Lotus Evija’s aero philosophy explained

For the first time, Richard Hill, chief engineer of aerodynamics and thermal management and has worked at Lotus for more than 30 years, supporting countless road and race car projects and who has guided this critical element of the 2,000 ps car’s design, details the philosophy of the Evija’s sophisticated aerodynamics.

“It’s about keeping the airflow low and flat at the front and guiding it through the body to emerge high at the rear,” he says..” Put simply, it transforms the whole car into an inverted wing to produce that all-important dynamic downforce.”

Asked to qualify the car’s porosity in aerodynamic terms, Hill replies: Most cars have to punch a hole in the air, to get through using brute force, but the Evija is unique because of its porosity. The car literally ‘breathes’ the air. The front acts like a mouth; it ingests the air, sucks every kilogram of value from it – in this case, the downforce – then exhales it through that dramatic rear end.

“The venturi tunnels through the rear quarters are part of the porosity as they feed the wake rearward to help cut drag. Think of it this way; without them the Evija would be like a parachute but with them it’s a butterfly net, and they make the car unique in the hypercar world.”

The front splitter is designed in three sections, as Hill explains. “The larger central area provides air to cool the battery pack – which is mid-mounted behind the two seats – while the air channelled through the two smaller outer sections cools the front e-axle. The splitter minimises the amount of air allowed under the vehicle, thus reducing drag and lift on the underbody. It also provides something for the difference in pressure between the upper and lower splitter surfaces to push down on, so generating downforce.

“The rear wing elevates from its resting position flush to the upper bodywork. It’s deployed into ‘clean’ air above the Evija, creating further downforce at the rear wheels. The car also has an F1-style Drag Reduction System (DRS), which is a horizontal plane mounted centrally at the rear, and deploying it make the car faster.”

The drag coefficient and downforce figures will be released later in the year.

The Evija has a carbon fibre chassis, the first Lotus road car to use this technology although Lotus pioneered it in Formula 1. “The chassis a single piece of moulded carbon fibre for exceptional strength, rigidity and safety. The underside is sculpted to force the airflow through the rear diffuser and into the Evija’s wake, causing an ‘upwash’ and the car’s phenomenal level of downforce”

As well as working on road and race cars, Hill was the brains behind the Lotus Type 108 and Type 110 – better known as the Lotus Sport track and road bikes ridden to glory in the 1990s by legendary British Olympic and Tour de France cyclist Chris Boardman. He has also been instrumental in the development of the new track bike developed by Lotus for British Cycling athletes who will compete in the rescheduled Tokyo Olympics.

“It’s like comparing a fighter jet to a child’s kite,’’ is Hill’s summary of the Evija to regular sports cars.