Date: Wed, 6 Sep 1995 12:47:09 -1000 From: jcampbell3@msmail3.hac.com (Campbell, James E) Message-Id: Organization: HAC Subject: "Active" Bridle Systems There have been quite a number of posts recently concerning bridles and how various adjustments to a bridle impact the performance of a stunt kite. Most of these posts pertained to traditional "passive" bridles. By "passive" I am referring to the category of bridle systems for which the tow points remain essentially unchanged during flight. Every so often, a new bridling scheme is developed which allows the tow points to shift in a controlled manner during flight thereby changing various performance aspects of the kite. For the lack of a better term, I call this category of bridles "active" bridles. I've seen several variations of active bridles over the years. The most recent example that comes to mind is the MEFM's Infinity bridle system. I'd like to get a few opinions from the rec.kite community on personal preferences for either the active or passive systems. If you like a particular active system, what behavior do you think the system accentuates and thereby makes the kite fly better? If you prefer the passive systems, what is it about the active systems that you don't like? Your comments and opinions would be appreciated. -- James E. Campbell (jcampbell3@msmail3.hac.com) Hughes Aircraft Company Leading Edge Kites = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Thu, 7 Sep 1995 00:27:33 -1000 From: Andy Wardley Message-Id: Organization: Peritas Multimedia Subject: Re: "Active" Bridle Systems >For the lack of a better term, I call this category >of bridles "active" bridles. More commonly referred to as "turbo" bridles or "dynamic" bridles, at least in my part of the world. >I'd like to get a few opinions from the rec.kite community on personal >preferences for either the active or passive systems. If you like a >particular active system, what behavior do you think the system >accentuates and thereby makes the kite fly better? If you prefer the >passive systems, what is it about the active systems that you don't like? In my opinion, it is the way to go. A well designed dynamic bridle (and the MEFM's is perhaps the most elegant) can be adjusted to give little or no dynamicity (i.e. just like a static bridle) or loads and loads. In that respect, a dynamic bridle, can only be better than a static one because it is a superset (i.e. it does everything a static bridle can and *more*). If we are to talk about the benefits of a dynamic bridle (that has been set up to be dynamic), then it comes down to 2 things: 1) Better tracking *and* 2) Faster turning The way it works is like this. A bridle set high flies straight and fast but turns like a pig. A bridle set low is radical in turning but tracks badly, oversteers and needs more wind. In addition, moving the tow point out (decrease the outhauls/increase the inhauls) increases the turning rate and vice versa. The dynamic bridle effectively raises the tow point and draws it in slightly when there is equal pressure applied to the lines. When uneven pressure is applied (i.e. when going into a turn), the tow point drops down and moves out to speed up the turn. Flying a well adjusted dynamic bridle is a strange experience at first. You will find the kite turns so fast, but comes out of the turn and almost "locks" back into a straight line. Having praised the dynamic bridle, it is not ideal for all kites. If you don't want a kite that turns too fast or one that really "snaps" back out of a turn, then a static bridle (or very subtle dynamic bridle) would be better. The Box of Tricks is a good example. Tim and I tried it out at Bristol and despite a hour or so of fiddling, it just didn't fly as well. The bridle was always too "soapy". What was happening was that in the first few fractions of a second as the kite went into a turn/trick, the bridle was shifting down. As this happened, there was a momentary lapse in transmission of power from kite lines to kite. This was particularly noticeable on the Box because it likes to act "snappy". You can pop it in and out of this, that and the other and it does what you want. With a dynamic bridle, the snappiness became softness. Not good. Apart from anything else, the Box turns so damn fast and doesn't overly suffer from oversteer so there isn't really that much to gain. Don't fix what ain't broke. Kites that really do benefit are those that change a lot when the bridle moves up or down. Chris Mattheson's Sandpiper '95 is a good example. It tracks really well but looses its puff in a tight turn. A dynamic bridle gives you that turn without sacrificing the tracking and control. When I have some more time, I might try to write some more sharing my experiences with dynamic bridles and designing them for existing kites. However, you can find it all out for yourself by just trying it out and experiementing. I had never even adjusted a bridle outside of the factory setting(s) until a couple of months or so ago, so it's not like some black art that takes years to master. Cheers Andy Andy Wardley is the man from abw@peritas.demon.co.uk. Thricefold decorated in the winky wars, he loves each and every one of you. No really, he does. "I'm honored and all that crap, but does this mean we're starting another round of quoting each other with the names munged?" - Sean Willyhard = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Fri, 8 Sep 1995 01:24:23 -1000 From: steveh@pyramid.com (Steve Hammatt) Message-Id: <42p957$hu@sword.eng.pyramid.com> Organization: Pyramid Technology Subject: Re: "Active" Bridle Systems Andy Wardley (abw@peritas.demon.co.uk) wrote: > Kites that really do benefit are those that change a lot when the bridle > moves up or down. Chris Mattheson's Sandpiper '95 is a good example. It > tracks really well but looses its puff in a tight turn. A dynamic bridle > gives you that turn without sacrificing the tracking and control. > When I have some more time, I might try to write some more sharing my > experiences with dynamic bridles and designing them for existing kites. Yes please ! I love the way my wife's Sandpiper 95 tracks, but I hate the way it turns so slowly. Steve. -- Steve Hammatt | steveh@pyramid.com | Camberley | - or - | Surrey, UK | steveh@pyra.co.uk | = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Fri, 8 Sep 1995 05:48:15 -1000 From: plepez@ulb.ac.be (Philippe Lepez) Message-Id: <42pojv$h3k@rc1.vub.ac.be> Organization: Free University of Brussels Subject: Re: "Active" Bridle Systems In article , jcampbell3@msmail3.hac.com (Campbell, James E) says: >I'd like to get a few opinions from the rec.kite community on personal >preferences for either the active or passive systems. If you like a >particular active system, what behavior do you think the system >accentuates and thereby makes the kite fly better? If you prefer the >passive systems, what is it about the active systems that you don't like? > >Your comments and opinions would be appreciated. My experience is limited but ... I particulary like the infinity bridle for its ability to stall,and generaly speaking for the so called radical moves but in near no wind condition, i prefer the "normal" bridle. Maybe this is just because the center of gravity of the kite with the infinity bridle is to much toward the tail. 1 ct. 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: Fri, 8 Sep 1995 21:50:17 -1000 From: mielse@euronet.nl (Emiel Stroeve) Message-Id: <42rggb$n6p@news.euro.net> Organization: Euronet Internet Subject: Re: "Active" Bridle Systems jcampbell3@msmail3.hac.com (Campbell, James E) wrote: >I'd like to get a few opinions from the rec.kite community on personal >preferences for either the active or passive systems. If you like a >particular active system, what behavior do you think the system >accentuates and thereby makes the kite fly better? If you prefer the >passive systems, what is it about the active systems that you don't like? >Your comments and opinions would be appreciated. I changed all of my kites to have the turbo's, turning is much more radical. Some time ago a tip turn (not Dave Culp's design, but a turn around the tip) was a fast turn, with the turbo you turn around f.i. the lower spreader connection point. Just read the article(s) of Andy Wardly and try tuning the thing, it's a lot of work but worth it. emiel @-home: http://www.euronet.nl/users/mielse/index.html (almost finished) = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =