Aprilia looks to leathers for aero advantage
By Ben Purvis
Has written for dozens of magazines and websites, including most of the world’s biggest bike titles, as well as dabbling in car and technology journalism.
23.03.2023
Modified leathers (bottom) give cleaner airflow than a normal suit
Over the last few years MotoGP bikes have been transformed by the addition of aerodynamic appendages and Aprilia’s RS-GP is arguably the most radical of them all – sporting wings, ground-effect side panels, swingarm scoops and bulbous brake fairings in the pursuit of cutting drag and maximizing downforce.
With all the effort that’s gone into sculpting the RS-GP’s shape, perhaps it should be no surprise that the company’s aerodynamicists have also been taking a look at the single biggest component of every GP machine. One that’s exposed to the airflow at all times and has a shape that hasn’t changed since the dawn of the sport. The rider.
While screens and fairings allied to tucked-in riding position do their best to keep riders out of the airflow on straights, their inherently lumpy shape is inevitably less efficient than the windtunnel-sculpted bodywork that wraps the rest of the bike. That’s something that Aprilia is looking to address, and the company has filed a patent application showing exactly how.
Ten panels, attached by Velcro, change the rider’s shape
Race leathers have sported aerodynamic humps on their backs for decades – the idea emerged from a 1988 project by Dainese to create an enhanced back protector that turned out to have unintentional aero benefits – but other than that and some developments in the shapes of helmets, mainly targeting improved stability, there haven’t been many attempts to make riding kit more aerodynamic.
The reason, as explained in Aprilia’s patent application, is that adding extra pieces to leathers, while potentially improving straight-line speed with smoother airflow, can also hinder the essential movement of a rider on the bike. That’s a problem the new design aims to counter.
Essentially, the leathers themselves are conventional, but Aprilia’s design envisages ten external panels Velcroed into place on the rider’s limbs and torso to improve airflow. These include a pair of forearm panels, cleaning up flow from the bars and rider’s hands, and two more on the upper arms and shoulders that give a smoother run for air spilling off the edge of the bike’s screen. Moving back, a pair of side panels help fill the gap between the rider’s armpits and hips. On the legs, there’s a thigh panel and a lower leg section – the latter incorporating the knee slider – to complete the transformation.
Cross-sections of the panels show they’re filled with lightweight padding
All these additional panels are designed to have a taut, plastic surface with enough flexibility to not hinder the rider. They stay clear of joints where they’d need to bend more severely, and beneath the surface there’s padding – made of a polymer foam like expanded polystyrene – to add an extra layer of safety to the suit in the event of a crash. Like a back protector, the semi-rigid nature of the outer skin should help spread the force of impacts, and the padded internal structure should absorb some of it before it can reach the rider.
Just as the aerodynamic humps on rider’s backs also serve a safety purpose, the Aprilia suit design is intended to be enhanced in its original function, not compromised in the pursuit of better aerodynamics. As an extra benefit, the patent application suggests that the suit improves rider comfort by reducing turbulence – the same turbulence that would be creating drag and hampering top speed.
Of course, it’s essential that a race suit’s primary purpose of providing protection in the event of a crash isn’t hindered by the pursuit of better aero, but if the Aprilia design can – as intended – incorporate the additional padding without hampering rider movement, it suggests leathers could become a new battleground in the aerodynamic war being waged in MotoGP at the moment.
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