This article needs additional citations for verification. (July 2016) (Learn how and when to remove this template message)
The Scandinavian flick, Finnish flick, or pendulum turn is a technique used in ice racing and rallying. Approaching along the inside of an upcoming turn, the driver steers sharply towards the outside of the turn, then lifts off the throttle and lightly applies the brakes. This causes weight transfer that rotates the car toward the outside of the turn. Then, steering into the turn and releasing the brake pedal while applying full throttle will cause the car to rotate into the corner. Towards corner exit, the driver might have to countersteer to control the oversteer, but when properly executed this technique neatly lines the car up for the exit while maintaining momentum.
A 2007 research paper initiates a mathematical analysis of this technique.
This technique is used to help the driver get around corners that have an increasing radius, but it is also used as a show off as the result of the flick involves the car oversteering heavily.
Origin of the name
The technique was named after the Scandinavian rally drivers of the 1960s who widely used it; front-wheel-drive cars of the 1950-60s, such as the Mini and the Saab 90-series, turned-in more readily if the driver steered into the corner and tapped the brake pedal. This caused weight transfer to the front, reducing grip at the rear until it started to slide. The "flick" part comes from the technique of "flicking" the wheel in a direction opposite of the turn to build up angular momentum.
Scandinavian rally drivers were, and still are, predominantly the best in Europe for driving in ice and snow conditions, due to their inclement weather in winter months. Because they drove on ice and snow regularly, they were the first drivers to develop techniques to drive at speed in these slippery conditions. (They also pioneered using the snowbanks on corner exit to straighten out the car.)
Since the concept was understood and developed, it has also found its way into drifting and tarmac driving events. It has even gone as far as Australia, where it has been used to induce oversteer in V8 Supercars. The Japanese name of this technique, Manji drift, is named after a Japanese meaning of swastika for the likeness of drift lines.
Every time a vehicle turns, the vehicle resists the change of direction due to inertia. This resistance results in a phenomenon known as understeer, which a driver experiences as the front of the vehicle running wide towards the outside of the turn. This is due to reduced grip between the front (steering) wheels and the road surface. This is particularly noticeable in Front Wheel Drive vehicle, as the drive to the wheels for a given throttle input overcomes the traction of the tire to the road surface (more power to the driven wheels creates more loss of traction, hence powerful Front Wheel Drive vehicles suffer with understeer). This is partially neutralized by the friction between the tires and the road, so the vehicle rather tilts than slides, but ultimately the front wheels will break traction in a corner. In some rear wheel driven vehicles, the suspension geometry is set up to create "push on" understeer, as this is easier to deal with for the driver than un-predictable and harder to address oversteer). As you abruptly flick the steering wheel in the opposite direction, the inertia of the vehicle that has been trying to slide in the opposite way is added to the force applied by the engine and the friction of the front wheels, thus exceeding the force necessary to break traction between the tires and the tarmac. Since most cars have their engines in the front, the load on the rear tires is less, so they break traction first, effectively causing the rear to slide out. Suddenly lifting the throttle causes additional weight transfer to the front, making the load on the rear wheels even less.
Real life usage
Most cars today are FWD and are prone to understeer. This makes a vehicle stable at high speed but requires larger steering inputs near the limits of adhesion, especially on low-grip surfaces. Skilled drivers are able to allow for understeer by using a maneuver similar to the Scandinavian flick, though with less steering input and control the possible slide by using opposite lock. In the best of cases, the driver would use the inertia of the feint to make the car enter the bend without initiating a slide. This requires excellent knowledge of the specific car. However, less skilled drivers must not attempt to use this technique, as it can prove very dangerous.
The ability of a vehicle to handle sudden changes in direction at high speeds without sliding or rolling over is assessed through the so-called moose test. This scenario occurs when the driver is trying to avoid an obstacle (ostensibly a moose, or any other large animal that may appear on the road) in his or her lane and then returning to the lane to avoid oncoming traffic. The succession of sharp turns in opposite directions combined with lifting off the throttle is exactly how the Scandinavian flick is performed. Since the technique is used at race speeds, it's not normal for a vehicle to start a slide while driving at road speeds.
It is possible to induce oversteer at 30 mph (50 km/h), which is well in the cruise speed range. However, it is not likely that in real life the driver would change the steering input from hard left to hard right within 2 seconds.
This technique is commonly used in ice-racing in North America and Europe (e.g. the Andros Trophy series in France). On loose surfaces, contemporary rally drivers tend to rely more on left-foot braking for directional control in cornering FWD cars.
Of course, when driving in winter in Nordic countries, one can utilize flick even at low speeds. This technique is trained by some countries in the Scandinavian/Nordic regions during basic driver training. It may also be trained in the UK for professional drivers (Police, Emergency Medical Response, Military) who may be required to drive on snow tires in ice/snow conditions, as a vehicle can behave differently and require different driver skills in winter conditions.
It was also used in the BBC television series Top Gear, in which Richard Hammond tries to achieve the Scandinavian flick whilst cornering in his "lightweight, mid-engined" Suzuki Super Carry. The result was a less than spectacular roll-over to its side. Additionally, it is featured on Top Gear in an episode in which James May hones his rally skills in the woods and snowy landscape of Finland.
Usage in drifting
In terms of drifting, the Scandinavian flick is classified as a weight transfer drift. It is also known as a Feint drift or Inertia drift. It's widely used in rallying, because it is simple to perform and does not require excessive engine power, nor does it cause a loss of speed at the exit of the corner. A drawback of the technique is that it requires somewhat wider tracks than the other drifting techniques.
Many drift drivers will utilise the feint or weight transfer drift on track, in order to send the rear of their car into a more accentuated drift where the track width allows them. In most situations, this is preferable to drivers of lower powered cars, who cannot induce a drift with engine power alone, but it is also useful to drivers of turbo charged cars, when they find that their car is not "on boost". Many Japanese based vehicles use smaller capacity engines with larger turbos, so can "fall" off the power band created by the forced induction. The alternative methods to create power pre-corner include the feint drift incorporated with a "clutch kick", which starts the weight transfer, but allow the engine to free-rev and create boost pressure in the turbo to create more power to break the traction of the rear wheels when the clutch re-engages on the drivetrain with the car unsettled.
There are two basic dangers when performing the Scandinavian flick
- If the center of gravity is too high (as in a SUV or a tall van), there is a great chance the vehicle would roll over instead of sliding.
- It takes practice to learn how to control the vehicle during the slide. A less experienced driver would be prone to overcompensating for the slide and driving off the bend.
Also, a drift is not likely to occur if the camber of the rear wheels is set too negative. On the other hand, if the camber of the front wheels is set too positive, they will break traction in the same moment the rear ones do, so the car will slide uncontrollably rather than pivoting around the front wheels.