Under the skin of the McLaren MP4-28

Amid recollections of McLaren's 50-year heritage, the new MP4-28 unveiled on Thursday owes very little to the past and was largely an all-new car.

Despite team boss Martin Whitmarsh's talk of evolution and the outwardly similar appearance to the 2012 car - at least to the casual spectator - the MP4-28 sports many new solutions based on ideas from McLaren's rivals and has had a huge amount of time and attention spent on its details.

The car is almost all new from tip to tail, with a new nose, monocoque, front suspension and rear suspension.

As is always the case, the car we saw up close at Thursday's launch at the McLaren Technology Centre is far from definitive and its details will change before testing next week. But the general layout will remain.

The sweeping shape of the nose is possible due to the vanity panel (yellow)

Visually the biggest change is the nose. Last year McLaren chose to keep the front of the monocoque lower to achieve a lower centre of gravity and better suspension geometry. This came at the expense of a better airflow under the car, with the resulting nose on the 2012 car low and arced smoothly back towards the cockpit.

This year's MP4-28 appears at a glance to follow the same path, but in fact the front of the chassis is some 75mm higher. The smooth nose is possible as the rules now allow a 'vanity panel' on top of what would otherwise have been a less attractive stepped nose.

Although not outwardly visible, the vanity panel is a thin carbon fibre skin, bonded on top of the structural nose cone. It smoothes the airflow over the top of the car and in a crash the light carbon construction will simply disintegrate, leaving the lower structural nose to form the crushable safety structure.

It's this lower structure that the 2012 rules set out to create, as the lower nose is less likely to ride over the cockpit of another car in a T-bone crash. However, teams wanting to maximise airflow under the raised section of chassis were forced into the ugly stepped noses. This fairing makes the area more aesthetically pleasing.

The front of the chassis is now higher than in 2012 (grey) with the vanity panel (yellow) hiding the step

McLaren has had to work hard to offset the higher centre of gravity and the changes in suspension geometry from the raised chassis. The centre of gravity height has been recovered by losing weight elsewhere in the car and placing it low down in the form of ballast. The main rollhoop structure alone has shed 5kg.

In redesigning the front suspension to suit the higher chassis, McLaren has revived an idea taken to Ferrari by ex-Woking man Pat Fry: pullrod front suspension.

On the MP4-28 the wishbones mount very high up on the chassis, the top wishbones being nearly at the very top corner of the monocoque. These more extremely angled wishbones now allow the correct geometry to make a pullrod suspension set-up work.

To suit the new chassis, the front suspension is all new with a pullrod set-up

From the outer end of the top wishbone, the pullrod passes almost horizontally to the bottom corner of the tub to operate the spring and dampers inside the nose. With this geometry the pullrod operates the suspension with almost the same efficiency as a pushrod.

So the real gains are a slightly lower centre of gravity, as the springs and dampers are mounted much lower in the car, and a major aerodynamic boost. The horizontal pullrod sits in perfect alignment with the airflow coming off the front wing, sending a better airflow to the rear of the of the car.

Also aiding airflow to the back of the car are revised sidepod fronts. These have been pulled backwards, to expose a small peak above the reshaped sidepod inlets. Moving the sidepod front backwards creates a smoother path for the airflow to pass around the car. These resulting peaks are needed to house the side impact protection structures, although they do also have a removable panel to aid with extracting hot air from the sidepods.

Last year McLaren had horizontal vanes over this area of the sidepod to direct airflow over the exhaust. These aren't fitted to the MP4-28 as yet, but no doubt will reappear in testing. One other feature to aid airflow in this area is a new wing mirror design with L-shaped mounts to point the air coming up over the nose towards the sidepods.

At the rear of the sidepods, the shape is now particularly undercut and slim, with the same semi-coanda exhaust outlets as McLaren pioneered last year. A lot of the bodywork at the back of the sidepods and floor were only for the launch, so there is clearly a lot more development to go on with the exhaust and sidepod shapes.

The rear suspension is new, with the upper rear wishbone having a range of aerodynamic profiles from rounded to teardrop shapes. But it is the lower wishbone that is special - as with Red Bull last year, the wishbone is oversized to perform several functions.

The lower wishbone is oversized to hide the driveshaft and trackrod

The rear leg is formed by a very large teardrop profile; this section houses the driveshaft and the rear trackrod. Having them all inside the wishbone creates less disturbance to the airflow passing over the back of the car.

As is normal for launch cars the front and rear wings are all revised versions of the previous year's wings. The front turning vanes and rear brake ducts were all either missing or grossly simplified. Again we can expect to see these rapidly changed for new designs as testing starts.

Under the skin McLaren has reworked the detailed engineering, while the power train from Mercedes AMG has also been in for revision. Mercedes AMG provides the engine and KERS, developed with McLaren's input. For 2013 the KERS set-up has been redesigned, although the combined battery and power electronics are still in a single module mounted under the fuel tank.

McLaren therefore has a new car, but with enough of an evolutionary element to also bring familiarity. This should allow the team to get on the pace straightaway, as it did last year, although learning the new tyres could again be a stumbling block for the team.

One issue that plagued McLaren last year has been resolved: reliability. The issues behind the gearbox failures have been understood and procedures have been tightened up to ensure the problems do not reoccur.