If anyone thought that the decision of the MotoGP Court of Appeal would bring the controversy over Ducati’s swing arm-mounted spoiler to a close, they were severely mistaken.

When the paddock reassembled at the Termas De Rio Hondo circuit in Argentina, the media – sparse in number, due to the astronomical cost of attending the race – had the opportunity to question the various factories involved in the controversy.

How happy they were with the decision of the court varied, understandably. But there was one thing that united all five manufacturers involved, no matter what side they were on.

Ducati on the one side, and Aprilia, Honda, KTM, and Suzuki on the other all felt the process fell far short of what is needed to manage the burgeoning field of aerodynamics. That meant that precious budget, destined for developing the bikes, was being spent on lawyers to represent the factories in court.

And even though the FIM MotoGP Court of Appeal has spoken, the feeling lingers that this is the beginning of something, rather than the end. The parties are just as far apart as ever, the decision of the court serving as a basis for division rather than something the rival manufacturers can unite around.

For Ducati, the decision was a vindication of what they had been saying. For Aprilia, the decision didn’t address the underlying problems, and was merely one FIM body backing up the decision of another.

Making Rules & Enforcing Rules

At its heart, this dispute is about two things: the way the rules are made and communicated, and whether Ducati’s spoiler violates the rules as communicated to the factories.

Ducati made their case in a press conference held with Gigi Dall’Igna, where the Ducati Corse boss got to put his side of the the argument. The decision showed that Ducati were in the right, according to Dall’Igna.

“We read and interpreted the rules in the proper way,” he said. “This is not only from the Technical Director’s point of view, but also the Court of Appeal’s point of view that had the possibility to read not only our documents but also the documents of our competitors.”

But he was not happy with the fact Ducati had been forced to go to court at all. “In front of the Court of Appeal we have to tell something about our knowledge. Not only in front of the Court, but also in front of our competitors, and I think this is for sure not fair and not the best way to do things in motor sport.” They had been forced to show data from the Qatar test and from computer simulations of “coefficient of heat exchange with the rear tire”, to demonstrate there had been an effect on tire temperature.

They had no wind tunnel data to present, because Ducati had never been interested in any downforce effects the spoiler may have. “We didn’t do any wind tunnel testing with the system, because our target was not the force of the device,” Dall’Igna said. “It was only the thermal effect on the rear tire.”

Seven Degrees

That effect was significant. “It works to put some air on the rear tire,” Dall’Igna explained, “and the results of our tests, at the Qatar test before the race, is that we can reduce the temperature of the tire by about 7°C on average. This is in the Ducati opinion for sure an important result in terms of the performance of the bike.”

Without seeing Ducati’s data, that seems like a major step forward. The Michelin MotoGP tires work best within a specific window of operation, somewhere around 120°C. If the tire gets too hot, it degrades more quickly, meaning the tire loses performance quickly.

Having the ability to lower the tire temperature by 7°C would allow Ducati to increase the load on the tire, and get more performance out of the tire for longer. In terms of a single lap time, the difference would not be large. But if the tire lasts longer at maximum performance, it could make a much bigger difference in the later stages of the race.

What makes Ducati’s claims a little harder to believe is that they chose to debut the system at Qatar. The race there is hold at night, on a cool track, and while temperatures are falling. Tire temperatures are already less of an issue than at some other tracks, so the added value of tire cooling is open to question.

At Qatar, Ducati’s Sporting Director Paolo Ciabatti had pointed out that MotoGP is now so close that even the smallest benefit can make a difference. “When you are competing at this level, every fraction of second, every fraction of a hundredth of a second counts.”

Small Force or Large Force?

Dall’Igna did admit that the device produced downforce, though he downplayed just how much force it generated. “All the parts that you put on in the air flow have a force, this is for sure.

Also the water spoiler that Yamaha used at the end of last year had this secondary effect for sure. In our case, I think that we can tell you that we have more or less 3, 4 Newtons at 180 km/h, 300 grams more or less.”

