F1: THE MCLAREN MCL33 IN DETAIL
It’s been a much-anticipated launch, as the new McLaren was revealed today (Friday). For a long time, everyone wondered what engine it would have, some wondered what colour it would be and some of us wanted to know how uncompromising its design would be.
With the car’s unveiling we now at least some of those questions answered. We knew the Renault PU was coming and there was little doubt the orange livery would be back, but questions over the car’s design are still in doubt. Clearly an incomplete car, but how much can we tell about what McLaren has already changed on the car?
Such is the strength of McLaren’s brand and the publicity its recent performances have had, I doubt any one reading this doesn’t already now about the past three years with Honda.
Yes, Honda have failed to create a power unit, that’s well-prepared, powerful and reliable enough for F1. McLaren’s recent documentary mini-series on Amazon Prime tells much of the story. But the switch to Renault engines is far from a silver-bullet for the team. Renault have been in F1 continuously for longer than Honda and even had an extra year racing with these current complex engines. Yet the Renault power unit still falls short of Mercedes and Ferrari in power and reliability, so this is a frying pan they’re jumping into out of the Honda fires. Additionally, McLaren are not at the top of the game with their chassis and it can even be argued that McLaren didn’t deal with Honda well enough during their partnership. Renault are a much better partner, so the latter point should be less of an issue for McLaren. By their own admission, the McLaren chassis still lacks in some areas, great in fast corners and less so in slower ones. The winter’s work has been not just to fit the Renault power unit, but also address the inadequacies in the chassis.
Although the technical regulations set out a huge number of dimensions and design aspects of the modern F1 power unit, the detail of every manufacturer’s unit is different. Fitting the Renault engine into the chassis is a significant task, but one McLaren handled well within the timescales they had. The aero team got on with the basic design of the bodywork, given a basic engine outline to fit around, so their work won’t have been greatly handicapped. The chassis team had the greater share of the work, reshaping the monocoque and gearbox to take the Renault engine, with its turbo, cooling and its hybrid systems. Again, work outside these areas could continue unabated, so the programme will have been able to keep on schedule, despite the late switch between PU suppliers.
In the end the differences between the PUs balance out, neither is a better package to install, just different. McLaren were able to push the engine forward in the chassis by shortening the fuel tank and extending the gearbox. Which is a useful shape to move forwards with as it allows the rear of the car’s aero to be slimmer. Otherwise wheelbase and the cars rake angle (low front ride height and high rear ride height for better aero performance) remain similar.
On the aero side the car is incomplete and may appear underdeveloped, the team are clear a lot more is yet to come. But at this stage the car appears to have regressed from 2017, as key details are missing the S-duct inside the nose and the complex vanes around the sidepod front.
What’s left on the car is still well detailed, the front wing amongst the most complex on the grid, gets ever more slots and edges to shape the airflow back along the car, while balancing the downforce created at the rear of the car. The nose is an identikit version of the 2017 design, with its wide thumb-tip design and the slotted\twisted pylons that hold the front wing on.
Again, the front suspension is not aggressively high, as with the MCL32, which is better for mechanical grip than aero. Although McLaren’s push rod set up retains the clever geometry used last year. The pushrod is the diagonal suspension member that transfers the loads from the wheel into the springs\dampers mounted inside the chassis.
Rather than mount this to the lower suspension arm, most teams mount it to the upright that steers with wheel. This way the suspension can be affected by steering, usually giving an anti-roll effect. McLaren and other teams have tried a more extreme geometry with the pushrod spaced a long way from the steering axis and aligned so that the ride height changes with steering.
Over the Winter the FIA issued a clarification that more than 5mm of ride height change with steering is not allowed. This was aimed at these extreme pushrod-on-upright designs. McLaren must therefore have arranged theirs so as not to exceed the 5mm change with steering.
Carried over from last year is the bargeboard set up, when McLaren had some extraordinarily shaped vanes around the side of the car. These may well change and the complex carry-over design seems to stop at the sidepod front. Instead a simple vertical a vane is fitted and the rest of the leading edge of the sidepods are bereft of vanes aside from two rows of vertical fins.
The sidepods themselves are shapely, and the mid-placed inlet is admirably small. Rather than fans worry about cooling issues, look at the Red Bull with the same engine and it has an equally small opening. Teams have really got on top of cooling these powerful engines, with a mix of engine work, aerodynamics and the radiators themselves.
Images from the car’s shakedown show the sidepod internals and its clear McLaren won’t follow the fashionable high-top sidepod design, as the crash structures on the side of the car are a huge job to change. This leaves McLaren with Mercedes and Renault as the teams will outwardly conventional sidepods.
Alongside the ‘pods the exposed floor is quite unique, with much of the edge made up of two long vanes, these relieve the pressure under the front of the floor and allow it to spill over onto the top of the floor, whilst also sealing the floor edge along the way. Most teams have short runs of these floor edge slots, but no one has gone this far with them.
MORE CLEVER SUSPENSION
Much of the aero talk around F1 is about wanting to turn upwash into downwash. As the front wing throws the air up and the rest of the surfaces behind would rather the airflow be horizontal or even better heading downwards (downwash). The rear wing in particular likes this downwash flow approaching it, but there’s a lack of legal surfaces with which to do this. There is still the lower T-wing, which will no doubt appear on every car, but McLaren have taken quite a strong direction with their rear suspension to help the rear wing.
The top suspension arm, is typically a “V” or wishbone shape, for structural efficiency the two legs of the arm join outboard near the joint with the wheel\upright. McLaren have joined the two much closer together, so rather than a joint of the two near the wheel, there’s a single teardrop section coming through the bodywork and reaching out to it. This arm profile can be legally angled by a few degrees to create the downwash to help the rear wing work better. The conventional “V” arm still does this to an extent, but the single section should be slightly better, even if it needs to be a little heavier to cope with the change in “V” shape.
Rules demand that there has to be a large endplate on the rear wing and the aerodynamicists also like this part as it seals the downforce-producing pressure the top wing creates. But airflow around an F1 car is anything but straight, so the large flat endplate becomes a burden. But there’s a limit to how much the rules allow it to curve, so instead teams create slots in the flat surface to let air flow in and out. McLaren have, like on many other aero surfaces, gone very complex with this. The endplate is cut open and the previously flat surface broken up into fins and slots. This allows the air to flow through wing more effectively, whilst still sealing the top wing at the sides.
The midfield battle will be fierce this year, other teams have made similar steps and even have more-complete aggressive cars ready for testing. We will have to hold our opinions on the level of the car’s design until it gets its race ready bodywork. McLaren have done a lot to the car already, some further steps are clearly going to come.