I'd imagine it is difficult for the causual or none technical fan to understand why there is such a disparity in performance between the front runners and lower tier teams. If we were to take Red Bull Racing and Caterham as examples for this article we will see differentiators in performance. I have decided to use these teams as an example as the 2010/11 Champions Red Bull are a team at the top end of their game. Meanwhile Caterham joined the sport in 2010 (under the guise of Lotus Racing and ran 2011 as Team Lotus before finally settling on the Caterham marque). Caterham initially entered the sport using the Cosworth engine and although they weren't quite upto the speed of the established teams they did make their mark as the best of the 3 new teams.
The main reason I have decided to use these two teams as the reference points is due to their common use of the Renault engine but also because Caterham purchase their gearbox and parts of the rear suspension from the Red Bull Racing team (albeit the Caterham uses the previous seasons setup, so for this year the RB7's setup)
KERS is something that both teams purchase from Renault Sport and can also affect the balance of the car whilst in both the harvesting and dispensing stages. Red Bull have more experience using the KERS system and although they struggled initially with system failures they now seem to be on top of the system. This being the first year that Caterham have used the system they not only had to find a way to package the system but also find a balance in order to gain additional lap time. KERS also has an aerodynamic effect as additional cooling is required in order to keep the batteries cool. (Imagine using a piece of electrical equipment for a while and then fetching the battery out, you will notice how warm it is. As electricity is dispensed the chemical reaction taking place inside the battery heats up the chemicals and in turn the casing. To give you an idea of the difference in a battery you use to the type installed in a KERS system: A small AA battery has a discharge rate of just less than 10,000 Joules or 1Kj, a KERS battery can store 400KJ's so that's 400 times the storage capacity. Heatsoak can be a massive factor in the performance of both the batteries life and performance. The more heat the battery is exposed to the faster the cells degrade and the less effective the cells produce optimum power.
Energy Harvesting is when the electrical motor connected to the crankshaft on the front of the engine withdraws power under braking (engine braking) which has an effect on the balance of the car. This is why you see drivers adjusting their brake balance during the lap. The team that can best manage the transition between harvesting, energy storage, battery cooling and energy release will attain the best system. This I believe is why Red Bull now have Super Capacitors located at the rear of the floor. These Super Capacitors help to store and release energy more quickly than the larger batteries housed under the drivers seat. Cooling them will require a more intense level of airflow and that's why they have been situated near the starter hole as it almost sucks airflow into that region.
Mechanical & Aerodynamic Platform
Firstly the ride height, the Red Bull car is running closer to the tarmac as we can see by the distance the front wing and skid block are from the tarmac. This not only has an effect on the suspension but the aerodynamic platform, you'll note that all of the suspension elements are much more upright on the Caterham this invariably leads to less motion available and in turn less adjustability. The CT-01 would also seem more softly sprung as you can see by the weight transference. The weight of the car is leaning over on the right of the car as the weight shifts under cornering load. Due to the softer suspension approach we can see the additional angle of attack that the Caterham driver is having to take in order to get around the same corner. Both the wheel angle and drivers hand position show the Caterhams deficiency to the Red Bull.
The front of the nose cone on the RB8 has a much more bulbous frontal area which is in stark contrast to the CT-01's almost pointed nose. The RB8's nose design is all about continued flow management in order to feed/push the airflow into the path of the next component. The CT-01's nose is a much more blunt design with perhaps the highest possible nose configuration available. This is done to try and drive more air under the car towards the floor and speed up the airflow to the diffuser beyond.
Red Bull's nose slot in the step area helps to stop flow detachment that usually occurs when airflow meets with a sheer surface. The step or ramp of the nose design although minimally will create some drag. This disadvantage has been deemed acceptable by the teams to gain the air underneath.
The Front wing planes used by the two teams are very similar in design even with the top element sporting similar pointed ends at the inner edge of the element. The RB8's front wing however has additional pylons/vanes just infront of this area that combine with the top element in order to generate flow vortices. These vortices travel at a higher speed than a normal laminar flow. In the case of the RB8 these vortices are then targeted at the turning vanes behind (mounted below the nosecone) in order to direct the flow further down the car. As Caterham don't have these pylons/vanes the vortice(s) generated from the wing tip is much smaller and so the turning vanes are also designed more neutrally.
The picture above is a very crude explanation (in 2D) to explain what I mean by a votice or vortex, the two wing tips create airflow that act on one another sending the airflow into a spin and create a higher speed airflow we call a vortice.
