Williams FW35

The Williams F1 Team launched its 2013 race car the FW35, at the Circuit de Catalunya in Spain on 19th February 2013. The latest Williams is a culmination of more than 12 months’ research and development by the team’s technical departments in Grove and features improvements in several key areas over last year’s race-winning FW34.

“Given the rule stability over the winter,” says Williams Technical Director Mike Coughlan, “I’m pleased with the gains that we’ve been able to make with this car. It’s a better, more refined Formula One car than the FW34 and I think everyone involved in the project can feel proud of the work they’ve done.”

Despite being an evolution of 2012’s car, more than 80 per cent of the FW35 is new. It has a new gearbox, new rear suspension, new radiators, a new floor, new exhausts, new bodywork, a new nose and a significant amount of weight has been saved as well.

With many new parts on the car, the team has carried out a lot of reliability work over the winter. The gearbox alone has already completed 3200kms on the dyno, a lot of which was conducted in the form of five straight Grand Prix weekends.

The unveiling of the FW35, however, with its drivers Pastor Maldonado and Valtteri Bottas is only the beginning. From here the car will continue to be developed throughout the year, beginning with an aerodynamic upgrade in time for the first race. By season’s end it is expected that the FW35 will have made strong performance improvements and Coughlan is in no doubt over the main area of gain.

“The Coanda effect is going to be a big thing for us,” Coughlan says. “There’s been no rule clarification concerning this area of the car, so we’ll work closely with Renault to maximise the available gains. Use of the DRS is more restricted this year, so we’ll take some resource away from that and focus on other areas.”

The Williams FW35 is heavily based on the FW34, so much so that it retains a very similar chassis. The similarity between the two cars roll hoops (FW35 above and FW34) below is easy to see.
Note the cooling gills on the FW35 below the Randstad logo.

The nose of the FW35 features a vanity panel as but the nose shape is very interesting especially the wing support pylons. It appears that this follows the concept employed on the Ferrari F138

At the rear of the car the FW35 retains pull rod suspension and its very low transmission. A key part of the Williams concept. Note the brake duct design and slits in the rear wing endplates

The flow of the exhaust gasses is key to the aerodynamic concept at the rear end of the car. The image below shows clearly the path to the rear of the car. Note the monkey seat winglet.

FW35 Exhaust Concept
The exhaust exits on the Williams FW35 look likely to stir up controversy before the F1 season has even started.

At the cars launch in Barcelona the exhaust channel was fitted with a plate that some feel could fall foul of article 5.8.4 of the 2013 Technical regulations which state that.

Once the exhaust tailpipes, the bodywork required by Article 3.8.4 and any apertures permitted by Article 3.8.5 have been fully defined there must be no bodywork lying within a right circular truncated cone which :

a)  Shares a common axis with that of the last 100mm of the tailpipe.

b)  Has a forward diameter equal to that of each exhaust exit.

c)  Starts at the exit of the tailpipe and extends rearwards as far as the rear wheel centre line.

d)  Has a half-cone angle of 3° such that the cone has its larger diameter at the rear wheel centre line.

Furthermore, there must be a view from above, the side, or any intermediate angle perpendicular to the car centre line, from which the truncated cone is not obscured by any bodywork lying more than 50mm forward of the rear wheel centre line.

There was also a technical directive issued by the FIA in 2012 which both designs could fall foul of . “I think the wording of the Technical Directive says something along the lines that any designs that re-ingest or redirect exhaust flow for principally aerodynamic reasons will not be permitted,” said James Allison in 2012.

The Williams solution is very clever however, whilst the Caterham turning vane is a solid piece running across the exhaust channel, the FW35 plate has a tiny gap in the centre clearly visible above. This interpretation of the rules may mean that the design could comply with both the regulations and the technical directive whilst still serving the same purpose as the questionable Caterham design.

No formal protest can be lodged yet as in testing the full regulations do not apply.

TEST 01: JEREZ
Chassis: FW34-03

Williams opted not to run its new car at the opening test of the season, instead running a FW34 based test mule fitted with FW35 components such as a new nose complete with vanity panel.

“This compliments our current philosophy of using rigs to pass off systems before running them on the car” explains Mike Coughlan, Williams F1 Technical Director. “The drivers have enjoyed themselves running through tyre comparisons and set-up changes that you would be reluctant to do at a race meeting due to time constraints. Although these results have been a little compromised by the very aggressive nature of the track surface here, we have acquired some useful data to carry forward. We now look forward to the next test in Barcelona and the launch of the FW35.”

Williams ran back to back tests using a nose fitted with a vanity panel and one without, a large sensor array with airspeed sensors was used to measure both configurations. 

TEST 02: BARCELONA
Chassis: FW35-01

The FW35 was shaken down ahead of its roll out but the first formal test came at Barcelona.

Early running gave a chance to look at the cars diffuser. Note the exposed driveshafts, sitting at a less extreme angle compared to other recent Williams designs such as the FW33.

At Barcelona there is a particular section of track that allows photographers to capture the rake angle a particular car is running at. Compare the Red Bull RB9 (above), with the Sauber C32 (below).
Finally take a look at the Williams FW35 with almost no rake at all (below)

Williams trialled three different noses on the FW35, the launch spec nose (below) appears similar in concept to that of the Ferrari F138, it may exploit a loophole in the regulations that allow vanity panels to exceed the maximum nose height.

At Jerez the Williams FW34 was fitted with a 2013 specification nose, this nose, lower than the one above was also run on the FW35 at Barcelona. The TV camera’s have been relocated from the edge of the nose itself to in-between the pylons.

Finally the FW35 was fitted with a nose without a vanity panel at all (below). This stepped nose may be developed into a Sauber style vented nose as the preseason testing continues. During most of these test runs the cars were fitted with sensor arrays – the mounting of which is visible in the image below.

This sensor array was mounted just behind the front wheel, it is not a type seen elsewhere and is made up of pitot tubes.

One of the areas of interest on the FW35 is its hollow hub (below). This is thought to be part of the brake cooling layout and could bring aerodynamic gains. Red Bull tried a similar system last year but it was outlawed as it rotated (movable aerodynamic device). The Williams design is thought to be legal as it does not rotate.

The FW35 has optional cooling vents behind the cockpit as is commonplace on the current breed of cars.

TEST 03: BARCELONA
Chassis: FW35-01

This image shows just how low the rear end of the FW35 really is, the low line transmission leaving a very large gap ahead of the rear wing.

RACE 01: ALBERT PARK, MELBOURNE, AUSTRALIA
Car: 16
Chassis: FW35-02
Engine: RS27-5322/2
Result: DNF (driver error)
Car: 17
Chassis: FW35-01
Engine: RS27-5340/2
Result: 14th

Read about the Williams FW34 in the October 2012 issue of Racecar Engineering