Ground Effect - How Did The Legendary Innovation Work?
Once the potential of using aerodynamic downforce to win races was realised, designers began experimenting with methods other than simply attaching inverted wings. Formula One technology developed at a furious pace in the 1970s and early 1980s, as F1 designers began mastering the art of making airflow work to produce downforce.
Yes, even 6 wheeled cars
Up to the early 1960s, designers were mainly focused on making cars streamlined and lowering drag. However, as the vehicles became faster, they started becoming dangerous and resulting in significant accidents.
After observing these accidents, and sometimes deaths, they realised that streamlined vehicles created lift at high speeds. Lift led to the cars essentially becoming airborne at high speeds, but most importantly greatly reduced grip while turning.
To resolve this, they tried to disturb the flow with front and rear spoilers, which surprisingly also dramatically increased grip.
To learn more about wings and their fascinating history, have a look at this article on racecar wings:
The Ground Effect turned the entire car into a large, inverted wing, using side skirts to glue the car to the circuit. The Lotus 78 was the first car to use the revolutionary design. It won its first race at Long Beach in 1978 and its winner, Mario Andretti, said the car felt astonishing, like it was 'painted to the road'. Colin Chapman's careful development of the ground effect principle had made conventional GP machines virtually uncompetitive in a little over 12 months. Lotus won an unprecedented nine of the 15 races in the 1978 season.
Unfortunately, the legend Colin Chapman would later pass away leaving 1978 as the last time Lotus would win a championship, as the other teams swiftly caught up.
How did it work?
Massive amounts of downforce were generated from the airflow between the underbody of the car and the ground plane. Low pressure, in particular, was created underneath the car by using the ground plane almost like the floor of a venturi duct. These new venturi ducts hung from the sidepods like wings, and their decreasing area in the throat accelerated the airflow, and crucially, created low pressure under the Bernoulli principle.
The gap between the bottom of the sidepods and the ground was sealed 'skirts'. These 'skirts' essentially stopped external air interfering with the critical zone and lowering downforce.
Ironically it was the skirts that got the revolutionary design banned. The problem was that it was fixed to the sidepods, meaning it didn't move with the ride height. Initially, this was good for downforce but once the car rode over bumps or kerbs it became too unstable, leading to spectacular accidents at high speed. The FIA was forced to ban it, and ground effect hasn't been seen since.
Today F1 regulations limit the underbody of the car to being flat making ground effect impossible, but last year the FIA decided to allow it for the 2022 regulation changes.
But isn't it unsafe? Well, yes it was.
But it won't be.
The regulations say the skirts must be fixed to the suspension so they'll move up and down with the car and it won't render it unstable. Problems solved!
The great thing about this effect is that it creates downforce with a small drag penalty, and most importantly, it doesn't disturb the wake of the car. This is all part of F1's effort to increase overtaking by making it easier to follow another car, and by banning bargeboards and using ground effect instead, more 'green' downforce can be created. (That is, downforce that doesn't destroy airflow for the chasing car).
Let's hope ground effect can solve this problem, and that we get some good racing!