The frontal entry point of the Sidepods of both cars are very similar dimensionally however where the top of the Sidepod on the RB8 slopes inward toward the cockpit the CT-01's lean away. The reason Red Bull follow that ethos is this helps to funnel the airflow towards the rear of the car creating a downwash towards the rear of the floor. Caterham's version will allow the airflow to tumble off the sides towards the floor and so less flow is contained and sent towards the rear floor. Although both cars run the same engine due to mapping requirements their cooling methods may differ and so radiator size and layout will differ between the two cars. This leads to the difference in sidepod size and shape (packaging).
Rear wing design has altered since the inception of DRS as teams try to balance the effects of using or not using the DRS system. Designing the heights of the two wing planes will effect not only the angle of attack that can be implemented in the closed position but also the effect of the effectiveness of DRS when active. This is a tuning decision made based upon the circuits characteristics.
The diffuser is obviously a key area in extracting rear downforce from an F1 car. Over the last few years the teams have exposed loopholes within the regulations in order to better extract more downforce. Each year the FIA has to re clarify areas within the technical regulations to try and reduce the amount of downforce the teams can generate. The latest of these has been the removal of EBD (Exhaust Blow Diffusers) unlike the top exiting exhausts of this season the exhausts used to channel their airflow in a cavity in the floor of the car in order to speed up the diffuser process and seal the diffuser edges. (When we talk about sealing the diffuser this is achieved by creating a channel of airflow, the stronger & wider the airflow the better the effect. The term sealing is like creating a wall of airflow to which outside airflow doesn't affect the performance with the diffuser channel.) Without EBD this has become a much more difficult task and means the teams had to start with a much narrower sealed area. This is all intrinsically linked to Rake as we discussed earlier and depends heavily on how much air can be driven underneath and over the rear of the floor/diffuser.
We have to remember that although most of us can only visualise airflow in a uniform way (front to back over the car) as the car turns and travels on it's suspension the airflow is also moving. This means that managing an element like tyre squirt can greatly affect the level of downforce and in turn the balance of the car.
Just like the gurney flap I mentioned in the Rear Wing section the diffuser is also allowed a gurney flap in order to generate downforce. As we can see from the pictures above both teams again have very different
Philosophies in this area to attain better performance. Red Bull's Gurney flap is slightly detached from the diffusers edge, this allows the flap to work as a wing in unison with the diffusers top edge. This bleeds airflow through the gap allowing an element of flex and allows more downforce to be applied to the gurney flap as the low pressure air goes beneath the flap. Meanwhile the Gurney flap on the Caterham is a much more blunt approach with a sheer 90 degree surface at the maximum 20mm permissible surface area.
In Season Updates
This is perhaps one of the more important aspects of racing within a series like F1, as the season progresses and the team are able to find additional performance gains they are bought to each circuit to be evaluated. Updates come in either Mechanical or Aerodynamic forms and sometimes utilise both in order to gain either additional balance for the driver and/or extra downforce. For example this season has shown the depths and pure rate of development that Red Bull can achieve having produced at least 4 major different exhaust configurations in quick succession. To say that the teams always get things right would be wrong though, Red Bull chased their Sidepod/Tunnel/Exhaust solution for a number of races only to abandon it in favour of a more neutral solution. Sometimes the over complexity of a design can lead it impacting how it feels for the driver. In terms of the Tunnel solution Caterham also briefly tested a version of the same type of idea at Mugello. This is something that I intend to write an article on in the future but will briefly touch on it now: Aero Convergence is when a seemingly leading team has a key area of aerodynamic gain, other teams see this a way of extracting more performance from their own package and so develop their own iteration. McLaren's exhaust system this season highlights this brilliantly, with the clear advantage at Melbourne the teams invested their development time chasing similar solutions to the McLaren style exhaust.
Red Bull are no stranger to the world of FIA rule changes / clarifications as they push the boundaries and interpret the rules in a different way. Having perhaps without the DDD (Double Deck Diffuser) the best car of 09 and then using their facilities to rapidly catch and overtake the initially superior Brawn GP car of that year. This was a year I believe Red Bull learnt many lessons both on and off track in terms of strategy, car design and how to handle the FIA's ever changing rule book. In 2010 & 2011 they produced cars that leant on the side of illegality and prospered using 09 as a yard stick for future processes. More recently they have fell to the wroth of the FIA's ever changing rule book and have had both their Floor and Front Brake housings banned under rule clarifications. This won't stop the teams pushing ever closer to their interpretations of what is legal and illegal.
As we can see from the disparity between these two teams, having the same/similar engine/gearbox and ancillaries is not the only thing required to produce a winning car. It's a multi faceted design process that requires decisions on everything from engine mapping, exhaust tuning, gear ratio selection, suspension geometry, tyre pressures, aerodynamics to name a few. These processes are also reviewed and changed based on the particular circuit F1 are visiting at the time.