Deconstructing Formula 1: Sidepods

Packaging the mechanical components of a Formula 1 car is never an easy task, especially when you consider that all of its body surfaces are there to influence the airflow and, in most cases, create downforce.

The current breed of F1 car will create something in the region of 1200kg of aerodynamic downforce at 155mph - so it's easy to understand why aerodynamics is a prime factor in packaging the car.

One area in particular that influences the performance of the entire car is the section immediately behind the front wheels. The airflow that passes through the inside of the front wheels, around the chassis side and bottom and the ground is basically what the rest of the car has to work with.

So any unnecessary blockage or need to have large radiator inlets or large front brake ducts only reduces this airflow and inevitably limits overall performance.

The detail of the chassis chin area and the leading edge of the sidepods helps the performance of the front wing, and the airflow through this area determines how much mass flow the underfloor has to work with and ultimately how it will perform.

McLaren

McLaren has taken a fairly different approach to its sidepod radiator duct entry. It has lowered the inner section of the sidepod to allow more airflow through to the back of the car.

Doing that has resulted in its radiator inlet becoming an 'L' shape rather than the traditional triangular shape, with the largest part of the inlet towards the chassis, as other teams have done.

In doing this I think the inlet area has had to be increased in size, which will cost the team some vital performance because airflow used for cooling can't be used to produce downforce.

The chassis chin area is similar on most cars - it is a legal requirement - and because of the high chassis it will have minimum blockage and some side fences to help control the airflow spillage that comes off the upper surface on to the leading edge of the underfloor.

Most teams house ballast in this area because it is well forward and low on the car, so it helps with weight distribution and lowering the centre of gravity.

The undercut in the leading edge of the sidepods allows the curved forward bargeboards to assist in extracting the airflow from under the chassis and the tall vertical turning vane again helps with this. It reduces the influence the turbulence behind the rear of the front tyre has on this area.

The floor extension under the undercut area works as a small wing in its own right with the gurney flap on the side helping to extract the airflow from its under surface.

The Ferrari is complex under the skin © sutton-images.com

Ferrari

Ferrari is more traditional with its sidepod concept and has quite a lot more space between the sidepod undercut and the vertical turning vane than the McLaren.

This allows the team to control and manage the airflow a little better than McLaren because the influence of the sidepod surface will not be so dominant.

Again Ferrari has a floor extension with a gurney flap on its trailing edge producing downforce, but it also uses another gurney flap further back to help scavenge more airflow from the underfloor.

The complete sidepod detail is neater than McLaren's as all the surfaces blend together much better, and being like this should help with the consistency of the airflow and in turn allow the surfaces to be worked harder.

As I said earlier the mechanical packaging is never easy and this shot of the Ferrari with its clothes removed shows the amount of 'stuff' that is required to make one of these cars run.

Renault's exhausts face forwards © sutton-images.com

Renault

Renault's packaging in this area is surprisingly 'normal', considering that it has exhaust outlets coming out just in front of the leading edge of the underfloor.

I would have thought that surfaces could have been further developed to make use of this high-velocity mass flow introduced through the exhaust system.

The forward exhaust system with its side exit can be seen just under the radiator duct. With an exhaust tail pipe this length, exhaust tuning must have been a nightmare for Renault and I would imagine that there has been some loss of top-end power as well.

The heat generated by this system must also have caused a few problems and we all saw what can happen when this gets out of control in Hungary, when Nick Heidfeld's car caught fire.

Nothing about the Red Bull packaging is overcomplicated © sutton-images.com

Red Bull

Like most of the detail on the Red Bull, nothing is too trick but everything works to the maximum.

The chassis chin detail has more turning vanes than other cars and the underside of the chassis blends into the leading edge of the sidepods more neatly. Because of this the airflow coming off the chin to the underfloor is more consistent - which improves the underfloor performance.

The pod hanging under the chassis is a housing for measuring equipment - the more understanding of the airflow in this area, the more you can exploit it to help with overall performance.

The sidepods are more undercut than most and the floor extension is just that, it is not so much a wing on its own but an increase in underfloor area. If you can get the low pressure under the floor to be lower, any increase in surface area will mean that it will produce more overall downforce.

Neat and tidy is what I would call the Red Bull, with all its surfaces working as one, but then I think its performance says all that anyway.

Toro Rosso has gone further than most with its sidepods © sutton-images.com

Toro Rosso

Toro Rosso is another team that has gone a little further than most with its sidepods.

The leading edge of the pod undercut continues further rearward than most and separates the sidepod from the top surface of the underfloor.

The rear end of the sidepod - which is called the Coke bottle area - works at a fairly low pressure and by connecting this area up to the leading edge of the sidepod Toro Rossi is trying to improve the scavenging of the air from under the front of the chassis.

Ferrari tried this with its twin-floor car in the mid 1990s and I'm sure there is possibly some small benefit. It means, however, that all the mechanical stuff that is mounted in the sidepod, radiators etc is raised that little bit higher - which hightens the centre of gravity.

These potentially small benefits can then be lost with the overall packaging requirements.

This sidepod undercut going further rearwards allows the team to have a gurney flap (which helps with performance) further back, meaning the floor extension can be further back creating a wing area of the floor extension that is bigger than most.

Rubber build-up shows how air flows © LAT

Force India

The top leading edge of the sidepod is another critical area and matching its shape with the airflow coming off the trailing edge of the front wing flap is very important.

If the profile is not correct this area can induce lift on the upper surface which is something you don't want.

The Force India has a very blunt upper leading edge making it not so critical to the airflow direction.

It also has a small hatch just behind the leading edge which can be opened if maximum cooling is not required. This again will allow some airflow through the duct reducing the lift on this area of the sidepods.

The rubber particles on the vertical turning vane show how this item controls the airflow coming off the rear of the front tyre. Without this component the performance of the undercut sidepods would be severely affected.

Mercedes has a deep undercut at the front © sutton-images.com

Mercedes

Mercedes' sidepod leading edge has a deep undercut, but then further rearward it almost disappears. This means that the Coke bottle area of the sidepod struggles to assist the airflow coming around the leading edge, which influences the performance of the front wing.

As opposed to all the other teams, Mercedes has a very small vertical turning vane mounted on the floor extension.

As I said earlier, all these surfaces work together and without the sidepod undercut connecting the Coke bottle area to the leading edge the airflow in this area will not be as critical. This means the team will not get any benefit from the taller turning vane.

Conclusion

Building a racing car is a bit like building a jigsaw: to get the best out of the overall package you need part one before part two fits - and will improve the aerodynamic performance.

This detail and vision is what makes Adrian Newey and his engineers at Red Bull so good. They have the understanding of where they are trying to get to before they know how to actually get there.