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Feel the Force – Part 1

By saltire | 3 Jan 2010 | 19 Comments | 17,715 views

Do you ever get it into your head that a particular word or phrase seems wrong and you can’t rest until you know the answer? Now I’m not a stickler for the English language but one such phrase that I intrinsically dislike is “F1-pilot” and since I can be pedantic at times I had to find out whether I was right or wrong in my dislike of the term.

It turns out that “pilot” has many definitions including;
1. One who operates or is licensed to operate an aircraft in flight.
2. One who is licensed to conduct a ship into and out of port or through dangerous waters.
3. To steer or control the course of.

So I had been wrong, but it did set my mind wondering what the parallels were between an aircraft pilot (specifically a fighter or stunt aircraft pilot) and an F1 pilot; they’re both involved in steering complex equipment at extreme speed requiring quick reaction times, but both are also subject to large g-forces… I decided to explore the topic further.

So what exactly is g-force?
The simplest explanation is that “g” represents gravity whilst “force” is an acceleration. When you are sitting at home quietly reading you are subject to 1g. At normal g, an average person will weigh somewhere in the region of 70 kg, but when subjected to higher g values their weight increases. At 5g, that 70 kg person would weigh 350 kg so even exposure for a few seconds leads to physiological responses as their body struggles to cope with the increased weight.
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Speed alone does not increase g, its forces like acceleration or breaking especially when coupled with a directional change that ramp up the intensity. You will have momentarily felt the effects of increased g if you have ever been on a rollercoaster ride or felt the acceleration as you take off on that holiday flight. But exposure to high g-forces especially when sustained for long periods can place extreme demands on the body.

This video of pilots undergoing training shows the acute effects of high g in the vertical (head to toe or “Gz”) direction; g-forces can also be front to back (transverse, Gx) or side to side (lateral Gy), the more likely directions of force felt by formula one drivers.
 


 
Effects of high g on fighter pilots
Straining exercises can help avert a loss of consciousness particularly when the forces are ramped up slowly, but when those forces are applied suddenly the effects can be devastating as the brain is deprived of blood, oxygen and glucose. So how does this come about? Normally, when you are lying down, your head is level with your heart and blood flow to your brain is maximised, when you sit or stand up your heart has to pump against gravity to push enough oxygen rich blood to your brain. You may have felt the light-headedness associated with postural hypotension if you have ever stood up very suddenly from a prone position and you felt dizzy.

As gravity increases it becomes more and more difficult for the heart to pump sufficient blood to the brain as the tendency is for blood to pool in your lower extremities. Fighter pilots can to some extent minimise the effects of high g- by use of straining exercises and by wearing a g-suit, a garment fitted with balloons which when inflated put pressure on the lower legs and help stop blood draining towards the legs. But even before the point where people lose consciousness (g-LOC, in the video) vision is affected. As g increases, both colour and peripheral vision are lost and it’s as though you are looking into a tunnel with restricted views either side, obviously this could be catastrophic for the person if they are also involved in some sort of extreme activity like flying or driving a formula one car.

Effects of high g on formula one drivers
Drivers are also subjected to high g (up to 5 g in a race situation), but rather than being in the vertical direction they are subjected to transverse and lateral forces which presents some different challenges to the body. This is nicely demonstrated in this video of Martin Brundle driving a Williams F1 car.
 

 
Transverse or lateral g places increased pressure on the parts of the body that supports the weight, with sideways forces in particular having an effect on the muscles that support the head and neck. It is for this reason that formula one drivers concentrate their training on strengthening their neck muscles and improving their cardiovascular fitness. But it’s not just stress on the neck and vision that’s affected, balance is too, with the vestibular system (inner ear) playing an important part in providing input to the brain, these signals result in spinal reflexes that brings about correctional changes to posture. Rapid changes in acceleration or direction can both confuse the system leading to confusion, dizziness and disorientation.

So how can drivers’ best adapt to the demands that increased g places on their bodies?
G-suits would be ineffectual in an F1 situation, the g is not sustained in any one orientation for long durations and the leg compression the suit maintains would be damaging for muscle control whilst driving. Instead, the most effective solution is exercise, upper-body strength is crucial as is cardiovascular fitness and strong neck muscles to support the weight of the head and helmet. For these reasons formula one drivers must be supremely fit to cope with the demands placed on their bodies.

The g-forces found during race conditions do not normally exceed 5g; however, during an accident they can be very much higher. Robert Kubica’s spectacular 230 km/h crash in Canada 2007 peaked at around 75g over one millisecond according to the official data released from the FIA, more on that in the next part of “Feel the Force”…

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19 Comments »

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  • Pat W

    Fantastic post. I especially love that ITV video.

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  • Aitch

    Wow, watching that Brundle video shows just how much of a beating a driver’s body takes each race. Great post.

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  • str8guy

    And Schumacher wants to come back aged 41 !!
    The age limit for training new Fighter Pilots in the US is 28.5 years.

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  • Streky

    G wizz Kubica’s 75G that’s heavy man.. Brilliant blog video 1 Hilarius (the guy trying to quit as soon as it started did it for me) … Glad you cleared up the G suits bit i always wondered why they didn’t have them as i knew some other race categories do and saved me looking like more of a idiot than i normally do.

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  • Alianora La Canta

    This is a lovely detailed entry. I haven’t really got anything to add, but thought I ought to say thanks :)

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  • skidmark

    Hmm, I’ve often wondered if a car could be designed with a gimbal seat hinged about the longitudinal axis of the car, that would reduce the sideways forces experienced when cornering by tilting…

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  • largeflowered

    Agreed, good post salti.

    >skidmark – re:gimbal seat idea. Interesting concept but a) wouldn’t it add a bit more width to the cockpit with allowances for the “swing out”? And b) raise the centre of gravity? (I sense a physics lesson might follow ;P)

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  • saltire (author)

    “I sense a physics lesson might follow “

    LOL not from me, the physiology isn’t a problem but I was worried that my physics isn’t up to scratch.

    I’ve no idea what a gimbal seat is so if someone wants to enlighten me (or do a guest post about it) that would be great.

    Thanks all for the nice comments, you might manage to turn me into a blogger yet :)

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  • Steven Roy

    Great post.

    I think the reason F1 drivers are known as pilots is very simple. The French word for race drivers has always been pilotes so it has just transfered to English.

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  • Pitmonster

    Great article Salti, with those G forces pulling on a driver’s body it’s no wonder they have such thick necks, and why saving a few grammes with a carbon fibre helmet can make a big difference. I know that some drivers use exercise machines where turning the steering wheel causes weights to pull sideways on the helmet, strengthening the neck.

    Regarding a gimbal seat, a gimbal is a pivoted support that allows an object to swing along one axis. Imagine if you could mount the seat in a cradle that was mounted on bearings, with the axis running along the length of the car and mounted at about chest level. As the driver turns a corner the centrifugal forces would pull sideways, causing the cradle & seat to rotate on the axis so that the driver’s bum and legs move outwards/sideways and his head and arms would move inwards. The result would be that the forces would be acting down through the whole body, not just trying to yank his head off sideways.

    But it’s not realistic as it would be heavy and bulky, would make the car a lot wider (you’d have to have the space to move into as you corner), there would be a gap between the driver’s head and the foam crash padding at the sides, you would have to mount the pedals & steering wheel in the rotating structure, and there is a possibility it could come free of the safety cell in a crash. Would be good fun going through the left-right-left-right corner sequence of Maggots/Beckets at Silverstone though!

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  • saltire (author)

    Thanks for the description PM :)

    Something I’m pondering about for part 2 is that maybe part of the reason Tilke’s tracks can seem boring is he has to take g-forces into account in the design and corners that deliver any more than about 4.5 g are to be avoided? I’d like to see if I can find out some detail on the load for some of his corners like corner 8 at Turkey before I explore that further.

