Tech Analysis: McLaren MP4-23

If their season off the track in 2007 was tumultuous, the car was nearly flawless on the track.

McLaren bounced back from their dreadful, winless 2006 season with a car that was both on the pace and reliable. Only the inability to beat Ferrari through high-speed turns let the car down in a tightly-contested season.

Heading into 2008 with the spy case now behind them, the team have been able to make another big step with the car, which foregoes many typical McLaren characteristics. Autosport.com spoke to Engineering Director Paddy Lowe about the car and its development.

The 2007 MP4-22 was the end of a generation of McLarens dating back to 2002. It exhibited an attention to detail in its packaging and aerodynamics that lifted it above its peers. Under the skin, the engine and gearbox gremlins were put to rest.

With such a huge leap taken over the winter after the 2006 season, could the team make a similar step 12 months later?

"Its difficult to say," Lowe remarked. "In 2006 we didn't have the best of years, so its much easier when you've not had benchmark performance to look hard at where you've been going wrong and close that gap".

Equally, pinpointing the advantage to Ferrari has been difficult, as Lowe explained.

"It's been up and down through 2007 relative to Ferrari. They were quicker than us in Brazil, which was typical of the season, really. We broadly were in the right domain by the end of the year".

On the surface, the Ferrari F2007 appeared to be faster at tracks which had predominantly fast corners. Lowe admitted that this in part was true, but also argued that the situation was more complex than that.

"I think that can be over-simplified [that] there was definitely a trend," he said. "If we were honest, neither we nor Ferrari would fully understand that.

"It's difficult to isolate the track from the tyre choice. I think some of the tyre choices combined with the circuit would suit theirs or suit ours. That's something we worked very hard to try understand, and I wouldn't begin to say that we've fully understood it".

With the understanding they did have of the car's deficiencies, Lowe explained the team's aim for 2008.

"This winter's been more about consolidating," he said. "We don't want to throw away anything. We don't want to take too much risk from where we are, but we want to build on areas we are confident will give us definite performance".

Some details of the new car were publicised through the WMSC evidence from the spy case. Moving weight forwards has been an obvious intention; this has been an effect of the single tyre supply from 2007 - the weaker rear tyre construction led teams to take load off the rear tyre.

Most teams were able to move a lot of weight forward in 2007, but with the chance to alter the layout of their cars over the winter, McLaren have greater scope to package the car around a front-biased set-up.

According to Lowe, the extra length came from the gearbox. By adding a section between the gears and the differential, weight is moved forwards.

The aim of moving weight forwards might have been compromised by the ban on traction control, where more weight towards the rear tyre might help traction. But Lowe suggests this wasn't necessary.

"We and the other teams will have been studying in the pre-Christmas test," he said. "It's not something that we've found to make a dramatic difference".

On the point of the single ECU, Lowe doubted the significance of the ban on driver aids.

"I think the loss of these toys can be overplayed sometimes, but it will demand more skill from the driver," he said. "If you remember when we've gone in and out of traction control over the years, I don't remember it being visibly that different".

He also suggested that the notion of drivers sliding the cars is not going to be a treat for the fans.

"It does put more onus on the driver to be more careful with the throttle, but then they're good at what they do," he said. "The net effect is that the cars don't slide, as the driver does what the computer would have done - you don't want slide".

When the tender for the single ECU supply was announced as a joint venture between McLaren electronics and Microsoft, the presence of the McLaren name in the title did not initially concern the other teams or media.

But events during last season changed that perspective and McLaren are now believed by some to have gained an advantage in having been running the McLaren Electronics ECU for years. Lowe is quick to point out the difference between the racing team and McLaren Electronics.

"MES [McLaren Electronics Systems] is a separate company," he said. "They've been very strict at honouring the contractual requirements. There was a complete separation between them and us; there came point where we severed links in software development".

Thus, the software is not common between the 2007 McLaren ECU and the new control version.

"They own and develop that code and it's the same for everyone, everyone can see it," Lowe reiterated. "It's not a black box code, every team gets to see the code so they can see how it works. It's open source".

Having said that, Lowe was open to admit there's been some commonality in specific areas.

"We have had an advantage," he admitted. "To say otherwise would be dishonest. The advantage is mainly that we haven't had to change the electronics hardware - which is always a big project, to change your ECU.

"To change the harness concept is a big technical challenge, and it takes a lot of preparation and testing. We have been spared that. It is almost as though we have had carry over on electronics hardware".

Yet McLaren have still had to write the control strategies for the SECU and to meet the new rules banning automated chassis control systems, like traction, slide, launch control and stability programmes preventing rear wheel locking under braking.

This has been the major task in adopting the SECU. The outgoing ECUs allowed an amazing level of control, as Lowe explained.

