Apr 172015

Sounds like an energy drink, right?

Listening to Kyle Busch’s press conference Wednesday was alternately fascinating and cringe-worthy. The fact that he remembers so much about the crash is amazing – it will be a great boon to the safety people who probably will use this as a case study in the future. And best wishes to Kyle to get well soon.

Kyle said he left the track at 176 mph, hit at 90 mph and sustained 90 Gs.  My twitter was flooded with people asking “90Gs? No one could survive that kind of a hit.”

That’s actually not true. Trying to quantify a crash via one number is a nice attempt at simplifying things, but totally wrong.

Warning – I wrote and researched this while flying halfway across the country, so we’re likely to need a re-write when I get back home Monday and have a little more time to make this prettier. But let’s start by clarifying terms.


The ‘G’ is quite possibly the most misunderstood unit in racing.  A ‘G’ measures acceleration, not force.   One ‘G’  is equal to the acceleration of any object due to Earth’s gravity. You are experiencing one ‘G’ right now. The product of your mass times the acceleration due to gravity is your weight.

Acceleration is how fast you change speed. If you go from 0 to 62 mph in 2.8 seconds (like the Lykan HyperSport in the Furious 7 Movie), you’ve got an acceleration of 22.4 mph each second. Every second, your speed increases by 22.4 mph. It’s an acceleration of a little more than 1G. (which, by the way does may the Etihad towers jump possible. I did the math, just thought I’d throw that in.)

Let’s set the scale. The Space Shuttle pulled 3G on launch, Apollo 16 pulled 7G on re-entry. A Formula 1 car pulls about 5-6 G laterally during sharp turns and 4-5G during linear acceleration. I’ve got a story in the Physics of NASCAR book about Texas Motor Speedway having to cancel an open-wheel race at the last moment because the drivers were pulling so many Gs that they were having mini blackouts. A good rollercoaster will give you 2-3G.

Electronics spec’ed for the military for use in shells have to survive 15,000 G.

Weight is the force resulting from the acceleration. Remember F-ma? When you experience ’3Gs’ of acceleration, the force you experience is the number of G’s times your weight.

We use the unit ‘G’ just like a unit like ‘dozen’.  I can express anything in terms of dozens:  a dozen eggs, a dozen jellybeans or a dozen beers.  Likewise, we can use the unit ‘G’ to express the acceleration of anything.  I can measure the acceleration when you step on the gas after stopping at a red light in ‘G’s.   I can measure the acceleration you feel on a rollercoaster in Gs.

Important: Although Earth’s gravity pulls down (toward the center of the Earth), we use ‘G’ to measure acceleration in any direction:  up or down, back or forth, or sideways.

How Many G’s Can a Person Withstand?

Again, this is by no means meant to minimize Kyle’s experience. He had a really hard crash and broke bones in both legs. So don’t interpret what I’m going to say as trying to say he’s lying or wrong or is trying to exaggerate his injury. It was serious.

But it wasn’t as simple as “90 Gs”

I’m pretty sure the numbers Kyle had were the numbers from the car’s transponder. As far as I know, NASCAR hasn’t instituted in-ear accelerometers like IndyCar.

An accelerometer is exactly what is sounds like: a meter for acceleration. Most iPads and iPhones today have one. Especially given the increasing concern about concussion, IndyCar and F1 have both provided drivers with a tiny accelerometer that fits into the ear and thus gives a much more accurate measurement of the actual acceleration of the head. (Remember that the problem with concussion is that the brain actually hits the inside of the skull.)

NASCAR relies on a transponder located near the frame rails (low) in the car. That means it measures what happens to the car, not the driver. A number of safety measures make the driver slow down less quickly than the car. I’ll come back to that.

There are three primary factors in a crash: The change in speed, the time over which the change in speed happens and the direction of the force.

So it’s not only how fast you’re going when you crash, it’s how fast you stop. When the people who study these things talk about crashes, they talk about the “crash pulse”, which incorporates the first two of these factors. Here’s one I drew for illustration.


When someone talks about 90G, they mean that was the peak value of the acceleration vs time curve was 90G. In my plot above, both curves show a crash from the same starting speed. The difference is that the red curve was a case in which the force/acceleration was spread out over a longer time. That’s why the peak value is lower.

How many Gs you experience depends on your starting and ending speeds and how long it takes you to stop. In the case of a crash where you go from 90 mph to stopped over 1 second, you experience about 4 Gs. If it happens in a tenth of a second, you experience 4o Gs.

Now let’s look at a real crash pulse.


Here, you see the crash and you see the backlash – that’s the negative acceleration on the right side of the graph. The details of these graph give you a much fuller picture of a crash because you learn how the force was distributed in time.

Although the peak force was 90G, that 90G was applied for a short time. Lesser accelerations were experienced during the rest of the crash. A peak force is like a snapshot of a dance. You get one impression, but it’s not the whole picture.

Let’s get back to measuring the car vs. measuring the driver. The driver is belted in by 2 to 3-inch-wide belts over the shoulders, around the lap and around the legs. Those belts are designed to stretch when they’re stressed, which means that the driver doesn’t stop as quickly as the car stops.

Same thing with the HANS device. The tethers on the helmet allow the driver’s head to move forward, but they slow the rate at which the head moves. So even if the car experiences 90G, the driver experiences less. How much less would require a lot of assumptions, but if the various safety devices double the time it takes for a driver to stop, it halves the force.

I mentioned direction is important. That’s because any force on your body also is a force on your blood. Pilots who make sharp accelerations up or down (parallel to the spine) have issues because the heart has to work extra hard to pump the blood. The human body can withstand higher accelerations perpendicular to the spine than parallel to it.

No, Really. How Many G’s Before It’s Really Bad.

StappSledYeah. That’s what you’re really asking, isn’t it? What are the limits of the human body? These are difficult questions to answer because you can’t really do the experiment. People don’t volunteer to be accelerated really fast so scientists can see if they survive.

With one exception.

Col John Stapp (Air Force, shown at left) was active in the late 40s and early 50s. We didn’t know how far or how fast airplanes (and rockets) would allow us to go. And even if we could build the machinery, would a pilot or passengers survive?

The military didn’t want to hand over soldiers for him to run experiments on.

So he experimented on himself.

Today, that would never happen because there’d be so much paperwork that he’d die of old age before he got approval. But back in the 50s, people got away with a lot more.

The picture shows a test in 1954 where Stapp accelerated at 15g for 0.6 seconds and reached a peak acceleration of 22 second. His record was 46 g, and he sustained more than 25 g for 1.1 seconds.

This was no 90 G, but whereas a driver might experience that acceleration for a couple hundredths of a second, Stapp did it for tenths or full seconds.

These experiments had consequences. There is one really big problem with acceleration perpendicular to your spine. Your eyes bug out (or in).

No, seriously. Your eyes are held into your skull by a couple muscles and optic nerves. High accelerations (and decelerations) is like putting your peepers on a bungee cord. What finally stopped Stapp’s experiments was that he sustained major damage to his vision. I highly recommend http://www.ejectionsite.com/stapp.htm if you’d like to learn more.

