Date: Tue, 8 Jun 1993 20:05:48 -1000 From: lmarko@aol.com Message-Id: <9306090205.tn55226@aol.com> Organization: Division of Applied Sciences, Harvard University Subject: Uplifting Question I have had a kiteflier friend ask me about suitable kites for lifting meteorology test equipment over the western Utah desert (aka. Military Jet Test Range). The payload will be about 3-4 lbs. to be lifted to various altitudes as high as 500' AGL. Winds will be above 10 knots as he will use balloons in lighter winds. No secondary wires or cables are needed from the equipment to the ground. I have forwarded him an article from Spring '92 KiteLines magazine and have seen some info about kite aerial photography but believe most cameras are less than 4 lbs. My first thought is to use a Stratoscoop 3 or a Sutton 30 but I am open to other suggestions. Thanks. Mark Levey LMarko@aol.com = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Wed, 9 Jun 1993 06:10:43 -1000 From: sasaki@das.harvard.edu (Marty Sasaki) Message-Id: <1993Jun9.161043.13839@das.harvard.edu> Organization: Harvard University Subject: Re: Uplifting Question In article <9306090205.tn55226@aol.com>, lmarko@aol.com writes: >I have had a kiteflier friend ask me about suitable kites for lifting >meteorology test equipment over the western Utah desert (aka. Military Jet >Test Range). The payload will be about 3-4 lbs. to be lifted to various >altitudes as high as 500' AGL. Winds will be above 10 knots as he will use >balloons in lighter winds. No secondary wires or cables are needed from the >equipment to the ground. I have forwarded him an article from Spring '92 >KiteLines magazine and have seen some info about kite aerial photography but >believe most cameras are less than 4 lbs. My first thought is to use a >Stratoscoop 3 or a Sutton 30 but I am open to other suggestions. Thanks. Flowforms and parafoils of various sorts will probably provide the most lift for the kite size, and if you have them or can afford them, they make a lot of sense. The work that Bill Tyrrell is doing involves high tech parafoils using mylar with spectra and Kevlar fabrics. Give him a call, if he has the time, he will talk your ear off about this project and anything else that he knows. 215-348-1744. Before the airfoil kites, the U.S. Weather service used the Hargrave Box Kite (check out Pelham or a similar book) and Eddy kites to lift instruments. The kites were flown on stainless steel wire that was attached to large motorized spools. -- Marty Sasaki Harvard University Sasaki Kite Fabrications sasaki@noc.harvard.edu Network Services Division 26 Green Street 617-496-4320 10 Ware Street Jamaica Plain, MA 02130 Cambridge, MA 02138-4002 phone/fax: 617-522-8546 = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Wed, 9 Jun 1993 23:07:46 -1000 From: pat@cs.strath.ac.uk (Patrick Prosser) Message-Id: <1v6tl2$4kd@kelvin-02.cs.strath.ac.uk> Organization: Comp. Sci. Dept., Strathclyde Univ., Glasgow, Scotland. Subject: Re: Uplifting Question Generally, I would recommend a flowform (Sutton FF) or parafoil. However, I read the same article, and the problem they encountered was (1) Thermals at low altitute (2) Wind shear at high altitude They had difficulty launching due to (1), and problems during flight due to (2). There is also the issue of altitude. How high do you want to go? Would you be flying up in the jet stream? If you are in the jet stream then you will need a very strong kite, and it might then be too heavy to get off the ground (in anything short of a gale). Then there is line. The altitude will be limited by a number of factors (1) the weight of the line, (2) the drag of the line. This is a complex equation. Ideally you would want a line that gradually tapered down to the ground. That is at the kite the line would be heavy/strong, and at the ground minimal strength. There is also the issue of UV radiation on flying line. Spectra/Dyneema/Kevlar are good strong lines (though Spectra and Dynema are actually quite dense), therefore relatively thin, but degrade in UV, therefore need sleeving just to protect from rays (yes folks, keep your lines out of the sun!!). So ... that all sounds kind of negative, all the things that can go wrong. You might consider using a Box kite. These were THE high altitude flyers of the 19th & early 20th century. Use a Hargraves box. These were used by the met office in the US. They have huge lift, are stable, etc. Built out of ripstop and carbon fibre it should be excellent. Dont use a Cody, I've yet to see a really stable Cody. Same for the TriD, every one that I have seen tends to list/dive. Conclusion .... I would recommend building 2 kites, a Hargraves box, and a FlowForm. The box will be more stable, but the FF will take the larger wind range. Patrick = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Fri, 11 Jun 1993 03:43:58 -1000 