Fernando Alonso excited as new McLaren car unveiled for F1 2018

Former champions McLaren showed their true colours on Friday with a new papaya orange and blue Formula One car they hope will take them back up the starting grid after three nightmare years with Honda.

Renault power under the new McLaren colours

The MCL33 is the team's first to be powered by Renault, the manufacturer whose engines took Red Bull to three race wins last season.

The striking livery, on a car with plenty of space for sponsors after the departure of some big names in recent years, revives the colour first used half a century ago by team founder Bruce McLaren.

"Looking at our new car, I feel incredibly excited -- but also apprehensive," said double world champion Fernando Alonso, who partners Belgian Stoffel Vandoorne in the lineup, in a statement.

"I know just how important this car is to the team, and I just hope that it delivers in the way we all want it to."

McLaren domination a distant memory

McLaren, dominant in the late 1980s and early 1990s with Ayrton Senna and Alain Prost, have not won a race since 2012.

Their last title was with Lewis Hamilton, who has won three world titles since at Mercedes, in 2008 and the past three years have seen them plunge down the pecking order to ninth of the 10 teams competing in 2017.

The Honda engine's lack of power and reliability led to McLaren announcing the split last September, a decision with some design implications.

"Making the switch had a big impact on the installation of the engine," said technical head Tim Goss.

"The advantage of the Renault layout means that we can push the engine forwards, but then you have the compressor at the back of the engine, so you've got to get the outlet pipes forward without impacting the packaging.

"We had to redesign the back of the chassis, the gearbox bell-housing area, the rear suspension, and the cooling layout. That was two weeks of intense effort to get right," he added.

Mercedes, Ferrari and Red Bull to be caught

McLaren face strong competition even in midfield while Mercedes have won the last four drivers' and constructors' championships, with Ferrari and Red Bull their closest competitors last year.

"We are humble about the challenge ahead, but feel we've prepared well, have a solid package that we can build upon and exploit as the season progresses, and have two excellent drivers who will make the difference in races," said racing director Eric Boullier.

The car was due to make its track debut at a filming day in Spain on Friday before testing starts in Barcelona on Monday. The first race is in Australia on March 25