Date: Wed, 20 Apr 1994 05:33:15 -1000 From: plepez@is1e.bfu.vub.ac.be (Lepez Philippe) Message-Id: <2p3hvr$5ek@rc1.vub.ac.be> Organization: Brussels Free Universities (VUB/ULB), Belgium Subject: Rokkaku questions Hi all, I intend to build my first single line kite (don't laugh !). The aim is to use it as a platform for paradroping (my daughters will love that, I hope). Finally, my choice is a rokkaku, but when you don't know, you ask silly questions. So I went and ask my good friend Raoul Fosset (he has build more than 50 Rok) and got very good information but there are still open questions I would like to ask to you. Did someone already has build a Rok with molded dihedral brace joints, instead of bowing the spreaders ? If so, is it a good or a bad idea ? Raoul's answer was : 'never heard of it, so probably it is a bad idea. Anyway won't be a *real* Rok !'. Raoul also suggested to keep away of carbon spars because of the bow that would lead them to split. With our Exell pultruded spars it seems to be a good idea. In the archive I saw that Marty Sasaki used Carbon spars. Can I ask you to comment ? Regards. Philippe. -- Philippe Lepez (CP 125), | | Good kite Universite Libre de Bruxelles, | Email: plepez@ulb.ac.be | + Good wind 50 av. Roosevelt, | Phone: 32.2.6503553 | ---------------- 1050 Bruxelles, Belgique. | Fax : 32.2.6503323 | = A lot of fun ! = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Thu, 21 Apr 1994 06:39:50 -1000 From: sasaki@das.harvard.edu (Marty Sasaki) Message-Id: Organization: Harvard University OIT/NSD Subject: Re: Rokkaku questions In article <2p3hvr$5ek@rc1.vub.ac.be>, plepez@is1e.vub.ac.be (Lepez Philippe) writes: >Did someone already has build a Rok with molded dihedral brace joints, >instead of bowing the spreaders ? If so, is it a good or a bad idea ? >Raoul's answer was : 'never heard of it, so probably it is a bad idea. >Anyway won't be a *real* Rok !'. I guess if you were a purist, a *real* rokkaku would be made of bamboo and hand made paper, and decorated with water soluable dyes and ink. There is no reason that the molded dihedral braces wouldn't work well. I've seen them used in nice flying Eddy kites. >Raoul also suggested to keep away of carbon spars because of the bow that >would lead them to split. With our Exell pultruded spars it seems to be a >good idea. In the archive I saw that Marty Sasaki used Carbon spars. Can >I ask you to comment ? I've used AFC and Beman graphite with good results. They can take a surprising amount of bow before breaking. They are a little expensive to be used in rokkaku's, especially since the light weight isn't as important with a rokkaku as in a stunt kite, but this is the only reason that I wouldn't use them in rokkakus all of the time. -- Marty Sasaki Harvard University Sasaki Kite Fabrications sasaki@noc.harvard.edu Network Services Division 26 Green Street 617-496-4320 10 Ware Street Jamaica Plain, MA 02130 Cambridge, MA 02138-4002 phone/fax: 617-522-8546 = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Thu, 21 Apr 1994 22:27:31 -1000 From: salanne@convex.csc.FI (Simo Salanne) Message-Id: <2p81pj$kq2@pobox.csc.fi> Organization: Centre for Scintific Computing Subject: Re: Rokkaku questions In <2p3hvr$5ek@rc1.vub.ac.be> plepez@is1e.vub.ac.be (Lepez Philippe) writes: >Raoul also suggested to keep away of carbon spars because of the bow that >would lead them to split. With our Exell pultruded spars it seems to be a >good idea. In the archive I saw that Marty Sasaki used Carbon spars. Can >I ask you to comment ? Philippe You can use Exel _glassfibre_ tubes instead of carbon, they are stronger, cheaper and more flexible. 8 mm for spine and 6 mm for cross spars are good choice for 1.5 - 2.0 m Rok. Smooth Winds Simo -- Simo.Salanne@csc.fi STACK Finland = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Mon, 23 May 1994 23:28:46 -1000 From: salanne@convex.csc.FI (Simo Salanne) Message-Id: <2rshce$mm6@pobox.csc.fi> Organization: Centre for Scintific Computing Subject: Re: Rokkaku questions In <2rsd6n$9q2@nz12.rz.uni-karlsruhe.de> micha@ekpux2 (Michael Schneider) writes: >after building my first single line kite, a sode dako, >i need a rokkaku. i looked at ftp.hawaii.edu >and read about 6:5:4, 5:4:3,... roks. i guess this are >the length-ratios of the spine:upper:lower spreader. right? No, it's spine:spreader:distance_between_spreaders. The spreaders are of same lenght, the lower one is just bent more. >if someone could tell me the distances top-to-upper spreader 1 unit. >and top-to-lower spreader i have all measures to build a rok. 5 units in 6:5:4, 4 units in 5:4:3. >the bridle points on the spreaders for a 4- or 6-point bridle >would also be necessary, because the infos i found were not >so clear(to me). 1 unit from the ends of spreader. (... and in the middle if 6 legs:-) In archive there's a plan called 1m7rok.ps (1.7 meter Rok), have a look and scale to your size. Hope to see your Rok on Fano! Simo -- Simo.Salanne@csc.fi STACK Finland = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Mon, 23 May 1994 22:17:27 -1000 From: micha@ekpux2.harvard.edu (Michael Schneider) Message-Id: <2rsd6n$9q2@nz12.rz.uni-karlsruhe.de> Organization: University of Karlsruhe, Germany Subject: Rokkaku questions hi kiters, after building my first single line kite, a sode dako, i need a rokkaku. i looked at ftp.hawaii.edu and read about 6:5:4, 5:4:3,... roks. i guess this are the length-ratios of the spine:upper:lower spreader. right? if someone could tell me the distances top-to-upper spreader and top-to-lower spreader i have all measures to build a rok. the bridle points on the spreaders for a 4- or 6-point bridle would also be necessary, because the infos i found were not so clear(to me). thanks in advance, micha -- ================================================================== Michael Schneider Institut fuer Experimentelle Kernphysik der Universitaet Karlsruhe Engesserstr. 7(Physikhochhaus), 76128 Karlsruhe 1 micha@ekpux2.physik.uni-karlsruhe.de | BD14@DKAUNI2.BITNET ================================================================== = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =