Article 23223 of rec.kites: Newsgroups: rec.kites Path: tug!andrew From: andrew@tug.com (Andrew Beattie) Subject: Re: Yeeeeha! Chevron progress Organization: /usr/lib/news/organisation Date: Tue, 26 Mar 1996 07:06:59 GMT Message-ID: References: >Further testing shows this to be inconsistant. While in light wind, the >Chevron has a clear edge, comparison in today's strong wind, showed no >difference between the Chevron and the Peel. *damn* I've been thinking about this and realised that we were measuring the wrong thing. To measure the L/D of the *kite*, take the arc-tan of the angle between the wind and the bridle at the tow-point. Note that this brings the drag of the bridle and also the weight of the kite into the equation, but I think that this is fair and useful. To measure the L/D of the kite and line system, take the arc-tan of the angle between the wind and the angle of the *bottom* of the line. The angle to the kite it'sself (what we were comparing) is of little interest. You can see how high your kite will fly here: L/D Angle of flight 1 45 degrees 2 63 degrees 3 72 degrees 4 75 degrees 5 79 degrees 6 80.5 degrees 7 81.9 degrees 8 82.9 degrees 9 83.7 degrees 10 84.3 degrees We're struggling to get from 5 to 6, whilst the sailers take 9 and 10 for granted :-( The Chevron was on brand new 300lb Dynema. The Peel was on old and clearly thinner 300lb Dynema (braid tightened with use). There was more sag in the line to the Chevron. I think that the Chev *kite* was flying at a more efficient angle, but the Chevron kite-line system was at a less efficient angle. The performance of the line is *so* important. Maybe the Chev was hampered by the drag penalty. Maybe it wasn't pulling as hard, but I don't care if my kite pulls slightly less (I'll just build a bigger kite and tell the morons who want to limit size to jump in a lake) because L/D is *everything*. Andrew -- Next time you visit KFS, download the bookmark file, the quickest way to surf.