Red Bull make startling claim over RB21 pace leap

Red Bull technical director Pierre Waché has revealed by how much the Milton Keynes squad has improved its car over the F1 winter break.

The six-time constructors' champions were knocked off their perch last season as the team struggled to develop its troublesome RB20.

Whilst Max Verstappen was able to hold onto his drivers' crown, the woeful form of Sergio Perez proved costly. The 35-year-old's lack of performance and a dreadful run of results led to Red Bull finishing third in the standings, behind McLaren and Ferrari.

The situation began to improve towards the end of the season once the team got a better handle on the pitfalls of its car, but nonetheless still needed to take a sizeable performance step for the season ahead - which it has done, according to Waché.

"Last year we did a patch, I would say," the 50-year-old explained to PlanetF1. 

He also revealed the early-season spec RB21 is "roughly" around three to four-tenths seconds a lap faster than the final iteration of the RB20, from the year-ending Abu Dhabi Grand Prix.

"A patch to reduce the potential a bit, make it a little bit wider, but it was a small patch. Now we did the full concept of the car in this direction."

Red Bull's wind tunnel correlation issues

Despite that, pre-season testing in Bahrain was still an underwhelming affair for Red Bull. Reliability issues hampered its running and it left the gulf nation with a sense of uncertainty as to where it stacks up in the current F1 pecking order - and some of the issues from last year are yet to be completely addressed.

The problems it encountered, which was a disconnect between front and rear balance, stemmed from a lack of correlation in the team's wind tunnel.

In short, what it saw in development through its wind tunnel and simulated CFD data did not marry up with what its drivers then experienced on track.

This is not unusual for contemporary F1, where the balance between conventional aerodynamics and ground effects goes a significant way in determining a team's performance.

Red Bull is not the only one to have been on the receiving end of such difficulties, but to matters worse, its wind tunnel, which it has used since entering F1 in 2005, is now 70 years old. Christian Horner has referred to it in the past as a "Cold War relic" given its age.

The good news, though, is that the team has a new facility opening soon. However, the RB21 still had to be created in the old one.

Meanwhile, the likes of Ferrari and McLaren are both using new wind tunnels - and have not endured similar problems to Red Bull's current plight.

"I’m not confident," Waché said of the team being able to counteract those issues. "But, at some point, you have to use the tools you have and take all the information you can to make some decision.

The Frenchman added: "We still have, and I think everybody has… not correlation, but you need some extrapolation of what will happen in your tools to the track.

"It is a part of the engineering job we are doing. The confidence is, I don’t think it is 100 percent, but it is not a show stopper.

"You have to use what you know, what you control, and make sure that the extrapolation works as much as possible, and improve the way you operate in your tools."