Iztech Seat Science

Alex Hawkridge from Iztech spoke to Karting1 about our design philosophy back in 2010 – His words are still absolutely valid today.

Iztech Seat Science

 

I first contacted Iztech after they had exhibited a lightweight kart seat at the London Kart show in 2007. At the time I was running my nephew, Freddie Lee in a lightweight ZIP Blade. We were overweight despite having a carbon seat and floor supplied by ZIP. At Iztech the seat and floor were designed to flex so that the chassis was allowed to twist with less resistance. This enabled the inside rear wheel to lift faster, making turn in to corners more positive whilst allowing the chassis to un-twist faster as steering lock was reduced exiting a turn. Freddie tested several prototypes and then went on to win the first Super One Round at Larkhall using an ultra light Iztech seat and floor tray.

 

When I first went motor racing in the 1960’s a Formula One seat was made by filling a black bin liner with two part resin sitting the driver in the car with the bag around his sides and back. The foam expanded all around until it poured out of the top, making an awful mess of everything it touched! Once dry, the ‘seat ‘was trimmed to size and covered in black tank tape. This gave the driver some comfort in the car and was universal practice for almost two decades!

 

By the time I was running the Toleman Formula One team in the 1980’s we had learnt that the driver was much more comfortable and could ‘feel’ what the car was doing better, when he was sitting in a rigid ‘made to measure’ carbon fibre seat. This conclusion was drawn from empirical development rather than pure science but the benefits were undeniable. I’ll come back to this issue later on.

 

Back to Karting and in the latter part of 2007 I was testing with different composite constructions of seats and floors manufactured by Iztech, trying stiffer and softer flexible seats. Several of my design team and best friends from the Toleman days were now key players at Ferrari and Renault F1. I was also Chief Executive of Reynard Motorsport for a couple of years, which is another place I met many useful contacts. They have all given me a lot of support in understanding the complexities of driver / vehicle interfaces. They helped me to understand the physics of Karts and the interaction of floors and seats with chassis: Some had direct experience of Karts personally, or as I had, through their son Karting some 25 or so years earlier.

 

Many people running karts will know that loosening the floor tray can substantially reduce grip, particularly at the front end whilst loosening the seat can reduce grip, particularly at the rear. This practice is illegal but not policed properly by the MSA’s overstretched resources, so it has become common practice when tracks are extremely ‘grippy’. The downside is that the seat and floor together act as a mass damper and when loosened, the chassis can become nervous and unpredictable in its handling. One driver described the feeling as “it’s got a mind of its own.”

 

The whole Kart chassis acts as the spring in a conventional suspension system, and its stiffness, together with weight distribution and centre of gravity, largely determines its handling characteristics. Generally, a stiff chassis develops higher grip in cold and wet conditions and a soft chassis produces less grip, which is often desirable in hot and dry conditions. The key for chassis manufacturers is to produce a chassis, which works over a wide range of conditions.

 

Stiff and soft, wide and narrow axles at high or low ride heights can vary the grip at the rear and different stub axles and changes to camber, castor and toe can achieve similar results at the front. Weight distribution is critical in achieving optimum front to rear balance. Constructors and teams constantly evaluate these parameters yet seats and floors are every bit as critical to grip and balance as any of these. Kart seat manufacturers seem oblivious to their importance in the overall scheme of things and many constructors and teams appear to have dismissed them as irrelevant! There is a general reluctance in Karting to try new ideas and testing is often based on past experience rather than a desire for continuous improvement, which is what drives people in F1.

 

Coming from a background in high level motorsport has made me aware that there is absolutely nothing on a race car or Kart that doesn’t affect performance! It has amazed me that seats and floors have been overlooked in the search for improved performance. I am not suggesting that they are some sort of magic way to go faster, although just as getting tyre pressures correct, the right seat and floor can make a massive difference to lap times!

 

This is really the crux of the issue: In order to optimise a karts performance under high, medium or low grip conditions it can be beneficial to change the seat and sometimes even the floor, in just the same way as you would change the type of tyre and the pressure it should run at. Having several identically sized seats, but in different stiffness’s makes just as much sense as having dry and wet tyres! They take very little room as they stack and compared to the cost of tyres, represent excellent value! The same is true for floors.