C’Mon. How Many G’s Has a Human Being Sustained Before…

O.K. A paper (Society of Automotive Engineers. Indy racecar crash analysis. Automotive Engineering International, June 1999, pages 87-90) says that IndyCar drivers have survived 100G+ crashes. I don’t know yet whether those are crashes measured with the in-ear accelerometer, so it’s difficult to make a direct comparison with NASCAR.

But remember that even smaller accelerations – if applied in just the wrong way — can have equally catastrophic results for the driver.

Closing note: You know what they use in doing crash research? Yes, Crash Test Dummies, but the human body is so complex and intricate that a dummy can’t tell you everything.

They use cadavers.






Apr 032015

There are three things you don’t mess with in NASCAR: engines, fuel and tires.

Tuesday, NASCAR handed down a P5 penalty – the penultimate penalty on the books – to Ryan Newman’s 31 team. Crew Chief Luke Lambert was suspended six races, fined $125,000, and Newman and his owner Richard Childress were each docked 75 points. The tire specialist and team engineer were suspended for six races as well. RCR is appealing the penalty, but I wager they’ve got an uphill battle.

NASCAR’s made its stand loud and clear in the last few weeks. Tire bleeding will not be allowed. If you persist in trying, they’ll come down hard on you.


Why Would You Bleed Tires?

The hotter the gas inside a tire gets, the higher the tire pressure gets (says the ideal gas law).


The tire volume changes a little with temperature and pressure, but it’s not a huge change. If you were doing actual calculations to use in a race, you wouldn’t ignore it. For us, it’ll be good enough to approximate that the volume remains constant.  The equation tells us then that the ratio of pressure to temperature has to stay the same. If the temperature goes up, the pressure goes up, and vice-versa.

The video below (from the National Science Foundation) details how and why the tire pressure increases. Steve Letarte is a nice person and a very clear explainer of things. I look forward to seeing how he does when NBC takes over broadcasting NASCAR later this year.

The main problem with changing tire pressures is that grip depends on tire pressure – a lot.  If the tire pressure is too low, you lose energy to rolling resistance. If the tire pressure is too high, the sides of the tread pull away from the track, giving you a smaller contact patch and less grip.

Tire builds can be significant. At some tracks, you might see a 35 psi change in tire pressure. A large build means teams have to start a run with very low tire pressure – 8-10 psi at some tracks. If you look at a car at Martinsville waiting to go out on track, it’ll appear as thought it has flat tires.

Bleeding tires prevents the tire build (increase in pressure) from getting too large by releasing some of the pressure once the tire pressure reaches some value.

Wait… Like a Pop-Off Valve?

This is the same principle teams use in the radiator systems. Put water into a closed metal tube and heat it. We call that “a bomb”. As the liquid gets warm, it turns into gas, the gas pressure increases and eventually the gas inside pushes so hard it breaks the radiator or the tubing in the cooling system.

So we use a little valve called a pop-off valve on the radiator. When you see steam pouring out from near the bottom of the windshield, it means the pop-off valve has popped. The video below explains the pop-off valve in the cooling system.


That’s a great idea, right? They ought to make something like that for tires, so that the tires can’t get overinflated.

TireBleedValvesThey do. It’s called a tire bleed valve. Shown at left, you install it in the valve stem of the tire. Most are adjustable between some range of pressures.

An o-ring sits atop a spring. When the pressure is low enough (left), the spring is relaxed. The o-ring forms a seal on the valve seat,which holds in the air.

When the pressure inside the tire increases past a pre-set value, the spring compresses and unseats the o-ring. Notice how by where it says “no seal” the o-ring doesn’t touch the sides of the valve anymore . This gives air a path to escape. As soon as enough air has escaped so that the pressure returns to the maximum value, the spring relaxes and the valve closes. There’s less air in the tire, which allows the pressure to remain lower.


Seems Like the Perfect Solution. So…?

So bleed valves (or tire pressure relief valves) aren’t legal in NASCAR. However much nitrogen you put into the tire is how much you have and the driver is supposed to deal with the changes in the tire pressure. The harder you drive the tire, the hotter it gets, so having a way to relieve pressure gives the driver the option of pushing the car harder than a driver who is limited by the building tire pressure.

The scuttlebutt around the garage is that the tires on the 31 had small holes poked in the sidewalls. Rubber is stretchy enough that you can get a tiny, tiny puncture and it won’t open up a gaping hole that lets all the air out of your tire. The rubber on the sidewall is thinner than the rubber on the tread, so a pin prick or something similar would do the job.

The disadvantage of this method is that it’s totally random. With a bleeder valve, you can set it to go off at 35 psi and you know it won’t let any air out until 35 psi. With something like poking tiny holes in the tire, you have to guess at the number and placement of holes so that you don’t let out too much or too little. There’s also a safety issue, in that your well-intentioned “tiny” hole might actually do more damage than you intended – or noticed until the right front below out going 180 mph into a turn.

Plus, one of the fundamental tenets of NASCAR is that you do not mess with the tires. It’s bad from a sportsmanship angle and from a safety angle.

How would you tell?  The easiest way to find out if there are tiny holes in the tire is to over pressure the tire (maybe fill it up to 50 psi) and toss it in a bathtub or a swimming pool. If there are holes, you’ll see air bubbles coming out from the holes. (We actually used to use this technique to find big leaks in our vacuum chambers.) If you can’t submerge the tire, you can overpressure the tire and then squirt a little soapy water on the suspicious areas. You’ll see bubbles (from the soap) appearing near the holes.

If you want to be really pedantic about it, you can look at the material under a microscope once you’ve narrowed down where you suspect the holes might be located.

Can You Really Be Sure Someone Cheated?

There are a lot of things that could put a hole in a tire. But not the same size/shape hole multiple times in multiple tires. NASCAR is pretty cautious about not nailing people without solid evidence. I will be majorly surprised if RCR wins their appeal. That’s not to say upholding the penalty means there was a plan by the team to cheat the tires that way. It could have been one person thinking they were helping and the folks who got fined knew nothing about it. Science says nothing about intention or motive.


Mar 062015

Jeff Gordon’s decision to step away from full-time NASCAR Sprint Cup racing has resulted in a lot of discussion about aging drivers. We’re on the verge of a turnover as a number of drivers (Johnson, Stewart, Junior, Harvick among others) reach their forties. And what an appropriate topic for this week as I hit one of those milestone birthdays next week myself.

Slowing down is a part of aging. The print on menus shrinks, you wake up with aches and pains you can’t figure out where they came from, and you find that it takes you longer to recover from colds and injuries. Sprint Cup drivers are no different. In fact, it’s probably exacerbated because they subject their bodies to more physical punishment than your average human being.

But there are some advantages to aging. You’ve got more experience.  And… well, I’m sure there are others.

So how does age affect a driver’s career? Let’s look at the numbers. (And while you’re at it, check out Eric Chemi’s blog – he took a different approach, but came up with mostly the same conclusions.)

What Do We Measure?

The challenge in questions like this is what to graph that actually makes some sense.

DriverAges_Stewart The first obvious thing to try is wins (or top 5s or top 10s) vs. age, right? I did this (at right) to look for obvious trends. (Note – you can click on any of these graphs and they should like to a full-size version so you can see details.)

This is pretty useless. Stewart won championships at ages 31, 34 and 40. All years where he won a respectable number of races; however, there are years where he won a lot of races and didn’t win the championship.

I also plotted Top 5s and Top 10s this way and it wasn’t any more enlightening.

So I had to re-think a little. What we’re interested in is whether a driver becomes a worse driver as he or she ages. This got me thinking about cumulative stats.

If you’re staying at the same level, you ought to add the same number of wins each year (on average, of course). So what if I plot the cumulative wins as a function of age. That turned out to yield some interesting information.

Cumulative Statistics

It’s always rewarding when you plot something and you realize you finally found the right thing to measure and graph. As a note, I did not include years at the end of a driver’s career where he (and they’ll all men here) didn’t run all the races that year. A number of drivers ran part-time at the ends of their careers, some for lower-tier teams and I didn’t think that would be a fair representation of their career to include those later years.

Let’s start by looking at stats for someone with a long career that spans a wide age range: Darrell Waltrip.

From top to bottom are cumulative wins, cumulative top 5s and cumulative top 10s. There are some subtle differences between the three graphs, but let’s talka bout what they have in common.

If you look at the later years, the graphs become essentially flat – which means there were no more wins, top 5s or top 10s. But the point at which they plateau changes. The wins flatten out first (no new wins after age 45), then the top 5s (only two more after age 50)  and then top 10s (8 after age 50).

The areas where the slope of the graph is constant over a period of time I would characterize as consistent. They are adding to their record at the same rate. All three of Waltrip’s championships (shown in the highlighted regions) came during that period of time.


DriverAges_Portrait_waltripByOwner2This would seem to suggest that this is a driver who reached a certain age and just couldn’t hack it after that – but there are some extenuating circumstances, namely a crash at age 43 and his transition from Hendrick to becoming a driver-owner shortly after.  I’ve put a thumbnail of the graph to right – click to see it larger.

Just a warning that you have to be careful about the rationale.

A number of drivers have very similar looking graphs: Both Labonte brothers, Dale Jarrett, and Mark Martin. But in those cases, there were also extenuating circumstances in terms of changing to lower-tier teams (Bobby Labonte went from Gibbs to Petty, for example). So let’s look at the drivers who don’t follow this pattern.



Wow. You want to talk consistent? Here’s a man who (until the nightmares of the last two years) is almost one straight line from start to finish. The top 5s and top 10s are almost perfectly straight lines. The wins have a little more scatter – but that’s typical because the overall numbers are smaller. Jimmie Johnson’s graphs look very similar.

When we analyze graphs we like to talk about curvature. There’s no curvature here. If the graph curved up (i.e. looked like a saucer), that means the person was getting better. If the graph curves down (as it does when it plateaus), then the person is getting worse.

And now for one of the the interesting ones. It’s interesting in part because Jeff Gordon has driven for the same company his entire career, which eliminates the question of equipment from the analysis. Here’s the raw data for wins.


Again, it’s small to save space – click to get a larger version. This is really interesting. You can divide his career into specific segments – see how the slope changes in different ranges of years? My first attempt to explain this was to look at personal events like marriages and children. There might have been a correlation there, but them I looked at his crew chiefs.


That’s sort of interesting, huh? I didn’t make a line during Steve Letarte’s (I know, I spelled it wrong in the graph) tenure. There was a jump there, then it was pretty flat. But that’s a pretty convincing correlation, I think.

Gordon’s still very consistent when it come to the top 5s and top 10s.


Okay, But Can Older Drivers Compete Against Younger Ones?

I know. I got carried away with the data. I do that.

I made a lot of other plots, but here’s the one I think is the most interesting.DriverAges_Champions

There’s been an influx of younger drivers – they start earlier and one might think that would lead the average age of the Sprint Cup Champion to be going down. Overall, though, it’s not. It’s going up. The most recent “Young” winner is Brad Keselowski – and he was 28 years old.


Don’t count the old folks out yet. Even at the advanced age of (gasp) 40-something, drivers like Tony Stewart (pre the last two years), Jimmie Johnson, and Matt Kenseth are remaining consistent with their performance when they started in the series.

Ever scarier, if you look at Kevin Harvick or Brad Keselowski’s graphs, they’re better than straight lines. These drivers are still improving (even as Harvick approaches 40 and Keselowski 30), which means we probably haven’t seen the best of them yet.


Feb 252015

TL;DR:  No.

As the extent of Kyle Busch’s injury Saturday evening at Daytona became evident, Twitter erupted in angry calls for SAFER barriers to be put up on every wall at every track. An interesting division of sides appeared. A small number of people cautioned that simply plastering every track with SAFER barriers was likely to not only not prevent driver injuries, but might actually introduce new problems. Other people accused this group of being insensitive and “stupid”.

Interestingly, the small number of cautionary voices were people like the folks who write Racecar Engineering magazine, people who have been involved with motorsports safety research and people with advanced engineering degrees.

So let’s be really clear here. While I appreciate the passion with which people responded to the accident, opinion has absolutely no place in science and engineering. We work with facts, realizing that oftentimes, we don’t have all the facts we need. In an ideal world, we would have data from collisions at every track in the world, from every angle, with every type of racecar. But we don’t.

It’s fine for fans (and especially for drivers and their teams) to raise their voices and demand more attention to safety, but the average fan (or the average driver) has zero business specifying what those safety measures ought to be. The average NASCAR executive or track administrator doesn’t, either.  Motorsports safety is a constantly evolving research field and luckily, NASCAR recognizes that and works with the top people in the field.


Let’s start with the obvious. A bare concrete wall at a track where speeds reach 200 mph is indefensible. To their credit, NASCAR and the Daytona folks promised to rectify that right away. Tire barriers – which are not ideal, but are definitely better than nothing - were up for the next day’s race.

Racetracks originally put up concrete walls to contain the cars and protect the fans. They weren’t there for driver safety. People don’t question the status quo.  It wasn’t until a number of serious accidents in both IndyCar and NASCAR prompted an effort to develop a better wall. I detail the origin and development of the SAFER barriers in my book, The Physics of NASCAR, based on my interviews with the barrier developers. The effort was initiated by IndyCar, but gained momentum when NASCAR threw their support (and money) behind it.

Once the technology was developed and proven, NASCAR mandated SAFER barriers on the outside walls of all tracks. It was a long road to development because it was a brand new (and frankly, counterintuitive) idea and everyone wanted to make sure it would work under as many conditions as possible.

How SAFER Barriers Work

For an overview of NASCAR safety, check out this video I made with the National Science Foundation. Here’s the brief version.


