Red Bull unveiled its new RB6 last week – the car it hopes will allow it to make the final step and claim a maiden world championship in 2010.
The team finished 2009 with the fastest car on the grid, so there's been no need to get so radical with this season's design. Essentially, the RB6 is an evolution of the RB5 and visually there is very little difference between the two cars.
Red Bull is very much in control of its development, so this car is about tidying everything up aerodynamically and getting it all to work that little bit better: more sculpting on the coke-bottle sidepods, tapered gurney flaps behind the turning vain in front of the sidepods, development of the front wing endplates to allow for the changes in tyre dimensions – these are the sorts of details that make the car work successfully.
Adrian Newey is probably the best aerodynamicist out there and the changes in regulations since the end of 2008 have allowed him to exploit this strength. There's nothing like a clean sheet of paper for somebody who thinks outside the box.
To that end, everything on the Red Bull is about attention to detail and maximising the quality of the airflow across the car, from the moment it first interacts with the front wing to the moment it leaves via the rear, getting the air to stick to the car and at each stage produce a kilo of downforce here and a kilo of downforce there. The Red Bull takes advantage of lots of small things, which allows you to spread your development risk rather than putting all your eggs in one basket, like McLaren has done with its large double diffuser.
Newey leads the way because he still uses a drawing board. It sounds simple, but it allows him to understand what will happen with each component on the car – he won't rely on an excel sheet telling him the aerodynamic numbers. From this mindset, he knows if he draws a line, what effect that line will have on the aerodynamic performance of the car.
He will also always trade peak downforce for consistency of downforce. This is about giving his drivers confidence that the car will stick every time rather than having to wonder whether the car will behave itself at the same corner on any given lap. If a driver knows he can trust the downforce it will give him a lift and improve the consistency of his performance over a grand prix weekend. That's what Newey does best with his cars.
The front wing
It all starts with the front wing. The rest of the car has to work with the turbulence coming off this component, so it determines the quality of the airflow across the whole car. The RB6 is the only car with a multi-piece front wing. The most popular arrangement is a two-piece, like that seen on the Mercedes and the Ferrari. Brawn moved from a three-piece to a two-piece in the middle of last season.
This will give you more downforce for a given angle, but really it's not about sitting in the wind tunnel and thinking about peaks of downforce. Peak downforce is so hard to access regularly to be almost irrelevant. The driver needs to drive the car at the bottom of the peak because that downforce is more accessible. The Red Bull looks for a lower peak and a higher average, which makes the overall performance of the wing and the car more consistent.
It's similar to chasing overall horsepower in an engine. You might be able to extract more bhp for a given amount of revs compared to your rivals, but torque is far friendlier to the driver.
Nose bulges
These are there to stop the air detaching from the top of the chassis and help give a better quality of airflow to the low pressure areas at the leading edge of the sidepods, which do their best to create lift.
You get a lot of lift from the top of the chassis and the sidepods and you want to minimise that. Also, the quality of airflow coming off the front of the car will dictate what the diffuser can do with it. The diffuser can't work its magic if the air is too turbulent.
The treatment underneath the front of the car is also U or V shaped. This creates a good shape that further assists airflow. Red Bull has spent a lot of time making sure its car gives the best quality of airflow it can to the downforce-producing devices.
Pullrod rear suspension
This system is all about Red Bull trying to optimise the complete car. It's a complex arrangement, but if executed properly it can bring significant benefits. There are lots of mechanical parts on top of the gearbox: dampers, rods, and springs for example, which a pullrod system allows you to site lower to the ground.
We're talking about four or five kilos of weight that you can lower by about 300mm, lowering the car's centre of gravity and improving handling. This system also brings aerodynamic benefits because you can reduce the prominence of parts jutting out from underneath the back of the engine cover. This improves the quality of the air flowing to the rear beam wing, which helps the rear wing work more efficiently.
The main disadvantage of this system is that it's difficult to package properly with a double diffuser, because the double deck diffuser is a larger component than a single one and takes up a lot of room. We now talk about double diffusers as something you have to have on a car, so most teams have focused on this area, producing the most powerful double diffuser they can. But they are difficult to make work properly because of problems with the airflow stalling as a car's speed alters and its ride height changes.