 

Seats and floors are devices that can reduce lap times when fitted in the correct conditions, however the majority of drivers are seated incorrectly and have neither the comfort nor fit that an anatomically correct posture and seat size offer. The installation of a seat in a Kart determines front to rear and side to side to side weight distribution, and this is often not considered!

 

Comfort and fit can significantly increase confidence and reduce fatigue, which in turn improves concentration. Confidence and concentration are, in my view, the two most important factors in winning! They enable a racing driver to drive faster without making mistakes. People spend fortunes to get more powerful engines or to throw new tyres at every problem, when for a fraction of the cost, they could really step up performance through such simple measures as correctly fitting the right seat!

 

I referred earlier to the changes I witnessed in F1 seats, over a couple of decades, 25 years ago. Only recently an objective experiment was carried out which discovered that physiological changes take place in young drivers that make them better able to adapt to extraordinary G forces, yaw, and rotation acting upon them! I touched on this subject in an interview I gave to Karting Magazine published in November 2008. Nearly every Grand Prix driver started their career in Karting and many team principles will not employ drivers unless they have a Karting background.

 

In the QinetiQ experiment the person being evaluated was sitting in a rigid seat rotated by a fluid drive. The subject had a button in each hand and had to press the appropriate button when a change in direction was sensed. The subjects had black out hoods and could see nothing, but two of the three F1 drivers correctly identified every direction change! Their reaction speeds were the fastest recorded compared to fighter pilots, and ice hockey players to name a few. One of the F1 drivers tested was as good as the fighter pilots and ice hockey players but not as good as the other F1 Drivers tested. He had started his career in cars much later than his team mates, who had been racing Karts since they were eight years old.

 

This research was undertaken to see whether youngsters could be selected, following appropriate testing and could then be subjected to moderate but extraordinary forces to cause physiological changes to take place. This would evolution could enable them to pilot next generation warplanes! Apparently, the President of the USA is unlikely to sanction 100 Billion Dollar Aircraft armed with Nuclear weapons to fly without pilots!

 

These pilots would be fitted with rigid, made to measure seats so they are able to feel every nuance in flight, whereas previous generations of pilots were fitted to padded ejector seats! This isolated them the critical contact from the spine with the seat back. The coccyx at the base of the spine to the third vertebrae below the nape of the neck is where the spine has sensors that receive the data transmitted via the seat, this is then computed by the subconscious brain, operating at four and a half Billion bits of Information per second! Flying fast and driving fast require no conscious thought, that is why pilots, like drivers can multi task, for example, talking over the radio whilst in the middle of a chicane!

 

Iztech have developed their Kart seats so they act in the same way as the seats now used by US fighter pilots. The seat has a channel for the spine while the back of the seat flexes to stay in contact as the driver transfers weight into, through and exiting a corner! All of the data from the chassis is fed into the seat, then our unique design and constructions enable the important frequencies to be transmitted to the receptors in the driver’s spine.

 

Ironically perhaps, many drivers handicap themselves by wearing rib protectors that cover their spinal column and effectively block transmissions from the chassis to the spine! Drivers using Iztech seats who have been advised to remove their rib protectors, have all been amazed at how much more ‘feel’ they have, and most have gone faster without any conscious thought to do so! There is no scientific evidence that proves that rib protectors prevent injury, but Iztech have a new product, which protects the sternum and ribs whilst using a small amount of elastic at the back which allows the spine to remain in contact with the seat! It also gives the driver freedom of movement to lean forward and duck down.

 

Iztech have produced the first Karting body armour with European Safety approval. This requires rigorous crash testing to gain compliance. It surprises me that there is no requirement for this standard to be achieved. The vast majority of products on the market wouldn’t get near to matching the standard of the Iztech protector.

 

Recently, Iztech have tested the frequency range of different mesh constructions and can now achieve very similar results over our entire range of seats. We now have instrumentation, which measures the torsional stiffness of each seat together with its acoustic profile. This has proved to be a reliable and effective method of testing and has given Iztech customers a better product, leading to enhanced driver performance.

 

There is further research and development ongoing for the foreseeable future to improve Iztech’s knowledge of Driver / Vehicle interfaces. We are working with several Universities to expand our knowledge of seats and floors and we are looking into steering wheels, as well as brake, and throttle pedals. All of these interfaces can be dramatically improved for ‘feel’ and as a by product will almost certainly become lighter.

 

I often hear Dad’s say “we already carry a load of ballast’’ as an argument against having a lighter seat and floor, when in fact, as is proven in Formula 1, the more ballast you carry, the lower your centre of gravity will be and there is so much more scope to change weight distribution! That is a huge performance advantage for small drivers, who already have an important aerodynamic advantage, as they punch a smaller hole in the air and create a lot less drag!

 

Situating ballast where you want it on a kart can also lower the polar moment of inertia, which allows Karts to change direction faster! Many Karts benefit enormously from ballast up front in wet weather to help ‘turn in’ or right at the back to aid traction. Only a fool would fit a heavy seat or floor to avoid carrying ballast. A typical Iztech seat is about one third of the weight of our competitors’! That is a significant performance advantage straight away. We are now shaping 5 kilos of ballast to fit exactly the profile under the leading edge of the seat to keep as much weight as low as possible.

 

Very small drivers, even in senior formulae, sometimes have problems with their chassis not lifting an inside rear wheel in wet or low grip track conditions.

This prevents the Kart from turning into a corner and causes it to understeer badly. Often I see lead weight mounted up high on seat backs to try to alleviate this problem. It would be much more effective to keep the weight low, for better handling when there is good grip available, but to raise the seat higher on its mounts when it’s wet.

 

These drivers can be raised by up to 50mm or more without having problems fouling the steering wheel and this raises the Kart’s centre of gravity dramatically. A pre-installed stiff seat, specifically for wet of slippery conditions, with lead ballast already mounted as high as possible, but not on the seat back, can be kept ready to switch in a few minutes when conditions dictate. This is much more effective solution than the soft pads, which some drivers try to sit on. It ensures good comfort and fit and, importantly, ensures the drivers coccyx and back remain in contact with the seat.

 

Raising the seat and driver increases the centripetal force which causes the inside wheel to lift. A small, novice driver should have a seat mounted as high as is practicable so that the Kart will turn into corners well and generate heat in the tyres. This feeling of grip will build a youngster’s confidence and speed quickly. When lap times start to be competitive the seat can be set lower for optimum handling in good grip conditions. These drivers will also benefit from carrying their ballast as high as possible.

 

Before I became Chairman of Iztech I had injected the funds required to undertake some serious research and development projects. We now have digital scanners that can output direct to CAD and FEA, which allows us to look at any seat requirement and carry out computer aided design and finite element analysis. We now have testing equipment that shows us how different combinations of composite materials will perform. We are not looking at seat design in isolation but as part of the Kart so we model chassis and seats separately and together.

 

Important data pathways are integrated into our seats so that the maximum amount of information passes from the seat mounting areas to our spinal recess in the back of the seat. We are also able to identify where we can save weight and also where we should mount lead to avoid damping the critical data flows that provide driver feedback. Lead ballast should never be bolted to the back of the seat as it effectively damps out this flow of information. It is very important that the seat is not stressed when installed. The seat should be fitted so that it sits onto mounting points without being forced in any direction.

 

We have the capability now to scale our designs up or down, wider or narrower so that we can make a seat to fit anyone of any shape. Many female drivers have a problem finding a seat to fit as they are usually narrower than men in the under arm but wider at the hips. They usually end up with a seat that doesn’t fit properly despite masses of padding. Iztech are producing seats designed specifically to solve this problem. We are also producing smaller than Cadet Size seats for children driving in the Bambino class and will offer exactly the same range as for Cadets. Smaller Cadet Drivers may find a better fit in this new range.

Science in seats is just the beginning for Iztech. We are beginning a new era where the old fashioned methods of Kart design and construction, as well as data capture, will join the digital revolution. I foresee science in chassis with computer aided design and engineering incorporating advanced finite element analysis, computational fluid dynamics and even wind tunnels being used to create the Karts of the future. All seats and floors will be integrated into the overall design process so that their effect can be modelled and assessed. This is all achievable today!

 

The only reason it hasn’t happened sooner is that the current generation of designers and engineers are not systems literate in the disciplines required, or they work for companies living off of past success

 

It’s a time for change and no industry, including Karting and those dinosaurs within it, will survive unless they embrace scientific principles to design, develop and construct products to micron tolerances in place of plus or minus a few millimetres!

 

The power of computer aided engineering has transformed racing car design and it’s about to do the same in Karting. Better performance and more consistent, high quality products will secure a bright future for everyone involved. It’s an exciting time and I’m enjoying this challenge immensely!

 

Alex Hawkridge

April 2010

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