Guide to the 2018 Formula One cars

The Formula One season gets underway in just under a month, with the Australian Grand Prix weekend starting on March 22 – which means it's that time of the year when the teams unveil their challengers.

Following on from last year's big regulation changes, the main difference to every chassis is the addition of the Halo head protection system – which has arguably made all the cars look less attractive.

But for F1 fans, this time of the year is always exciting as they get to see all the new models they'll be seeing on track this season during the 21 races.

The first pre-season test starts on February 26 at the Circuit de Catalunya in Barcelona, and here are the cars that will be there...

Alfa Romeo Sauber

Following another disappointing season for the Swiss outfit last year, Sauber has taken on a new title sponsor which marks the return of a legendary F1 name.

With Alfa Romeo coming in for 2018, Sauber continues its partnership with the Fiat Chrysler Group, which owns engine suppliers Ferrari, by providing the Italian brand as the main sponsor. With that comes what is arguably the best livery on the grid, with a truly stunning white, red and blue paint job.

The team has even added aerodynamic detailing to the halo to improve air flow over the top of the car, meaning that the additional bit of bodywork doesn't disrupt the aero too much. Swede Marcus Ericsson and Monegasque newcomer Charles LeClerc will take control of the Ferrari-powered machine for the 2018 season.

Aston Martin Red Bull Racing

Although the full 2018 car is yet to be revealed, Red Bull gave us the delight of showing the RB14 with a camouflage livery that looked truly brilliant. The special dark blue look will only be used once, but fans were fawning over it.

The team – now with the Aston Martin title sponsor – will return to the standard dark blue, red and yellow livery for the 2018 season, and to the naked eye few changes have been made apart from the reduction of the shark fin engine cover concept – which has been clamped down upon by the FIA.

Daniel Ricciardo and Max Verstappen will be hoping to bring the Austrian team back to the front of the grid – as the team hasn't properly challenged for the world title since 2013 – and with a design ethos that has always meant that the cars are always great aerodynamically, the hope is that the TAG Heuer-badged Renault powertrain will offer the grunt to compare with the Mercedes-powered teams – especially the Mercedes-AMG works team.

Haas F1

As the first car to be revealed this year, the Haas VF-18 gave us the first glimpse of how F1 cars would cope with the addition of the halo. It didn't fill many fans with hope, but the car overall is a solid effort by the American team.

Incorporating the red, white, grey and black colours found on the first two Haas F1 chassis, the new version will again be powered by a Ferrari unit and run with the Italian manufacturer's technology. Logically then, team boss Gene Haas has set sights on the Scuderia – but the aerodynamic department has a lot of work to do to catch up with Ferrari's package.

As with last year, Dane Kevin Magnussen and Frenchman Romain Grosjean will be at the wheel, with both looking to move Haas forward from the back of the midfield, where it has spent its first two seasons.

McLaren F1

The McLaren name is synonymous with success, but can you believe the Woking outfit hasn't won a grand prix since 2012? Following a rocky relationship with Honda, the MCL33 now has a Renault power unit in the back – which is more reliable than the Japanese setup to say the least.

The most striking thing about this year's car is the Papaya orange livery, which made a return last season, but is now back in full force. Using the Indianapolis 500 car that Fernando Alonso drove in 2017 as a base design, the orange is flanked with some tasteful blue detailing that makes for a great-looking package.