From: ar12@quads.uchicago.edu (Andre Robotewskyj) Subject: To build a 15' or 18' delta? Message-ID: <1993Jan26.212522.5733@midway.uchicago.edu> Date: Tue, 26 Jan 93 16:25:22 EST Organization: University of Chicago OK- it's the middle of winter here in Chicago and I've got the worst case of kite withdrawl symptoms immaginable... So, since I can't go out and fly my kite in sub-zero weather (actually, I can, but I don't care to), I'm doing the next best thing- building one! Ah, but this will be no ordinary delta: those tiny "full-sized" deltas (like my Fire Bee) just don't cut it anymore- I want something BIG and DANGEROUS- so, I'm debating whether to make it a 15' or 18' swept wing- I'm going to use .505" FG and 1.5oz ripstop- the design will probably be similar to the Force 10. Any suggestions out there? Any experience flying such beasts? Thanks in advance, Andre . = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = From: pat@cs.strath.ac.uk (Patrick Prosser) Subject: Re: To build a 15' or 18' delta? Message-ID: <11485@baird.cs.strath.ac.uk> Date: Fri, 29 Jan 93 09:19:12 EST Organization: Comp. Sci. Dept., Strathclyde Univ., Glasgow, Scotland. In article <1993Jan26.212522.5733@midway.uchicago.edu> ar12@midway.uchicago.edu writes: >OK- it's the middle of winter here in Chicago and I've got the worst case >of kite withdrawl symptoms immaginable... So, since I can't go out and >fly my kite in sub-zero weather (actually, I can, but I don't care to), >I'm doing the next best thing- building one! Ah, but this will be no >ordinary delta: those tiny "full-sized" deltas (like my Fire Bee) just >don't cut it anymore- I want something BIG and DANGEROUS- so, I'm debating >whether to make it a 15' or 18' swept wing- I'm going to use .505" >FG and 1.5oz ripstop- the design will probably be similar to the >Force 10. Any suggestions out there? Any experience flying such beasts? >Thanks in advance, >Andre >. First of all, I think you should correct the terminology. Generally a delta is (assumed to be) a single line kite, with a keel. It is semi-flexible and is a derivative of the regallo. A 15' delta would be a nice size, since it would be based on 2m long spars (about 7' high). In fact, it's my standard size for delta's (I've built about 6 this size, and I've kept 2 because they are so nice). Second, I think we will all join together on this one Andre. You have not presented a good excuse for not flying a kite. What kind of conditions do you think Simo's flying in? We, in Scotland, have been hit by gale/hurricane force winds over the last 2 to 3 weeks. We've been flying in winds gusting to 80mph (using a 10' flexi amongst other things). So, get out there. Okay, now we've got that out the way (foreplay? :-). So far I have built 3 swsk's (swept wing stunt kites) that are 14' tip2tip. I took the LiteFlight-S and doubled it's dimensions, such that the LE spar is 96". The last one I built I used 10mm dia carbon. The frame cost in excess of 50 quid (call that $70 US). Generally, they cost about 100 quid each to build (materials alone, call that $140 US), so they are really good value. I have gone as low as 8mm dia carbon, and that's okay as well. Obviously a swsk of this size has different characteristics from the 3/4 or full size kites (I'd call these 1.5's). First of all, it has a VERY low density, so it flies in VERY light wind. That is (as Andrew Beattie says) if you can work out which direction the wind is blowing, this will fly. It will fly without wind if you walk backwards. I would estimate that 3mph is sufficient to have good flight. Secondly, it pulls! It pulls so strongly that I wouldn't dare fly it in anything but a breeze. I could build the kite stronger (stiffer) but it would be too much for me. I fly it on 300lb spectra in a breeze, and 120lb spectra in no wind (when I walk it). It is slow! It is like a jumbo jet. It will do wing-tip turns, but those wing tips are a hell of a distance apart! It is fun. I love flying it. There is only one thing that I am not happy with, and that is that we (Clyde Kites) haven't yet had all 3 in the air at the same time in the same place. For a team kite, this would be "different"! Whenever I fly it, everyone wants a shot. My most recent