The on-track development programme for McLaren’s MCL-HY Hypercar is in full swing, with the 2027 WEC-bound LMDh prototype completing its first full endurance test and beginning to turn early reliability running into a deeper understanding of its performance potential.
The big recent milestone came at Motorland Aragón, where the MCL-HY ran for more than 30 hours in a test designed to replicate the demands of an endurance race while stress-testing the car, its systems and the newly assembled McLaren Hypercar Team.
It is a significant step for a programme that only began on-track running in May with the car’s first shakedown at Varano. Since then, McLaren has taken the MCL-HY to Imola, Magny-Cours, Aragón and most recently, Silverstone.
The team isn’t ready to put a number on how much running it has completed to this point, with team boss James Barclay simply telling reporters: “We’ve got a lot of mileage.” Nevertheless, there is plenty to be positive about across the board as the car edges closer and closer to homologation.
The MCL-HY is not simply a new prototype being developed by an established race operation. The Hypercar project represents the creation of an entirely new team, combining personnel and experience from Formula 1, Formula E and sportscar racing.
The programme is now fully staffed, with just under 100 people working on it, meaning the recent test days and the endurance run were as much a test of the organisation as it was of the machine.
The test at Aragon was not a completely uninterrupted 30-hour run. McLaren made short stops to inspect the car and ensure that nothing was being damaged unnecessarily, but it did not need to abandon the test for extended periods before returning to the track.
“We did our 30-hour test as planned, which was great,” adds Barclay. “We did over 30 hours, so we went beyond.
“We were running it as if we were running a race. There are things we want to stop and check for because we don’t want to damage something inherently. We do a quick stop and a check and go again, but it was a 30-hour test.”
That was precisely the point of undertaking the test so early in the development cycle. The MCL-HY uses a known Dallara LMDh spine, but much of what surrounds that platform is unique to McLaren, including its aerodynamic package and its purpose-built 2.9-litre twin-turbocharged ATM V6 engine.
“Systems-wise, does everything work as it should do? It’s everything from refuelling… it’s the team operation side of things. It’s the powertrain, absolutely the ICE side,” Barclay notes. “You can do dyno, but doing dyno is one thing. But when you’re riding over kerbs for a race distance, does everything hold together the way it should do?”
The early endurance running also allowed McLaren to start establishing the life expectancy of individual components. Some parts are being pushed towards their limits to see where the margins actually lie, while longer-lead components have been validated early enough to allow time for redesigns if necessary.
“We’re in that kind of fail-fast phase as well to see where we are with certain life and mileage on parts,” Barclay says. “There’s only so much we can do on a dyno. We have to kind of pound round and see where we are on some of those bits and pieces in the car.”
The result of Aragón was therefore encouraging without being treated as a declaration that the MCL-HY is finished.
“We weren’t confident. We weren’t unconfident,” Barclay admits of the team’s expectations before the test. “You know, we had good tests, but we couldn’t… we didn’t really know. What we don’t know, we don’t know. The whole point of doing it early is to understand where we are.”
That uncertainty is one of the reasons McLaren wanted to conduct a long-distance test early. The fact that the car made it beyond 24 hours and past the 30-hour mark has provided an important first indication of inherent reliability.
Though Barclay, without going into detail, admits that there were minor issues related to “maturity” in some areas from “the usual things that you’d expect, the things we’ve designed that are bespoke to us.
“We’re making small tweaks and changes to certain fixings, mountings, brackets,” he adds. “And you might see some cooling elements on the car change.”
The tests have also served another purpose: bringing the people behind the programme together.
The Aragón driver line-up featured factory drivers Mikkel Jensen and Laurens Vanthoor, plus Ben Hanley, Grégoire Saucy and Richard Verschoor, while Jensen, Vanthoor and Hanley subsequently handled the Silverstone test.
The different backgrounds within the group are representative of the wider operation. Sportscar specialists are working alongside people coming from single-seater disciplines, and the endurance test offered a particularly valuable opportunity to establish the routines and mentality required to run a car deep into the night.
“Cars have a team operation. They’re really important,” says Barclay. “A really good group of experienced people from sportscar racing, but yes, some from the Formula One side as well. And we’re almost kind of gelling that group together.
“For those who come from Formula One or the Formula E background, taking them into uncharted territory around running a car beyond 24 hours… is a different mindset. At the end of that test, the camaraderie in the group was fantastic. You bond as a group.”
