The spoon, swingarm spoiler, etc. Regardless of the term used, this part made an impact in the MotoGP paddock at the start of 2019. According to Ducati, the function of the spoon was to cool the rear tire by directing the air flow directly onto the surface of the tire. But while MotoGP prototypes are gaining performance, why has this part disappeared?
Ducati introduced this part at the Qatar test in early 2019. The spoon is a device that was originally intentionally attached to the front of the swingarm by Ducati, almost matching the shape and position of the water deflector which is installed on the Yamaha M1 during rainy races, but with the aim of cooling the tires according to the engineers at Borgo Panigale.
The segmented form at the time presented a lot of mistrust on the part of other manufacturers, notably Aprilia, a team to which Massimo Rivola, from Formula 1, had just arrived and who had really understood the concept of 'aerodynamic.
The other competitors appealed to the FIM authorities to have this part removed. If anyone thought the MotoGP appeal court ruling would end the controversy over Ducati's swingarm-mounted spoiler, they were seriously mistaken.
Ambiguity is a source of conflict
There was one thing that united the five manufacturers involved, no matter which side they were on. Ducati on one side and Aprilia, Honda, KTM and Suzuki on the other all felt the process fell far short of what was needed to handle the burgeoning field of aerodynamics. This meant that valuable budget, intended for motorcycle development, was spent on lawyers to represent the factories in court.
At its heart, this dispute is about two things: how the rules are established and communicated, and whether Ducati's spoiler violates the rules communicated to the factories.
Ducati made its point during a press conference held with Gigi Dall'Igna, where the Director of Ducati Corse was able to give his point of view. The decision showed that Ducati was right, according to Gigi Dall'Igna. “We have read and interpreted the rules correctly,” did he declare.
But he was unhappy that Ducati was forced to go to court. “Before the Court of Appeal, we must present our knowledge. Not only in front of the Court, but also in front of our competitors, and I think that is certainly not fair and not the best way to do things in motorsport. » They were forced to show data from the Qatar test and computer simulations of the “heat exchange coefficient with the rear tire”, to demonstrate that there had been an effect on the tire temperature.
They had no wind tunnel data to present, as Ducati had never been interested in the downforce of the spoiler. “We did not do any wind tunnel testing with the system, because our target was not the downforce of this system,” said Gigi Dall'Igna. “It was just the thermal effect on the rear tire. »
A certain cooling…
This effect was significant. “It works to put some air on the rear tire,” explained Gigi Dall’Igna, “and the results of our tests, during the Qatar test before the race, are that we can reduce the temperature of the tire by around 7°C. This is certainly an important result in terms of motorcycle performance in Ducati's opinion. »
What makes Ducati's claims a little harder to believe is that they chose to launch the system in Qatar. The race takes place there at night, on a cool track and while temperatures drop. Tire temperatures are already less of an issue than at some other tracks, so the added value of tire cooling is questionable. In Qatar, Ducati sporting director Paolo Ciabatti stressed that MotoGP is now so close that even the slightest advantage can make the difference. “When you compete at this level, every fraction of a second, every fraction of a hundredth of a second counts. »
But also an aerodynamic device…
Gigi Dall'Igna admitted that the device produced downforce, although he downplayed the force it generated. “All the parts you put in the airflow have force, that's for sure. Also, the water spoiler Yamaha used late last year definitely had this side effect. In our case, I think we can tell you that we have more or less 3, 4 Newtons at 180 km/h, 300 grams more or less. »
It was this figure that other factories disputed. Honda had carried out wind tunnel tests on a part very similar in design to Ducati's and came up with very different figures. They found that their device produced between 4 and 6 kg at maximum speed, or between 39 and 59 Newton.
It is worth noting the speed differential at this point. Although we don't have a value for maximum speed, it seems reasonable to start at around 360 km/h, which corresponds to the maximum speed recorded in MotoGP (rounding up). It's also almost double the speed Dall'Igna mentioned, and that's significant. Aerodynamic force increases with the square of the speed, so twice the speed equals four times the force.
But precisely because of the exponential nature of this relationship, even small differences in strength are quickly amplified. If the shape and angle of the blades are slightly different between the Honda model and Ducati's current spoiler, a small difference in downforce (essentially, reverse lift) is amplified to become a much larger difference at twice speed. If the Honda model of Ducati's spoiler produces 6 Newtons of downforce at 180 km/h, instead of the 4N that Ducati claims, it would generate 36 Newtons at 360 km/h, which is close to the figures claimed by Honda.
But then why did she disappear?
Looking more closely at the Ducati, this controversial device has disappeared. Indeed, since the 2021 Styrian GP, which took place on the Spielberg track in Austria, after the summer break, Ducati no longer uses the spoon on the swingarm.
The most likely hypothesis is that since this Grand Prix, Ducati has started to use the Ride Height Virgin in a more radical way, that is to say the modification of the height of the chassis while driving, whether they operate manually or semi-automatically, and this with all its drivers and at all Grands Prix, while it was used occasionally before.
If we look at the structure and functioning of the Ride Height Virgin, we can see that the area under the swingarm is where it is located, and it is difficult to have more space for the spoon. After all, when the suspension is fully depressed thanks to this device, it is possible for the swingarm spoon to hit the fairing. Certainly, this was retained by the technical teams during the development of the Ride Height Virgin, but it was used sparingly. From now on, it is unthinkable for a driver to ride without this system.
But again, this hypothesis is not just about the position of the spoon, although it is at the exact position where the device is Ride Height Virgin. This raises the question concerning the initial effect sought by Ducati with the spoon: if fundamentally the function of “cooling” the tires is not really important for Ducati or at least that its importance is lower than the aerodynamic and geometric effect provided speak Ride Height Virgin, didn't this famous spoon have a significant aerodynamic effect?
The current work from Ducati and its masterminds is pretty darn interesting because it suggests that performance in MotoGP is reaching a point where more adventurous minds are once again looking for alternatives to conventional chassis design.
