Can anyone tell me what 's the idea behind Naish kite bent leading edge is ???? ?? I also see Airrush bringing out a kite with flat part of leading edge ????? 
Naish designed it originally because there was a seagull over population in the Hawaiian islands, and they wanted to scare them away, so created a giant Scaregull kite.
Hi Toad,
The SIGMA concept is designed to keep the centre of effort in your kite behind the front tow point. As long as you keep the CE behind your front lines you will always have pressure on your back lines, allowing you to control your kite easily when fully depowered.
With nearly every kite on the market without SIGMA, once you sheet out radically, the CE moves forward of the front lines and your back lines either go slack or very light, this makes it very hard to get input into your kite for steering, and in many cases you have to sheet on a little bit to make the kite respond. This is not the case with SIGMA, the kite will respond nicely way into radical angles of attack.
It also breaks up the surface tension making relaunch much faster and easier.
Check out the diagram below
JB
