Now that we are aware of the properties of leading edge tubercules, it is clear that a sword blade with such a shape will have aerodynamic advantages. When swung a sword behaves as a wing and produces lift ( and drag ) whenever it is not aligned at a zero angle of attack using 'perfect edge alignment'. During typical sword actions any relatively flat wide bladed cutting blade is prone to stalling at the high angles of attack experienced when the sword redirects before and after cuts. When the sword stalls it produces a lot of drag and it also tends to flex a lot more, none of which is conducive to speed, control, and efficiency.
As has been proven conclusively, leading edge tubercules reduce drag by around 5%. This will make swords with tuberculed blades faster and easier to accelerate. More importantly the tubercules enable the wing to handle greater angles of attack by 30 percent or more. This means in sword terms that imperfect technique is not punished as severely, and the blade will spend far less time stalled during tight maneuvers. The turns executed by a sword are, in terms of angles of attack, equivalent to those of highly aerobatic aircraft. The result of an increased angle of attack capability is greater speed with less effort, and better maneuverability, which are excellent bonuses for any sword. The blades with the undulating flame pattern will spend less time 'flapping' when turning. They must also experience less drag if swung through cuts when misaligned, particularly as the lower drag advantage is increased at higher angles of attack.
This idea is supported by the fact that the undulating blades are most often found on the very largest of two handed wide bladed cutting swords. Such swords were designed to be used against multiple opponents, which means that they must have used in large sweeping circular motions and with many redirections. With the high tip speed these long blades achieve and their large surface area, they have the most to gain from improved angle of attack capabilities and lower drag. Narrower more thrust orientated blades used primarily against single opponents or in formation, and shorter blades, would have less to gain from the unulating leading edges.
http://olosurfer-woodensurfboardsatpipeline.blogspot.com/2010/05/new-zorb-fin-for-future-primitive-106.html
http://olosurfer-woodensurfboardsatpipeline.blogspot.com/2010/05/leading-edge-tubercules-for-7-8-jets.html
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