Australian GP technical round-up

No one has brought major developments to Melbourne, but still the endless grind of new parts starts from the very first race. Teams' shipping crates would have been packed with both well-tested parts and development items, with a few of the latter sneaked into personnel's hand luggage too.

Melbourne's sweeping layout is punctuated with short, fast corners, so it is a track that makes big demands on engine power, brakes and front end grip. Allied to the track evolution, this means that Albert Park isn't necessarily a good barometer for season long performance. It's merely the first test, in what has now been confirmed as a 19 race season.

Aero tests

Teams continually need to assess new aero parts, so the first practice sessions included some special aero tests. As the track is not giving great grip in these early laps, session time can be allied for data gathering, rather than the usual Friday schedule of qualifying and race preparations.

Caterham working on aero tests © XPB

So again the aero rakes were brought out and flow-viz paint applied to the new parts' surfaces to assess how the airflow is travelling over the bodywork.

Often on the pit radio we heard drivers requested to complete a fixed speed run, a common aero testing practice. The driver will drive down the straight at a specific, fixed RPM. Thus the car will have a predetermined top speed, and the data gathered during the run at a stable speed will be easier to compare to simulation data.

Red Bull

Even if its pace on the first day was not a surprise, this year Red Bull's apparent lack of exciting innovations is.

Through the last days of testing no major updates were tried, there were small revisions to the sidepods and a new front wing endplate, but only the former made it to Australia.

So the RB9 remains largely in its launch guise, but somehow has gained enough speed over the winter to keep it ahead of the pack. Indeed the car runs a tiny rear wing, so it must be producing plenty of downforce from the back of the car.

Red Bull's rake is a key advantage © XPB

One trick Red Bull has is the amount of rake the car can run. Rake is the angle of the car relative to the track, low at the front and high at the rear. Red Bull has the rear of the car more than 10cm off the ground. The huge gap created between track and diffuser is sealed by the exhausts. This high rear end effectively makes the 12.5cm tall diffuser nearly twice as tall. As the diffuser makes over half the rear downforce for very little drag, this is a very efficient way of setting the car up.

Other teams follow this route, but don't seem to have the same rake angles and levels of grip that the RB9 achieves. No doubt the car is quick out of the box, but other teams look to have potential as yet untapped.

Ferrari

Testing and Melbourne practice suggest Ferrari has made a big step since last year. The F138 uses the late-testing sidepods, with the more drooped Coanda outlet, although the upper bodywork differs between the two cars.

Ferrari's two cars have different cooling set-ups © XPB

The cooling outlet at the tail of the engine cover is different; Felipe Massa appears to have more cooling outlet area, whereas Fernando Alonso has a sleeker, more enclosed end to the bodywork. Cooling obviously helps reliability, but also affects area, with the drag created slowing the car's ultimate top speed. We saw last year the drivers split on cooling strategy, although there's no reason to think Massa's car runs hotter.

One detail on the Ferrari appears to have been dropped for this race; the slot under the nose cone is closed off. The slot is disguised as a driver cooling inlet, but this is simply due to the rule that allows a hole in the nose cone. For Ferrari the slot is primarily an aero aid, to clean up the airflow under the nose. Any cooling effect is secondary.

McLaren

It was clear in testing from driver comments that the MP4-28 is a car not yet fully understood and finding a set-up quickly is tricky.

Driver comments ranged from a lack of grip at the front or the back, to harsh ride over bumps and kerbs. As Melbourne demands positive turn-in to the corners and traction out of them, McLaren's woes are being amplified.

McLaren's Australian specification uses the newer front wing with the flatter frontal profile, a very large rear wing and the early 2012 turning vanes mounted to the nose cone.

McLaren has made changes to make its car more accessible for enginers © XPB

Underneath the front of the chassis is an access hatch. This is used by the mechanics to get to adjust the springs and dampers of the front suspension. The newer turning vanes mounted around this hatch and having them in place hindered access. Thus having the older vanes mounted to the nose which is removed during set-up changes makes the mechanics' lives easier and speeds up changes.

