old fashioned diamond kite that we all made as kids is probably not the best place to start with single line kites. These are surprisingly complex and getting one to fly well requires a large amount of skill (or a lot of luck). A good quality delta kite is probably a good place to start. These range from the toy store variety costing a few dollars to high tech ripstop nylon and graphite stick kites costing hundreds of dollars. Most will fly well in a variety of wind conditions. Another good kite would be a Delta-Conyne, often referred to as a DC. A DC is a cross between a delta and a Conyne box kite. Dragon kites are also good kites to start on. These consist of a head, usually arch shapped, and a long tail. 6Q2: I've "mastered" the delta, what's next? 6A2: After a bit more experience you might try a box kite of some sort, or a parafoil. Box kites come in a dazzling number of designs. Parafoils (and their relatives, flow forms, strato-scoops) don't have any sticks. They use the air to fill them and hold them rigid enough to fly. 6Q3: I've heard of fighter kites. What are they all about? 6A3: People have been engaged in kite battles probably since people have been making kites. A fighter kite is a kite made to be flown in battle. In many places kites are flown on line that has been coated in ground glass. The combatants try to saw through their oponents line. The last kite in the air is the winner. 6Q4: What is a rokkaku? 6A4: A rokkaku is a Japanese kite with six sides. The kite has a single vertical spar and two horizontal spreaders. Rokkakus are often flown as fighter kites since they can be very manueverable when flown by an experienced flyer. Section 7: Stunt Kite Questions =============================== Please see the Stunt Kite Review portion of the FAQ for more information about individual kites. 7A1: What is a stunt kite? 7Q1: Stunt kites are also referred to as Sport Kites. Usually, the term applies to any multi-line, controllable kite. 7Q2: What are good stunt kites to start with? 7A2: "The easiest to learn beginners kite is a diamond (Peter Powell, Trlby, Dynakite, etc.) One of the biggest advantages to a single diamond is the ease with which you can re-launch after a crash. Kiting can become very frustrating when you have to keep walking 150' to set up a kite. These kites also verge on indestructible. "3/4 deltas (Hawaiian Maui, 3/4 Spin-off, North Shore Extreme, El Nino, Stinger 750, Wizard, etc.) might be good second kites, but their increased speed, both forward and turning, make them harder to learn on (though I certainly know people who have learned on them). Their lower pricing (usually between $75 and $130) makes them attractive to beginners who aren't willing to dump a lot of money into a new hobby, but this doesn't necessarily mean they're good kites for beginners. "Full-sized deltas (Spin-Off, Hawaiian Team, Super Sky Dart, Slingshot, LiteFlite, Phantom, Big Brother, etc) are a fairly good place to start, though the price can be inhibiting to a beginner. However, there are plenty of good full-sized kites that are good for learning on; slower air speeds, a nice tendency to never stall, and so on. "With all of these kites, as Marty Sasaki says, it's probably best to stay away from graphite-framed kites at first, as they are easier to break." Jeffrey C. Burka jeffy@syrinx.umd.edu 7Q3: How long should my flying lines be? 7A3: Most organized competitions have a maximum line length of 150 feet, so your flying lines should probably 150 feet or less. 7Q4: How does one get started in competitions? Where do I find rules and how do I learn the figures? How does one find out the locations of events? 7A4: In the USA, write to the American Kiteflyers Association (AKA) or a local club. The AKA/STACK rules book lists the official rules for competitions and gives many standard figures for precision flying. The AKA also maintains an insurance policy that covers members while flying in the United States, or competing in an AKA sponsored event. American Kiteflyers Association 1559 Rockeville Pike Rockeville, MD 20852 1-800-252-2550 In the rest of the world, STACK is the world wide association of Stunt Team And Competitive Kiting, with more than 500 members and national directors in 15 countries. 