McLaren have revealed the car they hope will return them to at least relative competitiveness.
The MCL33 has switched from Honda to a Renault engine and is predominantly orange, echoing McLaren's historic 1960s livery.
The car is a clear design evolution of last year's, which was regarded as one of the best chassis on the grid.
Executive director Zak Brown said success would be "racing and qualifying at the front, getting on the podium".
Star driver Fernando Alonso, who is dovetailing his Formula 1 commitments with a full season with Toyota in the World Endurance Championship, was first behind the wheel in testing on Friday.
"It felt great. It's always a special moment to drive the car for the first time. Everything felt good," said the two-time world champion after his first laps in the new car.
"Trying to fight for podiums and race victories, that will be our aim.
"The car certainly looks very neat and well thought out, and I think the new colour looks really great - really eye-catching."
The 36-year-old Spaniard will be partnered again this year by Stoffel Vandoorne of Belgium.
Racing director Eric Boullier said: "We never took the easy route or looked to shortcut a process or a solution - and the result is a car that is neat and well-resolved.
"That said, we are under no illusions that it will be difficult to splinter the hegemony at the front and that the midfield will be full of well-funded, experienced outfits with plenty to prove.
"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."
The Renault engine switch
McLaren have not won a race since the last grand prix of the 2012 season in Brazil and no McLaren driver has finished in the top three since the first race of 2014, when Kevin Magnussen was second in Australia.
The team made their decision to abandon Honda and switch to Renault relatively late - in September last year - but the design team say there were able to adapt the car within two weeks.
The two engines have different mechanical layouts and philosophies, but chief technical officer - aerodynamics Peter Prodromou said the change "didn't really change our [car design] concept very much".
The front of the launch car is reminiscent of last year's with a series of intricate louvres and slots in the front wing and associated parts. The side pods have high air intakes and a deep undercut to enhance airflow to the rear, and the back of the car is narrowly waisted, in a fashion similar to that seen so far in other cars from leading teams.
It is noticeably light on sponsorship names, indicating McLaren's relative lack of budget compared to the top teams Mercedes, Ferrari and Red Bull.
But Prodromou said he "didn't see why" McLaren could not compete with the leading teams despite their restricted resources.
Renault lagged behind engine power leaders Mercedes and Ferrari last season but Goss said: "They have developed the engine, they've improved it, it will be more powerful."
Prodromou and chief engineering officer Matt Morris said McLaren were "excited" about being compared directly with a competitor with the same engine for the first time since 2014.
"It has been difficult for us the past three years not having someone to measure yourself up against," said Prodromou, who rejoined McLaren from Red Bull in 2014.
"It is a very positive thing that we have two first-class teams to measure ourselves against and that is a very strong motivating factor for everyone in the workforce."