Diffuser
The single deck diffuser is a far more stable aerodynamic component and easier to tune at different ride heights. What Red Bull has done is maximise the amount of downforce its single diffuser can produce, meaning it has less of a deficit to make up to other teams with the double deck part. This means it is using a smaller double diffuser than its rivals, which gives the car the breathing space at the back to utilise the pullrod suspension system.
The other teams are not using the pullrod rear suspension because people see the double diffuser as the be all and end all. The McLaren approach for example, has been to make it bigger and better in the hope it will reap rewards. For Red Bull's rival teams it is too late to sanction a re-design of the rear suspension because of the gearbox package. The gearbox has such a long lead time that you have to decide on your package early, which means also deciding on your rear suspension arrangement early.
Force India
Force India is very much out of the same mould as Red Bull in terms of having a development of last year's car. Obviously, it has its engine, gearbox and electronics package from Mercedes, and the McLaren philosophy in terms of the double diffuser has allowed it to join that club too. It will be good for them if it functions properly, but if it creates air separation problems the rear wing will be affected and it could end up with a very inconsistent car.
Force India has a fairly complex two-piece front wing with lots of little tricks and flicks, and the radiator inlets on the sidepods are nice and neat. The tops of the sidepods are quite bulky, which won't help the air stay attached to them.
Normally, you try to align this area with the airflow, so perhaps there is something on the front of the car we're not seeing at the moment that allows this rudimentary design to work properly. The McLaren, for example, has removable panels there – there's nothing quite like taking surface away to reduce lift.
The backs of the sidepods are tidier than last year and the exhaust outlets don't drop off as dramatically, but there is less attention to detail at the front of the car. Red Bull has added surface to create a nicely sculpted interface between the chassis and the nose and improve its interaction with the airflow, whereas Force India's is just a very simple, square box surface, to minimum regulation size.
Last year Force India had a very good car at some tracks. Every circuit has an aerodynamic efficiency to drag ratio. If you beat that ratio you go quicker, if your car falls below that ratio you will struggle. Generally you will design a car to perform on the majority of tracks and ignore high-downforce extremes, like Hungary and Monaco, and low-downforce extremes, like Monza.
The Force India was always one of the fastest cars in a straight line last year and was good at Spa, which is a medium downforce track, but when it tried to add downforce it tended to get slower. This suggests it had a car that produced quite peaky, inconsistent downforce and the team will need to address this to do well in 2010.
Virgin Racing
Much has been made of Nick Wirth's digital approach to designing Virgin's VR-01. The team has produced about what you could expect from a Computational Fluid Dynamics-only design – it's a simple car, with straightforward lines and shapes. That's what CFD will lead to. There's nothing wrong with that, but it lacks the tweaks and flicks you find by using the wind tunnel before hitting the track.
CFD is very good for understanding the aerodynamic performance of a car, but it's a very rigid system that doesn't allow for experimentation. If you imagine a wind tunnel is like Lego – you can play with it and build whatever you like with the pieces.
CFD is more like a puzzle – it has to be a certain shape and only gives you one end result. If you want to use a kitchen analogy, imagine you have a recipe for a cake: CFD would mean re-writing the whole recipe if you want to alter it, the wind tunnel allows you to add ingredients as you go and taste the mixture.
The Virgin will be a nice, simple, efficient car through the air, but will need extra bits of detail to generate those extra bits of downforce that make all the difference. Everything on the car is quite basic and will need development. If you consider the Red Bull to have 100 per cent aerodynamic complexity, the Virgin is at about 40 per cent – it's got everything but nothing looks exciting.
Wheelbases
The need for the teams to fit much larger fuel tanks for this season means speculation over the differing wheelbases of the various cars has come up again and again during the first two tests. But it's difficult to know exactly which cars are the longest and shortest because it's been difficult to get hold of information.
You're talking about a short car being about 3.05m and a long one 3.2m, so the difference from longest to shortest is only about 150mm. McLaren and Ferrari probably have the longest cars and Virgin probably the shortest.
Red Bull moved its rear axle line backwards in the middle of last season to get more weight over the front wheels, and I would imagine the RB6 is a reasonable length car.
Longer wheelbase cars will generally perform better on high-speed circuits with longer corners, so expect the McLaren to find the going easier at Monza. Shorter wheelbases are more suitable for twisty circuits like Monaco, so the VR-01 will be better suited to this type of track than the McLaren. I would imagine Newey has designed a compromise for Red Bull that works at the majority of tracks, but a wheelbase at either end of such a narrow spectrum isn't the end of the world.
