How does the car drift?

Drift principle: Blame one: the rear wheel loses most (or all) grip, and the front wheel should be able to maintain grip (at most, only a small part can be lost, and it is best to gain extra grip). At this time, as long as the front wheel has a certain lateral force, the car will swing and drift. How to make the rear wheel lose grip: 1. Make the rear wheel have a negative speed difference with the ground during driving (the rear wheel speed is relatively low) 2. Make the rear wheel have a positive speed difference with the ground under any circumstances (the rear wheel speed is relatively high). Reduce the positive pressure between the rear wheel and the ground during driving. As long as one of these three items is satisfied, in fact, 1 2 is a method to reduce the friction coefficient, which is separated by different application methods. How to keep the front wheel grip: 1. During driving, don't make the speed difference between the front wheel and the ground too large. 2. Do not reduce the positive pressure between the front wheel and the ground too much during driving, and it is best to increase the positive pressure. These two items must be met at the same time. In actual operation, the handbrake must ensure that there is a negative speed difference between the rear wheel and the ground during driving (the speed of the rear wheel is relatively low) and there is no big speed difference between the front wheel and the ground during driving; Simple operation of drifting initial state: The methods of drifting are: 1. Pull the hand brake straight and then hit the direction. 2. Hold the brake in turn. 3. Brake suddenly on the straight road and then hit the direction. 5. Rear-wheel drive with sufficient power (or four-wheel drive with the driving force distribution ratio of front and rear wheels inclined to rear-wheel drive) slams on the accelerator to hit the direction when the speed is not very high, among which 3 and 4 adopt weight transfer (rear-wheel weight transfer) 1, and 2 are only used for front-wheel drive and four-wheel drive in rally competition, unless they are not afraid of damaging the car, they are free. Note that 1 and 2, 3, 4 are separated, because the movement route of the car will be very different. Important note: Drift cornering, like ordinary cornering, has a speed limit. The speed limit of drift cornering can only be higher than ordinary cornering at most, and the speed limit of drift cornering on hard ground is lower than ordinary cornering! As for whether the tail can be flicked in the end, it is related to many factors, such as friction coefficient between tire and road surface, vehicle speed, braking force, throttle size, front wheel angle, vehicle weight distribution, track wheelbase, suspension hardness and so on. For example, it is easy to wag your tail when driving in rainy and snowy days, but it is more difficult not to wag your tail; The higher the driving speed, the easier it is to flick the tail (so the first rule of safe driving is not to drive too fast); Hit the direction quickly, easy to flick the tail (the master who taught me to drive told me not to hit the steering wheel too fast); The smaller the wheelbase, the higher the body, the more intense the weight transfer, and the easier it is to shake the tail (and it is easy to roll over! ); The weaker the anti-tilting effect of the front suspension system, the easier it is to swing the tail. Some people have mentioned a variety of drift modes, which are actually within the above five types. Control in tail flick: If the car drifts with the handbrake, you should release the handbrake when the car rotates to the angle you want. The task in the middle of drift is to adjust the posture of the car body. Because the road surface is uneven, the degree of route bending, the cornering characteristics of cars and other factors will often change. Therefore, drivers often have to control the steering wheel, throttle, brake and even clutch (not recommended) in order to make the car follow the route that the driver wants. Explain the principle first: to make the wheel slide long, we must try to reduce the friction between the wheel and the ground; In order to keep the wheels from slipping, we should increase the friction as much as possible. As mentioned above, the way to reduce friction is to make the wheel rotate too fast or too slow, and reduce the positive pressure between the wheel and the ground. The method of increasing friction is the opposite. Among them, the way to make the wheels rotate too slowly is to step on the foot brake or the hand brake (again: the foot brake acts on four wheels and the hand brake acts on the rear wheel. Whether or not the handbrake acts on cars with other wheels, I said all the cars I know with handbrake. Pedal braking: all four wheels will slow down, and ultimately it is impossible to generalize whether the friction lost by the front wheel is large or the friction lost by the rear wheel is large. Hand brake: the front wheel will not lose friction while the rear wheel will lose a lot of friction, which is easy to oversteer. Because both the foot brake and the hand brake can slow down, the car will soon stop skidding. Real drift: And if you want the wheels to slide for a long distance, the only way is to let the driving wheels idle at high speed. Only cars with LSD and enough power can do this. Why are there LSD? Because the car body will tilt when drifting, the pressure of the outer wheel on the ground is large, and the pressure of the inner wheel is small. Without LSD, the inner driving wheel will idle and the outer driving wheel will rotate slowly. The friction between the slow-moving wheels and the ground is large, and the side slip of the car will soon stop. Cars are divided into front drive, rear drive and four-wheel drive, and wheels without driving force cannot idle at high speed. Then the rear wheel of the front drive can't do long-distance sideslip. If the driving wheel (that is, the front