McLaren’s progress has also allowed it to move away from simply asking whether the MCL-HY works and towards understanding how to get the most out of the package. The initial stages of testing were focused on basic systems integration: making sure the engine, hybrid system, chassis and software were communicating correctly and that the car was fundamentally operating as intended. Those checks have now given way to broader performance and setup work.
At Silverstone, the team was conducting “sweeps” across brake balance, aerodynamics, aero mapping, systems and controls, as the team continues to get a feel for the car’s performance potential running at full power.
It is the beginning of a more sophisticated phase of the programme in which McLaren is looking not merely for a headline lap time but for the car’s operating window across a complete stint.
The MCL-HY can already run at full power, having done so from the first day of its initial shakedown. At Silverstone, however, the team was deliberately exploring different ranges rather than simply chasing the maximum permitted Balance of Performance output.
The next challenge is to understand how the car behaves throughout the BoP window it will encounter in competition, while also beginning to establish which of the available Michelin tyres best suit the MCL-HY.
“We’re not sat here running low fuel,” Barclay says. “We’re being realistic and understanding where, with the BOP window as well in terms of weight and power, and understanding how the car performs across that range, which we’ll have to race with as well.
“And everyone is racing the new tyre already. So now it’s starting to understand the different compounds, how they overlap, where the overlap is, how they differ, what suits the car as well.”
That learning process is being supported by another major piece of infrastructure at McLaren: a dedicated driving simulator for the project from Dynisma, now installed at the McLaren Technology Centre.
The new driving-loop sim became fully operational around the end of June and beginning of July, giving the Hypercar programme a dedicated tool with which to prepare drivers before tests and correlate what happens on track afterwards.
The process is already becoming cyclical: prepare in the simulator, test on track, return to the simulator and close the correlation gap.
“Mikkel’s example was in the sim before coming here, and then we’ll do a correlation after,” Barclay says. “Every test we can kind of prep, test, come back and close that gap.
“The closer we get to the correlation, then we can really start relying on that for setup information, for tuning as well.”
The car itself is also approaching its final specification before being taken to the wind shear tunnel for homologation. Although McLaren will continue developing the MCL-HY ahead of homologation, Barclay says there will be no major visual changes to the car seen at Silverstone.
The team intends to continue developing with a single car until it is confident that it is effectively ready to be frozen for its debut season, before adding a second chassis into the mix.
There is little value, Barclay argues, in producing multiple sets of prototype components while the specification is still changing. Nor does the team want to overwhelm itself with feedback from too many drivers simultaneously.
“We’ll go eventually to two cars when we’re kind of comfortable and ready,” he says.
The same philosophy applies to the remainder of the test programme, which is still being mapped out as its plans to run in the Middle East before homologation have been scuppered.
McLaren has more endurance running planned, including tests that will take the MCL-HY beyond the 30-hour benchmark, while shorter tests will increasingly concentrate on performance. The balance will be critical: enough running to uncover weaknesses, but enough development time between tests to make each subsequent outing meaningful.
“It’s great to say we’ll test again next week,” Barclay says. “But if we roll out exactly the same thing with no updates, it’s kind of pointless.”
That relentless cycle of test, analyse, change and retest is now the central task. And while Barclay is keenly aware of how much ground McLaren still has to recover against Toyota, Ferrari, Cadillac and BMW — manufacturers with years of experience in the category — he is encouraged by the foundations laid during the opening months.
“It’s team development, not just car development,” he says. “We’ve been testing nonstop since May, and a lot of development behind the scenes.”
For now, the most important achievement may be that McLaren’s ambitious roadmap to its race debut has remained intact. The MCL-HY rolled out when promised, has progressed through a varied programme of circuits (and made a public appearance at Goodwood), operated at full power, experienced wet running, begun meaningful performance work and now completed its first 30-hour endurance exercise.
Most importantly, it did so without a fundamental reliability problem bringing the programme to a halt.
“We’re in really good shape here,” says Barclay. “The baseline of the car is really positive, and the fact that we’re on time, we have no showstoppers, which is really important as well.”
But there is no suggestion inside McLaren that the first endurance test represents the completion of anything. If anything, it has opened the next chapter. The team now has a clearer picture of what needs to be improved, which parts need more mileage, where the car’s performance window lies and how its drivers interact with it over a stint. Barclay’s own description captures the stage of development neatly.
“It’s going to be a long journey. We got out, the drivers are smiling, with full power on the first full day; it has potential, but that doesn’t mean anything right now. When the green light goes in pit lane, and we do our first competitive session, our first qualifying or two, or the first race or two, then we can judge where we are. But the indications are that we’re in that ballpark.
“We’ve got an outline of a painting. We’re kind of colouring it in.”