The SAFER barrier works by extending the time of impact. It’s much more comfortable to fall on a mattress than a floor because the mattress gives. The mattress absorbs and dissipates energy, so that the energy isn’t dissipated through you.

BSPEED_SAFERBarrier_HitA NASCAR stock car going 180 mph has approximately the same kinetic energy as stored in 2 pounds of T.N.T. When the car comes to a stop, all that energy has to go somewhere. Energy can be dissipated by skidding (friction between wheels and asphalt), light and sound (it takes energy to make that screeching noise and to produce sparks), spinning (energy is used to rotate the car) and deformation (energy is used to crunch or break things).  The key is that you want to dissipate energy any way except through your driver.

A mattress won’t make much difference to a speeding stock car. You need something much stiffer, and that’s the purpose of the SAFER barriers. They’re like mattresses for race cars. They use the energy of the car to deform the barriers and spread out the impact over a longer time. This directs energy away from the driver.

Why SAFER Barriers Aren’t the Only Answer

SAFER barriers save lives and this analysis is meant in no way to diminish their importance. But the inventors of the SAFER barriers would be the first folks to remind us that it takes multiple safety devices, working in unison, to protect the drivers (and the crowds). HANS or hybrid devices, helmets, restraints and the car itself are all part of the equation. You can’t address any one of those elements without considering the others. So here, briefly, are some things to think about.

Kinetic Energy Ranges

SAFER barriers work best in a specific kinetic energy range. I was surprised when interviewing drivers for my book to find that more than one mentioned that hitting a SAFER barrier at low speed actually hurt worse than hitting a concrete wall. But it’s true. The wall works by giving. If you don’t hit it hard enough, it doesn’t give and then it is just like hitting a concrete wall. This is relevant for a couple reasons.
1.  Most tracks host more than one kind of racing series. The kinetic energy scales of those series can vary widely. Any solution has to make the track safer for everyone who races there, not just stock cars.
2. Different tracks have different speeds, so even just within a single racing series, this means different kinetic energies. Compare Martinsville and Daytona, where the maximum speeds are a factor of 1.5-2 different. That means the kinetic energy scales differ by a factor of 2.25-4. That’s a big range. The response of the SAFER barriers can be tuned by using different strength foams and different types of steel tubing – but again, it has to work for all series racing there, not just NASCAR.

Get Off Your Grass

Get rid of the grass. Grass has no business being anywhere in a racetrack that cars could possible end up in.

a. Remember how I mentioned that you can dissipate energy by friction between the tires and the ground? The higher the coefficient of friction between the two materials, the more energy you dissipate. You know what the coefficient of friction is between grass and rubber? Very small. It’s even smaller when the grass is wet. This is why road courses have gravel traps. Huge friction that slows down the cars and hopefully stops them before they hit. (Gravel traps have their problems, notably that it’s near impossible to get out of one once you get in one, and that flying gravel is dangerous and difficult to clean up.)

b. Second, there is a drop off between the asphalt and the grass – a lip on which the car can catch, creating a torque. Check out Elliott Sadler’s crash at Talladega.

When he comes from the grass back onto the track, the roof of the car catches on that lip and starts the car rolling again. If I were a driver or an owner, I would be after every track to get rid of any grass near the track.

The Car Itself

NASCAR has done an amazing job engineering a much safer car than we had fifteen years ago. But the job isn’t done. There hasn’t been a career-ending injury (including death) during a race in any of NASCAR’s three major series since 2001. (Note added. It was pointed out to me that Jerry Nadeau‘s career ended after a very hard hit in 2003 during practice for a race at Richmond.) The injuries we have seen have all been below the knee. Dario Franchitti broke an ankle at Talladega. Brad Keselowski hit a wall testing at Road Atlanta and broke an ankle. Kyle Busch’s injuries from the Daytona crash were to his left foot and right lower leg.

The pedal box and the front of the car need some attention. Can the idea of collapsible steering columns be worked into the pedals? The front of the car is designed to crush (thus dissipating energy) in a crash, but maybe there is a way to refine how the crushing happens and reinforce the driver’s cockpit near the legs. I’m sure the folks at the NASCAR R&D Center are already thinking about this side of the problem.

Perhaps there are driver safety devices than could be developed as well, similar to the HANS device that prevents the head from slamming forward in  a wreck. Maybe there’s a carbon fiber leg brace or similar piece that could provide some extra protection for the driver’s legs in a crash. Of course, anything developed can’t interfere with the driver’s ability to control the car after a crash.

The Fallacy of Safe Racing

Motorsports is dangerous. People are killed participating in motorsports - especially at the lower levels, where the safety requirements are much lower than in the high-dollar, high-visibility series. But even in NASCAR, even in F1, even in Indy, there will be serious injuries and – I’m sorry to say – we haven’t lost our last driver to an on-track incident. All you need is that one in a thousand, one in ten-thousand confluence of events.

What Should Fans and Drivers Be Demanding?

Don’t tell NASCAR and the tracks that they should cover every conceivable wall with SAFER barriers and then sit back and congratulate yourself for a job well done.

Consider for a moment the ratio of people whose job it is to make cars fast to people whose job it is to make racing safer.

NASCAR has become so much more proactive about safety in the last years. If I were a driver, I would be lobbying NASCAR to hire more people at their R&D Center focused on safety, and to support more motorsports safety research at universities and industry.

The FIA has an Institute for Motorsports Safety.  It’s a non-profit foundation that centralizes safety initiatives and testing and works to get safety innovations on the track quickly.

Maybe it’s time for NASCAR to team up with IndyCar and the Tudor United Sports Car series and form something similar in the U.S. This isn’t an issue that should come up only after a serious wreck. It’s an issue that needs long-term, on-going commitment and attention. As a fan, I’d pay an extra buck or two on top of a race ticket if that ‘tax’ were earmarked for safety research.

For More:


Nov 202014

One of the biggest changes NASCAR has instituted for the 2015 season is eliminating individual team testing at any tracks. In 2014, teams were limited to four tests and were not allowed to test at tracks that were included in the schedule.  NASCAR may run some limited tests, but they won’t be having the week-long marathon that was Daytona Speedweeks.

Given the intensive schedule in February, most teams are happy to be losing the Daytona tests. A lot of focus for one race – and a race in which the probability that the car comes home in one piece is vanishingly tiny.

Will It Save Teams Money?

Even though some teams will amp up other types of testing, eliminating sending a dozen people and a car out to a track will most likely result in a net savings of money.  NASCAR’s done a good job lately talking with the teams and most teams were in favor of the new rule.

Perhaps more important than the dollars saved is the time and energy of the team members. The season is already 36 points-paying races, plus the week before Daytona and All-Star week. That’s a lot of time to be away from home.  Even when they are  in Charlotte, the team members are at the track enough that they don’t really have time to be “at home”. They get to sleep in their own beds, which is nice, but it’s still pretty intense work.

