Article 25938 of rec.kites: Newsgroups: rec.kites Path: tug!andrew From: andrew@tug.com (Andrew Beattie) Subject: Re: Chevron progress Organization: /usr/lib/news/organisation Date: Sat, 1 Jun 1996 23:25:52 GMT Message-ID: References: I had such a positive response to my postings about my my trials and tribulations with the Chevron that I thought I'd fill you in on the latest one. Whilst it has been fun to turn up at no-wind festivals and tease everyone with the 13m^2, it's not very parcatical when the wind does show, so I decided to make another 5m^2, much along the lines of the the black and white one has just managed to crawl by the slowest possible snail mail to John Gabby. First problem was fabric. I had quite a lot of fabric in various stages of being delivered to me, but none actually within my posession, so when I got the chance of some 1/2 oz Red Icarex, I jumped for it. I've still retained the Chevron graphic, it's sewn into the panelling, but it's somewhat subliminal - a red Chevron on a red background... The Chevron graphic is designed not only to look good and to show which way it's going, but it also to make good use of the fabric. The idea on the 5m is that the widest part of the rear panel is the same as the width of the fabric, and you should be able to fit two front panels across a width of fabric. It's not as easy to work this out as it sounds. The front panels are different widths front and back (carefuly calculated so that the chevron graphic on the front is aligned with the graphic on the back, so that the colours don't shadow each other). The leading edge panels arn't even parallel, they taper slightly, so it's a pig of a job trying to work out if a top panel tapering one way and a bottom panel tapering the other is going to fit in the fabric available. The upshot of this is that on John's 5m, there was a lot of waste because it didn't *quite* fit on the fabric as planned. Some *very* small changes and it's spot on for this kite. I paid particularly close attention to the amount of waste. I don't actually know how much fabric I used (I keep meaning to measure what I use, but never remember...), but I do know how much I wasted: I gathered up all the little scraps and it weighed 46g. Taking the 32g/m^2 as gospel, that's 1.4m^2. Hmmm... it was ever such little scraps, but it's still somewhere around 10%. *sigh* I've been looking at building kites with Mylar(*) bladders, which I can use either air-filled (for playing in the water), or Helium/air filled (to replace the heaviest structural component in the kite with something a little lighter...). For this, I need easy access to the interior of the kite, to service the bladders, so I contacted YKK and bought myself 200m of bulk zip. This isn't exactly a barrel of laughs to sew onto the kite. You can't do it with the zip closed, because it's on the trailing edge as you seal up the kite, so you don't get any registration marks to tell you how you're doing. It was a bit of a struggle, but I'm pleased with the end result. The zip is the lightest dress zip I could find, it weighs 10g/m, so it's around 10% of the weight of the kite (not including air). It's a small weight penalty, but it's interesting to note that its all at the trailing edge. I think that this kite is even *more* stall resistant than John Gabby's one. People commented about how high it flies, (while I thought it looked poor, 'cos the lines were too heavy...), but I couldn't make it collapse due to over flying no matter how hard I tried. I think that the slight shift of C-of-G meant that when it stalled, it basically sat back by it's self without reference to the bridle and glided till it ready to fly again. (*) It's not actually Mylar, but it's a similar film... I had hoped to use the experience of John's kite to get the primary bridle perfect first time, but life's not like that. It worked OK, but I had to fiddle with it this evening to get it "just so". I've changed the cross bridle a little. The kite is now even flatter across the middle, yet it seems to turn even tighter and with even less input than John's 5m. (I say "seems". I'm pretty sure, but John's 5m is 8 timezones away, making cross comparison a little difficult...) During the day, it was never very happy in a tip-stand position, but I've adjusted the tips to make them flatter too and a brief test suggests that this has been successful. As usual, it's for sale so that I can afford to build the next one. (I'm running kinda short of things to fix or improve, but I've got work to do on other sizes...) First person to offer US$450+shipping secures it. (if you want to see it, have a look at the 5m at the bottom of http://www.kfs.org/kites/chevron and think "red") Andrew -- Chevron Performance kites: http://www.kfs.org/kites/chevron