7Q5: How does one adjust the bridle on a stunt kite? 7A5: "Kites SHOULD be tuned whenever you have a change of >5-10 Mph. "Bridled kites should be lofted by the fly-line attachment clips so that they hover right over your head. Putting your index finger right behind the clips so that the kite is held by the bridle, you ease up (or down) on BOTH sides by, oh, 1/16" at a time. Make sure that you go in the same direction with the same increment on both sides at the same time, or as close as practical. What you are looking for is the greatest pull that is stable with the accent on pull. You then move the clips to that position and you are set. Just remember, if you take it out at another time when the wind conditions are different, you must re-tune! "RE:FLEXIFOILS - Yes, Virginia. You CAN tune flexis - you move the rubber grommets at the ends of the strut in or out (about 1/8th inch increments should be about right). Out for lighter winds and more speed, in for heavier winds and better turning. "On most kites, tuning is a trade-off between (more power, tighter turns) vs. (lighter winds, broader turns). So, it's a matter of personal preference. Myself, I like 'WHAMMING', hard pull, lots of power and TIGHT turns. One other way to achieve this in ADDITION to power tuning is to fly VERY short lines (I once flew on 40-45' lines). Not real good for a light wind, but then I find anything less than 25 Mph BORING." Ben Nagata Kite@Busadm1.Cba.Hawaii.Edu Section 8: Safety ================== Here are some kite safety tips. Most are just common sense. Please Stunt kites are very light and can fly very fast, in a suitable wind the speed can exceed 100 km/h even 100 miles/h! Any device with such a speed can damage property or injure people. Also the thin line can cut like a knife (especially Kevlar and Spectra lines!). If you get in a dangerous situation release ONE HANDLE and walk towards your kite. Your lines might be tangled, but usually your kite willnot have harmed the environment or itself. NEVER give a large, hard pulling kite to an inexperienced flyer. NEVER leave a ready to launch kite unattended. NEVER fly near an airport, except with the permission of the air traffic controllers. I have not included the appropriate regulations, because they are different in different countries. Most American universities -- and I assume other universities -- keep complete copies of Federal Regulations and Laws (all of them). If you wish to fly near an airport or at a very high altitude, check with your local university library or the air traffic controllers. NEVER fly near power lines (or in electrical storms for the same reason). Keep your kites, especially lines and bridles, in good condition; this will avoid embarrassing and dangerous situations. = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: 26 Feb 1993 08:03:26 GMT From: malle@rpksun1.mach.uni-karlsruhe.de (Bernhard Malle) Message-ID: <1mkise$h9r@nz12.rz.uni-karlsruhe.de> Organization: University of Karlsruhe (FRG) Subject: Re: FAQ, part 1 general questions Hello, I have just read part 1 of the faq and I am now curious to know: what's a "strato-scoops"? I have just built a flowform from the book of Jim Rowlands and have seen in the book "make and fly stunt kites" from nop velthuizen what is a speed-foil, but I have never heard of a strato-scoop. Does anyone have more information (maybe a plan?)? Bernhard +------------------------------------------------------------------+----------+ | Bernhard Malle | RPK / Ma | | Institut fuer Rechneranwendung +----------+ | in Planung und Konstruktion | | Universitaet Karlsruhe | | Kaiserstr. 12 Tel.: +49 721 6082762 | | D-7500 Karlsruhe Fax.: +49 721 661138 | | Germany e-mail: malle@rpksun1.mach.uni-karlsruhe.de | +-----------------------------------------------------------------------------+ = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Fri, 26 Feb 1993 16:41:20 GMT From: sasaki@netop3.harvard.edu (Marty Sasaki) Message-ID: <1993Feb26.164120.3541@das.harvard.edu> Organization: Harvard University Subject: Re: FAQ, part 1 general questions In article <1mkise$h9r@nz12.rz.uni-karlsruhe.de>, malle@rpksun1.mach.uni-karlsruhe.de (Bernhard Malle) writes: >I have just read part 1 of the faq and I am now curious to know: > >what's a "strato-scoops"? A Strato-scoop is a parafoil variant with a closed front end. Where most 'foils have openings at the front of every cell, the stratoscoop has smaller openings along some of the keels. The theory is that having the rounded front of a 'scoop decreases the drag of the airfoil, thereby increasing the efficiency of the airfoil. -- Marty Sasaki Harvard University Sasaki Kite Fabrications sasaki@noc.harvard.edu Network Operations Division 26 Green Street 617-496-4320 10 Ware Street Jamaica Plain, MA 02130 Cambridge, MA 02138-4002 phone/fax: 617-522-8546 = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Sun, 28 Feb 1993 07:52:50 GMT From: andrew@tug.com (Andrew Beattie) Message-ID: Organization: Negligible. Subject: Re: FAQ, part 1 general questions In article <1993Feb26.164120.3541@das.harvard.edu> sasaki@netop3.harvard.edu (Marty Sasaki) writes: >The theory is that having the rounded front of a 'scoop decreases the drag >of the airfoil, thereby increasing the efficiency of the airfoil. I understand that the difference is significant. It is not the only way to round the front - it can also be done by using gauze to hold the vent in shape. Witness the Flexifoil and Peel Andrew -- andrew@tug.com = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =