Date: Fri, 20 Oct 1995 17:08:05 -1000 From: daveculp@bdt.com (Dave Culp) Message-Id: Organization: Beckemeyer Development, Oakland CA Subject: Wild "kite" ideas (or maybe not?) We ordinarily think of a kite as flying, in wind, while tethered to stationary ground. However, running, with the kiteline, in still air, is also kiteflying, no? So, define kiting: (I'm not going to wax poetic here, or split semantic hairs; please bear with me) It's really a device which exploits differentials in fluid flows (or between a fluid and stationary ground, but that's boring ;-), to create lift, or tension in its tether. Note that such a definition might allow BOTH ends of the kiteline to be in motion, as with buggying and kitesailing. This precise definition is important to me as a kite sailor; I can theoretically "kitesail" through a moving water current and still air, can't I? There's a fluid flow differential, and I can exploit it. (I'm not going to go anywhere fast, but I AM "kiting.") Let's go a little farther afield. We know all about kiting and kitesailing on "stationary" substances; land, ice, and usually water. How about using differing flows of air? Why couldn't I build a blimp, fly it at low altitude, and send a kite up to higher altitude (might have to be helium inflated, or assisted), where the airflow is markedly different? (Like maybe up into the jet stream where it blows 150kts!) Note that I could "sail" both in the direction of the faster flow, and also "sail" ACROSS the current, or even tack "upwind." (The blimp would have to have wings in this instance, or at least an aerodynamic shape. It needs to create "lift" too, in order to "sail" cross wind.) How about exploiting water currents? I could build a buggy in Florida, fly an underwater "kite" on several miles of kiteline, out into the Gulf Stream. I could pull quite heavy loads Northward, no? Or go back to the blimp, this time trailing the underwater kite into the Gulf Stream. Now I could "sail," without any wind, at right angles to the stream, East and West, or I could "sail" North, or, by tacking, I could "sail" up-current, back to the South. (Blimp needs wings again) Let's move underwater now, and think in three dimensions. (I'll need the ability to dive deep here.) What if I "launch" my underwater kite from a mini-submarine near the edge of the afore mentioned Gulf Stream. Not only can I hitch a ride North, but I can sail "accross" the fluid interface, straight up or down! Back to the blimp flying a kite (this is probably the least impractical scheme). Why not "snuggle" up to the nearest change in wind direction/speed (I'm calling this a "fluid interface", a term usually reserved for an interface of different fluids--like water and air--but since I'm interested in the difference in flow direction and speed, not the difference in fluids, I think it valid), and let my kite out. Note that such an interface might be between vertically displaced air masses (the kite flys either above or below the blimp, and motion will be horizontal; at a fixed altitude) or between horizontally displaced air masses (Fly the blimp within a high or low barometric pressure area, and send the kite out into the high-speed stuff between the high and low), in which case the kite flys to the side of the blimp and motion is either up or down. I think this device could actually be built, and sailed at very cheap cost. (I didn't say cheap to build, however!) So, what do you think? Perhaps I've been sitting in the sun too long? -- Dave Culp Speedsailing daveculp@bdt.com 312 Flaming Oak Drive http://www.bdt.com:80/home/ Pleasant Hill, CA 94596 daveculp/speedsail.html USA (NEW Website) = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Sat, 21 Oct 1995 07:27:03 -1000 From: ray@cyberhighway.net (ray) Message-Id: <46bah7$6gt@host-3.cyberhighway.net> Organization: CyberHighway Internet Services Subject: Re: Wild "kite" ideas (or maybe not?) In article , daveculp@bdt.com says... > >scheme). Why not "snuggle" up to the nearest change in wind >direction/speed (I'm calling this a "fluid interface", a term usually >reserved for an interface of different fluids--like water and air--but Hanglider pilots call this a shear. I enjoyed this article:) ray> = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Sun, 22 Oct 1995 14:19:42 -1000 From: daveculp@bdt.com (Dave Culp) Message-Id: Organization: Beckemeyer Development, Oakland CA Subject: Re: Wild "kite" ideas (or maybe not?) >>This precise definition is important to me as a kite sailor; I can >>theoretically "kitesail" through a moving water current and still air, >>can't I? There's a fluid flow differential, and I can exploit it. (I'm not >>going to go anywhere fast, but I AM "kiting.") >>Me >Yes. A kite-powered river-ferry should be a good proposition in dead >calm, but completely stuck when the wind is blowing down the river. >The question is, can you get up-river in dead calm? >Andrew Beattie Sure! you'd have to "tack" up-current, plus use a *very* efficient ultralight kite, but I'm sure it's possible. -- Dave Culp Speedsailing daveculp@bdt.com 312 Flaming Oak Drive http://www.bdt.com:80/home/ Pleasant Hill, CA 94596 daveculp/speedsail.html USA (NEW Website) = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Tue, 24 Oct 1995 05:28:34 -1000 From: coh@i-2000.com (Chuck Henderson) Message-Id: Organization: I-2000 Inc. - Internet Services Subject: Re: Wild "kite" ideas (or maybe not?) In article <46bah7$6gt@host-3.cyberhighway.net>, ray@cyberhighway.net (ray) wrote: > In article , > daveculp@bdt.com says... > > > > >scheme). Why not "snuggle" up to the nearest change in wind > >direction/speed (I'm calling this a "fluid interface", a term usually > >reserved for an interface of different fluids--like water and air--but > > Hanglider pilots call this a shear. I enjoyed this article:) > ray> Personally, I think Dave is nuts! (and I say this with nothing but admiration) Perhaps the term "boundary layer" would help in his thought experiments? Submariners reserve this term for describing temperature differentials, but I suppose it might also be applied to differing currents or wind shears. I enjoyed the article, too! --Chuck Henderson = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Tue, 24 Oct 1995 11:01:17 -1000 From: daveculp@bdt.com (Dave Culp) Message-Id: Organization: Beckemeyer Development, Oakland CA Subject: Re: Wild "kite" ideas (or maybe not?) In article <46bah7$6gt@host-3.cyberhighway.net>, ray@cyberhighway.net (ray) wrote: > > Hanglider pilots call this a shear. I enjoyed this article:) > ray> Yes, of course they do. I wanted a more geneic term which wasn't fluid-specific. (Though I don't know why you couldn't have "water shear" as easily as "wind shear) Wouldn't it be nice to have a vehicle which used shear for GOOD, instead of killing folks with it? -- Dave Culp Speedsailing daveculp@bdt.com 312 Flaming Oak Drive http://bdt.com:80/home/daveculp/ Pleasant Hill, CA 94523 speedsail.html (New Website!) (510) 689-4360 = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =