Wind tunnel comparison


Wind tunnel comparison

Aero plan

A test in the wind tunnel had to prove whether the motorcycle manufacturers are proceeding according to plan with the aerodynamic design of their super sports bikes.

Faster, lighter, stronger is the motto of the manufacturers of supersport motorcycles. Above all, the 1000 Yamaha YZF-R1 claims the top position among the super athletes of this world with 202 kilograms fully fueled and 150 hp. In terms of power-to-weight ratio, she is actually in pole position. But in terms of top speed, the Kawasaki ZX-9R with less displacement steals the show from among its peers. Obviously the Yamaha R1 has weaknesses in the aerodynamic area. Ultimately, however, only measurements in the wind tunnel can provide information about the aerodynamic qualities. So with colleagues from the Italian motorcycle newspaper Motociclismo, MOTORRAD went into the wind tunnel of the helicopter manufacturer Gruppo Agusta, precisely the company that used to produce the legendary MV Agusta motorcycles. A Ducati 916 served as a reference, which had won the wind tunnel comparison in MOTORRAD 10/1997 with the lowest air resistance. As a further novelty candidate, the new Aprilia RSV 1000 also had to prove its aerodynamic qualities.
Even the determination of the frontal area brings a rather unexpected result. The Aprilia, which is almost brawny compared to the Ducati, with the comparatively voluminous cladding, has exactly the same projection surface with the driver as the much more delicate Ducati. The two-cylinder from Bologna is visibly slimmer in the lower cladding area and the window is measurably lower. But the driver protrudes a long way out of the fairing even when it is folded up. And even the Yamaha, with its wider in-line four-cylinder, has just 1.5 percent more frontal area than its two competitors.
But even when the hurricane raged around the driver’s ears at 160 km / h in the wind tunnel, the Aprilia provided a surprise. With a value for the product of drag coefficient and frontal area of ​​0.314, it puts the Ducati in the slipstream with 0.322. The Yamaha, on the other hand, shows clear aerodynamic deficits with a value of 0.354.
This becomes even more evident when looking at the pure drag coefficient cw, the measure of aerodynamic quality. While the Aprilia occupies the top position with 0.52 and the Ducati closely follows with 0.53, the Yamaha falls sharply with 0.57 and also looks comparatively old compared to a Suzuki GSX-R 750. Even its direct predecessor, the YZF 1000, masters this discipline far more confidently.
Aids such as stuck-on threads, plumes of smoke and laser light relentlessly reveal the aerodynamic deadly sins of the Yamaha. The windshield is way too short and too low. The air flow falls behind the edge of the window down onto the tank and hits the driver in the entire upper body and helmet area, with the result that the wind protection is poor. Since the windshield does not deflect the air flow over the driver, the flow is broken up and forms a turbulent wake behind the helmet in the back area, which also hits the aerodynamically unfavorable, upward-facing rear. Further inadequacies in the area of ​​the lower part of the fairing that is too short and the powerful silencer also cause turbulence that saves performance.
The Ducati already offers better conditions. The pane, which is also too short and deep, has a counter-draft on its upper edge that deflects at least part of the air flow upwards over the driver. There are no free-standing silencers in the rear to create turbulence. Nevertheless, the fairing still offers plenty of space for aerodynamic fine-tuning. The clear winner on points is the Aprilia, whose higher paneling directs the air flow over the driver and also offers by far the best wind protection. Many measures, such as the lower fairing part that is long to the rear or the favorably shaped rear end, shows that the Aprilia has already seen a wind tunnel before. But their fairing can also be optimized aerodynamically.
S.Especially the Yamaha proves that aerodynamics is to be found low on the agenda of the Japanese motorcycle developers in terms of priorities. All the more regrettable because good aerodynamics usually go hand in hand with good wind protection, saves fuel at high speeds and benefits a high top speed.

Aprilia RSV 1000 – all-rounder

The Aprilia RSV 1000 has good aerodynamic facilities. The fairing looks bulky compared to the competition, but directs the air flow well over the driver and thus ensures a low air resistance and proper wind protection. Further details, such as the closely laid muffler and the fairing that is drawn backwards on the lower part, bear witness to aerodynamic considerations. The stern, which tapers towards the rear and slopes slightly, does not offer any additional resistance to the current flowing over the driver’s back. The Aprilia proves with the lowest air resistance and the best wind protection in the trio that both criteria can be combined excellently.

Ducati 916 – show talent

The Ducati 916 loves the show. The slim, sporty fairing offers the driver at least some wind protection thanks to the small counter-pull of the windshield. The lower part is placed tightly around the narrow engine and offers little contact surface for the wind. Smart solutions characterize the Ducati in the rear area. The silencers located in the seat hump do not cause any unnecessary air resistance, and even the single-sided swing arm is comparatively narrow. With a more favorably shaped windshield, the Ducati would not have to accept any loss of aerodynamic qualities, but would improve the protection of the driver. There would be a point deduction in front of the ice cream parlor in terms of appearance alone.

Yamaha YZF R1 – Windei

For the Yamaha R1, fairing makers were at work who are not familiar with the word aerodynamics. The short windshield provides the driver with minimal wind protection because the airflow is deflected downwards at its upper edge and thus hits the driver’s upper body. At high speeds, the enormous wind pressure can only be endured for a short time. At the side, part of the flow is diverted around the upper body and forms a widespread vortex in the driver’s back. But the design of the seat hump and the lower part of the fairing, which leaves plenty of space behind the engine for vortex formation, are not an aerodynamic feat either. Both in terms of aerodynamics and wind protection, the R1 deserves the red lantern by far.

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