January 15th and 19th, 2009: Williams and Toyota launch their 2009 challengers
The two outfits are alone in having opted for a different design concept at the rear of the car compared to their rivals. The diffusers at the rear of the Williams FW31 and the Toyota TF109 appear to exceed the maximum height of 175 mm at their peak through clever aerodynamic shaping of the rear crash structure.
January 28th, 2009: Teams to seek diffuser clarification
It is understood that several teams are looking at seeking clarification from the FIA about the matter, with Renault the first to confirm it will do so. Renault executive director of engineering Pat Symonds told Autosport: "They (the diffusers) are certainly interesting, although I don't think I can comment on their legality. "That's something for the FIA to comment on. We will be asking the FIA about it, but we haven't yet."
January 29th 2009: FIA aware of rear diffuser issue
It is not clear when rival teams will contact the FIA about the Toyota and Williams designs, but a high level source at the governing body has confirmed that it is aware of the situation. The source also said that approval for one diffuser design had been granted - although would not state whether it was a design that currently featured on any of the cars. The source told autosport.com: "The FIA has had some correspondence with Toyota about diffusers but hasn't actually seen what they've been testing. "One design has been approved by the FIA but we cannot confirm that it is the design in question." Should the FIA confirm to rival teams that the design concepts of the Williams and Toyota cars are legal, then it may force a number of outfits to redesign the rear of their cars prior to the start of the season.
January 31st 2009: Autosport's technical analysis
Williams came up with a 'double decker' diffuser design, while Toyota initially tested an extension to the middle of their diffuser, and then later added a double decker section of their own. Both these designs raised eyebrows up and down the pitlane, as they appear to stretch the wording of the new rules.
Having spoken to both teams' technical directors at the Portimao test, neither feels their designs are that different to their rivals' and clearly both are confident that they are not contravening the regulations.
As part of the 2009 package of aerodynamic rule changes designed to reduce downforce and increase overtaking, the FIA mandated a smaller diffuser in a more rearward position.
With the shock of losing 50 per cent of their downforce because of these changes, teams have been working hard to get the bodywork shaped to the new rules to regain the lost downforce.
2009 McLaren in testingOne of the critical elements in making a diffuser work is internal volume, so the new regulations now limit the main part of the diffuser to a width of 1000mm, a length of 350mm and a height of 175mm - as seen on the McLaren in the picture.
However the diffuser rules are simply a section of the wider bodywork regulations, which also include sections which allow bodywork in areas not intended for the diffuser. Williams and Toyota have exploited these areas with their new cars. No doubt other teams know of these loopholes, but have yet to run their interpretations.
There are two interpretations of the regulations being exploited with these diffusers.
1) Both cars appear to use the same loophole that allowed the teams to run an extra channel above their diffuser under the outgoing rules.
Although the rules now demand a diffuser height of 175mm above the reference plane, this is measured from below - using the 'bodywork facing the ground' articles in the rules. Therefore the actual diffuser can be taller, if they can get around the second paragraph of the article 3.12.7 that demands a continuous line where it meets the flat floor at the axle line.
2009 Williams diffuser, illustration by Craig ScarboroughThis is an ambiguous rule which appears to allow more than one surface to exist in this area. Thus both teams have been able to create a double decker diffuser, their main diffuser (highlighted in yellow) is as long, wide and tall as the rules allow (the red line), but they have made the middle section stop short of meeting the flat floor - instead the floor extends into the upper diffuser (shown in green).
This is a creative way of interpreting the F1's Technical Regulations as outlined below:
Article 3.5.2: The width of bodywork behind the rear wheel centre line and more than 200mm above the reference plane must not exceed 750mm.
Article 3.12.7: No bodywork which is visible from beneath the car and which lies between the rear wheel centre line and a point 350mm rearward of it may be more than 175mm above the reference plane. Any intersection of the surfaces in this area with a lateral or longitudinal vertical plane should form one continuous line which is visible from beneath the car.
Williams and Toyota's interpretation has a precedent, as it was exploited by most teams last year. The area above the lower diffuser is covered in article 3.5.2, which allows bodywork to be up to 200mm above the reference plane (25mm higher than the lower diffuser) and as wide as 750mm.
This can create about 10 per cent more diffuser exit area, and the higher expansion of the flow through the diffuser creates more downforce. A couple of teams have questioned whether this interpretation is allowed under the current rules, although it is not thought any has lodged a formal question with the FIA.
2009 Toyota diffuser design, illustrated by Craig Scarborough2) Toyota have an additional diffuser aft of the main diffuser (shown in blue). This sits in a 150mm wide area that is intended for the rear crash structure and rear wing mounts. The same area has been exploited in recent years with small winglets mounted atop the rear crash structure.