A lot of NASCAR crew members simply burn out. It’s fun being part of a traveling circus – for a little while.  But eating out all the time, getting irregular sleep and dealing with the stress of the race weekend takes its toll. Once you start having kids, or a crisis at home, being on the road becomes a huge barrier to living the rest of your life. There are a lot of former crew chiefs who are very happy working out of the shop.

The few at-track tests that will be allowed will be run by NASCAR, and one assumes that they will schedule those immediately before or after race weekends, which again will minimize transportation costs, although it’s another day away from the shop for the participating crew and the driver.

Types of Testing

You can divide “testing” into two broad categories:  testing with the driver and testing without the driver.  NASCAR has historically come at it from both sides, hoping they’ll meet in the middle.  The testing rule has effectively taken away a lot of the tools on one side with the intent that tools from the other will compensate.

Remember that NASCAR’s goal isn’t so much keeping the status quo. It’s ensuring that whatever the rules are, they don’t give one company a huge advantage over the others.

So here’s my breakdown:


You’ll notice the driving simulators are in a different color – that’s because that’s the only type of ‘testing’ that really involves only the driver. Teams are trying to use this tool in a more scientific way (see my blog on the Ford tech center, for example), but it still doesn’t address the communication between the team and the driver – which I happen to think is one of the most critical aspects of driver-involved testing.


With Driver vs. Without Driver

Some properties of a car are driver independent.  Drag is never a good thing, so any testing that shows you how to lower the car’s drag is useful and requires absolutely no input from the driver.  Similarly, downforce is almost always good, so changes that increase downforce are also good and will be the same, regardless of who’s inside.

But a lot of the magic in setting up a car is finding out what your specific driver prefers for specific conditions at specific tracks. Someone who comes from a dirt-track background has very different preferences than someone who grew up racing open-wheel cars on asphalt.

All drivers want more grip, but different drivers can make do with different levels of grip in different places along the corner. The really successful long-running crew chief/driver combinations (Chad/Jimmie, notably) work because the driver and crew chief have learned how to communicate. The driver can express what the car is doing and the crew chief knows how to change it so that it favor his driver.

What They’re Losing

This will be one of the few seasons where teams have no say in where and when they test. This eliminates their opportunity to strategize. When there were no rules regarding numbers of tests, you did as many tests as you could afford. You might test at places you were historically good at to optimize your changes of winning, or you might test at places you normally didn’t run well at so that you could get better.

When numbers of tests were limited, teams had to strategize. For example, some teams decided to make sure they were really good at one of the three races in a each segment of the chase eliminations. If you won one of those races, you were automatically in. And just about everyone who was in the Chase wanted to test at Homestead. Now those choices are out of the teams’ hands entirely.

Goodyear will run tire tests – but they aren’t promising they’ll include everyone. Tire tests exist for Goodyear to get the information they need to produce a good tire. That goal is often at odds with the information the teams would like to get from testing. Goodyear prefers 3-5 cars in a test.  You need one from each manufacturer at a minimum to ensure fairness, but you don’t want too many voices providing feedback because it becomes impossible to get detail.

Goodyear also has drivers and teams they like testing with. Some drivers are better at providing the kind of feedback Goodyear would like. And, frankly, some teams are just easier to work with than others. If you mandate that every car running the full season get to participate, that disadvantages Goodyear – which means disadvantaging the rest of us.  That kind of scheme means more Chevrolets test than the other brands, simply because there are more Chevrolet cars.  But if you limit the test to one or two teams per manufacturer, then some Chevy teams will be disadvantaged because there won’t be enough slots for everyone.

NASCAR-run tests are the best shot most teams will have to get real testing with the driver in the car.  The tests will be open, so everyone has a shot at participating. The disadvantage is that NASCAR decides the tracks. Given history, NASCAR is likely to hold tests at tracks that have been repaved, or for which there are new tires. Helping teams perform in the Chase is not part of their strategy.

Although both tire tests and NASCAR-run tests will allow the driver and crew chief additional practice at communicating, drivers who are changing companies and/or crew chiefs are the ones who will suffer most from this testing ban. The crew chief-driver relationship is critical. I maintain that one of the reasons Tony Stewart struggled the first part of this year (I’m talking before the accident in New York) is that his time out of the car with the broken leg the year before interrupted his developing the routine week in-week out relationship you need with your crew chief.

If I were Rick Hendrick, for example, I might put Keith Rodden (Kasey Kahne’s new crew chief) and Kasey in an XFINITY Car (that still sounds weird) just to give them some quality one-on-one time during an actual race. Because the cars are different, not a lot of specifics will transfer; however, the practice in driver giving feedback and crew chief adjusting is absolutely critical. Those lower-level series may be the only opportunity some drivers get to forge a bond with a new crew chief.

Without the Driver

I’m going to cover each of these techniques in a little more detail over the break, but for now, suffice it to say that the type of information you get from a technique like a seven-post rig or a wind tunnel is much more general. Yes, the particular car being tested will have the setup (springs, shocks, etc.) that the driver favors, but you’re missing the crucial component of the driver telling you how it feels.  All the charts and graphs in the world do not compensate for having a driver’s butt in the seat.

Below is what the underside of a seven-post rig looks like.  The four large pillars make the tires go up and down. You program the movements of those pillars based on sensor data you collected from on-track testing. The quality of the results go up the better input data you have. If you have data from a couple years ago, or data from the car with a different driver, you’ve lost some fidelity, some precision.


And the unfortunate fact is that we just don’t know enough about reality to be able to replicate it in our theories. A wind tunnel has a huge advantage over a computation fluid dynamics simulation because one of the hardest things to simulate in a computer is turbulence (shown below, in red just because turbulence looks way cooler in red.)


Will The New Rule Level the Playing Field?

One of the claims I’ve heard people make is that banning on-track testing will help the smaller teams. Let’s start by saying that there are very few teams that are single-car operations anymore. Not because a given company has more than one car, but because manufacturers are doing a better job sharing information between their teams. So the question of one-car vs. multi-car really isn’t a relevant as it used to me.

The question of smaller vs. larger teams, however, is very relevant. Anyone can book time at a wind tunnel, but with time running $1200-$1700 an hour, smaller teams will spend much less time in the wind tunnel than teams with higher budgets. Larger teams have their own seven-post rigs, so they can run 24/7 if they are so inclined.

But even if NASCAR limited wind tunnel time and even the amount of computational fluid dynamics calculations you can make, it still wouldn’t be even. Smaller teams pay less. They generally have less-experienced crew and smaller R&D divisions. If you gave everyone exactly the same amount of data for their cars, the smaller teams would not gain as much as the more experienced teams.

RCR has (at last count) five Ph.D.-level people on staff.  The whole point of getting a Ph.D. is that you are being trained not to implement things that are already known, but to figure out things no one else knows. That is the level at which teams are analyzing this data. If I want to work at SpaceX or Orbital Sciences developing the next alternative to the Space Shuttle, there is a very well-defined path I take.  I train for eight to twelve years, learning as much as I can about what we already know. Then I strike out and try to learn things we don’t know.

There isn’t a Ph.D. level program in race car engineering in this country. The folks who are working in the industry have created their own set of knowledge and boy, is it proprietary. Their experience isn’t in books. So even if a team suddenly got a windfall and can hire smart people, they have to find a way to pull them away from the existing teams. I’ve got a Ph.D., but I couldn’t walk into a race team and help them. It would take me months, maybe years, to understand what they’re doing and what they know before I’d be able to make a contribution.

I think the upshot is that the new rule will keep things pretty much the way they are already, with the exception that teams with new driver/crew chief combinations are going to be at a disadvantage because of the lack of on-track testing.



Nov 072014

Flared side skirts became an issue when social media started noticing them somewhere around Kansas. The fact that the most obvious example of this was on the 2 car and Brad Keselowski is rapidly taking over from Kyle Busch as most-love-to-hate driver in NASCAR may have brought the issue to the fore faster.

The side skirts (or ‘vertical extension panels’) help seal the bottom of the car to the track. This picture, of the 2013 Toyota Camry, shows the clearest example of the side skirt because you can see the line where the side skirt joins onto the side of the body. The cutout is for the jack – if there were no pit stops, there’d be no reason for the cutout. The side skirts help funnel the air that does get under the car smoothly out, and they keep air from coming on on the sides.


Side skirts are made of a durable rigid plastic — except for one spot on the right side of the car near the tail pipe area. The rationale for this is that exhaust pipes get very hot. Although plastics are indeed the material of the future, plastics that are really, really heat resistant also tend to be expensive and harder to work with.

The plastic from which the side skirts are made is pretty rigid. You can cut it and bend it a little, but you really can’t monkey with it too much.  Except for that metal part, near the right rear wheel.  You know… this part:


Flaring out the right rear of the side skirt started out being done by a couple of teams and now you can find most all of the teams doing it.  So now for the burning questions.

Is it illegal?

Nope. NASCAR hasn’t fined or taken points from anyone for doing it.

Is it happening accidentally?

A lot of internet pundits initially claimed that this was the result of hard racing, no ride-height rule, and drivers racing on the apron, where the possibility of banging the car on the track is maximum. But not when it’s happening to so many cars and happening every week.

And then video appeared that showed jackmen pulling out the skirt during pit stops – right in front of the NASCAR officials overseeing the pitstop.  So no, it’s not happening by accident.

Is it really an advantage?

There have been a number of times in the garage where a team started doing something goofy just to see how many other teams would copy them. There are some cases I know about where teams made a modification they’d seen other teams make without understanding it — but they also had their engineers figuring out whether it was doing anything. If one of the backmarker teams had started doing this, I doubt anyone else would have noticed, unless that team all-of-a-sudden improved.

NASCAR does have a history of allowing something and then cracking down on it when it becomes too blatant, so the first teams doing this knew they might get their hand slapped.

The argument people have made is that it changes the balance of aerodynamic force. you’re providing a couple more square inches for air molecules to slam into. In this case, I doubt there’s much of an effect down the straightaway (especially with the rear-end skew), but it probably does help a little in the corners.

It certainly isn’t hurting the cars, or teams wouldn’t be doing it.

Why are they only doing it on the right? If it increases downforce, wouldn’t you do it on both sides?

They can’t do it on the left. The left-side skirt is entirely plastic and you can’t bend it. Plus, the issue here is really in helping the car turn, so you wouldn’t want to make the same change on both sides.

Should NASCAR prohibit it?


First, let’s note that this has been going on for much longer than most people realize.  Like most things in NASCAR, it starts with one team sticking their nose out a little (or their skirt out a little) and escalates until it’s a big enough effect that those of us sitting at home notice.

It’s not like NASCAR hasn’t been aware of what’s going on.

The main reason I can see for NASCAR stepping in is that a sharp piece of metal sticking out at wheel height has the potential to turn Phoenix and Homestead into the Roman Colosseum.

Not that anyone would purposely try to cut someone’s tire down, but it makes bumpin’ and bangin’ a very different proposition.

Here’s the problem. It’s going to be tough to police. And I don’t say that just because Jeff Burton said it and he’s almost always right. It is possible for the skirt to get bent and banged by (for example) a tire being pulled off at an angle, or contact on the track.

The NASCAR pit officials can’t see everything. Their primary job during pit stops is to make sure the wheels aren’t going to come off again. Do you want them to take their eyes off the tires so they can check what the jackman is doing? Maybe with the electronic pit officiating coming next year, that will be possible.  Not this year.

NASCAR’s Sprint Cup Series Director Richard Buck told popularspeed.com

“I will say the garage is comfortable with how we’re managing it right now.  It’s the same for everyone. That’s how we try to manage everything — that it’s the same for the big teams as it is for the little teams.”

NASCAR has done a really good job not knee-jerk reacting to things. They tend to wait and see how things evolve. When they threaten to get out of hand, NASCAR makes a rule. This happened with the skewed-out rear ends a few years ago. It got to a certain point and then it got silly.  The cars couldn’t even get up on the rails for tech. When NASCAR made the rule, it had all the details – how much they would allow, how it would be measured.

I wouldn’t be surprised if they do something next year, but don’t expect anything to happen in the next two races – unless there’s a catastrophic accident that can be linked back to the flared side skirts.

And on a chemical note…

I always tried, as a teacher, to find analogies to help my students understand scientific concepts.  For example, my mental picture of “potential energy” is of a cat about to pounce or a sprinter on the blocks the second before the gun starts the race. You can see the energy ready to go in the tensed up muscles and once they move, you can see the kinetic energy (energy of motion).

Last Sunday at Texas, I got another one.

A catalyst is a chemical that initiates or speeds up a chemical reaction, without taking part in said reaction itself. All I need is a good video from Texas to make my point now.

That, or chemists everywhere should start referring to catalysis as “Harvicking”.





Jul 292014

My friend at the Milwaukee Journal Sentinal, Dave Kallmann (whose online column should be a regular read for race fans) asked about the confiscated firewalls from the Number 11 car at Indy.  That reminded me of the  first NASCAR race I was supposed to attend as research for my book The Physics of NASCAR. That was California in 2007. I was to follow around the number 19 car, at that time driven by Elliott Sadler and crew chiefed by Josh Browne.

VentedScrewsThen Josh and three other crew chiefs got themselves suspended at Daytona for using bolts in the spoilers that had tiny holes drilled all the way through the shanks. I know what these are (and where to find a picture) because we used to use them in the lab in our vacuum systems.  If you put a bolt into a hole, you trap air in the hole. We’re trying to leave on about 1 in every 1,000,000,000,000 molecules in the vacuum chamber, so it’s absolute critical that we can pull them all out.

The reason the team used… excuse me, I mean allegedly used… the bolts is because it gave the air trapped in the trunk of the car a way out and that should decrease drag and thus increase speed. So my first research race turned out to be Atlanta.

During Indy post-race inspection, some rear firewalls from the number 11 car were confiscated. A firewall is a piece of sheet metal that puts a barrier between the driver and anything you don’t want the driver exposed to, which may include fire, hot oil and other fluids, carbon monoxide, smoke, etc.  I’ve indicated the front firewalls on the picture because I couldn’t find a good picture of rear firewalls.


Apparently the firewalls, or their positioning, was suspicious to the NASCAR inspectors. It’s possible there was just an error in the way the parts were installed (the teams manufacture a lot of cars and sometimes there are mistakes). But there is also the possibility that moving the rear firewalls around does pretty much the same thing that the vented bolts did: they provide a path for air to get out of the car and thus reduce drag and increase speed.

Seems like a pretty minor thing to move a few pieces of sheet metal around just a little; however, the positions of the sheet metal are specified pretty precisely. Modifying the arrangement can compromise drive safety in terms of an opening allowing smoke or fire into the cockpit.

We’ll see this afternoon whether NACSAR comes down hard on the team because this is a safety-associated issue. It may just have been a mistake; however, NASCAR doesn’t consider intention in determining the severity of a penalty.

Incidentally, Dave does an online race chat on Wednesdays at 1 pm Central. It’s not limited to NASCAR, so if you have a chance, join in the chat.

And can you believe it? I’m finally getting back to Milwaukee and it ends up being a week when the Brewers are out of town the entire week.  I’m going to have to just break down and go see them when they come to town and play the Nats.  At least Karl Ratzsch’s is still there.  And the Zoo.





Jun 202014


Brad Keselowski, that never ending source of material on slow news days, had a few words about the state of American Motorsports Engineering. These quotes are from an article by Mike Pryson in Autoweek.com.

“It’s probably a larger story in itself that the American engineering pool is very shallow right now,” said Keselowski after he qualified sixth at Michigan International Speedway on Friday for Sunday’s Quicken Loans 400 NASCAR Sprint Cup Series race. “Penske is moving to any other country [to find them]. We’ve hired multiple engineers from Europe over the last three or four years and we’re pilfering everyone we can in the great country of Canada, so if you know any of them, send them our way.

“It’s just very hard to get engineers with the educational background and commitment that we need to be successful at this level from the United States. There’s certainly a shortage, not just at Penske, but throughout the garage.”

His comments (here and in the last few days) have to be interpreted in the context of their being responses to questions about why Ford (and Penske) were struggling compared to Chevy (and Hendrick in particular).  The mainstream motorsports media (try saying that fast five times) tend to want a simple answer, like “They have more horsepower”. As we know, racing is a holistic enterprise and often it’s the interplay of things and not just the things that is most critical.  And people want to reduce answers to more provocative things like “Keselowski hates American Engineers”.

I know a lot of racing engineers who found his comments derogatory. It reminded me of being in grad school and always hearing the professors complain that they needed “More and better graduate students”. When I finally called on on this and told him it bothered us, he looked at me blankly. “We don’t mean you guys. You guys are great. It’s our applicant pool…”

Sometimes a little clarification makes a huge difference to the people involved. The big thing I got out of it after reading all the media reports I could find about Keselowski’s comments was that he said that Penske got a very small number of applications from highly qualified American engineers.

Let’s look at the numbers. In 2012, according to the American Society for Engineering Education, 88,176 bachelor’s level and 49,372 masters level engineering degrees were handed out.  There were 1.7 million bachelor’s degrees in all fields, which means that engineering degrees make up only 5% of all bachelor’s level degrees. Compare that with Japan and Chine where engineering degrees are 50% of the degrees granted.  That’s for all fields of engineering. Most people working in motorsports have degrees in mechanical engineering (few schools offer a dedicated motorsports engineering degree), which is somewhere around 20,000 degrees at the bachelor’s level and 6,o00 master’s level degrees. (85- 90% of mechanical engineering degrees are earned by men, incidentally).

The schools that offer motorsports engineering degrees are schools like Indiana University – Purdue University at Indiana (IUPUI), UNC-Charlotte and the University of Northern Ohio.  In fact, UNC-Charlotte boasts that 10% of NASCAR engineers come from UNC-Charlotte.  Other schools, like the University of Colorado – Denver offer motorsports specializations within mechanical engineering. Nothing against these schools. But if I look at the engineers I know who are successful in NASCAR, they’ve got degrees from places like Northwestern, Duke, Penn State, Stanford, Carnegie Mellon.  Newman went to Purdue. Those universities attract a different level of student. Nothing against folks who went to a small state school. I did. But if you want the best and the brightest, you’ve got a higher likelihood of finding them at the elite engineering schools.

Europe, in particular, has a well-established stream of motorsports engineering because of the high technical level of F1. I was at Oxford On Brookes in England a few years ago and their facilities and program are amazing. Well ahead of most of what we have in the States.

The numbers are small to start with, and I think three factors narrow the pool:  Money, work environment, and personal goals.

The mean annual wage for mechanical engineers, according to the U.S. Bureau of Labor is $85,930 – and it’s much higher (over $100,ooo) in select field like energy.  I started off thinking salary wasn’t an issue because teams like Hendrick and Gibbs have very deep pockets and understand how important it is to have strong engineering. On second though, few people get to start with the big teams. So salaries may  be a contributing factor to there being a smaller application pool. If someone’s faced with a starting salary from an auto manufacturer or a  Nationwide-only team, the production car job might look a lot better.

Even if the salary is high, you have to consider the job responsibilities relative to the salary. NASCAR engineers work in an extremely high-stress, rapid output environment. They have to work with a broad range of people, from mechanics to public relations people (to drivers, some of whom are not shy about throwing their teams under the bus when they don’t finish well). Failure in motorsports is extremely visible. If you are slow, the whole world sees it. Many engineers spend a significant amount of time on the road, away from family. Even those that don’t travel as part of the raceday team are involved in testing.  A lot of people don’t want an eighty-hour-a-week, high stress job.

Finally, there’s the question of what you want out of your career. People I know who have worked in motorsports and left are working in everything from production car development to trying to make the country less dependent on foreign energy sources. A number of them enjoyed motorsports, but there are bigger and more significant problems in the world than making cars go fast. People want different things out of life. You have to really like racing to make a career of it.

Keselowski pointed out as much in a tweet.




But that didn’t make it into any of the stories, of course.

Jun 162014

Equilibrium. It’s more than just a neat word. It’s the holy grail for a racecar driver.

Brian Vickers lost his car on the first lap of yesterday’s Michigan Sprint Cup Race. Vickers said (quote from an article by Jay Pennell of Fox Sports).

“I was going into Turn 3 and expecting to follow the 48 in there and the 22 jumped inside of us and it just came around,” Vickers said. “I mean I just lost it. I have no idea what happened or why. The car just got really loose into three and I chased it all the way up to the wall. I thought I had it saved and it just came all the way around.”

A racecar driver’s goal is to keep the car exactly at equilibrium. Equilibrium means that all the forces acting on a object equal out.  For example, I’m sitting in a chair at my desk. Gravity pulls me down with a force equal to my weight. The chair pushes up with a force equal to my weight. If you add them up, they equal out. If the chair were to break, it would exert less force on me than gravity and I would accelerate downward.

The chair is actually capable of exerting a much larger force than my weight (which I know because people heavier than me have sat in this chair and it didn’t break.) Most things we use have a safety factor – they’re much stronger, or capable of exerting a greater force, than we will ever need.  We’re not even close to having to worry about equilibrium.

Racing is the act of keeping the car exactly at equilibrium. I like to think of equilibrium as applied to racecars like this:

EquilbriumWhen the forces are exactly balanced, you’re living up to car’s potential and getting it to go as fast as it’s capable of going.  If you’re not pushing the car to the limits of the tire’s traction, you’re giving up speed.  If you push the car beyond the tire’s limits, you crash. Look at the in-car cameras during a race and see how tenuous the connection is between the car and the track.

With the car perched on the top of an unstable equilibrium like the one diagrammed above, all it takes is a little perturbation and the car moves off the peak position. If the perturbation is small, the driver may be able to recover. But it doesn’t have to be very large – a good wind is more than enough – and the driver is caught in a spin. The side of a racecar presents a huge area for the wind to push on. It’s not surprising that a good wind, hitting at exactly the wrong angle, could spin out even a 3,480 lb racecar – because the racecar is already on the edge of crashing.


Jun 132014

You are hurtling down the frontstretch at Michigan, your speed approaching 215 mph.  Your seat moves up and down as you hit the seams, but your focus is squarely on getting into Turn 1 losing as little speed as possible.  You squeeze the brakes and feel yourself moving forward, only to realize that you’re still moving too quickly. As the car starts to head toward the wall, you panic and squeeze the brake even harder.

The car snaps loose and the next thing you feel… is an engineer’s hand on your shoulder.  You turn around to see her barely suppressing a smile.

“Let’s try that again. Maybe you want to brake earlier this time, huh?”

The latest racing simulators are far more involved than your steering-wheel-feedback-enabled video game. When you hear drivers talk about using simulators to familiarize themselves with new tracks, you are only hearing about the surface layer.

Ford opened a new Racing Technology Center in Concord NC just about a month ago.  The old Ford facility used to be called “The Shack” because of it’s size. The new facility, which is across the street from Roush Fenway Racing, is 33,000 square feet. One of the main features is a driving simulator similar to the ones that F1 uses.  Five screens provide a 180-degree view for the driver. The cockpit is the front half of a NASCAR Sprint Cup car that is set on a full-motion platform.  The platform duplicates the exact motions you would feel in the car – bumps, slips, sways, yaw.

Let’s move away from the driver for a moment, because he (or she) is a relatively recent addition. All race teams use vehicle dynamics simulations: computer programs that predict lap times for specific setups. A crew chief changes the setup on the computer – camber, cross weight, track bar, etc. – and can see in advance whether the changes make the lap time better or worse.


Simulation programs have to be validated, meaning you have to make sure they correspond with reality. Every team also has (or rents time on)  K&C and seven-post rigs.  (K&C stands for Kinematics and Compliance – I’ll be getting into those in upcoming posts.) These machines attempt to quantify how the car responds to external changes, like turning, bumps, etc.

Engineers thus went back and forth between theory (the simulations) and experiment, developing a model of the car, testing it against how the car behaved, and then refining their model.  (Unsurprisingly, this is exactly how scientific research on things like alternative energy sources and cancer works.)

This is a great model for the Google driverless car. But that’s not how racing works. Racing requires a living, breathing, thinking (hopefully) human being in the seat who has to constantly take in information, process that information and act on it.

And that’s where racing simulators are moving. The buzzword is “Driver in the Loop”, which means that you’re creating a model that includes the driver.  This is not an easy step. Drivers are very different in terms of their preferences for set-up, what they’re comfortable driving, how loose they’re willing to be early in a run to make the car faster later, etc.

The simulator in the new Ford Tech Center is a sled-type simulator. Less advanced models have hydraulic pistons that raise and lower the cockpit to simulate bumps and change attitude.  The sled can actually duplicate all six types of motion: three linear motions (up/down, left/right, front/back) and three rotational degrees of freedom (yaw, roll and pitch).  This motion platform was developed by a British company called Ansible Motion and the picture below is from their website. You can see the sled rails at the back, and the 180+degree surround on which the images of the track are displayed. The steering wheel provides feedback to the driver and even the seatbelts are cued in so that when you brake, the seatbelt tightens just as it would in a real car. Ansible is the same vendor that worked on McLaren’s F1 simulator. The Ford folks claim that this design has a much faster response time, meaning that the time between when you turn the steering wheel and when you feel the result, is shorter and more like real life.




At present, they’ve got ten tracks in the library for the new simulator – eventually they will have all the NASCAR tracks and, since the Tech Center is meant to support all of Ford’s motorsport activities, they will be able to change out the cockpit to, say, a Daytona Prototype, and including tracks like Sebring.

So far, I’ve made it sound like they’re just one-upping iRacing, but a prime feature of the center is that there is a whole room associated with the simulator that is filled with engineers who are watching both the driver and the racecar input/output data.  The driver is being assimilated into the simulations. This is why it’s called “Driver-in-the-Loop” simulation.


On the one hand, the driver will help validate all the models.  If there’s a bump on Pit Road at a track that gives a driver trouble, he or she will recognize when it’s not in the model of the track used by the simulator. (And since tracks change significantly, the models have to change to keep up with reality.)

While we’re talking tracks, let’s point out that the track models aren’t made by someone sent out with a tape measure. Tracks are laser scanned to a resolution of a few millimeters. Every dip and bump is recorded and used in modeling the tracks. Laser scanning not only collects three-dimensional location information, it looks at the quality of the reflection.  Laser scanning can differentiate between a white painted line and a yellow painted line, between two different lanes of asphalt, or even skid marks. When you’re traveling at top speed, any surface irregularity becomes important because all it takes is for the car to be throw a little out of equilibrium and you’re in the wall.

In addition to the track, the driver can also provide feedback about whether the “car” responds the way it does in real life. But at the same time the driver is evaluating the simulator elements, the engineers are evaluating the driver. They can start to look at things like how a particular driver’s comfort level may dictate a different line for them relative to another driver. They can run repeated tests to find out how constant a driver is. Do they brake the same way going into Turn 1 at Charlotte every time? Or are they hyper aware of something like tire fall off and able to tailor their braking to the condition of the car?  This type of research has great potential to improve communication between the team and the driver.

Skeptics will worry that we’re getting uncomfortably close to a situation in which we have a bunch of engineers sitting around driving the racecar via remote control and the driver is no more than a warm body executing commands as he’s told. The beautiful thing about human beings is that you can’t model a human being. Having done research in both physics and science education, there’s a huge difference between measuring electrons and measuring people. You kick an electron twenty times and it will pretty much do the same thing each time. You kick a person twenty times and (aside from the danger of being kicked back), you’ll get at least ten responses depending on the person’s mood.

It’ll be interesting to see whether tools like this can help the Ford teams (especially Roush Fenway Racing) catch up to Chevy.

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