Mercedes

Revitalised for 2013, Mercedes had a bumpy start to testing with a gearbox failure for Nico Rosberg and a mechanical failure sending Lewis Hamilton off. Although testing then continued as a beacon of reliability, first practice had an eerie echo of the early days with Rosberg again stopped by gearbox problems and the Hamilton sent off the track by a loose splitter.

Technical maladies notwithstanding, the W04's pace seen in testing seems to be real. Visually the new car appears little changed from the 2012 car, so it seems the car has simply matured. A new front wing concept, Coanda exhausts and revised suspension appeared to have been targets for development.

To fully understand the effect of the exhaust flow, Mercedes has permanently fitted these three sensors in the floor to measure air pressure in the critical area ahead of the diffuser. This is where the exhaust flow passes and the better this area is understood, the better Mercedes can tailor the exhaust to create more downforce.

Mercedes has a passive version of active suspension © XPB

Already this year, one area much talked about is the Mercedes interconnected suspension. Termed FRIC by the German press (presumably for Front Rear Inter Connected) the system is in fact far more complex than that.

Equally the system is not as new as has been reported. In fact in 2011 Mercedes had already raced its car with suspension using complex hydraulic interconnections. A paddock source confirmed the car has this fully interconnected system fitted in Melbourne this weekend.

Renault had used a simple hydraulic link between its front and rear suspension since at least 2008. The engineer responsible was ex-bike racer/designer Dr Rob Tuluie, who had linked the front and rear suspension with a passive hydraulic link to reduce dive under braking.

Such systems had been used in the pre-active suspension era two decades ago, but were reinvented for the high-rake low-fronted set-up that makes the current cars work so well. Tuluie moved to Mercedes and has developed the system to replace conventional springs and dampers, to link not just the suspension front-to-rear, but also left-to-right to control roll as well as pitch (dive).

Effectively it replicates active suspension, although as an entirely passive system. A system of pipes alters the way fluid moves forwards-backwards and sideways as the car negotiates the track. It's possible to tune for each different change in attitude, but in doing so it's easy to get lost in set-up. It's likely that Mercedes has lost a lot of performance while perfecting this system over the past two years.

Aldo Costa has been hailed as the person to have helped Tuluie refine the system in the latter part of 2012. With the FRIC suspension fully optimised, the car can run the suspension soft for slow corner grip and a stiffer for fast corners, allied to being able to run more rake, with the front of the car lower for better front wing performance and a higher rear ride height.

If Mercedes has found a way to reliably tune this system other teams will need to re-engineer their simple front-to-rear interconnected systems.

Williams

Tough times for Williams so far © XPB

Having only brought its new car to the second test and introduced the new Red Bull-style Coanda sidepod in the last two days of testing, Williams arrived at Albert Park with two very different specifications to assess. Each driver had a car fitted with different sidepods and slightly different front wing specification for the morning session.

It was decided that the simpler launch specification sidepod should be used for the balance of the weekend. This set-up is more akin to McLaren's semi-Coanda design and not the ramp/tunnel design introduced at the last test.

Lotus

Having had reliability problems cost crucial testing time, the car arrived in Australia with some of the parts seen only briefly in testing. The E21 was fitted with the vaned bargeboards, complex front wing and extra slip angle sensors for Friday practice.

Since the aero rules were tightened up in 2009, the bargeboards mounted ahead of the sidepods have been a relatively stagnant area for development. Lotus has found a new solution by splitting the board into several smaller vanes.

Lotus is playing with its bargeboards © LAT

Bargeboards help manage the complex airflow under the raised chassis in passing around the car. Flows over the top edge of the bargeboards pass into the sidepods' undercut, while the flow passing under the board is critical in setting up the airflow going under the floor to the diffuser.

Many teams have stepped upper edges to the boards. Each step sets off a small vortex to aid flow downstream, whereas a smooth top edge sends a single stronger vortex around the sidepods. It's the same concept with the flat plate along the bottom of the board, which will alter the pressure distribution under the floor to improve diffuser performance.

By splitting the board into these separate vanes, Lotus can probably bend the bargeboard into a more extreme curve, without the airflow breaking up behind it. Then each of the vanes will set off a vortex to alter the airflow further back or under the car. All these effects are a way to get the correct airflow to the diffuser for more downforce.