The term slipstream or sometimes also called drafting, is one thing that is very common in racing. Ever see in a straight lane the car behind can go faster then overtake the car in front of it? The car in front seemed slower. Is it because the car in front of the engine performance is less than the rear? Well, it could be also, but not necessarily.
If we present two cars with the same performance, the car behind on the straight lane will be able to accelerate faster than the car in front of it. Why? because of the slipstream.
Have you ever seen a video of a group of geese flying in migration with a V formation? Well, this also has to do with the slipstream.
Talking about slipstream will be closely related to aerodynamics such as drag, downforce, and dirty air. The name aero, will not be felt when we drive casually in the city. No mopping. But make no mistake, if in high speed, especially in racing, all of which are important factors. That is why aero setup in professional racing is vital and calculated so carefully!
Let’s just start reviewing driving techniques this time. Are you ready for the coffee?
Drag and Aerodynamics
Drag or obstacle in this case is air resistance when our car is moving. Ah, how can air get in the way? Do not believe? Try to break the windshield of your car and drive 100km / hour. Feel the air that hits you. The strong air will be faster pushing backward along with the speed of our car. Imagine the air pressure when the car drove 160 km / hour or even 240km / hour!
That is drag.
But the car is heavy. How could you cheat? The plane is even heavier, and thanks to the air flow he can fly hehe.
Now, even though it creates drag, the air flow also has uses. In addition to creating backward thrust, he also creates downward force. This is what makes the car stick to the road, not shaking or even flying. Downward pressure increases the grip or grip of the tire to the road. The bigger the grip the faster we go too!
But back to the design. If on the plane, he was designed to create elevators, so they could fly. When in a car, it is designed for downforce. With the exception of daily cars, it doesn’t seem to focus very much on aero design. Back, because when used for daily use, aero won’t have much effect.
So, air creates drag that inhibits but also creates downforce which improves grip. This is why aerodynamic setups on performance cars or race cars are so important. The racing engineer team will see the characteristics of the track. How is the character of the line and the turn. At the line we want to reduce drag so that the car can go up. But at the turns we need to drag to increase downforce which affects the grip of the tire when turning.
Earlier we discussed cars that drove through the air which created drag. How about for example there is another car behind him?
The car will get a drag that is much smaller than the car in front. The air in front collides with the car in front leaving an area with low pressure in the back. In this area, the car behind can go more optimally due to less air resistance.
This is why on a straight track, the car behind will be able to go faster and be used for one of the following moments when racing.
To feel this we can try by entering the pool. Try walking in the water. It’s heavy right? Now that’s a drag. Now try walking behind the person who is walking in front, definitely lighter. That is slipstream.
Why, then why are swans flying in V shape, not rows?
In contrast to cars, the slipstream area behind the swan is precisely the area that is avoided. Why is that, because the flutter of a swan’s wing also creates a circular flow of air. The area behind the swan is the air down while on the rear the air is upward. Ok, we blocked the air in front, but the wind from the wings of the bird in front of us pushed us down.
Back to the car, then how about when it starts to turn?
The car in front has a large drag and of course downforce which increases grip to the road. The car behind? It has a small drag so it can go fast but the downforce is also small so that it is tight but the grip is not as big as the car in front. If not careful, the car that lacks grip can understeer or oversteer twist!
This has not been exacerbated by the presence of dirty water.
As the name implies, dirty air which means dirty air can also be referred to as used or residual air. Who are the leftovers?
The air that was hit by a moving car in the form of solid air and has not been disturbed. When the car drove and crashed into this air, the air will then scatter and break in various directions. Although the rear area of the car, the slipstream, has low air pressure, the other area behind the slipstream has air (or wind) from the rest of the collision, which is difficult to predict or disheveled.
This is called dirty water.
The wind that surges with an unclear direction will adversely affect the aerodynamics of the cars that hit it. Especially if the car has aerodynamic devices such as the front wing, rear dear or splitter. Unlike drag which increases downforce, dirty air makes the car lose downforce and also makes it unstable.
The most definitely is when when maneuvering turns and get dirty water. The car is then very vulnerable to understeer or oversteer twist.
Dirty air is also believed to have a bad influence on the engine because it disrupts engine performance and cooling system. The residual air from the car from the front is believed to have a higher temperature and also has less oxygen content than normal air.
But the good news, this dirty air phenomenon will only be very influential on race cars that really rely on aerodynamics and downforce like Formula 1.
For the cover, let’s look at the bike speed record of 300 km / h thanks to the slipstream!
Thus the review this time.
Slipstream provides the advantage of lower drag thereby increasing acceleration and top speed. This is one way to overtake that is very common in racing when on a straight track. This technique is also often used for hypermiling, aka saving fuel. Slipstream is done to reduce engine work, which means to reduce the energy used.