Nitro4 Development by Bill Hansen
This entry was posted on December 4, 2014 by Bill Hansen.
The Nitro3 was such a successful kite we had to work hard to improve it. The fabric improvements developed for the Element3 clearly created an opportunity to implement them on the Nitro4 but, there were also other improvements based on rider feedback we felt needed work.
At the same time we clearly wanted to maintain or improve the boosting, power and dynamic high performance nature of the kite. In order of importance, overpowered form stability, better de-power and faster turning were at the top of the list.
At the same time we clearly wanted to maintain or improve the boosting, power and dynamic high performance nature of the kite. In order of importance, overpowered form stability, better de-power and faster turning were at the top of the list.
Overpowered Form Stability
The Nitro series is an SLE (Supported Leading Edge) Bridled kite. As such, it relies on a bridle to support the leading edge and maintain shape under load. However, when de-powered, the bridle tension is much reduced and the resulting loss of support to the Leading Edge allows it to move about constrained mostly by the inherent structural integrity provided by the tube diameters and internal pressure. Being a high performance design where low drag and upwind efficiency are key criteria, the tube diameters are relatively small with a lower unsupported stiffness. The obvious solution to build higher form stability is a larger Leading Edge tube diameter with a compromise to efficiency. The other possibility is a more complex bridle to add support to the Leading Edge when de-powered.
Our approach was a combination of both. Since the de-powered stability was mostly evident in the wingtip, that is where we concentrated our development. First, without changing the kite in the central power-producing sections, we made a diameter increase in the LE wingtip tube starting at the T4 outer wingtip strut and extending around the corner to the tube-end with a final steeper termination taper. Second, we placed additional bridle attachments along the LE to distribute the load more evenly - particularly in the center and wingtip area. Although the bridle became more complex, it allowed us greater freedom over the Nitro3's 4-line bridle in adjusting the front towpoint positions while supporting and controlling the wingtip.
Our approach was a combination of both. Since the de-powered stability was mostly evident in the wingtip, that is where we concentrated our development. First, without changing the kite in the central power-producing sections, we made a diameter increase in the LE wingtip tube starting at the T4 outer wingtip strut and extending around the corner to the tube-end with a final steeper termination taper. Second, we placed additional bridle attachments along the LE to distribute the load more evenly - particularly in the center and wingtip area. Although the bridle became more complex, it allowed us greater freedom over the Nitro3's 4-line bridle in adjusting the front towpoint positions while supporting and controlling the wingtip.
Better De-Power
The new bridle allows a wider variation in front towpoint position which along with the overall planform and profile distribution, is of prime importance in allowing the kite's AOA to reduce creating de-power. It is important that the kite have the freedom to 'tip' forward sufficiently to reduce lift without overflying due to a loss in rear line tension or an excessively forward towpoint. The Nitro3 4-line bridle had a single line to the wingtip which limited the 'tipping' near the maximum de-power extent. Beyond this point, the de-power was therefor limited and exchanged for the rear lines becoming slack with an increasing loss of rear line tension and steering input. The new bridle has additional connection nodes which allow greater freedom of movement and geometry change.
Faster Turning
Turning speed can be thought of as controlled by the separation and resultant leverage between the front and rear towpoints. The new bridle with superior LE and wingtip support allows the towpoint separation to be increased for faster turning. In addition, the greater freedom provided by the more complex bridle 'smooths' out the response to control inputs. The new bridle has turned what was once a rather impulsive input/control response in the Nitro3 into a very refined and smooth character which is immediately noticeable by Nitro3 riders. The same smooth nature and more precise control enhances the rider's ability to put the dynamic power of the Nitro4 to use with higher, more controlled boosts and better overall positioning in freestyle or other radical moves.
Overall Conclusion
The improved structure and support along with the improved materials decidedly makes the Nitro4 the absolute best ever. As a pilot, I like to compare it to the North American P51 Mustang. Now in it's fourth generation, the Nitro4 has truly become the 'Cadillac of the Skies.'
Close Up with Bill Hansen Video
Watch the video as Bill takes us step by step, through the creative process and design theories that have generated the Nitro4.
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