Porsche has created a special hybrid race car to take on Le Mans: the 919 Hybrid. Just as special is the steering wheel its drivers are holding.
Put aside any preconceived notion of how a steering wheel should look like. In the case of this race car, the steering wheel is a small computer that also happens to allow the driver to steer the car.
The drivers of the Class 1 Le Mans prototypes in the FIA World Endurance Championship have a computer with 24 buttons and switches on the front as well as six paddles on the reverse side.
This steering “box” allows the driver to control the most complex racing car built by Porsche to date.
The flat rectangle shape is due to the space required during driver changes. Tall drivers such as Mark Webber or Brendon Hartley, in particular, would otherwise have difficulties getting in and out quickly because of their long legs.
The steering computer has a large display in the center, which displays a multitude of information to the driver, including the speed, what gear is engaged, the currently selected motor management, and the charge status of the lithium ion battery, i.e. how much electrical energy is available to be called up to drive the front axle.
In this Porsche hybrid, the electric motor on the front axle supplements the turbo charged two liter, four cylinder combustion motor, which drives the rear wheels. The control button at the top left is used to select the displayed information, while the drivers use the control button in the right grip handle to dim down the display brightness at night. The identical control button in the left grip handle is for the volume of the pit radio, and the fourth rotary-type control at the top right varies the interval timing of the windscreen wiper, said Porsche.
The buttons and switches on the steering wheel were carefully positioned in co-operation with the drivers, explained the German company, to facilitate reliable operation at racing pace. The most frequently used buttons are positioned along the top outside edge, so they are easily reached with the thumb. The blue button at the top right which is almost always in use, is the headlamp flasher, used by the fast prototypes to warn the slower vehicles in the WEC field before they are lapped. When pushed once, it causes the headlamps to flash three times. In daylight, the drivers keep their thumb on it almost permanently, as the headlamp signal is more difficult to perceive at that time.
The red button at the top left is also used often. It is used to demand electrical power from the battery, the so-called “boost.” The drivers can boost to pass but must be clever about rationing the power. The amount of energy per lap is limited. The yardstick is one lap in Le Mans, where six megajoules are available. The amounts are converted accordingly for shorter circuits. For example, the amount of energy a driver chooses to use in the middle of a lap to free himself of traffic will not be available at the end in the straightaways.
A bit further inside on the right and left are the plus and minus switches to adjust the front and rear traction control and to distribute the brake balance between the front and rear axle. These (yellow, blue and pink) are not used quite as frequently.
Porsche continued by stating the orange buttons further down operate the drinking system (on left) and put the transmission in neutral (on right). The red button at the bottom left is for the windscreen washer, the red one on the right side activates the cruise control to restrict the speed in the pit lane.
At the top center, there are the green buttons for radio communication (on the left) as well as the OK button on the right. Drivers use the latter to confirm they have performed a setting change, which was requested from them via the pit radio. For these settings, they use the rotary switches, and usually only in the straightaways as they need to pull one hand out of the steering wheel grip for this purpose, explained Porsche.
The two rotary switches called ‘Multi’ correspond with one another. The left one is available for ABC settings, the right one is number-based. Programs for engine management or fuel management are designated by combinations such as A2 or B3. Three other rotary switches are available to preselect the brake balance, set the traction control for wet or dry conditions and the hybrid strategy.
To make the switches easier to recognize in the dark, their colors are fluorescent and react to a black light lamp, which is located above the driver’s helmet.
The steering wheel is made of carbon and the grip handles are covered in slip-resistant rubber. Though small in size, drivers can use this steering to steer the car without any difficulty, even with the relatively narrow grips, through the use of the race car’s power steering system.
When reaching through the openings, Porsche said driver’s fingers touch six paddles on the reverse side of the steering wheel. The center paddles are used for changing gears – pulling the right paddle is for upshifts, and pulling the left paddle is for downshifts.
The lowermost paddles operate the clutch and their function is identical on either side; depending on whether the driver just entered a right or left curve, he can decide which side is easier to operate. The paddle at the top left operates the boost; whether the drivers use this paddle or the button described on the front is purely a matter of preference.
Drivers use the paddle at the top right to initiate manual energy recuperation. This feels like a slightly engaged hand brake and supplies the battery reservoir with electric energy gained from kinetic energy.