MotoGP Winglets

In 2010, stubby little wings appeared on the sides of Ducati MotoGP bikes' fairings. Analysts were puzzled by the apparent contradictory nature of these aero elements. Were they supposed to generate downforce to help prevent wheelies or increase airflow from the fairing vents to improve cooling or what? Then as quickly as they had appeared, the wings vanished, only to reappear in 2015, billed as an "experiment."

The 2016 Ducatis have four wings, two on the fairing sides level with the top of the front brake rotor and two on the fairing nose adjacent to the bottom of the ram-air intake opening. Talk now focuses on how they help control wheelies. The new, mandatory common ECU software is apparently less effective at wheelie control than before, so the winglets were increased in number and size. The other factories took note, imitations soon appeared, and the winglet war was on.

Winglets make sense in terms of minimizing wheelies, but the motorcycle is only accelerating hard and vertical for a fraction of the lap. What are the winglets doing the rest of the time? If they’re good at fighting wheelies, are they good for anything else?

It doesn’t seem so. The most obvious problem is that downforce generated by winglets is directed parallel to the longitudinal axis of the bike, straight down when the motorcycle is vertical but at an angle when the motorcycle is leaned over, which in MotoGP can be 60 degrees or more from the vertical. And it’s not evenly distributed front and rear, as the bike’s center of pressure is far forward of its center of gravity.

On race cars, downforce always pushes the car straight down, which makes it consistent and relatively predictable, and the angle of attack--—the angle between the chord of the wing (a line from the leading edge to the trailing edge when the wing is seen in section) and the ambient airflow—varies no more than 1 or 2 degrees as the suspension moves.

But on a MotoGP bike, with a much shorter wheelbase and 100mm or more of suspension travel front and rear, the angle of attack can vary as much as four or five times that of the Formula 1 car’s, maybe even enough to “stall” the winglets or upset flow. When two cars run nose to tail, turbulence generated by the leading car disrupts and decreases the downforce of the trailing car; the same will likely happen with motorcycles.

In fact, some riders noted increased turbulence when running behind a bike with winglets. With aircraft and cars alike, increased wake turbulence means increased drag. Why wouldn’t this be true for motorcycles as well? Unfortunately, I’ve seen no direct comparison of top-speed data for the same bike running in the same conditions with and without winglets.

There are also safety issues raised by the possibility of injuries caused by winglets in crashes or collisions between riders. But the question is now moot because winglets are banned starting with the 2017 season. MotoGP basically said that if the teams could unanimously agree to keep them, they’d be approved. Ducati definitely wanted to keep them, but other teams were on the fence, so winglets will pass into history at the end of this season.

I hope we eventually get some data detailing how these things actually performed. My guess is that for every plus there were two or three minuses, and for most participants and observers, winglets won’t be missed.