The Scandinavian flick is a rally driving technique used to rotate a car quickly before entering a loose-surface corner. The driver briefly steers away from the turn, then sharply steers into the turn while controlling throttle and braking. This creates rapid weight transfer that reduces rear tire grip and helps the car slide into the correct angle.
Engineers study this maneuver because it connects vehicle dynamics, friction, momentum, and suspension behavior in one dramatic motion.
During the flick, the car's center of mass keeps moving while steering inputs shift the normal forces on the tires. When weight transfers to the outside and front tires, the rear tires may lose enough grip to swing outward. On gravel, the lower coefficient of friction makes this rotation easier to control than on dry pavement.
The goal is not simply to slide, but to aim the car so it can accelerate out of the corner with minimal time lost.
Key Facts
- Weight transfer during acceleration or braking can be estimated by ΔW = m a h / L.
- Lateral weight transfer during cornering can be estimated by ΔW = m ay h / t.
- Maximum tire friction force is Fmax = μN, where μ is the coefficient of friction and N is normal force.
- The Scandinavian flick uses an initial steer away from the corner, then a sharp steer into the corner to create yaw rotation.
- Yaw moment increases when tire forces act at a distance from the car's center of mass: τ = rF.
- Loose gravel has a lower μ than dry asphalt, so tires reach the sliding limit at smaller forces.
Vocabulary
- Weight transfer
- Weight transfer is the shift of normal force among a vehicle's tires during acceleration, braking, or turning.
- Center of mass
- The center of mass is the point where a vehicle's mass can be treated as concentrated for analyzing motion.
- Yaw
- Yaw is the rotation of a vehicle about a vertical axis, changing the direction the car is facing.
- Coefficient of friction
- The coefficient of friction is a number that describes how strongly two surfaces resist sliding against each other.
- Scandinavian flick
- The Scandinavian flick is a rally technique in which the driver first steers away from a corner, then steers into it to use weight transfer and momentum to rotate the car.
Common Mistakes to Avoid
- Thinking the flick works only because of steering angle is wrong because the key effect is the rapid shift of tire normal forces and the yaw moment created by changing direction.
- Ignoring the coefficient of friction is wrong because a maneuver that works on gravel may cause too much grip or too high a speed on dry asphalt.
- Assuming all four tires keep the same grip is wrong because braking, steering, and suspension motion change the normal force on each tire.
- Entering the corner too fast is wrong because sliding beyond the available friction limit can prevent the car from rotating controllably or accelerating out of the turn.
Practice Questions
- 1 A 1200 kg rally car brakes at 4.0 m/s^2 before a corner. Its center of mass is 0.55 m above the ground and its wheelbase is 2.5 m. Estimate the front to rear weight transfer using ΔW = m a h / L.
- 2 On gravel, a tire has μ = 0.60 and a normal force of 3500 N. What is the maximum friction force that tire can provide using Fmax = μN?
- 3 A driver wants to turn left using a Scandinavian flick. Explain why the driver briefly steers right first, and describe how the car's weight transfer helps the rear rotate into the left turn.