Although the rules demand no bodywork above 175mm, this only applies to the area between the rear axle line and point 350mm behind it: article 3.10.4 creates a void between 350mm and 500mm behind the axle.
This extra 150mm x 150mm area can be up to 400mm high, some 225mm taller than intended for the diffuser, and it is this area that Toyota have taken advantage of. Again the taller exit creates more potential for downforce.
In addition, the rule also allows this part to extend beyond 500mm (behind the axle line) as long as it sits alongside the rear impact structure (200mm and 400mm above the reference plane). This is an area yet to be exploited by any team's diffuser:
Article 3.10.5 states: Any parts of the car less than 75mm from the car centre line and more than 500mm behind the rear wheel centre line must be situated between 200mm and 400mm above the reference plane.
Teams often approach the FIA during the design process to clarify whether their interpretations of grey areas are within the regulations, although in this instance sources have informed autosport.com that neither Williams nor Toyota submitted their design to the governing body - although Toyota are believed to have exchanged correspondence with the governing body regarding diffusers.
Interestingly, FIA sources have revealed that a diffuser design related to the current intrigue has been approved - although it has not been confirmed whether this is one used by Williams or Toyota.
Testing is not bound by the technical regulations, so the issue could continue to be debated until the opening race. Melbourne is the first time that the cars are formally scrutineered, and the first opportunity for any protest to be lodged - although it is possible that the FIA could clarify its view of the rules in question before Melbourne.
February 5th 2009: Williams, Toyota diffusers given all clear
Mosley says, however, that the FIA has seen nothing illegal about the "clever" design, although he admitted a protest could not be ruled out during the season-opening Australian Grand Prix. "It will always happen when you have got new regulations," Mosley told selected reporters on Thursday. "The current FIA view is that Williams and Toyota have been clever and have exploited the wording of the rules in a clever way. But somebody may challenge it and the stewards may take a different view - it could happen.
Complaints start to build up
March 11th 2009: Briatore frustrated by diffuser rules
It's not right that some diffusers are made in a certain way while others in a different way, because I don't think it fair that everyone has his own rule book," he was quoted as saying by Gazzetta dello Sport. "Looks like there are two sets of regulations: the one that allows some teams to have the diffuser built in a certain way that is forbidden to others because it's considered illegal. That's not what we expect. We want black or white rules but equal to everyone." He would not be drawn on whether Renault would lodge a protest. "We'll see, because at least three teams don't respect the regulations," said Briatore.
March 23th 2009: Red Bull considers controversial diffusers illegal
Mere days ahead of scrutineering for the Australian Grand Prix, Red Bull's motor racing advisor Helmut Marko declared that the solutions on the Toyota, Williams and Brawn cars are "illegal." "They have a double diffuser which gives them five tenths per lap (extra)," the Austrian told sportnet.at on Monday. "Seven teams - including Red Bull - are united: they are illegal," said Marko, raising the probability of a formal protest at the scene of the season opener this weekend. He claims both Renault and Red Bull discussed the legality of a similar aerodynamic concept with the FIA early last year and "at that time there was a negative answer."
March 23th 2009: Stefano Domenicali thinks it doesn't correspond to the nature of the rules
The Ferrari boss also said he is expecting the governing body to clarify the regulations regarding the rear diffusers, as F1 could be heading for another row at the Australian GP this weekend. FIA president Max Mosley admitted a protest could not be ruled out after Sunday's race due to the diffusers used by Williams, Toyota and Brawn GP. Domenicali is hoping the issue is resolved before there are protests launched. "We are convinced that certain interpretations that have been applied do not correspond to the nature of the rules," he added. "We expect the federation to clarify as soon as possible its position over the diffuser. If that extractor is illegal then it must not be used, while if it is legal it's up to the other teams, including us, to try to adapt as soon as possible, because performance is found in that area of the car. "There needs to be a great sense of responsibility on everyone's part. I hope this issue can be resolved beforehand."
...And a rival backs the diffuser design!
March 23th 2009: Symonds backs divisive diffuser designs
Pat Symonds has contradicted his Renault boss Flavio Briatore over the rear diffuser saga. While Briatore recently accused three teams of fielding illegal solutions at the rear of their 2009 cars, technical boss Symonds patted his rivals on the back for clever engineering. "Toyota and Williams have found a very good, very interesting solution with the diffuser which we hadn't done and I'm sure that everyone is looking at that at the moment," the Briton is quoted as saying recently by Australasian Motorsport News.
We have 1 week left for the season opener and one big problem that is waiting to be solved. What a season!