It was that number which other factories disputed. Honda had done wind tunnel tests on a part with a very similar design to Ducati’s, and had come up with very different figures. They had 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 juncture. Although we don’t have a value for maximum speed, it seems reasonable to assume around 355 km/h, which is about the top speed being recorded in MotoGP.

That is also nearly double the speed which Dall’Igna mentioned, and this is significant. Aerodynamic force increases with the square of velocity, so double the speed equals four times the force.

But precisely because of the exponential nature of this relationship, even small differences in force are quickly magnified. If the shape and angle of the vanes are slightly different between Honda’s model and Ducati’s actual spoiler, a small difference in downforce (basically, inverted lift) is magnified to become a much bigger difference at twice the speed.

If Honda’s model of Ducati’s spoiler produces 6 Newtons of downforce at 180km/h, instead of the 4 N which Ducati claim, then it would generate 36 Newtons at 360km/h, which is close to the numbers Honda are claiming, and over twice the 16 Newtons Ducati’s spoiler would generate.

This, of course, is all speculative. I don’t have the data from either Ducati’s spoiler, nor the model Honda tested. Without access to that data, we must choose whose word to take.

Ambiguity Abounds

Downforce is at the heart of the discussion for two reasons. Firstly, the guidelines issued by MotoGP Technical Director Danny Aldridge expressly forbade the use of attachments whose purpose was to generate downforce.

Their only permitted purpose was to protect the tire from water or debris, or to cool the rear tire. By Dall’Igna’s own admission, the Ducati swing arm spoiler generates downforce, though his argument is that its purpose is to cool the tire.

Secondly, the process by which the guidelines were arrived at is much in dispute. Mostly because other factories also asked to use devices similar to Ducati’s but were rejected. The process by which Danny Aldridge went from rejecting Aprilia’s idea for a spoiler to accepting Ducati’s was opaque enough to generate significant protest from the other manufacturers.

Aprilia CEO Massimo Rivola felt that Aprilia had been particularly hard done by. They had asked Danny Aldridge on 19th February whether a spoiler on the swing arm would be legal, and were told it would only be allowed if it was fitted in wet conditions.

“On the 19th of February we asked Aldridge to study and develop something in that area,” Rivola told Neil Morrison. “We saw the Yamaha idea on the water. It was quite cool. We said, ‘Can we develop something there?’ The answer was ‘Bear in mind you can develop something there only if you use a water device and for wet conditions only.’”

Then came the test at Qatar at the end of February, and Ducati tested their spoiler, despite the fact it was dry. And on 2nd March, Danny Aldridge sent out the guidelines stating that spoilers whose purpose was to generate downforce would be banned, but cooling tires or shifting water were permissible.

Inconsistent Messaging

Rivola’s bone of contention is that the Aldridge gave different explanations of what was allowed. Rivola claimed that Aldridge had explained in an email after Qatar that he had ruled the spoiler legal because Ducati had stated that “purpose of the attachment was to aid cooling of the rear tire only”.

At the hearing, Honda and the other manufacturers, including Ducati, showed that the spoiler also generated downforce. When Aldridge was asked about this in the hearing, he clarified his position, saying that he understood that the primary purpose of Ducati’s spoiler was to cool the tire.

That would appear to be a contradiction. In Rivola’s mind, and the mind of the other manufacturers, the question is simple: if it can be demonstrated that a spoiler generates downforce, then it should be banned. “In a way as long as you demonstrate it generates downforce, you should ban the device. I mean it’s easy,” Rivola said.

At the heart of the problem is that the goalposts keep shifting, and the wording of the guidelines is too ambiguous. Swing arm attachments are permitted if “their purpose is not to generate aerodynamic forces with respect to the ground”. Massimo Rivola, and the other manufacturers take that to mean that if the spoiler generates downforce, then it should be banned.

But the way the rule is written, it allows for an alternative interpretation, which is that a spoiler will be judged on its stated, primary purpose, rather than any side effects it may also have. That this is a loophole you could fly a Northrop Grumman B-2 Spirit through should be blindingly obvious.