"All sorts of things that used to be selectable to any input you like," he said.

"Circuit position was the big one. The biggest loss was to be able to tune the car to the metre around the circuit - things like the differential control, which you could tune all the way through the corner if you wanted, also the traction control and the slip on entry with the engine braking. Now you are left with one map, although you can pick different maps".

Thus, this year the driver will start each lap with one map for each allowable function. Each map can only be altered by the driver via the switches on the steering wheel - they cannot be pre-programmed.

This level of complexity makes setting up the car simpler due to the lack of option, but also more difficult as a compromise needs to be sought to make a set-up suit more corners.

"A lot of time was spent last year tuning the car," Lowe said. "In effect, you could dial out local problems. In a sense that's what set-up work is anyway. You've got less knobs to turn now".

The new McLaren

As with any new Formula One car, the first glance suggests little has changed. In many respects, the MP4-23 is no different.

But McLaren have built up a dictionary of design ideas and shapes, which have evolved over the years. This year's car eschews many of those concepts and as a result looks less like a McLaren, aside from the familiar colour scheme.

Starting at the nose, the trademark low nose has been dropped for a wedgier conventional nose. How McLaren choose to mount a bridge wing with the higher nose will be a challenge.

The forward pair of bargeboards are also new, no longer being formed as an L-shaped extension from the keel area of the monocoque. Instead, a smaller board hangs from a simple strut. This set-up makes for a much cleaner flow under the nose.

Likewise, the main bargeboards have been revised, with the extra vanes added to the trailing edges now moulded into a more homogeneous design.

This integrated philosophy continues with the pod wings, which are usually mounted to the top shoulder of the sidepod. This year's McLaren has split the wing, with the lower pod wing being integrated into the sidepod inlet, creating a neat set-up that confuses the eye.

Inside the pods the radiators continue to be sloped forwards and vent through chimneys joined to the upper pod wing. The rest of the sidepods are slight more waisted, and the exhausts slightly closer to the centre line of the car. But big gains in this area are limited by the packaging of the radiators and exhausts.

More significant is the way McLaren have slimmed the upper engine cover to improve flow to the rear wing. This starts with an innovative roll hoop. The snorkel that the hoop forms has been undercut to create along protruding snout - there is barely any structure forward of the rear bulkhead.

However the strength of the structure is now aided by two coved supports and two slimmer struts. The latter are used to act as the lifting eye should the car need to be lifted on a crane from a dangerous position.

With a smaller structure to cope wit the impact tests, I asked Lowe if the set-up was heavier.

"Its very similar actually," he said. "It's an aerodynamic benefit we've gone after there; its quite novel".

This streamlined roll hoop then leads back to a slimmer airbox cover. With a cleaner approach the rear wing is free to do more work, and the struts to support it are slightly revised from the versions raced late last year.

The rear wing itself and diffuser on the launch car were 2007 items, and are due to be replaced before Melbourne.

Not present on the launch car but seen in testing were new hubs and uprights to mount the static wheel fairings raced by Ferrari last year. Lowe explained their absence:

"At this stage we're just testing it. It's certainly something we working with, it comes with some penalties; you've got to be careful you end up with a net positive by the time you get involved with the mechanism to stop it turning and get the wheel nut on. It's a bit of a head-scratcher".

As has been noted the gearbox is longer for this year, but the case design and the gears within it are evolved from the 2007 set-up. The quick-shift gear cluster that has been raced since 2005 now needs to last four races. Lowe is wary of being over-confident that the task has been achieved.

"It requires a lot of focus to be confident that it will run for four races," he said. "We will have to see. I think its going to a challenge for everybody, and we're giving it out best effort".

But with the unit having been raced for so long and having been so reliable throughout 2007, I wondered where the issues would come from.

"As with all these things, you've got to push the envelope," Lowe said. "If it's working, then somebody wants to take some weight out of it and then it doesn't work until we sort it out".

Aiding McLaren's quest for reliability is their carbon gear case, which tends to be ore durable than the metal casing.

"A carbon case is a lot more expensive as a component, but you don't need to make so many," Lowe said. "They do last some time compared to the old magnesium ones, which eventually would crack quite after a short while".

One oddity of the McLaren gearbox is where the starter is attached. Every other team insert the starter into a continuation of the input shaft in the gearbox. This shaft connects through the clutch to the engine, thus when the starter spin the engine turns over.

But McLaren starter shaft is offset to the right. Was this a sign that the McLaren gearbox has a different layout of shafts internally? According to Lowe, the shaft layout is conventional, but the starter shaft is separate and drives the engine via spur gear.

"It saves you getting involved in going straight the middle through the diffuser."

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- The Autosport.com Team

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