Will Gray

Tech Talk: Can design put Red Bull in front?

It may have ended in disappointment for Sebastian Vettel on Sunday but his upgraded Red Bull car showed impressive pace in Valencia — and it demonstrated the design determination that is key to their success.

Since the start of the season, Red Bull has been focused on finding a solution to a complex airflow conundrum at the rear of the car after their initial design failed to perform as expected.

As the team that had developed the most advanced blown diffuser concept they had the most to lose when it was banned this year, but they lost out more than expected at the start of term when other teams produced more simple but more functional designs in that area.

Last weekend, however, may just have seen a crucial turnaround.

Red Bull has always been on the case in terms of car development but the modified car represents an astonishing amount of work put in at the Milton Keynes base since the start of the season.

The developments were so significant it could easily be described as a 'b-car' — with a new front wing, new rear wing endplates, new floor, revised suspension, new brake ducts and new sidepods that included two new aerodynamic front turning vanes.

The suspension modifications could be one of the most important changes from a performance perspective, giving the engineers a new range of set-up options as well as a new dynamic movement. That should give more flexibility in the crucial balancing of front/rear tyre degradation.

But it is the exhaust exit design that really shows the level of determination and professionalism in Red Bull's design philosophy.

Red Bull has been trying so hard to make a 'best of both worlds' solution for the complex flow regimes in and around the diffuser area at the rear of the car that this is their fourth different design development since pre-season testing.

So far McLaren has perhaps the best approach. Their design steers the high energy exhaust flow out through an angled side duct that points it towards the outer edge of the diffuser while also allowing the smooth flow from the front of the sidepods to travel around the undercut sidepods to the centre of the diffuser undisturbed. Both of these flows result in improved rear downforce.

The only problem is that the location of the exhaust exit is quite far forward on the sidepod and therefore risks a loss of flow strength and direction as the air travels unguided towards the diffuser.

Red Bull prefers to exit the exhaust on the top centre of the sidepod and use longer bodywork to feed the flow more directly into the diffuser area (which is now also helped by the turning vanes on the leading edge of the sidepod that steer flow over the top).

In theory, this gives improved downforce performance over the McLaren solution but so far it has also come at a price - the bodywork blocked the undercut sidepod flow and Red Bull lost out in that area.

Red Bull's initial solution to overcome this was a regulation-limited 50mm high tunnel that aimed to keep the two flow regimes separate and feed the undercut sidepod flow beneath the exhaust flow — but it did not work because the flow refused to go into the tunnel.

Red Bull technical director Adrian Newey, however, clearly believed the concept could still be made to work and that when it did it would offer significant benefits over their rivals' approach.

His team persisted with the design and, using aerodynamic modelling and flow visualisation on CFD, concluded they could make the design work by widening the tunnel's opening and, according to reports, splitting the flow to steer it in two directions — one into the starter hole and the other to the top centre of the diffuser.

If the performance in Valencia is anything to go by, then it seems they have now made it work - and perhaps Newey and his team's determination will pay off in the end...