I got a call out of the blue in the office yesterday. A biomedical physicist/radiation oncologist from UC-Irvine who had just gone to his first NASCAR race at Auto Club Speedway had a question about my book, The Physics of NASCAR (which, by the way, you don’t have to be a physicist to read. In fact, it’s probably better if you’re not.)
How did he get interested in NASCAR?
The American Association of Physicists in Medicine 2012 conference was in Charlotte. The social event (yes, physics conferences do have social events!) was held at the NASCAR Hall of Fame and the exhibits piqued his interest. Returning home, he found a fan among his coworkers and last weekend, he got to his very first race. And boy, did he pick a great first race to attend. NASCAR got a couple new fans last weekend — welcome!
I always tell people who can’t see why racing is interesting that they need to go to a race in person because television and radio can’t capture the in-person sights, sounds and smells. You’ve got to go to the track to understand why people become fascinated with cars traveling in circle.
One of the questions this physicist had was the noise level. He had brought earplugs, but he was surprised by how many people didn’t have them.
If you’re ever in the NASCAR garage, take a careful look at the over-50 crowd. Many of them are wearing hearing aids because they spent a lot of time at the track without earplugs. A racecar easily breaks 120 decibels 15 feet from the exhaust. 120 dB is the level of a jet engine or a rock concert. It’s also the threshold for permanent hearing damage. Despite the great advances we’ve made in science, we are still not able to restore people’s hearing. Your hearing is already getting worse just because you’re getting older. Don’t give Mother Nature any help. Bring a pair of cheap foam earplugs to the track and wear them. Heck, buy a couple pair and give your extras to anyone you see who doesn’t have ’em.
I know… it’s a thrill to hear the cars fly past, but permanent hearing damage is, well… permanent.
Bonus Tuesday Geek Joke
You’ve all heard this one, right?
Q: How do you tell the extroverted physicist at the social event?
A: He’s the one staring down at other people’s shoes.
A short note on Denny Hamlin’s comments on the Gen-6 car and subsequent fine.
I’ve talked to a lot of the people in the trenches involved in designing and creating the Gen-6 car. That includes people from manufacturers and teams. All of them have said that the development of the Gen-6 car is a major sea change for NASCAR. This is the most collaborative that NASCAR has been with introducing a new car in some time. Manufacturers and teams were consulted and they all feel that their opinions mattered and were taken into consideration. This was a very, very different process than the COT introduction, which was designed by NASCAR and plans delivered to teams.
So when a driver talks trash about the Gen-6 car, they aren’t just talking trash about NASCAR – they’re insulting the people on their own team and their manufacturer, all of whom have been working collaboratively to make the best car possible. NASCAR deserves some major accolades for opening up the process. One team principal even declared it “a new business model where we are partners with NASCAR”.
Is the car perfect?
But when did you ever do something and get it perfect the first time out? I’ve said already that we’re going to have revisions throughout the year as we learn more about the car. No one expected it would come out and be exactly right the first couple of weeks.
If drivers want to help with the tweaking, then they need to make constructive specific comments (like where and under what conditions they’re having problems passing) rather than blanket condemnation of the car and the process.
Having said that, I also disagree with NASCAR fining Hamlin. I can see their point of view. Changing corporate culture is a very, very hard thing to do. NASCAR met the teams more than halfway. They did a lot of the things people behind the scenes have been asking them to do for some time. And then a driver comes out and slams the car in the most general, broad way possible.
I suspect it’s like parents who tell their kid he can come in a 9pm instead of 8pm and then the kid stays out till 10 pm. For heavens’ sake — they were trying to do something nice and they got slapped in the face. NASCAR is rightfully aggravated.
But I think most fans listened to his comments and thought the same thing as one caller to SiriusXM Speedway, who said
“Of course he’s complaining about the car. He lost!”
We know drivers are frustrated when they get out of the car and often for some time afterward. We know they say things that are not always tactful and are sometimes rather wrong-headed. You don’t have to fine a driver to let us know that you think he or she was out of line. Hamlin’s fine shifted the focus from racing to public relations. And that’s not why most of us watch.
Danny LaDue asks: Can you explain the location of a NASCAR oil tank reservoir and how the lack of one could improve aerodynamics?
Thanks for the question, Danny.
NPR got this one wrong. Frank DeFord in his usual Wednesday commentary made a comment that was essentially — look, the lid was still in the car, it didn’t give him a weight advantage, so NASCAR was wrong to penalize the team. Don’t these folks known anything?
That’s the problem with aerodynamics — you can’t see it happening.
Unlike your car, the oil in a NASCAR car isn’t stored in the engine (called a wet sump system). NASCAR uses a dry sump system, in which oil is
stored in an oil reservoir. The oil reservoir is located behind the driver’s seat and is surrounded on the sides and top by sheet metal, which forms the oil tank. The sheet metal minimizes heat radiating into the car, traps fumes from the hot oil, and serves as an additional firewall. This function is so important that NASCAR doesn’t allow the top of the tank to be attached using quick connect fasteners. Some teams duct tape the lid on. The picture to the right shows the location of the oil tank with respect to the chassis. It doesn’t show the cover, which would sit on top of the tank. The oil reservoir itself is closed and pressurized.
So if the oil tank cover plays such an important role, why would you leave it loose, much less leave it off? The answer is aerodynamics. The air exerts forces on the car in different directions. Drag is the force air creates along the length of the car. Air creates drag when it hits the front of the car, but it also creates drag when it gets inside the car because there is no way for it to get out. Drag always acts opposite the direction the car is trying to move, so you want to eliminate as much drag as possible.
Downforce and lift are the names for the forces pushing straight down or up on the car. Downforce pushes the tires harder into the track and provide grip, while lift pulls up on the car. These two forces are in direct opposition to each other. The bigger force wins. You want to maximize downforce and minimize lift.
The oil tank is open to the bottom of the car. Air under the car creates lift. Even though you try to keep the splitter close to the ground, there is always some air that gets under the car. If the oil tank lid isn’t firmly tightened down, it creates a path for air to get out of the car, which reduces lift.
When the amount of lift decreases because of the loose oil tank cover, then the net downforce is larger because there is less air pushing upward. More downforce translates directly into more speed, as shown in the figure below. Remember learning about ‘net force’ in physics? Yep – it is actually useful. The loose oil tank cover likely provided a little extra downforce — in a sport where races are won by thousandths of seconds, even “a little” advantage is important.
One of Rusty Wallace’s cars originally penalized in the Nationwide series won its appeal on the basis that all of the bolts on the oil tank cover were engaged fully and the design of the oil reservoir was such that it led to the apparent opening. I can imagine (especially having seen graduate students overtighten bolts) that if you screwed down really hard on the bolts and the oil tank lid were on the thin side, you might be able to warp the cover on the oil tank lid a little and get some air escape. The problem with this argument is that you can only use a ‘bad design’ argument once because NASCAR will make you redesign it.
The case of the No. 99 car’s oil reservoir lid is a little different, though, because the reports have been that the lid was entirely missing. In fords, the oil tank cover is held on by a single bolt. Carl Edwards said on NASCAR This Week that a “bolt backed out”. Jack Roush made the argument that the vibrations in the car caused vibration harmonics that caused the bolt to unscrew itself. Even if that’s true (and I have to admit I’m a little skeptical about it), should you really have a safety feature held in place by a single bolt?
NASCAR fined the driver and the owner 100 points (old points scheme!), fined crew chief Bob Osborne (B.S. in Mechanical Engineering from Penn State) $100,000, 100 points and suspended him for six weeks.
A number of reports reports that the focus of the Daytona investigation is the catchfence gate (umm… a surprise?). There are a bunch more, but they all report on the same press conference and have mostly the same information.
I suppose it’s really our own fault because of the way we teach science.
We give you labs constructed to get the right answer on the first try. We have you measure things you already know the value of. We tell you that things were invented by a single person on a specific date.
We give you an absolutely bogus model of the scientific method, putting it into a nice pretty, linear flowchart that is perfectly designed for multiple-choice tests. (Right, from HowStuffWorks.)
In reality, the scientific method looks a lot more like the figure below than the one to the right. Visit the webpage to read the text on the flowchart. It’s worth it because a lot of the boxes lead to explosions and/or lab fires. It may be NSFW — depending on where you work. If you work in a lab, you’ve already said all those words today, I bet.
This blatant misrepresentation of how science and engineering actually work is probably why the blogosphere and all electromagnetic radiation methods of communication (that would be radio and television) are full of people calling on NASCAR to ‘fix’ their ‘safety problem’ before we go back to Daytona and preferably before Phoenix.
Sorry, folks. Science and engineering just don’t work that way. We’re talking about research here – which means we’re dealing with things we don’t understand completely. You can’t set a timetable for when you’re going to discover something. It happens on its own schedule.
You may hear about R&D, which is research and development. Research is figuring stuff out. Development is making it happen. Research is “what type of barrier do I need to stop a 200-mph car?” Development is making the barrier that comes out of the research.
You can’t do ‘D’ before you do ‘R’. Einstein once said “If we knew what we were doing, it wouldn’t be research”. By definition, research is trying to answer questions for which we don’t already know the answer.
Who Does Motorsports Safety Research?
The car companies all do extensive safety research — but not at 180 mph. Their results, which are on passenger cars, can’t be extrapolated to high speed racecars, so there’s not much useful information there for racetracks.
There are a couple university groups that do motorsports safety research, but you can count them on one hand. There are a few consulting companies that are involved with motorsports safety research (sometimes as an offshoot of defense-department research) but again, it’s a small number. The FIA is a centralized automotive organization focused on F1 that does extensive research in Europe for open- and closed-cockpit cars.
Safety research is inherently expensive. Take barrier research. Start by getting a racecar – which is an expensive proposition to start with – and then figure out how you’re going to accelerate a driverless race car into a wall at a very specific angle without a driver. You have to set up high speed cameras, high speed and high strength data acquisition equipment and it all has to work right. The companies that are looking at protective gear for soldiers can get funding from the Defense Department (at least before sequestration they could) and some of those results can be applied to motorsports. The FIA dips into the coffers of the F1 enterprise. It doesn’t make sense for auto manufacturers to pay for motorsports safety research, since little of it will impact safety in passenger cars. That pretty much means that motorsports sanctioning bodies, tracks and teams have to foot the bill for safety research. And it’s a really big bill.
It’s big in part because we not only have to do experiments, we have to design experiments. Anyone got a spare F1 car we can crash into a barrier for testing?
I have a great story in my book, The Physics of NASCAR, from Dean Sicking, the inventor of the SAFER barriers about their first attempt to demonstrate to the Indycar people that they could crash an Indycar into a barrier. It wasn’t pretty. It also wasn’t successful — the first time. They learned from their miscues and — years later — they had the first SAFER barrier design. The SAFER barrier research started in 1998. The first SAFER barrier was installed at Indy in 2002. It took that long to figure out what the right design for the barrier was.
Research also never really ends. They’re looking at how to make portable SAFER barriers for street circuits, SAFER barrier gates, cheaper SAFER barriers for road courses, and how to protect the ends of pit walls. Even when one problem is mostly solved, there’s lots of fine tuning and specialization to be done.
The Problem with Multi-Car Accidents
With all the computer power we have to do simulations, shouldn’t we be able to use a computer to predict in advance what types of accidents are most likely? Let’s say you want to create a computer program that would generate all the possible types of accidents. Start with a single car. Consider all the places on the track where an accident could happen and the types of accidents (hitting the front of the car first, hitting the rear of the car first, hitting the pit road wall, getting airborne, etc.). I bet you could list a hundred possibilities (at least) without having to think too hard. When you get done with your list, let me know.
Now list all the possibilities for two cars. It’s not two times the number of possibilities for one car because the two cars can interact in many different ways.
There were twelve cars involved in the Nationwide accident at Daytona last Saturday. There is no way anyone could go through all of the possible outcomes of a twelve car pileup. The problem with plate tracks is that they cars are running in a bunch and therefore the probability of a lot of cars being involved in an accident increases relative to, say, Martinsville, where most of the accidents are a few cars at most.
Here’s the other problem. If I want to simulate a program that shows me how a fence will respond if a car hits it, I need real-world data on which to base my simulation. So at some point, you’ve got to have a way to propel racecars into catchfences.
The Most Important Data Comes About When Something Doesn’t Work
You don’t learn anything if you don’t get data. You don’t get a lot of useful data in motorsports safety research when everything works perfectly. The only time you get real data is when something goes wrong.
The number of accidents at any one track is actually pretty small, so the amount of data we have is very limited. NASCAR has an accident database where they’ve collected every bit of video, data from crash recorders and anything else they can get their hands on. Every bit of data gives them a little more information on which to base future work. But the most valuable data, unfortunately, comes when something doesn’t work. This is true for every type of safety equipment: barriers, HANS devices, seats, roof flaps, and yes, catchfences.
Priorities: Ends and Openings
Most people in motorsports safety will tell you that the most challenging problem right now is building protective gear that is also required to move. Window nets, for example, need to keep speeding car parts out of the car, but must be rigged so that they driver can lower the window net very quickly if necessary. Ends and openings are the most challenging aspects of track design. One of the challenges to putting SAFER barriers on the inside of tracks is that there have to be openings for emergency vehicles to get on the track. This requires SAFER barriers on hinges that can’t be damaged if the car happens to hit the hinges.
Saturday’s accident involved a pedestrian crossing gate – gates are the literal weak links in the catchfence design. I suspect that if you had the exact same accident happen on a different point of the track, the results would have been very different. It was the unfortunately perfect storm. I’ve addressed most of the simple suggestions for catchfences in a previous blog post and those arguments apply here.
Where We Need to Focus
If we gear our efforts to simply preventing the type of accident that happened Saturday, we’ve missed the whole point. The odds of that exact same type of accident are very small. Then a different kind of accident happens and now we all run to prevent that specific type of accident. Remember that a racetrack is a system: it’s the cars, it’s the drivers’ safety equipment, the configuration of pit road, the track shape and size, and the catchfence. All of these things work in concert with each other and focusing on any one of them misses the point. It’s a complicated system and it takes time to figure it all out.
I wish I could say that, at some point, motorsports will be perfectly safe – for the drivers and the fans. But it’s unrealistic. There will never be any guarantees. We can just do the best we can.
My hometown newspaper, the Milwaukee Journal-Sentinel, has a nice article on safety by Dave Kallman