Never mind. Posted as to why it goes airborne.
It’s as simple as this, I think (not to dispute that there are other forces at work, as other posters have explained). A car rolling along the ground will stop relatively soon due to friction. A car rolling while in the air suffers much less friction and so will rotate more. It could be that this causes an illusion of its rotation speeding up (which could also happen due to aerodynamic or other forces).
My wife likes to watch the Triple Crown races every year (from the comfort of our living room). I watch them with her even though I don’t particularly care about horses or racing. Every now and then you get to see a wreck, and as much as you’d hate to see a really nasty one you’d hate to miss it.
Kind of a related question: why is the coefficient of friction of the tires so fickle. In the yaw spinning scenarios, it doesn’t take much to get the car spinning but it does take a lot to get it to stop. It seems as if the tires and the pavement have sufficient friction between them right up until the moment that they don’t. And then there seems to be almost zero friction in the system and it remains this way even as the car slows and loses energy. . .the spin continues. what is going on there?
mc
Sliding tires exert less grip on the road than tires that aren’t sliding. The difference is even more dramatic on race cars that use aerodynamics to enhance grip. This is especially true for IndyCars and F1 cars, on which the aerodynamic downforce can be even greater than the downforce due to gravity. The aerodynamics only work when the car is pointed in the direction of travel; under these circumstances, we get accustomed to seeing the car decelerate rapidly under controlled braking (as much as 5 Gs). Get the car sliding sideways, and the aerodynamics offer zero help with traction; put that together with slipping tires, and max decel will be a small fraction of what we are used to seeing under normal forward travel. Get the car sliding backwards, and the aerodynamics may actually reduce total downforce, further reducing grip/decel.
A couple of reasons come to mind.
One is the fact that static friction is greater than kinetic friction, at least for racing tires on a typical track surface. Before the spin the tires are maintaining grip with the track under static friction. When a spin and/or brake lockup occurs, the tires are now sliding on the surface under kinetic friction. So relatively speaking it appears to an observer (and driver too I’ll bet!) that the car is skating on the surface compared to when it was under control. Even when the driver releases the brakes there’s still the issue of the tires trying to rotate back to speed, who’s direction is constantly changing as the car spins. Thus it’s very difficult for the driver to regain control of the car under those conditions.
The second reason is race cars are designed on the bleeding edge of stability for the track in question in order to maximize its speed. And the stability is optimized pretty much only when the car is moving forward. Increasing stability in the aerodynamics of the car body and in the design/settings of the suspension would result in a slower car compared to the competitors. Racing teams that designed a car to recover quicker from spins would never win a race against the competition that pays their driver the big bucks to (barely) keep the car under control at max speeds for the conditions.
ETA: Wow, was I ninja’ed by a great post!
I agree with them. Crashes can be fatal. Remember Jules Bianchi.
Right. But I would never sit and watch cares driving around a track without something interesting happening.
Thanks for the link. For what it’s worth, it looks to me in that example like the rotation of the car about its longitudinal axis speeds up after the initial contact with the wall. Looking at it in slow motion, it seems to take a couple of seconds to complete its first rotation and perhaps a second to complete its second. Its third rotation looks even faster but at that point, the car is basically standing on its nose and pirouetting.
I think there could be at least two effects here. One is, as you note, the momentum contributed by the engine changing speed when the tires leave the ground. But, would the engine be gaining speed or losing it when the tires left the ground? I’d imagine the driver might be off the throttle before he hits the wall and the engine is slowing. Even if he were still on the throttle, the engine would hit its computer-controlled redline really quickly after the tires left the tarmac and the engine and other rotating parts would stop accelerating.
The bigger factor would seem to me to be the car’s forward momentum being redirected after it hits the wall and bounces off the ground a few times but I don’t really know. After all, the car’s rotation is accelerating but the car itself is losing forward momentum much more quickly.
Even when they’re not, they can be really bad. I was watching the race when the crash linked to in post #7 happened on August 19. It’s been more than three weeks since the crash and the driver, Robert Wickens, is still in the hospital recovering from a horrifyingly long list of injuries:
Here’s wishing him a speedy and full recovery. There are, sadly, many others who died or were severely injured.
There’s no doubt that auto racing is a dangerous sport, though, just as technological and safety advances have made passenger cars far safer today, auto racing, too, is safer than it was in the past. (Note that “safer” does not necessarily mean “safe”; there are still many accidents, injuries, and even deaths in auto racing.)
There’s a line in the 2013 film “Rush” (about 1970s Formula One drivers Niki Lauda and James Hunt), in which Lauda says:
Yes, the film is a fictionalized version of the events of that era, but that quote isn’t far off: in Lauda’s time as a driver, one or two F1 drivers did die every year. In the past fifteen years, there have been only three deaths in F1 racing. In NASCAR, the last driver death in the NASCAR Cup series was Dale Earnhardt Sr., in 2001.
[quote=“Jasmine, post:6, topic:821161”]
Spin is produced when a force is applied from an angle perpendicular to the direction the car is traveling.
Since race cars on an oval track have to negotiate a major turn at each end of the track at the highest speed that they dare travel …QUOTE]
That’s just the yokels in Nascar. The real pro’s (F-1 and similar) also have to deal with left AND right turns, and, on certain tracks, dips and hills.
[quote=“dstarfire, post:33, topic:821161”]
The IndyCar series features a mix of ovals and more squiggly tracks.
And by my count, the distribution of the track type mix per series (for 2018) is:
- Indycar: 10 road courses, 6 ovals. Most famous oval is its namesake, the Indianapolis 500.
- NASCAR: 2 road courses, 34 ovals. Watkins Glen and Sonoma make for an interesting diversion, but obviously a oval-based series.
- F1: 21 road courses, 0 ovals. Except for Monaco, all tracks used to be purpose-built courses, but lately F1 has added more street courses to its schedule.
ETA: Fixed quote attribution.
That’s not correct. Spa was not purpose-built (clue: it has a chicane called Bus Stop), and I think Le Mans was originally just public roads too BICBW. A number of the courses that held the British GP were converted airfields.
In the 1920’s the race was designed using public roads, true. But since the 70’s it’s been converted to a purpose-built race track. The Bus Stop chicane is long gone, and the only way you’re going to drive your car on that track is to pay a fee, attend a drivers meeting, meet clothing and equipment standards, and be supervised by course marshals while you drive a lap. Not hardly what I’d call a public road. Spa had to convert to a purpose-built track to meet safety standards to be allowed to continue hosting F1 races.
Also true, but all in the distant past. F1 only drove at Le Manns once, in 1967 (for many minutes as was the fashion at the time :)), on a specially modified and shorted version of the track called the Bugatti Circuit. It was a boring, unloved event never to be repeated. F1 has never raced the Circuit de la Sarthe, the famous track known for the 24 Hours of Le Manns. And you can drive your car on the Circuit de la Sarthe, including the Mulsanne Straight, Indianapolis, Arnage Corner etc. providing you respect the French driving laws and speed limit. And of course, providing that there’s not an event going on at the time. 
Huh, turns out the highly modified corner there is still referred to as the Bus Stop chicane, though its shape no longer resembles the road when it was a bus stop. And of course, no public bus regularly stops there anymore. 