When McLaren unveiled the MCL35M for the 2021 FORMULA 1 season, on the surface it didn’t look too different from the MCL35 used for the 2020 season. However, under the hood, the car tells a different story…
The MCL35M does look different, much more than many other cars on the grid, because of the switch to the Mercedes engine from the Renault engine. The difference in dimension of the two engines and the homologation restrictions in place caused McLaren to make a few changes in the monocoque as well as in the bodywork.
Structural changes had to be made to the monocoque to replace the Renault engine with Mercedes. In mid-February James Key, McLaren Technical Director, spoke about the changes and explained them. McLaren was the only team that was changing the power unit on the car which is a major project for any team.
McLaren had to get an exemption from the FIA for the change of the power unit which they successfully did. What made matters difficult was that the McLaren team had very little time to fit the new engine in the car. Moreover, because of the pandemic (COVID-19), most of the team was working from home. James Key feels that his team has done a good job despite the handicaps.
Fitting the Mercedes Power Unit In The MCL35M
The Mercedes power unit is markedly different from the Renault power unit. With the homologation rules in place, the McLaren team had to fit the Mercedes Power Unit in place while striving to carry over elements of the previous season and car. This made the redesigning of the monocoque and the bodywork mandatory.
The chassis modification was done in close consultation with the FIA to ensure that McLaren was complying wit the homologation regulations. As the Mercedes gearbox bell housing is longer than Renault’s, the wheelbase had to be lengthened. At the end of the day, the new McLaren car has a new gearbox; fuel, electrical, cooling and hydraulic systems, and a brand new chassis.
James Key is still not fully stisfied with the results of the changes to the car. “We would have done it differently were it not for the restrictions put in place for 2021” he says. He further adds that they could not make changes to the chassis as much as they would have liked to because of the homologation rules. He contends that the car is not fully optimised.
The new bodywork is in line with last year’s car except for the changes forced to be implemented by the new power unit’s geometry. Many of the changes brought about in the shape of the car are a result of fitting the Mercedes engine. James Key does not think many changes will be done to the bodywork as the season progresses.
Homologation rules and their effect on MCL35M
As a part of cost-saving measures, the FIA along with all the teams have mandated that the teams use the same cars used during the 2020 season in the following season. Key parts of the car are “homologated’. Each of these parts has a designated token value of either one or two tokens. Each team can only spend a maximum of three tokens. They have to wisely choose which parts of the car to change to avoid a penalty
The rounded nose
A set of parts to be homologated were announced before the start of the last season. Some parts, including the nose, were to be homologated at the end of September 2020. McLaren decided to adopt the slightly narrower nose with a curve across its width. This was done to avoid spending valuable tokens at a later stage.
The MCL35, the car that reced in 2020, had a panel with slotted vanes channelling the airflow to the barge boards. The rounded nose with a ‘cape’, a flat section of bodywork beneath the nose, is more favoured by Mercedes and Renault. Although it is a new development, constructors believe that optimising the system will take another two years of observation and modification.
Engine cover and side pods
As per James Key, they had to “make the changes we needed to the homologated parts so that was to change the chassis, which of course has to change with a new engine and the energy store, aspects of the gearbox for packaging purposes and after that, it is all identical to last year.”
Most of the changes are within the bodywork and cannot be seen. The most noticeable change is the side pods which are pinched as you go down. This gives an hourglass look, the same as was seen on the Mercedes W11 towards the end of last season. This is understandable since the power unit is supplied by Mercedes.
The plain floors without the intricate designs and cutouts will be characteristics of all cars this season. This is a regulatory requirement introduced by the FIA to reduce the downforce achieved towards the rear end of cars. The rear end of the floor also narrows inwards thus altering the direction of the airflow.
The MCL35M has incorporated cooling gills. These gills are used because of the split turbo concept used by the Mercedes Power Unit. The gills were sported by Racing Point RP20 last season, Remarkably, the other car using a Mercedes power unit, Williams FW43 did not use them. The airbox has changed to allow for the cooling of the new Mercedes engine. The brake ducts have been shaped for better efficiency in cooling and to be aerodynamically helpful.
After turning many heads with their performance at pre-season testing, it will be interesting to see the performance of the MCL35M during the first few races of the season. McLaren fans will also be waiting to see what changes McLaren will make to its new car as the season progresses. James Key thinks that the changes if any will be minor and very few going forward into the season.