The secret slipperiness of shark skin
Shark Skin is not the newest modification to raceplanes, but unlike winglets it's not caught on as fast. Hannes Arch had them on his raceplane when the series returned in 2014. It has been slow for other pilots to also decide if it's worth adding, but the number is growing.
Considering that the teams are not allowed to modify the engine or propeller of their raceplane, they have to look at ways to make the aircraft as aerodynamic as possible, to create the minimum amount of drag, and one of the modifications is shark skin.
So, what exactly is shark skin? It is a synthetic replica that mimics the animal's skin surface texture. The original view on aerodynamics was 'the sleeker the better'. However, in recent years, thanks to extensive studies and trials, this stance has since changed. It is now believed that just the right amount of roughness is in fact better.
A shark's skin is the natural embodiment of perfect aerodynamic efficiency and streamlining. A shark slices through water with impeccable ease and speed. From a distance, its skin appears smooth and sleek to the touch. But on closer inspection, shark skin is in fact made up of jagged scales covered with longitudinal ridges. These ridges help to channel the water along the shark's body and prevent eddies that produce drag, therefore speeding up the shark's passage through the water.
Matt Hall's shark skin shimmering in the sunshine ©Predrag Vuckovic/RBAR
The same phenomenon also applies to aircraft aerodynamics, with synthetic shark skin helping to reduce air surface flow resistance when moving at speed. Another added bonus is that a shark skin coating also helps to increase an aircraft's fuel efficiency.
Since 2014 several other pilots have added shark skin to the wings of their raceplane. Matt Hall added it towards the end of last season and even though he has replaced his raceplane, the shark skin is on his new Edge 540. Michael Goulian has his wings covered and in San Diego this year Petr Kopfstein had the newest version of the product added. He said: "This is the next generation of the product and I'm the first to have it on a raceplane."
When asked if he felt it would make a difference, Matt Hall commented: "It's better to have it on the wings than to lose by 0.010s and think it's because of not making the modification!"