Tech analysis: Red Bull Racing RB2

While most teams were wrapping up their 2005 testing at Jerez, Red Bull Racing surprised everyone by running their new car in the last few days before Christmas.

As the first full 2006 car to run, the RB2 picked up on most of the key design changes adopted by most teams. The curved sidepods and chimney cooling arrangement, supplemented by a "V" keel, suggested the team were losing their conservative design focus from the jaguar days and being more adventurous.

Installed in the back of the car was the new Ferrari V8, which - along with the revised chassis and aerodynamics - suggested Red Bull were on the rise.

Jaguar Racing never quite threatened to lead the midfield pack of team, and Red Bull's acquisition of the team in late 2004 did not, at first, suggest the team's position would improve. Moreover, the RB1 did not promise much, as the car appeared to be a lightly updated Jaguar R5.

However, Red Bull signalled their intentions first by signing David Coulthard, then by recruiting ex-Renault designer Mark Smith, who had been with Jordan briefly before joining RBR last year.

Smith was one of the pair of designers that alternated on the Renault chassis programme, and his influence is clear on the new RB2 car. The tight sidepods, "V" keel and strut-reinforced engine installation are clear developments from recent Renault thinking.

Another indication of Red Bull's commitment was their decision to purchase the more costly Ferrari V8 engine for 2006.

In late 2005, the team commissioned their second wind tunnel, a critical element in developing the car's aerodynamics. Most teams are now finding that one tunnel running to capacity creates a bottleneck in their development cycle, and the second tunnel is also needed to expand the team's design and production facilities.

The last and to most people perhaps the most critical use of Red Bull's considerable money was the signing of Adrian Newey from McLaren - still considered the best designer in F1, despite several years of problematic cars from McLaren.

Newey's influence on the Red Bull car will not be felt for many months; no doubt, he has already made changes to staff structures and processes internally. But this won't lead to any changes on the car until mid season, and even then it will only be the 2007 and 2008 cars that are truly Newey designs.

Overheating

The RB2 has had to have larger chimneys fitted and holes placed in the bodywork to maintain cooling © XPB/LAT (click image to enlarge)

The car's looks belie an inherent problem between the car and its engine. Even the car's roll-out at a typically freezing Silverstone winter test produced overheating problems. The Christmas break allowed the team some time to work on these problems, but January testing saw the car still blighted by cooling issues.

A car's cooling system starts with the engine supplier specifying the unit's heat rejection requirements. From here the team can work with radiator sizes and then cooling ducts inlet and outlet area.

This is a fairly simple mathematical exercise and this year's cooling requirements for the V8 engines are only slightly down compared to the V10s. Equally, last year's Cosworth engine may not have been as powerful as the Ferrari, but the difference was again very small, so neither target has changed very much.

The radiator layout for the RB1 was very similar to the Jaguar that preceded it; both had developments of essentially the same Cosworth engine. Jaguar/Red Bull used flat vertical radiators placed very close to parallel to the car's centre line.

They did not use the usual single pass cooling matrix as used by other teams, but a double pass set-up that has the cooling pass over the front and then back of the radiator's face. This set-up is efficient and has plumbing that is easier to package.

This year, Red Bull have made two changes: firstly, the volume of the sidepod has been reduced. This places more emphasis on the chimney and less on flow reaching the rear of the sidepods.

The second change is the re-layout required to the radiators themselves to fit within the new sidepods. The radiator sits in a similar position to last year's, but now the cooler is folded slightly, with the lower section of the cooler folding inwards towards the centre. This isn't as exaggerated at the Ferrari/Sauber set-ups used last year, but Red Bull have been the only team to fold their coolers this year.

Holes made in the RB2 bodywork to maintain cooling © XPB/LAT (click image to enlarge)

In testing the car's overheating has forced the team to open up the bodywork, initially cutting large holes in the sidepods, ruining the car's aerodynamics. Later on, the solution was to use the largest possible chimney, similar to the ones run in the hottest races last year.

While this is cleaner aerodynamically, the larger duct still costs aerodynamic efficiency and with the opening races being at such hot venues, the team's potential to open up more cooling is severely compromised.