Data Point

This, presumably, is why the MotoGP Court of Appeal upheld Danny Aldridge’s original ruling that the spoiler was legal, despite the evidence presented in the court, that the spoiler also generated downforce, which even Ducati admitted.

The purpose of Ducati’s spoiler is to cool the tire, something they could demonstrate with data from the test and from simulations provided by MegaRide, the software start up Ducati has been working with on modeling tire behavior. That it also produced downforce was an unfortunate side effect, Ducati argued.

And this is why Aprilia Racing CEO Massimo Rivola is so angry. “First, the rules are not really clear. Second, the way they are policed is a joke.” Rivola believed that Aldridge should not have just taken Ducati at their word. “When you do a rule you need to be in a position to measure the rule and police the rule,” the Aprilia Racing boss said.

“I mean, if you give the OK to an aero device, first you should ask for some data. Second you should be in a position to read the data. And third you should spend a bit of time. They declared they had spent ten or 15 minutes in the garage to see the wing.”

The fear among all manufacturers, not just Aprilia, was that it would cause an explosion of costs. “I think that if we go in the aerodynamic direction we all lose,” Rivola said. “That is not the direction where even Dorna wants to go, otherwise they would not homologate just the bodywork. That is not the way to limit the cost or the aerodynamic development mainly.”

Cheaper Than You Think

Yet Gigi Dall’Igna waved that objection aside. The cost of aerodynamics was much lower than people were claiming. “We, Ducati Corse, spend only 1% of our budget for the aerodynamics,” Dall’Igna said. “So if we cut something there it is something ridiculous in comparison to the other costs of the MotoGP.”

“We spent, for the lawyer and everything at the Court of Appeal, something equivalent to five days in the wind tunnel, and in 2018 we developed our fairing, our MotoGP bike with ten days in the wind tunnel. So 50% of the aerodynamic wind tunnel budget is gone only for the Court of Appeal.”

Dall’Igna reiterated that there was still much to be learned for road bikes in terms of aerodynamics. “I think there is a shyness about aerodynamics,” he said. “It has been neglected in the last years in the motorcycle world. But for sure this is important, not only in racing but also in production.”

“We are working close to the production department of Ducati to develop not only the supersport bikes of Ducati but also the more normal motorcycles in terms of cooling, in terms of thermal comfort for the rider. And everybody of you knows very well how important the thermal comfort is for the rider. So I think it’s something that we have to develop for the future.”

Copycat Contest

If an aerodynamic war does erupt, then the finger of blame will be pointed at Ducati, but Dall’Igna freely acknowledged that Ducati had copied idea for the swing arm spoiler from Yamaha. He expected the other factories to copy Ducati, because Ducati had copied Yamaha.

“Honestly speaking, yes, because Ducati had this idea copying Yamaha. Because Yamaha used a system like this in Valencia and maybe also before in some practices, but for sure during the Valencia race. So Ducati had this idea to watch what another of our competitors are doing. So I think that the others will copy us.”

Ironically, Ducati copying Yamaha is how the whole dispute erupted. Aprilia saw the Yamaha spoiler, asked Danny Aldridge if they could do something there, and were turned down. Ducati turned up at the test with a working part, told Aldridge it was for cooling the tire, and had their design accepted.

But it also seems inevitable that the system will change. With the MSMA split on the usefulness of aerodynamics, it seems unlikely they will be able to agree on proposals to put forward. And the current method of publishing rules, and then backing them up with changing guidelines has demonstrably not produced clear and unambiguous instructions to manufacturers.

There will be meetings through this weekend where the method and approach will be discussed. No doubt aerodynamic attachments to the swing arm will be one subject discussed. The way rules are drawn up will be talked about.

And the way in which the rules are monitored, policed, and enforced is sure to be a major topic of debate. The Court of Appeal was not the last word on Ducati’s swing arm spoiler. Most likely, it was just the first.

Photo: Ducati Corse