wheel) idles at high speed, and the side slip is more than that of the rear wheel, the drift angle will be reduced, so the front driving wheel can't do long-distance drift. Four-wheel drive cars are obviously possible. What about rear drive? The front wheel of the rear wheel drive has no driving force, but the front wheel can swing at a certain angle in the direction of the car body sliding, so the rear wheel drive can also drift a long distance. The sideslip distance is related to the speed before the sideslip starts. Usually, it will slide slowly and finally stop. However, if the site permits and is well controlled, it can theoretically do infinite sideslip. Because the skidding wheel still has a certain acceleration, the skidding tire is also resisted by the ground. When these two functions are balanced, the speed of the car will not decrease. For example, doughnuts are one kind of infinite drift, but they can also make an infinite drift with a big turning radius. All the above are methods to control the side slip length of the driving wheel. After knowing these principles, let's talk about the method of adjusting body posture: 1. Control the angle of the front wheel, not too big or too small, especially the rear drive. 2. Adjust the throttle and brake to make the car tend to accelerate or decelerate, resulting in weight transfer, and control whether the front of the car is slippery or the rear of the car is slippery by weight transfer. 3. Use the hand brake again to produce oversteer. Note: In 2, the effect of refueling with rear-wheel drive (or four-wheel drive with power distribution ratio tending to rear-wheel drive) is not necessarily acceleration. If you refuel too hard, the friction may be reduced because the rear wheel speed is too high, and the rear of the car will slip more outward. Important note: maximum drift angle: maximum drift angle-in the middle of drift, if the angle between the head direction and the body direction is greater than this angle, you must stop (if you don't stop, you will crash). Note that it does not include the time when the drift occurs. For rear-wheel drive vehicles, because the front wheel has no driving force, it can't produce high-speed idle steering and sideslip, so it can only rely on the lateral force facing the front wheel to control the movement of the front wheel. Therefore, the included angle between the head direction and the body movement direction can only be equal to the maximum swing angle of the front wheel at most (the swing angle of the front wheel of different cars is different, and the swing angle of the front wheel of a general car can be about 30 degrees). If it's any bigger, there's no way to get back to normal driving except to stop and start again. Note that the "large-angle drift" generally refers not to the angle between the direction of the car head and the direction of the car body movement, but to the angle marked in red in the attached drawings. The steeper the curve, the greater the angle. The rear wheel drive also has the situation that the front wheel has insufficient grip and insufficient steering. In this case, the included angle between the head direction and the body movement direction cannot exceed the maximum deflection angle, otherwise it is necessary to stop and resume normal driving. Because the front wheel can keep the grip of the rear wheel and increase the throttle to make the front wheel slide outward, the maximum deflection angle of the front wheel is very large, which can be close to 90 degrees. Four-wheel drive because the front and rear wheels can idle at high speed, it is more likely that the front wheels will slip outward when refueling (why? Because the weight is transferred to the rear wheel when refueling, the friction between the front wheel and the ground is small), and the front wheel can swing outward, then the maximum deflection angle of the four-wheel drive is greater than that of the rear drive. (Drift: There is an objection. Under the complete frame setting, the drift angle of the rear-drive vehicle is greater than that of the four-wheel drive vehicle. ) comparing the three driving forms, the front drive is the easiest to drive and the safest. (drift: objection appears, hehe, I think FR is the best to drive, and it really feels great when parking. ) Drift out of the bend: Drift out of the bend is about to end, and the ending method is the same as the method of reducing the drift angle during drifting. For front drive, 1. Come on, let the front of the car slide outward (because the front drive is basically understeer except when drifting) 2. The front angle is corrected by swinging the front wheel 3 outward. You can also put a little throttle after the front wheel swings outward. Four-wheel drive, 2 is usually necessary, 3 is also effective, 1 is not necessarily effective. For rear wheel drive, the most important thing is to rely on 2. Depending on the specific situation, weight distribution, driving force distribution, previous drift angle, road conditions and other factors have an impact. Pay attention to the whole drift process (including the beginning, middle and end), so when preparing to turn, don't point the front of the car at the outside of the road, but point it at the inside, so that when the car slides to the outermost side of the road, the lateral speed is just zero, which is a perfect turn. Postscript: To drive different cars to drift, there must be an adaptation process to understand the characteristics of the car; There should also be an adaptation process on different roads. In the rally, because you don't know the specific situation of each corner, even if you ran this stage last season, the road surface will not be the same as before. Therefore, the curve of rally advocates the principle of "slow in and fast out"-slow down before entering the curve, and then increase the throttle after seeing the curve clearly. Using this principle to turn a corner will not be much slower, and the safety will be greatly improved.