A final resolution will be to rework the whole sidepod engine cover to provide a more efficient outlet set-up, which doesn't cost too much in aerodynamic terms. This revised bodywork may not be radically different to the shape of the current set-up, but it will subtly offer air exits in more places than just the chimney.

How Red Bull ended up in this position is puzzling. Ferrari, for their part, have had plenty of experience in supplying customer engines, while Red Bull's aero department consists of highly skilled and experienced designers. Furthermore, both Red Bull and Ferrari have admitted the problem does not stem from the engine or the cooling figures Ferrari provided to Red Bull. So how did it all go wrong?

As the solutions so far seem to be pointing at cooling outlet area and not the radiators themselves, then the aerodynamics of the set-up are likely to be the culprit.

The RB2

With such a striking colour scheme and some very visible design features, the RB2 does not at first sight appear to be a great stride from the RB1, which in itself was a development of the Jaguar R5.

Mark Smith's Renault influence is apparent on the 'V' Keel © XPB/LAT (click image to enlarge)

But with the problems the team have had, restricting running and forcing the team to focus on the cooling issues, it is not surprising the rest of the aero package has not evolved too greatly since its launch. In its first tests, the car appeared to be using clear development of the 2005 wings, bargeboards and floor - although there are, no doubt, new aero parts currently being developed for Bahrain.

Around the nose, the wing and the nosecone are very similar to the RB1, and only where the monocoque begins do the differences become apparent.

Adopting Renault's innovative "V" keel, Red Bull have created their own interpretation of the set-up, and the sides of the "V" are much longer and have swept back edges. This creates more of a duct within the "V", and flow passing through this duct could be put to use to speed up flow under the raised chassis.

Despite the "V" keel, the front suspension arms are reminiscent of the deeply faired previous versions, aided no doubt by a different geometry to maximise tyre usage, now that tyre changes are allowed again. Back from the nose, the complex bargeboards are carried over in concept but front all new sidepods and front floor.

The extreme rounded section of the sidepod fronts is a little misleading. While McLaren and BMW-Sauber make the undercut part of a continuous line running from the shadow plate, which is the logical progression for undercut sidepods, Red Bull instead have a distinct change from chassis to sidepod front.

Rounded sidepods are not as extreme as McLaren's or BMW-Sauber's © XPB/LAT (click image to enlarge)

Allied to this, the front edge of the floor is very thick, although this leads back to a very wide flat floor passing under the undercuts to the coke bottle shaped area. This thickness might be an aerodynamic solution or may simply be to package the side impact spars.

As with all 2006 cars, the sidepods sweep inward and downward towards the exhaust system. On the Red Bull, the actual black carbon fibre heat shields around the exhausts is permanently attached to the engine area, hence when the sidepods are removed a large amount of bodywork is still wrapped around the engine.

With all the heat shields, it is just about possible to detect that Red Bull are running the engine semi stressed, and there is additional bracing to make the engine installation as stiff as possible.

Another Renault influence on the car's design is a carbon fibre strut linking the back of the monocoque with the gearbox. This is something Renault have employed for several years to improve the beam stiffness of the car. Why Red Bull may have chosen to do this may have something to do with the Ferrari engine installation and their wheelbase.

All teams have chosen to keep similar wheelbases despite the shorter V8 engines. However, Ferrari - running on Bridgestone tyres - have opted for a longer chassis and hence a shorter gearbox. This keeps the weight distribution rearwards biased. Red Bull are running on Michelin tyres and need a more forwards weight bias. This has lead them to extend the gearbox to shift weight forwards.

As the Ferrari engine is designed for the smaller lever effect of the shorter gearbox, the Red Bull casing is some 5-10cm longer and exerts a greater strain on the engine. Therefore, some reinforcement may be necessary.

Tighter sidepods use clever exhaust heat shielding © XPB/LAT (click image to enlarge)

Otherwise, the engine installation is tidy with quite a tall airbox, similar in shape to the Ferrari F2004 test car, emphasising Ferrari's technical input to the engine's installation.

The rear of the car is a clear progression from the RB1 - the torsion bar/damper layout over the gearbox, the aerodynamics comprising the suspension fairings, the floor and rear wing are all very similar, albeit very easily changed.

As yet, a strut mounted rear wing hasn't been adopted, while the rear impact structure has been revised in light of the stiffer impact tests for 2006.