Date: Wed, 24 Feb 1993 20:56:10 GMT From: sasaki@netop3 (Marty Sasaki) Message-ID: <1993Feb24.205704.23749@das.harvard.edu> Organization: Division of Applied Sciences, Harvard University Subject: Bridling Please note: This message is being forwarded by hand. The message was received before the auto-magic forwarding software was in place. - Marty Sasaki ---------------------------------------------------------------- From: "Rodger Duffett" Date: 23 Feb 93 18:11:15 SAST-2 Subject: Bridling Priority: normal Hello again!! Apologies to the rest of the group. This mail is intended for Ron Reich. (Feel free to read and correspond if you wish) Ron, I have tried to reach you directly at flounder.harvard.edu but recieve an unknown host error from our local gateway. Thanks very much for your reply. It is of great interest as I am struggling at the moment to get a two line delta type kite which is short and wide - high aspect ratio?? - to fly. Frame something like: /_|_\ / | \ /___T_|_T___\ / | \ The T's represent little struts which push the sail away from the bridle. My sister went out and spent a fortune on it as a birthday present a while back and I have yet to get it to fly. The best I have managed to do is to get it up, in the centre of the wind zone, upon trying the gentlest of manouvers it stalls and spins wildly into the ground. Mostly it goes up a couple of metres and plummets spectacularly back into the ground!! I have tried what bridle arrangements I can think of, but not based on a methodological approach as you have described. Thanks again. Bye __________________________________________________________________ Rodger Duffett Internet Address: rodger@ray.uct.ac.za Dept. Radiation Oncology Telephone : (021) 404 3135 Radiobiology Section University of Cape Town Groote Schuur Hospital South Africa = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: 28 Apr 93 14:00:36 +1200 From: Colin_Douthwaite@equinox.gen.nz (Colin Douthwaite) Message-Id: Organization: Equinox Networks Subject: BRIDLING Re: BRIDLING Is there any comprehensive literature on the subject of Bridling ? All the books I have seen, including the "Penguin Book of Kites", do not cover the subject in sufficient detail. Most of the information is fragmented and incomplete. Many kite constructions do not even discuss bridling except to comment that a two-leg, three-leg etc. is used. I recently bought two Indian Fighters, both made in India. Both were bridled with a special knot which creates 3 small loops at the knot. The flying line is then attached to this triple loop. If you pull each loop it slides through the knot and you end up with a lengthened bridle. I discovered this when the loops were accidentally pulled out. In deciding how to re-tie the loosened bridle I got round to some detailed measurements on 3 Indian Fighters and 1 Nagasaki Hata. ---------------------------------------------------------------- ( All measurements in mm ) GREEN BLACK SPEC HATA ---------------------------------------------------------------- Kite width 665 435 610 770 Kite length 550 385 590 710 Kite width/length ratio 1.21 1.13 1.03 1.08 >From top of kite to : cross-spar/spine joint 95 70 95 155 : top bridle point 95 70 95 100 >From bottom of kite : to lower bridle point 165 120 180 0* Distance between bridle points 310 190 315 610 Bridle length (total) 635 ? 670 2000 Length : lower leg of bridle 340 ? 345 1070 : upper leg of bridle 295 220 325 930 Ratio Upper/Lower legs 1.15 ? 1.06 1.15 Tail length (for stability) 2000 1900 ----------------------------------------------------------------- *** NOTES on the data : I have only flown the BLACK and GREEN kites. SPEC and HATA details are from plans in : "Kites,Kites,Kites, the ups and downs of making and flying them" by Bruce H. Mitton, 1980 Sterling Publishing Co Inc, Two Park Avenue, New York, N.Y. 10016. ? - the original flying length of the bridle was lost when I accidentally pulled out those three tricky little loops. The total (increased) length is now 940 mm. Fortunately the remains of the knot tells me the original upper leg was 220 mm. Applying the ratio of 1.15 the bottom leg should be 253 mm. The three loops must have used up 467 mm of bridle. 