From: chubbard@beta.tricity.wsu.edu (Charles William Hubbard) Message-Id: <1993Jun11.134358.15977@serval.net.wsu.edu> Organization: Washington State University Tri-Cities Subject: Re: Uplifting Question In article <1v6tl2$4kd@kelvin-02.cs.strath.ac.uk> pat@cs.strath.ac.uk (Patrick Prosser) writes: >Then there is line. The altitude will be limited by a number of factors >(1) the weight of the line, (2) the drag of the line. This is a complex >equation. Ideally you would want a line that gradually tapered down to the >ground. >So ... that all sounds kind of negative, all the things that can go wrong. >You might consider using a Box kite. These were THE high altitude flyers >of the 19th & early 20th century. Use a Hargraves box. These were used >by the met office in the US. They have huge lift, are stable, etc. >Conclusion .... I would recommend building 2 kites, a Hargraves box, and a >FlowForm. The box will be more stable, but the FF will take the larger >wind range. I've got some questions that sort of go along with this thread. Hopefully some of you guys have the answers! I have a small 4' delta which I fly on 1000' of 50lb line. After the first 500' it's my impression that the kite stops going any higher and just goes farther downwind. I'm really interested in getting some altitude! Now I figure that 50lb line is probably too heavy for my delta, but even more than line weight I think the problem has to do with line drag, which is considerable with wind blowing across 1000' of line. Until reading through this thread I was thinking about trying to fly multiple kites on the same line say at 100' intervals. The theory was each kite would do its part to support a section of the kite line so the first kite out could do a little better about getting some altitude. I've never seen this done. Is there problems with a kite train where the kites are seperated by so much space? I've seen the Hargrave box kite mentioned a lot in this thread. I don't know anything about box kites - not even what type a Hargrave is. Where can I get plans (even .GIF or Postscript maybe?) for one of these? Or even a verbal description of the Hargrave and/or a description of its performance characteristics compared to other box kites and other kites in general. I'm sure not against buying a book(s) if someone has some recommendations. Keep in mind that our local bookstores don't have a very good selection of anything so I know I'd have to order them. I'm also interested in lifting payloads. From what I've been reading here I get the impression that a box kite or parafoil is the best kite for this kind of thing. I have a very small parafoil (The Pocket Parafoil - I'm sure you've all seen it) which I like but it's not a very good flyer. Tends to stay low to the ground and is pretty unstable. I've thought about buying a real one (meaning bigger) but they are pretty expensive and I don't want to plunk down the cash if they are hard to fly, require a lot of bridle tuning, are unstable in the air, etc, etc. Can someone share their experiences with large parafoils as far as ease of flight and lifting capacity? Lastly, in an earlier post someone mentioned flying in the stratosphere. Is that even possible? Talk about line drag! Wow! Thanks, C. = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Tue, 15 Jun 1993 00:07:10 -1000 From: pat@cs.strath.ac.uk (Patrick Prosser) Message-Id: <1vk70e$5u6@kelvin-02.cs.strath.ac.uk> Organization: Comp. Sci. Dept., Strathclyde Univ., Glasgow, Scotland. Subject: Re: Uplifting Question Kite moves away rather than gains altitude ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This happens when the drag induced by the line is greater than or equal to the lift of the kite. You have a number of options: reduce line drag, increase lift. You can reduce line drag by using thinner line, such as spectra/dyneema/kevlar. Increase lift by using secondary kites to lift the line. I used to do this. I used to fly kites (in Fife) over 2,000 feet of line. I had a collection of small sleds. I would have the main kite flying off about 200' of line. I'd then launch a sled of about 60' of line and then connect to main tow line, and repeat this process every 200 feet. It works really well. In many occasions I managed to fly above the clouds. Payload Lift ~~~~~~~~~~~~ It depends on what you want to lift. Do you want stability (camera work)? Do you want altitude (met work)? Is it for teddy bear jumps (want to get kite up and down quickly)? Quite a few factors to consider. Hargrave Box ~~~~~~~~~~~~ Hargrave came from New Zealand. He was a pioneer in kite design, and never patented any of his designs. All his work was made available to the public at large. Hargrave's box was (and still is) the ultimate box kite design. If you want to know what it looks like .... it looks like the Wright brothers first air craft !!! Stratosphere ~~~~~~~~~~~~~ Mmmmmm ... I'm not sure where the stratosphere begins or ends. There was a "leak" >From the Hark project (I think that was its name) where a kite was raised to an altitude in excess of 98,000 feet (my figures may be wrong, and I'll check them if you wish). The project was funded by some "Multi National Corporation". The line tension was measured in tons, and I believe (again I'll check) that they used in excess of 27 miles of line. Now why would some one want to fly a kite at 98,000 feet? Patrick MI5 Prosser = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Wed, 16 Jun 1993 04:10:31 -1000 From: chubbard@beta.tricity.wsu.edu (Charles William Hubbard) Message-Id: <1993Jun16.141031.21776@serval.net.wsu.edu> Organization: Washington State University Tri-Cities Subject: Re: Uplifting Question Thank you very much for the reply! I appreciate the information and would like to hit you with some follow-up questions. >Kite moves away rather than gains altitude >~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This last weekend while flying my small delta on 50lb dacron line I was able to get in nearly straight overhead at 1000' feet at times (normally this is not the case). I think it was because of very light (sometimes none) wind near the ground but stronger winds aloft. I'm pretty new to this. Is this behavior common? >You can reduce line drag by using thinner line, such as >spectra/dyneema/kevlar. I understand there is a problem with these lines degrading in sunlight because of the UV. Is that true? Seems like shielded line defeats the purpose (no longer thinner). When you fly bare kevlar do you just accept replacing your line frequently as part of the territory? >Increase lift by using secondary kites to lift the line. I used to do >this. I used to fly kites (in Fife) over 2,000 feet of line. I had a >collection of small sleds. I would have the main kite flying off about >200' of line. I'd then launch a sled of about 60' of line and then connect >to main tow line, and repeat this process every 200 feet. I've thought of flying multiple kites myself but could never quite figure out how to attach them. I'd like to try your idea of running secondary kites on secondary lines. How do you attach the secondary lines to the main line? I'm worried about knots decreasing line strength or the friction of one line wearing on the other causing breaks. Maybe this isn't a problem? >Payload Lift >~~~~~~~~~~~~ >It depends on what you want to lift. Do you want stability (camera work)? >Do you want altitude (met work)? Is it for teddy bear jumps (want to get kite >up and down quickly)? Quite a few factors to consider. Well I guess I'm interrested in both stability and altitude but not necessarily at the same time. Which lifting kites are more stable and which are better for altitude? As for teddy bear jumps... Fly and release sounds like fun but primarily I'm interested in the other two. >Stratosphere >~~~~~~~~~~~~~ >Mmmmmm ... I'm not sure where the stratosphere begins or ends. There was a >"leak" from the Hark project (I think that was its name) where a kite was >raised to an altitude in excess of 98,000 feet (my figures may be wrong, >and I'll check them if you wish). The project was funded by some "Multi >National Corporation". The line tension was measured in tons, and I >believe (again I'll check) that they used in excess of 27 miles of line. Wow! I'd really like to see some more information on this or similar projects! C. = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Fri, 18 Jun 1993 04:53:28 -1000 From: pat@cs.strath.ac.uk (Patrick Prosser) Message-Id: <1vskt8$6ni@kelvin-02.cs.strath.ac.uk> Organization: Comp. Sci. Dept., Strathclyde Univ., Glasgow, Scotland. Subject: Re: Uplifting Question No Wind, Kite way up ~~~~~~~~~~~~~~~~~~~~ This can occur due to thermals. You may have a vertical column of hot air, rising straight up. I have only experienced this once (not much opportunity in Scotland) and it freaked me out. I just kept on letting out line, as fast as I could, and the kite just rose up, as if on an elevator. The kite was slowly rotating as it rose. Suddenly it stopped, and I had a kite way up there, with all that line, and no wind. Sometimes you will see the thermals, at least evidence of thermals, because there will be a whole load of birds taking a free ride in a circular motion. Train ~~~~~~ To connect a kite line to a kite line you can use a wodden toggle (like you get on duffle jackets) on the line or you can tie rings on to the line (larks head), or you can lash and glue D rings, ... I use all of these techniques for connecting things to the tow line (things like flags, wind socks, dirty washing, ...) One thing I have been thinking of doing for some time, but have not properly pursued. I wear overalls. I would like to buy a mannikin (you know, the kind they use