Finding the "secret" to the Red Bull RB9's seemingly unstoppable performance in the second part of the season has been quite a quest for specialists and fueled much discussion among fans.Towards the later part of 2013 interest began to focus on the T-tray area, the flat section under the driver's seat which channels air to the the diffuser. There was much discussion about images seen via the FIA's thermal cameras, it was thought Red Bull had come up with a system which would allow movement once the oddly large amount of titanium fasteners were heated by friction. This theory was championed by BBC's Gary Anderson and it raised enough interest for the FIA to perform a special test, applying heat along with the required 200kg force to the part. It did not budge.As it turns out Anderson was getting warmer. He wasn't the only one, many were curious as to why Red Bull mechanics were both very protective of and yet constantly adjusting something in that area. Giorgio Piola, along with Franco Nugnes at Omnicorse now shed some light on how Red Bull was able to run what is a completely forbidden moving aerodynamic device, perfectly legally!First off, let's be clear that if a car passes FIA technical regulations as written it is by definition, legal. Making an end run on regulations and getting away with it is part of the essence of racing and engineering: the " Unfair Advantage ", read it.Newey, argues Piola, has always been a designer who has tended to miniaturize and willing to risk reliability to do so (case in point the size and placement of the KERS batteries which have caused many issues but were never changed). It was a surprise then when in Brazil, thanks perhaps to the team being a bit more relaxed, a photographer was able to snap a picture which showed the inside of the t-tray and keel assembly. It revealed a very large (for F1, 30cm) structure, bow shaped and hinged in the middle.The structure, it is said, worked as a spring but only at values above the FIA's test. A force above 200 kg applied to one side of the lever would raise the front of the t-tray enough to allow Red Bull to run the car lower and with more rake without worrying about wearing though the compliance skid plate.Combine this with the better exhaust blowing Renault engines were able to produce and the better way Newey channeled that energy to seal the raked rear and Vettel's ability to figure out how to take full advantage of the package and you understand how Red Bulls were able to regularly trounce their rivals.