Date: Sun, 21 May 1995 00:46:12 -1000 From: newlite@crl.com (Rick Ramsey) Message-Id: <3pn5lk$7jt@crl11.crl.com> Organization: CRL Dialup Internet Access Subject: Foil ribs Am ready to build a 5m Sputnik. According to the Kite 1.0 software you can use 24 or 39 ribs. What are the effects of less/more? = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Mon, 22 May 1995 10:12:06 -1000 From: nop@euronet.nl (Nop_Velthuizen) Message-Id: Organization: Euronet Internet Subject: Re: Foil ribs > Am ready to build a 5m Sputnik. According to the Kite 1.0 >software you can use 24 or 39 ribs. What are the effects of less/more? 39 ribs means more material (costs) and more cutting and sewing time. When you make your own kite, production time is not a big issue neither is a few dollars worth of extra material. 24 ribs should work fine which you can expect to find in a lot of procuction foils. But the 39 rib version will result in a more smooth average airfoil shape. Better aerodynamics, higher kite speed, more pull. And it simply feels better when you make your own kite when you know that you didn't take any short-cuts. MAZZEL NOP = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Mon, 22 May 1995 10:41:37 -1000 From: andrew@tug.com (Superuser) Message-Id: Organization: /usr/lib/news/organisation Subject: Re: Foil ribs I can't speak specifically about Sputniks (except that I'd put more ribs in high aspect kites and less in squarer shapes), but here is some words on the matter lifter from Peter Lynn's Buggies Boats & Peels: ------------------------------------------------------------------------------- A simple and informative experiment with Peel development was to construct some prototypes with twice as many ribs and bridles as the standard. The results were as expected: 1. Higher L.D.R. (goes further around the edge, and over head, has less pull at its equilibrium over head position than standard models) 2. Faster 3. Smoother skin less wrinkles, especially along trailing edge. 4. Marginally more liable to collapse - thinner, has less compressive strength from internal air pressure. 5. Less liable to "clap hands" - thinner mid section has relatively less drag, wing tip drag doesn't change as much. 6. For buggying, generally slower around the course. Top speed , especially on reaching legs, is higher. 7. A problem is that, the weight of ribs approximates to the weight of the lower (or upper) skin. I have thought that this significant overall weight increase would have dramatic and damaging effect on light wind performance and on that very critical situation in stronger turbulent winds when the kite flies into a "hole". From experience flying wet kites, (rigid frame single skin, soft or semi soft) kite handling characteristics deteriorate alarmingly. More recent tests seem to be showing that flying characteristics are more dependent on how weight is distributed rather than the total, and that wet kites lose performance more because the fabric becomes soft and sticky than because of increased weight. ------------------------------------------------------------------------------- One of the points that is taken for granted and not explained above is that due to billow, the shape of the skin is only remotely related to the shape of the ribs. The closer the ribs are together, the closer the skin follows them... Andrew -- New to rec.kites? START HERE! | To: www@kfs.org send an email message like this->| Subject: service /-\ () >< () |\/| () >< () /-\ | http://www.kfs.org/kites/welcome/index.html = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =