Date: Thu, 19 May 1994 21:38:52 -1000 From: rolf.oestergaard@thranethrane.dk400.dk (Rolf V. ?stergaard, RO) Message-Id: <000050A2. MAI*_G=rolf_S=oestergaard_PRMD=thranethrane_ADMD=dk400_C=dk_@MHS> Organization: Division of Applied Sciences, Harvard University Subject: Adjusting speed-wind stacks Kiters, I have only been on the r.k list for a week or so, but it has already been very very interesting to me. Hope You like getting one more aboard... I have been trying to adjust a stack of 3 speed-wings (build from the "Stuntkites to make and fly" book), but found it quite difficult to get that perfect trim. The problem is that the stack tend to osccilate, with the middle kite going back and forth between the front and back kites. When I start to think of the problem, it only makes me more confused. The front kite gets all the wind, but must fly the shortest distance. The back kite gets much less wind, but must fly the longest distance. On the other hand, I have seen these stacks fly perfectly, and before my last crash, I was lucky to get a close-to-perfect trim. The kite dragged me down the beach, and was behaving much like one big-and-slow speed-wing. But now I am back to square one. Can any of You point me to a source of information about how to trim these stacks, or du You have any valuable experience, You want to share? NB: For those of You, who are going to build the speed-wing from the "Stuntkites to make and fly" book, I can only say that the description is very good. Not a single error was found during construction of now 5 speed-wings from it. I do make one minor change to the kite: A 20 mm wide piece of dacron is folded and sewed on the trailing edge, before the wing-sleeves are mounted. This makes the kite much less noisy (the remaining noise is of a much higher frequenfy). The top is made with a piece of reinforced plactictube, with a key-ring through a hole in the middle of it. The bridle is mounted to the key-ring, and this puts a lot of stress on the key-ring and it becomes the weak-spot (If You know a better and stronger way to construct the speed-wing nose, please let me know...). See You at FAN0, Rolf V. Oestergaard [rolf.oestergaard@thranethrane.dk400.dk] = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Sun, 22 May 1994 00:06:56 -1000 From: salanne@convex.csc.FI (Simo Salanne) Message-Id: <2rnas0$16f@pobox.csc.fi> Organization: Centre for Scintific Computing Subject: Re: Adjusting speed-wind stacks In <000050A2.MAI*_G=rolf_S=oestergaard_PRMD=thranethrane_ADMD=dk400_C=dk_@MHS> rolf.oestergaard@thranethrane.dk400.dk (Rolf V. ?stergaard, RO) writes: >See You at FAN0, 27 days and counting... Simo -- Simo.Salanne@csc.fi STACK Finland = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Mon, 23 May 1994 20:01:00 -1000 From: andreas@scooter.ping.de (Andreas Hardtung) Message-Id: Organization: AKA: andreas@scooter.ping.de FIDO: (2:243/4813.12) Subject: Re: Adjusting speed-wind stacks Rolf V. ?stergaard, RO@2:243/4813.1 meinte am 20.05.94 zum Thema "Adjusting speed-wind stacks": > From: rolf.oestergaard@thranethrane.dk400.dk (Rolf V. ?stergaard, RO) > > > Kiters, > > I have been trying to adjust a stack of 3 speed-wings (build from the > "Stuntkites > to make and fly" book), but found it quite difficult to get that perfect > trim. > The problem is that the stack tend to osccilate, with the middle kite going > back and forth between the front and back kites. > > > The top is made with a piece of reinforced plactictube, with a key-ring > through > a hole in the middle of it. The bridle is mounted to the key-ring, and this > puts > a lot of stress on the key-ring and it becomes the weak-spot (If You know a > better > and stronger way to construct the speed-wing nose, please let me know...). > > See You at FAN0, > > Rolf V. Oestergaard [rolf.oestergaard@thranethrane.dk400.dk] > Hello Rolf, adjusting Speedwings IS a problem. It's a problem because it is a smal kite with a short bridel. A little change on the bridel (1mm) can make a big difference. Make