0* - the HATA bridle lower leg is attached to the base of the spine. It is flown on a very long bridle. *** Now... do all the aeronautics engineers out there have some simple formulae for calculating bridle lengths and leg ratios in relation to kite dimensions ? I would be nice to know them. Alternatively, how about some pointers for further study ? ( I do have Gomberg's book on Fighters on order ). = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Wed, 28 Apr 93 10:23:56 GMT From: cdt@zoo.bt.co.uk (Clive Dennett-Thorpe) Message-Id: <1993Apr28.102356.22475@zoo.bt.co.uk> Organization: BT Laboratories Subject: Re: BRIDLING An interesting question - as someone who makes kites frequently and tries out many different types of kite I must admit that bridling ,for me anyway , is the most difficult aspect of the whole thing. {I still can't appreciate why Pelham's "Penguin Book of Kites" is often regarded as "the Bible" of kites . I think it's a stimulating book and the "gazeteer" of kite types on the coloured pages at the end of the book is certainly a good reference for browsing/choosing your next design BUT it has no complete details for producing even one complete kite and scant information on construction techniques and the mystic art of bridling. I would also say that it is in need of an update and I don't recall seeing many of today's popular kites in there either. A better book is Ron Moulton's "Kites" which has more detail on everything.} As far as the bridling goes I have these tips/hints: 1) Look at the bridled kite sideways-on with someone pulling the bridle - you may then decide the kite is "sitting-back" too far and spilling too much wind. 2) Attach overly long bridle lines with loops tied-in at intervals which can then be undone/adjusted to make the line longer. 3) Balancing the kite indoors(i.e. in windless conditions). A drawing pin in the ceiling suspends the kite by a short length of line to the bridle ring and then you can use visual inspection to check the balance. Recently I've found this simple technique very useful -it made me notice that flight problems were due to imbalance in wing weights rather than asymmetry in the bridling of two of my kites. I might still be tweaking bridles and getting nowhere if I hadn't done this!! My current bridling problems surround a nicely-decorated 80cm square sail. I've constructed the kite as a True Malay so it looks like:---- A _________________________ B | | | | | | | | | | | | | | | | | | | | _____________ C |_______________________| D __________________________ A is the top of the kite,D is the bottom , CD is in contact with the ground here The kite is flown tailless. AB=AC=CD=DB=80cm 6mm spars AD and BC; BC is then bowed by a tensioned cord. Bridle lines emanate from A,B,C and join at a central ring. How long should those three bridle lines be??????? Regards, Clive Dennett_Thorpe "......Wow,Mum! .................Look at that Kite!!!!!!!!!!!!!!!!......." P.S. There is a book called "Kites-The Science and Wonder" by two Japanese authors and the whole book is mathematically-based so there's lots of info on forces/ratios etc. Perhaps it has some good bridling info?? = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: 28 Apr 1993 16:24:39 +0100 From: pat@cs.strath.ac.uk (Patrick Prosser) Message-Id: <1rm7jn$624@kelvin-02.cs.strath.ac.uk> Organization: Comp. Sci. Dept., Strathclyde Univ., Glasgow, Scotland. Subject: Re: BRIDLING You mentioned a book by two japanese on the science of kites. It's so so, and does give some theory. It's worth having, but is no substitute for experience and common sense. Generally, when I build a kite with a bridle (that is something other than a delta) I build it so that I can easily adjust it on the field. Long bridles are generally better than short bridles. Preferably, have a bridle that is the same length as the tow line :-) as on a REV!! Patrick unbridled Prosser = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: 1 May 93 11:23:14 +1200 From: Colin_Douthwaite@equinox.gen.nz (Colin Douthwaite) Message-Id: Organization: Equinox Networks Subject: Re: BRIDLING Patrick unbridled Prosser (pat@cs.strath.ac.uk) writes : > You mentioned a book by two japanese on the science of kites. It's > so so, and does give some theory. It's worth having, but is no > substitute for experience and common sense. ^^^^^^^^^^ ^^^^^^^^^^^^ Both of those attributes are variable in quantity and quality :-), and, where do you start if you have _no_ experience ? > Long bridles are generally better than short bridles. Useful advice. As a starting point though, a basic idea of what is long or short, relative to each kite is needed. Looking at the data on my Indian Fighters, the total bridle length is about equal to the kite width. [ I now have two more Indian Mini-fighters, 325 x 304 mm ( W x L ) with bridle lengths of 343 and 368 mm ]. Upper/lower leg ratios range from 1.10 to 1.20 over the 5 kites. Taking your advice of starting with longer bridles I guess you would start with about 1.5 to 2.0 times the kite width for these little Fighters, then work from there. The Nagasaki Hata traditionally