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  • King_Alonso786 (In Process Of Making A Name Change)

    Fantastic blog saltire. Credit to you for talking about something complex yet making it easy to understand

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  • Sebastian (Birmingham, UK)

    Excellent stuff. Look forward to reading more.

    Champ Car had to cancel a race at the Texas Speedway in 2001 because the 24-degree banking proved to subject drivers to forces of 5G to 5.5G for much of the lap resulting in disorientation and tunnel-vision that on occasion meant they did not even see other cars. There is a surprisingly detailed article, about this on Wikipedia.

    To be horribly pedantic, kilogrammes are units of mass, not weight. A 70 kg person would weigh 154 lbs on Earth; in zero-gravity they would become weightless but still have a mass of 70 kg.

    I question if cardio-vascular fitness is as key as you suggest. Before reading your article, I was cynical about cardio-vascular capacity being critical to F1 drivers. It is something fitness trainers preach at first opportunity because the scientific terminology may make them sound brighter than they actually are. Equally, portraying themselves as bona fide athletes is part of the PR-code for modern drivers. For example, Mika Hakkinen made a show of going to the gym after practice and kept his cigarette smoking quiet, despite racing for a tobacco sponsored team!

    To a long distance runner or cyclist, cardio-vascular capacity is critical to competitive performance but to a weight-lifter or 100m sprinter, it is over before getting out of breath is an issue. Cardio-vascular capacity is the efficiency that the lungs can absorb oxygen into and expel carbon-dioxide out of the bloodstream combined with how powerfully the heart can pump that blood around the body. Olivier Panis once tried an adhesive strip across his nose and was asked after if it improved his breathing. He replied, “Yes, but I didn’t drive any faster.” Such strips would slightly help cardio-vascular efficiency but drivers do not use them. A guy moving crates stops to rest because his arms or back need a break, not because he is out of breath. F1 drivers need huge strength in their legs, arms and necks and may slow down if for example their arms weaken, but not because they run out of breath.

    However, having read your article, I do wonder if cardiac capacity might help reduce the ill-effects of high G-forces but I think I doubt it. If the heart beat harder to push the blood around at higher pressure and/or the lungs worked harder to put extra oxygen into the blood, it would help counteract the negative effect of G-forces, but the body would set breathing-rates and heart-rates based on oxygen depletion, not levels of G-forces.

    Obviously, drivers need pretty good cardio-vascular ability, but physical strength is I feel much more critical and the training for that strength (and endurance of that strength) would probably provide the cardio-vascular ability they need.

    (If you go to the official F1 site and go to ‘Races’ and ‘2010 Calender’, click on any of the races and the interactive maps include G-force data.)

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  • saltire (author)

    Champ Car had to cancel a race at the Texas Speedway in 2001 because the 24-degree banking proved to subject drivers to forces of 5G to 5.5G for much of the lap resulting in disorientation and tunnel-vision that on occasion meant they did not even see other cars. There is a surprisingly detailed article, about this on Wikipedia.

    Hehe, I was intending writing a bit about that in part two :)

    Thanks for the link to the official site also, I had found some details from Williams site about g at various corners so that will prove useful. I’m hoping to have part two up by tomorrow.

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  • Maverick

    However, having read your article, I do wonder if cardiac capacity might help reduce the ill-effects of high G-forces but I think I doubt it. If the heart beat harder to push the blood around at higher pressure and/or the lungs worked harder to put extra oxygen into the blood, it would help counteract the negative effect of G-forces, but the body would set breathing-rates and heart-rates based on oxygen depletion, not levels of G-forces.

    Olivier Panis was hooked up to a heart monitor and a microphone to record his breathing many moons ago – and both shot up as he approached a corner. Train a body’s cardiovascular-capacity and it will use it.

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  • Viva F1 » Feel the Force – Part 2
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