one kite EXACT parallel behind the other. The linelength may differ, depending on the attachmentpoints. Eventualy adjust the topline of the last kite(s) (usualy it should be a little (up to 5mm) longer) to make them faster. Maybe your problems come from your way to mount the topbridel. - The original way, is to mount the ring in 2 holes in the tube (dist. = diameter). The bridel-line and the connector to the upper kites are attached on the ring at the same side of the tube. The stress on the ring is then minimal. But the whole tube can be twisted around the spars - the kite can be disadjusted. - The Way described in your book (i think), is to not use a ring at all. They write to mount the bridel direct through a hole in the tube. The hole should only prevent the bridel from sliding away to one side. The tube is only stressed by compression and the forces of one kite. Twisting the tube makes mutch less difference because of the mutch shorter lever. Good wind, See You at FAN0, Andreas (Wolkenkratzer) = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Tue, 24 May 1994 02:33:37 -1000 From: rolf.oestergaard@thranethrane.dk400.dk (Rolf V. ?stergaard, RO) Message-Id: <0000522F. MAI*_G=rolf_S=oestergaard_PRMD=thranethrane_ADMD=dk400_C=dk_@MHS> Organization: Division of Applied Sciences, Harvard University Subject: Re: Adjusting speed-wind stacks Andreas (Wolkenkratzer), >> The problem is that the stack tend to osccilate, with the middle kite going >> back and forth between the front and back kites. > adjusting Speedwings IS a problem. It's a problem because it is a smal > kite with a short bridel. A little change on the bridel (1mm) can make a > big difference. Make one kite EXACT parallel behind the other. The > linelength may differ, depending on the attachmentpoints. Eventualy adjust > the topline of the last kite(s) (usualy it should be a little (up to 5mm) > longer) to make them faster. Thank you for the advice. My experiments are going in the same direction, only that I started making _both_ top stacklines a little longer. While certainly better, it is still not very good. Next time the wind is right, I will try making the two front kites parallel and restrict myself to adjusting only the top stackline of the rear kite. >> (If You know a better and stronger way to construct the speed-wing nose, >> please let me know...). > - The Way described in your book (i think), is to not use a ring at all. > They write to mount the bridel direct through a hole in the tube That sounds right! I might not have read that part very well.... When using a keyring, I often see even the strongest keyrings simply breaking apart. No keyring = no broken keyring. Keep it simple. Right! See You at FAN0, Rolf V. Oestergaard -------------- Copenhagen, Denmark \ /\ / -------------- \/ email: \ /\ / rolf.oestergaard@thranethrane.dk400.dk \/ \/ = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Wed, 1 Jun 1994 21:35:49 -1000 From: rolf.oestergaard@thranethrane.dk400.dk (Rolf V. ?stergaard, RO) Message-Id: <000057DA. MAI*_G=rolf_S=oestergaard_PRMD=thranethrane_ADMD=dk400_C=dk_@MHS> Organization: Division of Applied Sciences, Harvard University Subject: Re: Adjusting speed-wind stacks Andreas (Wolkenkratzer), [How to adjust a speedwing stack of 3 kites] > Make one kite EXACT parallel behind the other. The linelength may differ, > depending on the attachmentpoints. Eventualy adjust the topline of the > last kite(s) (usualy it should be a little (up to 5mm) longer) to make > them faster. I just did that last week-end, and it certainly helped. I still need some finetuning, but it seems to be a _very_ good starting point. Thanks again for the advice. If You are going by car to FAN0, please notice that rumours say, that You can now make reservations for the ferry to/from FAN0!!!! See You at FAN0, Rolf V. Oestergaard -------------- Copenhagen, Denmark \ /\ / -------------- \/ email: \ /\ / rolf.oestergaard@thranethrane.dk400.dk \/ \/ = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =