These so-called downwash ducts, also known as flow diverters, first appeared on the MotoGP stage in 2021, when Ducati introduced the Desmosedici GP21 with downward-facing air ducts on both sides of the fairing during pre-season testing in Qatar.
Since then, these have been picked up by other manufacturers, and Yamaha has unveiled its own version of this design in 2024. The exact way the ducts work has been the subject of much speculation, but initial analysis shows interesting results.
At first glance, the ducts seem contradictory: they sit under the winglets, which are clearly designed to generate downforce when driving straight ahead. The ducts, on the other hand, take air from the sides of the motorcycle and direct it downwards. At first, you might think that this would cause the front wheel of the motorcycle to be lifted. But studies such as the «Aerodynamic Study of MotoGP Motorcycle Flow Redirectors» suggest that this is not the case.
Functioning of the Downwash Ducts
These air ducts appear to serve a dual function. When driving straight ahead, they suck up the «dirty» airflow behind the front wheel and fork and direct it under the motorcycle. This helps to reduce drag and generate some downforce. When cornering, a different effect occurs: the air pressure is higher at the front and inside of the motorcycle, where the fairing is close to the ground. This causes air to flow under the motorcycle at high speed and exit on the other side, where there is lower pressure. The downwash ducts amplify this effect, thereby providing additional downforce.
Yamaha’s additional cooling benefits
Yamaha’s new patent application points to another benefit of the downwash ducts: improved cooling of the motorcycle. The turbulent airflow that comes from the front wheel and hits the front fairing edges is discharged through the ducts, creating a low-pressure area behind the ducts. It is at this point that exhaust ports are located that discharge the hot air that has been passed through the radiator and oil cooler. The low-pressure area helps to pull the air through the radiators, allowing them to work more efficiently. This allows the radiators to be made smaller and lighter, resulting in a slimmer design of the motorcycle.
Possible application in series motorcycles
Yamaha’s patent application may indicate that the company plans to use similar ducts on future production models. Patents for purely racing-related technologies are rare, as patents are usually intended to protect commercial innovations. Whether this idea is actually patentable, especially given the similar designs already used by Ducati and others, remains to be seen and is ultimately in the hands of patent examiners.
Conclusion
With the downwash ducts, Yamaha could in future incorporate an aerodynamic innovation from MotoGP into production motorcycles. This technology could both reduce air resistance and improve cooling, which could influence the design and performance of future models. How this idea develops further remains exciting, especially with regard to commercial use and possible patent protection issues.
