Article 28611 of rec.kites: Newsgroups: rec.kites Path: tug!andrew From: andrew@tug.com (Andrew Beattie) Subject: Re: Chevron progress Organization: Tug the line kites Date: Sun, 4 Aug 1996 07:31:35 GMT Message-ID: References: <9607100941.aa03230@tug.com> <4s10os$6h4@news.euro.net> In article andrew@tug.com (Andrew Beattie) writes: >Now I can go back to the 10m that's taking shape on the floor with a little >more enthusiasm... This kite is now flying. Every time that I make a new kite, I resolve that *this* one will tbe the on that I get *perfect*, first time. Every stitch the same length, never running out of thread on a seam, every bridle knot right first time. Not a hope. I sewed the ribs to the wrong side of the hem. When you sew the rib to the bottom skin, the rib should be on the right and the seam allowance on the left. If you do it the other way round, you have to stuff the newly completed section of the kite under the machine arm every time that you later attatch the rib to the top skin. This makes no difference to the finished kite, but it sure does annoy the seamstress... nb: stuff Political Correctress. I'm trying to be a better seamstress, not sewer, seamster or tailor. Then came the bridle. I have a program that I use to calculate and plot bridles for me, (nothing special, it just uses the principles I've explained here and creats a file similar to the ones in SK1.0). Rather than work from first principles, I took the bridle that's now working on Matthew Hurrell's kite, smoothed it out a little and plotted that. For plotting bridles from numbers measured off another kite, rather than calculating from first principles, the program does the following: 1) Calculate the length of the shortest (B) line from first principles 2) Add on a difference supplied by me to each of the other bridles on that rib. I added the ability to use non-calculated numbers specialy for this kite. I screwed up. I stuck the numbers in the wrong order. The program added differences intended for the tip bridles to the bridles in the middle and vica-verca. I didn't notice until the bridles were attatched to the kite. *sigh* The kite got it's maiden flight yesterday at Berrow (true to form, I was still building the cross-bridle on the morning of my deadline) I had hoped that at with the experience from Matthew's kite, it would fly well. It didn't. It was a complete dog. It inflated well enough, and started flying, but it was slow *and* it overflew. I couldn't believe it. The kite seemed to be bridled too far forward *and* too far back. I checked the bridle. It was within 2mm of spec everywhere. (and mostly within 1mm...). Any error was on the safe side (eg: A-line 2mm too long) On closer inspection I noticed a crease right across the middle, from tip to tip. From closer inspection, it was between the B and C bridles. I didn't have time to do much adjusting in the field (having too much fun with the 13), but I tried increasing C significantly on just 1 rib. The crease remained and C just hung loose. I increased D on that rib. It looked better, but still didn't look fixed. I figured that the whole of the primary bridle was too short. The angle between B and C was too wide and the bridle was pulling the nose and tail together to make the crease. Last night, I cut 13 identical lengths of line to make v-lines between the A-B and C-D loops. It was quite a lot of work. It took more than the length of a film to do, but when I took a little test flight this morning (in zero wind), I could tell immediately (within 5 seconds of launch) that this was a different kite. All the spark and magic is back. I'm *delighted*. It flies like a dream. Oh yes, and I've got some new fabric in my mother-in-law's favorite colours, this kite is purple and flo-yellow. "Plums and custard..." I'd like to keep it at least until Berrow (September) so that I have something to fly during the UK buggy week (still looking for more people to share accommodation with), but it'll be up for sale for US$550. Andrew -- Andrew Beattie. Born 1965. Still enjoying his childhood.