for modelling natty clothes in shop windows). I'd like to dress it up in my overalls, lash it into a light weight chair, and raise with one of my big parafoils. I'd like to put a walky talky up there so that I can shout at people below ... things such as "HELP!" and other witty things. I could also arrange the dummy so that it appears to be climbing up the line to the kite. I'd also like to release it with a teddy bear mechanism, with a teddy bear's parachute (you know, the size of a hanky). Where can I get such a thing Patrick = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Fri, 18 Jun 1993 06:06:35 -1000 From: chubbard@beta.tricity.wsu.edu (Charles William Hubbard) Message-Id: <1993Jun18.160635.9070@serval.net.wsu.edu> Organization: Washington State University Tri-Cities Subject: Re: Uplifting Question In article <1vskt8$6ni@kelvin-02.cs.strath.ac.uk> pat@cs.strath.ac.uk (Patrick Prosser) writes: >No Wind, Kite way up >~~~~~~~~~~~~~~~~~~~~ >This can occur due to thermals. You may have a vertical column >of hot air, rising straight up. I have only experienced this >once (not much opportunity in Scotland) and it freaked me out. Yes, I bet that's exactly what happened! We live in a desert and I was flying on a hill with hang gliders everywhere. Now that you mention thermals it seems so obvious I can't believe it. I wonder why we didn't think about that the day we were flying. >Train >~~~~~~ >To connect a kite line to a kite line you can use a >wodden toggle (like you get on duffle jackets) on the line >or you can tie rings on to the line (larks head), or you >can lash and glue D rings, ... I use all of these techniques >for connecting things to the tow line (things like flags, >wind socks, dirty washing, ...) Hmmm, these all sound like good ideas but I have a problem. I still don't quite know what you mean by wooden toggle. Tying rings to the line sound simple enough but what's a larks head? I hear the term a lot on this newsgroup. I figured it was some fancy knot. Now lash and glue D rings I understand! >One thing I have been thinking of doing for some time, >but have not properly pursued. I wear overalls. I would >like to buy a mannikin (you know, the kind they use >for modelling natty clothes in shop windows). I'd >like to dress it up in my overalls, lash it into a >light weight chair, and raise with one of my big parafoils. >I'd like to put a walky talky up there so that I can shout >at people below ... things such as "HELP!" and other >witty things. That's a great idea! I'd love to see that too. I especially like the hanky sized parachute gag. Charlie = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Fri, 18 Jun 1993 13:55:33 -1000 From: rock@netcom.com (Anne Rock) Message-Id: Organization: NETCOM On-line Communication Services (408 241-9760 guest) Subject: Re: Uplifting Question Charles William Hubbard (chubbard@beta.tricity.wsu.edu) wrote: : I've seen the Hargrave box kite mentioned a lot in this thread. I don't : know anything about box kites - not even what type a Hargrave is. Where : can I get plans (even .GIF or Postscript maybe?) for one of these? Or : even a verbal description of the Hargrave and/or a description of its : performance characteristics compared to other box kites and other kites in : general. I'm sure not against buying a book(s) if someone has some : recommendations. Keep in mind that our local bookstores don't have a very : good selection of anything so I know I'd have to order them. I'd recommend David Pelham's book, "The Penguin Book of Kites" which Marty Sasaki mentioned earlier, as the best general "reference" book. It covers history, construction (in a general way, not detailed instructions for any particular kite; also knots), flying (lift & stability, bridles, location, launching, etc.), and kite patterns/diagrams. Each pattern suggests materials to use for skin, tail, and frame, how many bridle points, suggested wind range; a paragraph or 2 two about the kite; and a good drawing. (There's a page each for Hargrave's box kite, the Blue Hill Meteorological box kite, and the Washington Weather Bureau box kites.) The book's copyright is 1976, so, although there's one dual line kite in the focus is on single-line kites of many cultures. ISBN 0 14 00.4117 6 $12.95 US. 228 pages. Lots of pictures and diagrams. Anne rock@netcom.com = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Fri, 18 Jun 1993 13:25:23 -1000 From: rock@netcom.com (Anne Rock) Message-Id: Organization: NETCOM On-line Communication Services (408 241-9760 guest) Subject: Re: Uplifting Question lmarko@aol.com wrote: : I have had a kiteflier friend ask me about suitable kites for lifting : meteorology test equipment over the western Utah desert (aka. Military Jet : Test Range). The payload will be about 3-4 lbs. to be lifted to various : altitudes as high as 500' AGL. Winds will be above 