Fernando Alonso and Jimmie Johnson. Both names are synonymous with success on the racetrack. The two men have left an indelible mark on the sport.
Now, two of motor racing’s pre-eminent superpowers are set to go head-to-head in a desert duel with a twist, as they get behind the wheel of each other’s cars at Bahrain International Circuit on Monday 26 November, 2018.
You could say the force has been with them throughout their stellar careers, and in a literal sense it has been when it comes to g-force.
On the face of it, there’s little common DNA between Fernando’s sleek single-seater F1 car and Jimmie’s sheet-metal stock car – but both will be equally governed by the forces of gravity.
So what is g-force and what does it mean for this epic role reversal?
No escaping it
You know that sensation you experience when hurtling along at what feels like the speed of sound on a rollercoaster? That feeling of your stomach jumping into your mouth, your shoulders pressed sideways, and your eyeballs sinking into your skull? That’s g-force.
Earth is constantly pulling down on you. It’s like death and taxes. There’s no escaping it.
As you can imagine, Earth is pretty heavy and that gives it a large gravitational field. But when you’re on a rollercoaster or in a race car making sharp movements, you’re thrown around by forces far stronger than Earth’s gravity.
The faster this change in velocity, the more force you experience.
These moments are quantified by engineers as g-force, and they use this as a measurement to explain and quantify how strong they are. For example, 1 g is the force that Earth’s gravitational field exerts on your body, and it’s enough to keep your feet on the ground.
Any time that an object changes its velocity faster than gravity can keep up, the forces will be greater than 1 g. At zero g, you would feel weightless. Go beyond 100 g, and you’re almost certainly dead… We did say you couldn’t avoid it.
Bank on that
Most NASCAR circuits are banked to enable drivers to travel faster around the corners. For example, the Talladega Superspeedway looms upwards at a daunting 36 degrees. The greater the banking, the higher the speed, and therefore more g-force.
It means that the vertical g-force loads for a NASCAR driver average between 3 and 5 g in banked turns. In a space shuttle launch, pilots pull 3 g for several seconds. NASCAR drivers are doing it for three or four hours.
G-force makes your body feel significantly heavier, reduces blood flow to your brain, impairing vision, triggering dizziness and disorientation.
That feeling of having your brain squeezed through your right ear is just what you need when travelling at around 200mph at the limits of adhesion.
It’s the banked nature of the tracks and the resultant vertical g-force, or Gz as the boffins at McLaren Applied call it, which sets NASCAR apart from Formula 1 in the g-force stakes.
Vertical g-force comes at a price, however – the risk of passing out. This phenomenon is known as G-LOC. Lungs get compressed and blood cannot reach the brain, leading to unconsciousness.
For Fernando’s sake, it’s probably just as well the Bahrain International Circuit doesn’t have any banked corners!
In this game of g-force top trumps, Formula 1 wins when it comes to lateral g-force. While the lateral force experienced in NASCAR reaches 3 g, Formula 1 drivers are hitting double that – 6 g.
A driver’s head and helmet weigh around 6.5kg, which is already a significant mass on the neck and shoulder muscles. And that’s before a wheel is even turned.
This figure is then multiplied by the g-force. With a possible 6 g under braking and through the corners in the Formula 1 car, Jimmie will enjoy a grand total of up to 40kg against his head.
That’s equivalent to resting a 10-year-old child on the side of your head unsupported. Something we strongly advise you don’t try at home.
Now imagine repeating this in the region of 60 times during a grand prix. It’s like being a pilot in a dog fight lasting one and half hours.
Mind you, the pilot of an F-16 fighter jet is likely to experience a mind-bending peak of 9 g, so Fernando and Jimmie cannot call themselves Maverick and Goose yet.
Around the clock
This will be compounded by the fact that, in NASCAR, nearly all the tracks are anticlockwise. There are a lot of left turns.
By contrast, most F1 tracks run clockwise, featuring a combination of anticlockwise and clockwise turns – predominantly the latter.
Although g-force will be nothing new for Jimmie’s body, being subjected to it repeatedly in the opposite direction will be. He is accustomed to having his neck and shoulder muscles stressed and strained all the time, but for most of the season it’s only in one direction.
And we hate to break the bad news Jimmie, but the Bahrain International Circuit is a clockwise circuit with a grand total of nine clockwise turns.
In comparison, numerous years racing around twisty tracks means Fernando’s brain and body have the upper hand with regard to rapidly engaging muscles in a clockwise and anticlockwise fashion.
It’s not all bad news for Jimmie, though.
G-force will be his friend when it comes to braking… well sort of.
The physical demands of braking in an F1 car are incredibly high. On average, drivers apply approximately 80kg of force through their left leg against the brake pedal.
This is all while being subjected to up to 6 g trying to launch them forward, rip through their seatbelts and prise them from their bespoke carbon fibre seat.
Have no fear though, Jimmie will be strapped in more tightly than a newborn kangaroo in its mother’s pouch.
That same force which will press his chest so hard into the seatbelts that he will forever be branded with the OMP Racing logos, will also assist him in his efforts to apply an almost superhuman amount of pressure on the brake pedal.
And on that positive note, good luck Fernando and Jimmie…