MotoGP News: Ducati aerodynamics responsible for top speed
The creation of Ducati Director Filippo Preziosi, the Ducati Desmosedici bike, has been the most powerful bike on the circuit for almost a decade. It has always been known for its top speed, which is produced by a roaring and amazingly engineered desmodromic engine. The other characteristic which compliments the engine in achieving the speed is the Bologna Company’s emphasis on aerodynamic design as compared to the other factories. Alan Jenkins, a former formula F1 engineer and now the aerodynamics consultant for Ducati Desmosedici, has played a large part in the sleek Ducati design.
Jenkins has been with Ducati on the Desmosedici to improve its aerodynamics, and the German Grand Prix at Sachsenring saw the Ducati sprout a pair of wings. Now, this new innovation on the Ducati - winglets protruding both forward and outward out of the fairings - raised curiosity in all the viewers and media alike.
When asked, both Ducati riders Casey Stoner and Nicky Hayden were at a loss to explain their purpose and said that they could hardly feel any difference in the machine. Meanwhile, the general consensus which developed, and was helped along by Ducati, was that these winglets increase the downward thrust on the bike’s front end at high speed preventing the bike’s propensity to lift the front wheel. This came as a rather accurate assumption, as the wisest in the business tended to agree with it.
However, other experts noticed that the downward force idea is just a nominal factor as the surface area of the winglets is relatively small and most likely to have a greater impact on high speeds. Figures from the paddock suggested that these wings only contribute 10kgs of downward force at the speed of 300 km/h, which is sufficient to thwart the front end of the bike from lifting. The problem is at lower speeds of 200 km/h; these winglets would not apply enough downward force at this speed. At lower speeds, with the bike under hard acceleration and engine revolutions, the lift force is much greater. The software systems used for anti wheelie here do help but there is a downside to it: it reduces power and impacts the rider when he drives out from the corners. Hence, the use of aerodynamic here would be much more beneficial than cutting down on power, but the exponential nature of fluid dynamics states that the air drag is squared when the speed is doubled. In layman terms, this means the slower you go, the less effective the wings are, since the machine is under constant acceleration it will still generate a lift force even at slow speeds which the wings would not cater to.
The horizontal flaps provide downward thrust; meanwhile, the inverted vertical flaps have an all new dimension to it altogether. These inverted flaps shape the airflow along the side of the fairings reducing the air pressure behind the winglets. As nature abhors vacuum, the hot air from the radiator vents (which are located directly behind the winglets) is sucked out with greater speed due to the low pressure, giving a cooling effect and dispersing the heat of the Desmosedici engine, which happens to be a notorious problem for the Ducati.
The regular fairing design vents have a problem. The air exiting the radiator immediately hits a wall of air which is passing by those vents, making the exhaust process slow. Although vents have been optimized, there still are limitations to the design.
This new design in the Ducati generates a pressure drop over the radiator which sucks the hot air out and the cool air, in turn, is sucked in at an accelerated rate, allowing the engine to run cooler. This in turn increases the life of the engine, which has been the pressing problem this season with the new regulations.
Ducati engines have been known for producing excessive heat: in 2003, the factory had to drill holes in the fairings to prevent Loris Capirossi and Troy Bayliss from having heat blisters on their hands. This solution has come as a panacea for the Ducati team which does exactly what the world of MotoGP has been trying to achieve.
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