How are the aerodynamics improved on the Ultima RS model?

The design brief for the Ultima RS aerodynamics was to improve high speed stability whilst reducing the co-efficient of drag to achieve a more aerodynamically efficient car, resulting in market leading levels of downforce. Minimum co-efficient of drag achieved in the MIRA wind tunnel was 0.304 with the ability to adjust downforce to a maximum of over 1000kgs.



In brief:



The front splitter has been engineered to mount directly to the chassis, thereby removing any flexibility and putting loads direct into the chassis. The optional carbon fibre version also incorporates diffuser ramps to the underside to increase downforce while minimising the co-efficient of drag. The integral vortex generators on the outside points help to control wake around turbulent air from the front wheels, at the same time giving smooth flow to the underside of front dive planes (if fitted). The carbon fibre front dive planes can be used to move the aero centre of pressure further forward and produce more downforce on the front axle. The only downside with using dive planes is that they will increase the co-efficient of drag.

The re-design of the front body has reduced the frontal area to a minimum and also adds a lower co-efficient of drag. At the same time it controls air flow over the leading edge and maintains a boundary layer over most surfaces. Now that the radiator has a totally uninterrupted flow of air it has improved cooling efficiency.

We designed an integral S Duct system for the front canopy. To control airflow at high velocity the entry into the radiator will generate a stagnation zone between high pressure and low pressure; this backs up in front of the radiator as speed increases and will bleed off through new slots in the front body stiffener moulding and exit on the top surface of the front body. This also helps with an additional small amount of downforce on the front axle while maintaining low co-efficient of drag. If air passes too fast through the radiator core you generate a boundary layer so the heat from the radiator cannot attach itself to air passing through.

The RS carbon fibre side splitters work in a similar way to the RS front splitter in that they separate airflow most importantly when the car is in yaw with medium and high speed cornering, this in turn will increase downforce on loaded tyres and prevent air rolling underneath the side pod and creating lift.

Front and rear wheel arch vents (available in body coloured gel coat or an exposed carbon fibre finish) generate downforce and reduce drag. Rear vents have the added bonus of allowing hot air to exit from the exhaust headers. The new RS carbon fibre side pod scoops come with integral NACA ducts and provide air flow for the air conditioning condenser and to the new LT engine air intake system.

The RS radiator exit divider is used to initiate air separation around the wiper arm and then further up the windscreen. The wake is used to divert the boundary layer either side of the roof scoop intake. This minimises hot air from the radiator entering the roof intake.

In full size wind tunnel testing we recorded an identical co-efficient of drag with side pod apertures completely blanked off versus side pod scoops fitted. This is due to having a very efficient exit point in the new RS rear wheel arch louvre vents. This resulted in additional down force and the centre of pressure to the rear axle increased.

New optional RS carbon fibre rear view mirrors have been moved to the front bulkhead area on the centre section to minimise disruption of the boundary layer over the top surfaces and improve airflow onto the rear wing.

To improve the efficiency of the RS rear wing it is now larger and the full width of the body. It is mounted on a new bespoke swan neck mounting system which transfers downforce directly to the chassis. The new swan neck mounting system has been engineered to increase downforce and reduce coefficient of drag, minimising wake to the bottom surface of the rear wing.

The addition of a new roof scoop has been used to improve air flow over the top of the car and maintain a boundary layer over the top surface. It also uses the intake air flow to assist in engine bay cooling.

The RS carbon fibre rear diffuser is a design feature added to enhance the appearance of the car whilst improving air separation off the rear canopy.