Head to head: Williams FW42 vs Williams FW43

Williams appears to be back on the right track, with the car build timed perfectly and running fine on the first day of testing. But what exactly is differerent on their new FW43 compared to the troubled 2019 car?

The team certainly did have a lot of work to get the new car sorted, given the 2019 was such a poor base with which the fabled Williams team managed to score just a single point, and hardly ever qualifying ahead of the back row of the grid.

But, everything is possible in F1, and the signs are positive. Whether it will be a major surprise is something else, but so far, things are at least better than what they were last year. In fact, the very first day of testing at Barcelona delivered a best lap for the Williams faster than their best they managed at qualifying for the Spanish Grand Prix.

So, what was changed - apart from the obvious livery change, which now included a fully red sidepod?

Even when we look only at the front of the car, it's still clear this is a Williams design, with the nose cone largely similar and not jumping on the slim nose bandwagon that most teams have jumped onto with their new 2020 cars.

It's still a classic thumb style nose without much channel complication. Underneath the nose, there's still the inlet for the S-duct, while the image comparison shows how the front wing pillars have been developed to improve undernose flow.

The front wing on the new Williams is very similar, if not identical, to the one Williams test at least year's post-season Abu Dhabi test, and a large step away from the earlier FW42 front wing design (the image of the FW42 is from the Hungarian GP 2019). It is clear that Williams is putting more downforce on the inner side of the flaps, while ahead of the front wheels, the focus is on managing airflow around the front tyres.

A major problem with the FW42 however was that it was a complicated car to drive. Not only did it lack downforce, but neither driver were happy with the balance of the car. It was difficult to set-up, difficult to keep on track, and difficult to predict. All these items were a focus of the Williams development team, hence there are quite a few suspension changes.

The front suspension of the FW42 features a particularly bulky upper wishbone pivot that has been considerably slimmed down for 2020. In addition to this drag reduction, other suspension arms also appear to be slimmer than they were before, while the upper front wishbone is now also attaching to the chassis in an aerodynamically more neutral position - with an 'ear' added just above the attachment point as well.

As Williams maintained the high mounted wishbones like on the Mercedes, it has also moved the pivot point for the pushrod inboard, presumably to help control ride height when cornering. It's a move that Ferrari have also made with their SF1000.

Further back, the car features a similar oval airbox but has a slimmed-down engine cover. The sidepod inlets have also been slimmed down as it appears the 2019 car was a bit over-cooled. The wings above the inlets have been redesigned and made thinner. The mirror wing mountings have stayed nearly identical, of which similar designs are being picked up by other teams now as well.

Only from the side view, one can see how Williams have focused on the downwash of airflow over the sidepods. The outer parts that house the radiators are very thinly shaped, allowing for optimal flow outside, while the hot air inside will flow through the bulkier central part of the sidepod, towards the rear air outlets. This too is a thorough development of a philosophy that was already appearing on the FW42.

Finally, a mention of the changes rear suspension. This has been redesigned to improve grip by extending the upright so that the connection with the upper wishbones is now further inboard that it was on the FW42.

Still, it's unclear now if it will be enough, but it seems certain that the team can look forward to a more positive 2020.