build is a scaled up version of the Rare Air Cheetah. I've taken it to full size using 6mm carbon. I've incorporated a number of minor modifications (that I think are improvements) for tensioning the sail. I flew the kite on Sunday, in a gale/blizzard. I believe that the winds were gusting in excess of 50mph in the Glasgow area that day, and it certainly felt like it out in the field. If you aren't familiar with the Cheetah, it is similar to Tim Benson's Phantom. The sail isn't "full" like the LiteFlight-S, so the pull is much more manageable. I think that this "generic" shape could be easily scaled up to 1.5 and be manageable in medium strength winds. I could fly it in those conditions (> 50mph), and the kite sustained no damage. So, I reckon this generic shape would scale up to 1.5 using 10mm carbon. In conclusion ... to scale up to full size times 1.5 I have been able to scale up the plans with no modifications. All I have done is increase the diameter of the carbon, and I think 10mm carbon is good enough for this size. I use standard weight ripstop. There is no need to use heavy sail cloth. Remember that you have to be able to fly it. If its heavy you will need a fair wind to lift it, and that sized kite in that wind will not be manageable. Keep this newsgroup up2d8 with your progress on this project Andre Patrick = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = From: dadams@dstrike.demon.co.uk ("David Adams") Subject: Re: To build a 15' or 18' delta? Distribution: world Organization: Data Strike Computers Ltd Date: Fri, 29 Jan 1993 20:26:06 +0000 Message-ID: <728356936snz@dstrike.demon.co.uk> In article <11485@baird.cs.strath.ac.uk> pat@cs.strath.ac.uk writes: > >My most recent build is a scaled up version of the Rare Air Cheetah. I've taken > it to full >size using 6mm carbon. I've incorporated a number of minor modifications (that > I think are >improvements) for tensioning the sail. I flew the kite on Sunday, in a I have a Pro Cheetah and think that it is a decent kite. It is certainly an improvement on the Rare Air kites of a couple of years back. I am interested as to the modifications you made. I have modified my standoffs so that the don't stick out the back of the sail so much - the lines were catching during ground-work. What modifications did you make when you made your extended version and what effect did they have? -- +---------------------------------------------------------------+ | David Adams | dadams@dstrike.demon.co.uk | | Data Strike Computers Ltd. | 100031.160@compuserve.com | +---------------------------------------------------------------+ = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = From: salanne@convex.csc.FI (Simo Salanne) Subject: Re: To build a 15' or 18' delta? Message-ID: <1993Jan29.201657.2646@nic.funet.fi> Organisation: STACK Finland Organization: Finnish Academic and Research Network Project - FUNET Date: Fri, 29 Jan 93 15:16:57 EST In <11485@baird.cs.strath.ac.uk> pat@cs.strath.ac.uk (Patrick Prosser) writes: >Second, I think we will all join together on this one Andre. You have not >presented a good excuse for not flying a kite. What kind of conditions do you think >Simo's flying in? We, in Scotland, have been hit by gale/hurricane force winds over the last 2 >to 3 weeks. We've been flying in winds gusting to 80mph (using a 10' flexi amongst other >things). So, get out there. Patrick, I might not be as brave as you expect. Haven't you noticed I've been quite busy on rec.kites, recently. Somehow "kiting" on computer makes me feel more comfortable these days :-) But I have been measuring the stiffnesses of carbon spars. (The results will follow later.) I belive the 10 mm carbon spar Patrick has used is RCF-10? It's 4.7 times as stiff as K-75 or Easton A/C 2-71 or AFC 2400. Dave Lord's "scale factor" for it is 1.47. So Patrick's 1.5's fits very well into theory! >(I'd call these 1.5's). First of all, it has a VERY low density, so it flies in VERY >light wind. That is (as Andrew Beattie says) if you can work out which direction the wind is Would you, Patrick, mind measuring the sail area and weight of these beasts? Just curiosity. Smooth Winds Simo Salanne = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =