2016 Indy 500 winner Alexander Rossi breaks down why the race is so difficult

  • At speeds of over 220 mph, drivers tear around the Indianapolis Motor Speedway for 500 miles, or 200 laps.
  • But while driving an oval racetrack may seem fairly straightforward, surviving just one lap requires an expert behind the wheel.
  • We talked to the Indy 500 2016 winner Alex Rossi who took us turn by turn through the track.
  • See more stories on Insider’s business page.

Following is a transcript of the video.

Alexander Rossi: Hey what’s up guys I’m Alexander Rossi. IndyCar driver for Andretti Autosport. I drive the #27 NAPA AutoNation Honda and I won the 2016 Indianapolis 500.

So you roll off on what is kind of four pace and parade laps. The first one, you do a salute to the fans. So the first lap is very slow and you’re just waving to the fans. Then the second and third lap you go single file and that’s when you get the engine temperature, the tire temperature, the brake temperature all to the levels that you want. And the team’s kind of talking you through that. And then the final lap you form back into the grid formation, eleven rows of three.

You know what you’re trying to do is just maintain the speed off the car on your inside because he’s really the one setting the pace. And then from that point you’re just waiting until the row in front of you accelerates, and you try to go with them. You know, you want to get a jump on the cars around you, but ultimately it’s a 500 mile race. There’s so much that’s gonna happen in the next three hours that the last thing you want to do is throw it all away going into Turn 1.

As we’re going into Turn 1 this is the first time you’re actually seeing the grandstands full. Because of that, it looks a lot narrower than it has the previous few weeks that you’ve been practicing because the light’s not coming in, there’s different kinds of shadows and reflections that you see. It’s actually kind of intimidating the first time that you go through there. It takes your mind three or four laps to adjust to the visual sensation.

So going into Turn 1, there’s cars that are taking a bigger risk than other cars for sure. Going two wide, or three wide you can only do on starts and restarts. And the reason for that is you’re accelerating from such a slower speed out of Turn 4 that by the time you get to Turn 1 you’re only doing 180, 190 mph. While that’s still fast, it’s a lot faster when you’re going 240 mph. So your margin for being able to explore different lines only exists on starts and restarts, and from there you see it kind of fall into more single file racing.

As much as geometrically Turns, 1, 2, 3 and 4 are identical, they’re all very different. So you’re using the short chutes to kind of change the balance of the car based on how it was through Turn 1 that lap.

The typical kind of balance you have is you have a bit of understeer exit of 1 and into 2. Between the short chute of 1 and 2 you are usually stiffening your rear anti-roll bar, softening your front anti-roll bar, or putting left front weight. So you can change the cross weight of the car. You can move up to 150 pounds from the right front tire to the left front tire. This obviously changes the balance of the car quite a bit.

So in terms of the easiest places to crash, it’s usually Turns 2 or 4. And that is because the tires are at their peak temperature exiting Turns 1 and 3. So when you go into Turn 2 and 4 you have much less margin for error. Whereas when you go into 1 and 3 they have the entire straightaway to cool down and center themselves. The short chutes between 1 and 2 and 3 and 4 don’t allow them to cool down enough so you have to be super precise with what you do or the price is just exponential.

These cars are so aerodynamically dependent, and they’re made to be run by themselves. So that means when the wings and the floor of the car are developed, they’re made in a space where the air coming at it is clean, and the cars go through it as if it was brand new virgin air. Well when you’re behind cars that are going through that air, they’re actually dirtying up the air and it’s coming at the car in a much more disconnected fashion so it actually reduces the performance of your car.

Where this comes back to your advantage is in the straights. So because they’re basically having to punch a hole through clean air, that means that you don’t have to do that anymore, so that’s where the draft and slipstream comes into play.

So the main goal of the Indianapolis is, how do you find a car balance that you can stay close enough behind the car in front of you to not lose a draft, but then still fast enough in a straight line to pass them. Because you can obviously put down force on, raise the rear wing angle, really glue your car to the track and be able to corner really well and follow someone super close. But then when you’re in a straight and you try to slipstream past them you don’t have enough straight line speed. So it’s all about finding that balance of “this is the least amount of grip I can get by with, while still being able to pass cars.

So going into Turn 3 you can see the sparks coming from the car in front. One thing to keep in mind in a race like this is that because it’s so long, the tire pressures are pretty low at the start of the stint. So what you have is the car bottom, it actually touches the ground. It’s what we call bottoming. So when that happens there’s actually less of a tire on the ground which is fine, but you have to be prepared for it because the car can actually move a little bit, and it’s hitting the deck so it’s not as composed as it would be.

And then going into Turn 4, as you’re completing the lap, this is the first time you’re able to get a balance check of what the car’s doing. That first lap you’re really seeing “Did I make the right call? Is everything as I expected it to be?”

But as I mentioned, it’s such a long race that even if the first balance check that you do isn’t quite what you were hoping for or expecting, there’s enough pit stops throughout the race where you can tune on the car, adjust tire pressures and wing angles, that theoretically if you play your cards right, by the end of the race you can dial in your car to be what you need it to be to win.

So as you start Lap 2 it’s at this point that you kind of start to have an idea of what the car is doing, and you start to analyze people’s strengths and weaknesses. And start trying to analyze your areas of attack as the day goes on.

And quite honestly that changes. It changes every 5 to 10 laps. As your fuel load decreases your car balance changes. Temperatures are always fluctuating, and a 2 to 3 degrees change in track temperature can make a big difference on the balance of your car. And it’s the guy that’s able to stay on top of it the most and make the right calls and obviously have a good car underneath him that’s ultimately able to win the Indianapolis 500.

The 2016 Indy 500 was my first 500. It was my second race ever on an oval. Throughout the race we were having a lot of problems refueling the car. Every time I came into the pits we’d kind of fall back, I’d lose position because we were taking so long to put fuel in the car.

My strategist and team owner, Bryan Herta, came up with a strategy, a high risk, roll the dice, we’re gonna do one less pit stop than everyone else and try to save fuel. So we’re gonna eliminate stopping one final time and stretch our fuel to make it to the end. We always knew we were gonna run out of fuel on the final lap, it was just gonna be a matter of when, and were we gonna have enough of a lead to basically coast across the finish line.

So we had enough fuel to get us out of Turn 2 into Turn 3, and as we were in the short chute between 3 and 4 we ran out of gas. So I just pulled the clutch in and just waited and literally just free-wheeled from the middle of Turn 4 all the way to the finish line. We started the lap with a 24 second lead and won by 3.8 seconds. Certainly a very strange way to win that race.

EDITOR’S NOTE: This video was originally published in May 2020.

Read the original article on Business Insider

How NASCAR’s banked turns help cars go faster

  • Many NASCAR tracks use banked turns that are sloped to keep race cars tilted inwards. These banks are both safer and faster than flat roads.
  • The race cars, which can reach speeds faster than 200 mph at NASCAR’s fastest tracks, would fling outwards and off the track if not for the banked turns.
  • Watch the video above for a deeper dive into the physics of NASCAR’s banked turns.
  • Visit Business Insider’s homepage for more stories.

Following is a transcript of the video.

Narrator: In 1959, something happened that revolutionized NASCAR’s stock-car racing: the introduction of Daytona International Speedway.

Daytona was unlike any race track before it because of these: banked turns. The turns had towering walls that sloped downwards to the center. Walls that NASCAR’s stock cars would drive onto. Daytona’s banks were a whopping 31 degrees, significantly steeper than the relatively flat 12-degree banks at Martinsville or Occoneechee Speedways.

In the first year of Daytona, stock-car drivers qualified at speeds of more than 140 mph. And today, at the same track, that speed is more like 200 mph – in large part because of the steep banks. Which raises the question: How do banked walls help cars go faster?

Detractors of NASCAR joke that, to finish a race, all you have to do is turn left. To NASCAR fans’ chagrin, it’s somewhat true. For the majority of NASCAR tracks, most of the lap is completed while turning, or cornering. What critics misunderstand is that it’s the turns where good drivers earn their keep. Oftentimes, viewers will see stock cars rocket past each other in the straightaways and think that the faster car had more horsepower. The speed that driver uses to pass, however, comes largely from the momentum they collect in the curve they just left.

The winningest NASCAR drivers, then, are the ones that understand the corners the best, change direction the fastest, pick the best lines, and apply power at the right times to navigate the corners better than their competitors. It’s the corners where the races are won. Going straight is easy. Newton’s law of inertia tells us that an object going straight will keep going straight until something makes it change direction.

So driving a stock car on a straightaway, even at 180 mph, would be fairly easy for you or I. It’s turning that presents some challenges. To turn, a force needs to push the car sideways. That force is centripetal force. Imagine a ball attached to a string. When I twirl the ball in a horizontal circle, the tension in the string provides the centripetal force needed to make the weight curve.

Our stock cars do not have strings attached to them. The centripetal force needed to move the car left is caused, instead, by friction at the tires. But at high speed, the force of traction at the tires alone is not enough to pull the car to the left.

Let me explain by example. Think about turning sharp circles in a flat parking lot. The faster you go, the more unsteady the car will be. With enough speed, the car will slide out. For cars traveling above 180 mph, friction at the tires alone is not enough to get the cars moving to the left. For example, taking the first turn at Bristol Motor Speedway at 130 mph requires an immense 16,000 pounds of force to move the car to the left. That’s where high banks come in handy. When an object presses onto a surface, the object feels an equal force in the opposite direction. So for a stock car on a flat track, the track will push up with a force equivalent to the weight of the car.

On a banked track, however, only part of the force from the track goes straight up. The angle of the track directs the rest of the force towards the center. And that’s exactly the direction the driver is trying to turn. The extra force from the banked track, combined with the friction from the tires, is enough to turn the car safely. So the steep, banked turns let drivers maintain greater speeds into and through the turns.

While the banked track isn’t the only thing helping the car corner – aerodynamic downforce too helps the car generate lateral force – it is one of the most important factors keeping stock cars cornering at speed. NASCAR’s banks are for cars going at race speeds. At lower speeds, the 33 degree bank at Talladega Superspeedway would be enough to slide a car down to the bottom of the track. In fact, if you or I wanted to take a lap around Talladega in a street car, we’d constantly be turning right to just stay up on the wall.

But you don’t need to be a stock-car driver to test a banked turn for yourself. Banked turns exist on our roads, too, on freeway on-ramps and interchanges. For heavy vehicles like trucks and buses, friction alone may not provide enough force to turn safely, especially if the driver doesn’t slow down enough. A slightly banked turn, with a gentle grade of 15 degrees or less, can help push the vehicle into the turn.

So, for NASCAR, banked turns simultaneously create lateral force that, in addition to friction force at the tires, create enough centripetal force in total to get stock cars moving to the left but also enable them to travel at higher speeds without sliding or flying off the track.

EDITORS NOTE: This video was originally published in August 2019.

Read the original article on Business Insider