Zero/White Motorcycle Concepts’ Intelligent Aero Prototype

Patented aero duct promises 10 percent drag reduction and improved range.

Zero Motorcycles and White Motorcycle Concepts teamed up to create a Zero SR/S with a pair of aerodynamic ducts running through the middle to reduce drag by 10 percent.WMC

Electric motorcycles have already proven they can be fast, accelerate rapidly, and occasionally even have a range that’s comparable to a combustion engine powered bike, but we’ve yet to see a battery-powered model that can achieve all those things at once. Energy density is the problem—gasoline is hard to beat on that front—and rather than throwing more batteries and more weight at the problem White Motorcycle Concepts has spent years focusing on how reducing aerodynamic drag could be a large part of the solution.

Now the team at WMC has partnered with Zero to create a working prototype that illustrates how the ideas can be incorporated into a near-standard, production-viable electric bike without compromising its practicality or adding substantially to its price.

The result of the collaboration between Zero and WMC is this prototype.WBC

We first came across WMC, based in the heart of Britain’s Motorsport Valley of Northamptonshire, home to a disproportionate number of F1 teams as well as the Silverstone racetrack, back in 2021. The company, formed around founder Robert White’s vision of radically reducing motorcycle drag via aerodynamic innovation, burst onto the scene with its WMC250EV, designed with an eye on the land speed record for electric bikes and created as the most extreme interpretation of White’s idea. The concept boils down to providing less frontal area and less drag by allowing airflow through the bike, not simply forcing the air aside. By creating a duct that lets air in through the front, straight through the middle of the bike, and out the back, drag is reduced without forcing the rider into uncomfortable contortions. As White points out, the human riding a bike is the one part of the package that they can’t alter in shape or size.

The WMC250EV took the concept to the extreme to prove the viability.John Wiles Photography

The WMC250EV was an extreme version of the air duct idea, with a gaping tunnel through the center of the machine, big enough for a child to crawl through. Impractical for a road bike, it served to illustrate the potential of the idea. WMC’s next project was at the other end of the speed scale, adapting the duct idea for its three-wheeled, Yamaha-based WMC300FR scooter, improving performance and reducing emissions compared to the Tricity 300 it’s based on. That machine has since gone into service with police in the UK and led to an all-electric version, the WMC300E+.

But it’s the company’s latest bike, a modified Zero SR/S built in conjunction with Zero to explore how the system could benefit a mainstream, real-world electric bike. It gives the best illustration yet of how the central duct idea could be applied to a showroom-ready bike—offering more range without the expense or weight of larger batteries and without adversely impacting the styling or practicality.

A look underneath shows how the pair of ducts crisscross to utilize space.WMC

Even though building the prototype around a standard Zero SR/S, without altering the frame, suspension, or powertrain, created compromises that could be avoided if the duct had been incorporated into the initial design stages of the bike, tests still indicate that it leads to a 10 percent reduction in drag, which should equate to a comparable improvement in range.

At first glance, the prototype, dubbed WMCSRS, looks much like a standard Zero SR/S. Seen from the side, only a slightly raised tail, a more enveloping front fender, and some teardrop-shaped aero fairings around the fork distinguish the prototype from the stock bike. Move to the rear, and a pair of red air outlets above the wheel pop into view, remarkably creating a clear line of sight straight through to the front intake underneath the nose.

The pair of outlets are stacked at the rear.WMC

There are two outlets rather than one simply because that front intake splits into a pair of ducts that channel the air around existing, immovable hardpoints that couldn’t be altered without changing the structure of the bike. The point is to show that the duct can help without the need to go to such extremes. To make space for it, some of the bike’s charging and control electronics have been repositioned above the duct, eating slightly into the storage locker on top of the “tank” area, and the seat has been raised a little—but it’s still at a manageable height and the front cubby remains big enough to keep your phone in. Testing so far has included computer fluid dynamics simulations and real-world tests using “aero-rake” sensor arrays to understand how the duct’s performance can be maximized within the constraints of the Zero SR/S’ shape and structure.

“The whole industry is currently facing a huge technical/commercial challenge to produce an electric motorcycle with performance close to its petrol equivalent,” Robert White said. “This problem space will not be solved by battery technology alone, it requires a blend of innovations to bridge the gap now and provide efficiency benefits in the future. When I first saw the Zero SR/S frame and battery architecture, I immediately recognized the opportunity to retrofit a duct. I’m proud of what we’ve achieved, though the duct is limited by existing packaging constraints. It would offer even greater performance if integrated from the start of a motorcycle’s design.”

Light at the end of the tunnel.WMC

The project kicked off a year ago when WMC and Zero hooked up at the 2023 EICMA show in Milan. Abe Askenazi, Zero Motorcycles CTO, said: “From our initial meeting at EICMA we have been interested to understand the potential impact of WMC’s aerodynamic duct. We are committed to innovation and, while battery development is advancing rapidly, we believe a combination of technologies is the key to developing the electric motorcycles of the future. This proof of concept has given us valuable insights into the potential benefits of integrating an aerodynamic duct into electric motorcycles, and we will continue to explore complementary technological advancements to deliver market-leading products for our customers.”

Will the project be carried forward to a production Zero model in the future? That’s unclear at this stage, but if WMC’s aero duct achieves the range improvement that’s predicted without the added weight and cost of more batteries, not to mention their technical complexity and the knock-on impact that might have on future reliability and warranty costs, it seems like a logical route to take.

A view from the front shows the unobstructed path that air takes through the bike.WMC
The front fender and aero fairings on the fork help channel air.WMC
Another view of the rear duct exits.WMC


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