10 knots as he will use : balloons in lighter winds. No secondary wires or cables are needed from the : equipment to the ground. I have forwarded him an article from Spring '92 : KiteLines magazine and have seen some info about kite aerial photography but : believe most cameras are less than 4 lbs. My first thought is to use a : Stratoscoop 3 or a Sutton 30 but I am open to other suggestions. Thanks. My aerial photo rig is in the neighborhood of 4 pounds *sigh*, and I lift it with a rokkaku about 6.25' tall and 5' wide. I figure I need winds ono less than 12 mph for the kite to develop enough pull to keep the camera up. I prefer a kite with spars because: 1. If the wind drops I have a better chance of keeping the kite aloft and bringing it down in a controlled manr. 2. It will not collapse (ok, the spars can break). My impression of parafoils is that they require steady, non-gusty winds to perform well. I haven't seen many flow forms, and the ones I've seen are Art Ross' huge ones, flying in the great ocean winds at Long Beach. Anne rock@netcom.com = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Fri, 18 Jun 1993 14:33:21 -1000 From: rock@netcom.com (Anne Rock) Message-Id: Organization: NETCOM On-line Communication Services (408 241-9760 guest) Subject: Re: Uplifting Question Charles William Hubbard (chubbard@beta.tricity.wsu.edu) wrote: : Hmmm, these all sound like good ideas but I have a problem. I still don't : quite know what you mean by wooden toggle. Tying rings to the line sound : simple enough but what's a larks head? I hear the term a lot on this ^^^^^^^^^^ : newsgroup. Take a pencil and a short piece of string. Put the string on a table in a u-shape. Put the pencil on top of the string, across both "lines" at a right angle to the lines. Pick up the two line ends, bring them over the pencil and under the "loop/u-shape" and pull the ends through the loop. = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Fri, 18 Jun 1993 19:57:41 -1000 From: chubbard@beta.tricity.wsu.edu (Charles William Hubbard) Message-Id: <1993Jun19.055741.23481@serval.net.wsu.edu> Organization: Washington State University Tri-Cities Subject: Re: Uplifting Question In article rock@netcom.com (Anne Rock) writes: >Take a pencil and a short piece of string.... Thanks Anne for the very clear explanatiion. I do this all the time (not on kites) but never knew there was a name for it. So then, if I wanted to tie a secondary kite line onto the primary line using a larks head how do I do it? I mean, is the primary line the same as the pencil in your example? And if so does that mean the secondary line is actually doubled in half with the loop end fastened to the primary line as described and then the other two lines going to the other kite? Or can you get away with just using a little loop like say 100' feet of line from the kite to the tow line, and then a little loop with the other end only a foot long (know what I mean?). Guess I'll just have to experiment. C. = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Sat, 19 Jun 1993 07:35:32 -1000 From: rock@netcom.com (Anne Rock) Message-Id: Organization: NETCOM On-line Communication Services (408 241-9760 guest) Subject: Re: Uplifting Question Charles William Hubbard (chubbard@beta.tricity.wsu.edu) wrote: : In article rock@netcom.com (Anne Rock) writes: : >Take a pencil and a short piece of string.... [stuff deleted] : I mean, is the primary line the same as the pencil in your : example? And if so does that mean the secondary line is actually doubled : in half with the loop end fastened to the primary line as described and : then the other two lines going to the other kite? Or can you get away : with just using a little loop like say 100' feet of line from the kite to : the tow line, and then a little loop with the other end only a foot long : (know what I mean?). Guess I'll just have to experiment. Sigh....after I logged out, I thought about my explanation, and it seemed half complete: it told how to make a larkshead, but not how to easily use it with kite line. I wondered if I'd get called on that :-) If I were attaching one kiteline to another, I'd fasten a ring to the primary kiteline using a larkshead. I'd attach the secondary kiteline to the ring using something I could release quickly, like a swivel or (for a stronger pulling kite) carabiner. To fasten the ring to the primary kite line, make a u-shape with the line. Pull the u-shape up through the ring (with the lines extending off to the right, for example), and to the left over the left side of the ring. Open up the u-shape, and slide/pull it back *under* the ring all the way to the right side of the ring and a little beyond. Pull the two "ends" of line to tighten. This way you don't have to try and pull your kite and reel through the ring :-) Anne = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =