Bladder-less Kites

[TheJoe]

We all ready have them. Peter Lynn and Flysurfer make bladderless kites.

[Eurus]

Best said they would come out with a bladderless kite in 2006 I think. I think it was mainly a ploy to try to take a some air out of the SLE movement, but they never really pushed out...it was also a conceptual idea..never seen any protos of it.


Peter: Do you think it would be easy to develop that? What material would be used? Would it be a plastic dressed type cloth? Obviously a requirement would be to not add weight to the overall kite.

Taut - the easiest way is to not change the current material used but to simply coat the side that will be the interior of the leading edge and the struts with a sealant which makes the entire structure air tight. It would have a slight rubbery feel to it. I can't imagine there being enough of a weight difference as opposed to a bladder. I could see a mfg coating one side of the fabric before they cut it out to the template and sewing up the kite. Actually...now that I am writing it out and thinking of it I might have just figured out why this idea might not work. As soon as they begin to sew the material they would effectively be punching small microscopic holes which would eventually bleed air over time.

[Eurus]

We all ready have them. Peter Lynn and Flysurfer make bladderless kites.

Except this is about LEI's chief. Not foils...but thanks for stating the obvious.

[XtremeBigAir]

here is an old article:
http://www.kiteboard.com/2006-flat-bladderless-nemesis/

In 2004, Best Kiteboarding started prototyping a flat, ultra wide span kite made from Dacron and rip-stop polyester. This kite, then internally designated ‘Project 12,’ is very similar in concept to recently announced licensed designs from Takoon & Cabrinha.| In early 2004, the kiteboarding market changed for the better when bestkiteboarding.com came online as Best’s aggressive pricing blindsided the status quo forcing other manufacturers to totally rethink their inefficient pricing and distribution strategies. In 2005, the technology of kiteboarding changed with Best’s introduction of Cuben Fiber and the Hellfish: simply the best performing kite ever made. In early 2006, the sport will undergo a radical transformation again with the introduction of the first bladderless inflatable wing. The 2006 Best Nemesis is a flat / elliptical shaped kite that will give power, performance and safety new definitions. In 2004, Best Kiteboarding started prototyping a flat, ultra wide span kite made from Dacron and rip-stop polyester. This kite, then internally designated ‘Project 12,’ is very similar in concept to recently announced licensed designs from Takoon & Cabrinha. It had a flatter arc and used a complex, multipoint bridle system in order to maintain its shape and deliver extended depower. While there were some interesting features to this kite in terms of wind range, hang time and total de-powerability, the overall performance was not up to Best’s high standards. All prototypes of the basic design had massively heavy bar pressure and awkward turning because of a tendency to ‘slide’ instead of turn through the air. Additionally, the intricate bridles and pulleys needed to maintain the kite’s arc were clumsy, difficult to tune and just an overall nuisance. However, the largest detriment to this design concept is that the canopy of a flatter kite is subject to significantly increased loads compared to ‘U’ shaped designs, especially in the bias directions resulting in considerable material stretch and loss of performance after only 20 hours of use. Project 12 had some intriguing performance and safety attributes, but it was very obvious that a stronger canopy material was needed. In late 2004, the Best R&D team, made up of Peter Stiewe, Thomas Gaehwiler, Shannon Best, Jeff Biege and Alex Shogren, began thinking ‘outside of the box’ and specifications for the ‘perfect’ kite concept were drawn up. It was decided that this perfect kite would need to have an aerodynamically thin yet ultra-rigid leading edge to support the kite’s flat shape on four lines without bridles. The center of the kite would need to be as flat as possible, but the internal air-spar for the leading edge would need to dramatically turn down at the wingtips to achieve proper stability. Steering input should not stall the wing tip; it should fully change the angle of attack on that side of the kite similar to an aircraft wing’s flap. Additionally, manufacturing the canopy out of a stronger, lighter material compared to rip-stop would enable the airframe to better respond to bias loads and torsional steering forces to further increase turning speed, responsiveness and longevity. Theoretically, this kite was in fact perfect, it was just impossible to build with current materials and technology. Then the Best R&D team found Cuben Fiber, an ultra light-weight, incredibly strong and non-porous material. Immediately the team knew that using a strong, non-porous material for the leading edge would enable higher inflation pressures and a far more rigid structure without the need for internal polyurethane bladders. And without traditional bladders, the weight of the whole kite would be reduced dramatically, which for any flying apparatus is obviously beneficial. While initial prototyping began on the flat, bladderless kite made from Cuben Fiber, the team realized that a traditionally shaped kite made from Cuben Fiber would hold significant performance advantages over all other kites made from Dacron and rip-stop and this kite could be brought to market very quickly. After extensive research yielding the conclusion that the patented Cuben material had no equal, an exclusivity agreement was signed between Best Kiteboarding and Cuben Fiber and the Hellfish was announced.Because custom Cuben Fiber made exclusively for Best is so strong, initial Hellfish prototypes were designed to achieve maximum aerodynamic efficiency through ultra-thin leading edges and struts that could hold a higher air pressure to support the shape of the kite. It astounded the R&D team to find out that the Cuben Fiber material was so structurally sound that the leading edge and struts did not need higher air pressure. The aerodynamically thin leading edge could be preserved without higher than normal pressures. The first Hellfish prototypes were flown in early 2005, and the whole R&D team instantly knew they were on to something very, very special. The Hellfish had amazing power and wind range, but because of the unique load bearing properties of Cuben material, especially in the bias directions, it turned and responded better than anything the team had ever flown. Needless to say, everyone was very excited and to this day, no one on the R&D team will fly anything except for a Hellfish. In early April of 2005, the decision was made to put the bladderless, flat kite concept on hold and focus exclusively on the Hellfish with the goal of bringing it to market by early to mid summer. The Hellfish went through six full generations of prototyping with the finished product being well beyond the R&D team’s wildest dreams in terms of performance. Mid development prototypes were released to the public in an unprecedented move that showed the willingness of Best to bring the potential of a Cuben kites performance to a mass market. The Hellfish has an amazing wind range with unmatched low-end power. The ultra-thin leading edge reduces drag and delivers superior aerodynamic efficiency enabling unprecedented capture of apparent wind. The Hellfish jumps higher, hangs longer, turns faster and is incredibly more responsive compared to any Dacron/rip-stop kite, regardless of arc span. The technology and performance of the Hellfish truly does make traditional kites obsolete, but more importantly, it makes kiteboarding much more fun. Critics argue that the Hellfish was rushed to market, and in a sense, that is true as Best’s management and design team did not see any reason to make kiters wait to enjoy the added benefits and fun the Hellfish makes possible. Also, the Hellfish was announced while still in the early prototype stage because of a number of reasons; It was obvious that a traditionally shaped kite made exclusively from Cuben Fiber could be tweaked and polished very quickly resulting in the best performing kite ever produced; Best had an exclusivity agreement in place with Cuben Fiber ensuring no other company could compete; and Management decided to adopt a semi-transparent / open source research and development program due again to the Cuben exclusivity and to reap the added benefits of rider idea generation and feedback. Even before the Hellfish was finished and in production, the team, with added input from the aerodynamic engineers from Cuben Fiber (Heiner Meldner & R.J. Downs), once again started focusing on the bladderless flat kite concept. The team was thinking that they needed to somehow bond (not sew) the Cuben material together for the leading edge to create an air-tight structure that would hold higher air pressures, and thus support the structure and wider span of the kite. Because of the complex, three dimensional shape of the leading edge, this was challenging to say the least. But, the group soon realized that Cuben had existing technology that Best could develop and apply to this kite concept. Cuben had experience manufacturing cost effective, high-pressure, light-weight, seamless spars for inflatable structures used in aerospace and defense applications. In fact, Cuben had already produced inflatable wings for aircraft applications, so with Peter’s kite design genius and Cuben’s added experience with aerospace applications, the idea took shape incredibly quickly. The small diameter, lightweight spar could be inserted into a tear drop shaped leading edge sleeve producing unmatched aerodynamic benefits as well as fantastic structural advantages in that it would properly tension the canopy and trailing edge. Initial prototypes for the 2006 Best Nemesis have yielded outstanding preliminary results. Best will bring to market the first bladderless flat kite, with unmatched technical and practical performance and total depower. It flies on four lines without overly complicated bridles or pulleys, has a wind range that simply has to be experienced to be believed, yields more power per square meter than obsolete rip-stop/Dacron kites of any span width, all while jumping higher and offering the unique ability to completely control glide. In fact, ‘hang time’ turns into ‘glide time’ as once a jump is initiated, one controls the glide rate by actively modifying the angle of attack. Best’s exclusive use of Cuben material has allowed the steering attachment points to be mounted directly on the inflatable spar delivering phenomenal turning speed and responsiveness while maintaining super light bar pressure. It relaunches automatically with a quick push and pull of the bar and from a safety perspective, it offers the rider instant, effortless and total depower without the possibility of catching any part of the kite in an unnecessary, complicated bridle. The rider does not have to proactively pull a release to depower this kite, the rider just lets go of or pushes the bar away and all power spills from the canopy. The 2006 Best Nemesis simply eliminates pilot error. This bladderless, flat kite would not be possible without the Cuben Fiber inflatable spar, but beyond that, the kite’s unequalled performance is also due to Cuben Fiber. The canopy material is a custom designed, multi-directional spectra laminate that supports and controls bias loads enabling instant response and fast turning speeds. Additionally, because this kite does not use polyurethane bladders or exceptionally heavy material such as Dacron, the overall weight has been reduced dramatically even compared to a Hellfish. Because of Best’s exclusive arrangement with Cuben Fiber, and the fact that no other company has the technology, research or development resources to copy Best’s patent pending ideas, the ongoing development of the 2006 Best Nemesis will, like the Hellfish, be done partially in the public domain, with an anticipated launch in early 2006. After successful initial prototypes, work is currently being done to refine the design, shape and torsional rigidity of the Cuben inflatable spar as this component is the base for all further development. On February 9th, 2004 a kiter from Australia logged on to bestkiteboarding.com and purchased the very first Best Nemesis. Seventeen months later, Best Kiteboarding is the largest kite manufacturer in the world delivering innovations that matter without sacrificing performance. Important Note: Flat (or elliptical) shaped kites behave and fly very differently from traditional kites. There are advantages and disadvantages to both and at the end of the day, it comes down to rider preference. Best Kiteboarding - See more at: http://www.kiteboard.com/2006-flat-blad ... 7gjfJ.dpuf

[Westozzy]

WTF!! ^^^^^????

[XtremeBigAir]

it is patented: http://www.google.com/patents/US20060192055

[Eurus]

it is patented: http://www.google.com/patents/US20060192055

Thanks for the article and patent reference X. So why did they not continue the Cuben Fiber kite? I found a couple of old articles on The Kiteboarder site that referenced the Nemesis in 2010 but nothing much after that. Sounds like cuben fiber is a pretty bad ass material for kites. Lighter, stronger, etc. Why did the industry standardize on dacron and rip stop?