has a very long bridle (2 metres ?) but all the Indian fighters seem to have relatively short bridles. ( Again, how can long and short be defined in general terms ? ) I don't have a genuine Hata, only a clone. It came with short Indian-style bridling. I replaced it with a 1.8 metre Hata-style bridle and it flew a little better, but not like a fighter. To date I have not seen an authentic Hata in N.Z. Rokkakus are fairly popular though and flown in contests occasionally. > Preferably, have a bridle that is the same length as the tow line :-) You would approve of the tiny "Ei Dako" kite made by Peter Lynn of Ashburton, N.Z. ( Yes ! he makes tiny kites as well as powerpaks ) No bridle. It has the tow line attached directly to the 390 mm spine at a point 140 mm from the nose. The "Ei Dako" is 280 mm [square] diamond, in lightweight ripstop with fibreglass spars and a 1.20 metre tail, it is a little gem. Flies like a fighter, or, if you prefer, it will sit in the sky all day whilst you take a nap :-) And now ? ...back to the drawing-board and tape measure :-) Colin Douthwaite New Zealand 1/5/93 = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Mon, 3 May 1993 17:21:59 GMT From: sasaki@das.harvard.edu (Marty Sasaki) Message-Id: <1993May3.172159.11554@das.harvard.edu> Organization: Harvard University Subject: Re: BRIDLING In article , Colin_Douthwaite@equinox.gen.nz (Colin Douthwaite) writes: >Patrick unbridled Prosser (pat@cs.strath.ac.uk) writes : >> You mentioned a book by two japanese on the science of kites. It's >> so so, and does give some theory. It's worth having, but is no >> substitute for experience and common sense. > ^^^^^^^^^^ ^^^^^^^^^^^^ > >Both of those attributes are variable in quantity and quality :-), >and, where do you start if you have _no_ experience ? The way to get experience is to just try things. Don't be afraid to make mistakes, and don't spend a lot of money and time on early attempts at something new, that way making mistakes isn't so costly. I finally got the hang of bridling rokkakus, getting them to fly the way I like them to fly, only after building 6 or 7 of them and playing with the bridles all along. >I don't have a genuine Hata, only a clone. It came with short >Indian-style bridling. I replaced it with a 1.8 metre Hata-style >bridle and it flew a little better, but not like a fighter. I've flown an "authentic" hata with long bridles and all, and they can fly very nicely, with good sensitivity to line control and good turning. Try playing with the bridle point to increase the performance. Generally speaking, moving the bridle up will increase forward speed, turning radius, and general stability. Move it down for better/faster turning. This is just like with a stunt kite! >And now ? ...back to the drawing-board and tape measure :-) This a standing joke with me. Back to the drawing board, but I don't use a tape measure. I usually don't measure anything, I often make mistakes like mis-remembering numbers or transposing numbers. So I have sticks with lines and words on them like "Katana long bridle", or "distance to first pocket". -- 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: Thu, 17 Mar 1994 05:11:34 -1000 From: friggeri@magma.cgg-massy.fr (Stephane Friggeri) Message-Id: <1994Mar17.151134.12447@magma.cgg-massy.fr> Organization: Cgg Subject: Bridling How do you determine the bridle length on a delta kite. What is the involved theory for determining the length of the bridle from the upper attachment point to the swivel ring,(a) lower attachment point to the swivel ring,(b) swivel ring to the center T joint (c) / | / | / | / | / | / | / | / | /\ | / \ a | / \ | / \ | /" " " " o, c | / b , | , | Practically, on the field, how do you adjust the lengths accordingly to the wind ? Thanks Stephane Friggeri = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Mon, 8 Aug 1994 02:51:28 -1000 From: andrewh@holly.harvard.edu (Andrew Hawken) Message-Id: <3259og$q0f@beta.qmw.ac.uk> Organization: Queen Mary & Westfield College, London, UK Subject: Bridling Any advice on what difference the total lengths (as opposed to relative lengths/clip movements) makes to a kite? La Hembra has total bridle length adjustments as well as the clip positions, and there are just too many variables to have a real idea what is gonig on. Thanks in advance Andy -- ____________________________Andrew Hawken______________________________ "However many ways there may be of being alive, it is certain that there are vastly more ways of being dead" R Dawkins. Home : 0895 420110 QMW : 071 975 5542 AIIT : 0494 677045 Email : A.Hawken@QMW.AC.UK = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =