Variable-ratio steering at St. Petersburg
Last week, the IndyCar Series introduced paddle shifting to its cars. This week, the variable-ratio steering rack complements the package on the streets of St. Petersburg [in an effort to help weaker drivers such as Danica Patrick, call it Danica-Steering if you like].
|You won't see Danica Patrick making a big fuss over the IRL's new variable rate steering like she did with the weight rules change. Why? Because the variable steering was implemented primarily to help her given she is not as strong as the male drivers and her poor little arms were tiring on the road courses causing her to fade as the race wore on. Not a peep out of her on the paddle shifters and variable rate steering. Not a peep|
Call it the VR for short. Its purpose is to diminish the amount of effort needed by the driver to turn the steering wheel on road/street circuits such as the 14-turn St. Pete course. Multiple drivers utilized the VR in competition and testing last year, and feedback was obviously positive.
"People felt that it would be a benefit in terms of reducing the overall fatigue levels during an event," said Les Mactaggart, senior technical director for the sanctioning Indy Racing League. "A majority of teams ordered them for the season."
The system is optional, and don't call it power steering.
A standard steering rack is a metal bar with a series of evenly spaced teeth that links to the front wheels of the car. A pinion controlled by the driver turning the steering wheel catches on the teeth of the steering rack, causing the wheels to turn in the corresponding direction based on the load and movement of the driver.
The variable-ratio steering rack mechanism is similar, but the pitch of the teeth on the steering rack change. Also, the teeth are not spaced evenly; they are closer together toward both ends of the steering rack. The pinion is also a different shape. These slight changes allow the pinion to catch on the teeth easier to turn the wheels. There's no compromise in space.
"Particularly with F1 no longer having power steering in their cars, it was a good reason for us to look at almost newer technology, which is really what the VR rack is," Mactaggart said. "It was designed originally to fulfill the gap that was in the Formula One regulations after they banned power steering; they could use this in their cars legally as well. It was by far the best solution."
True power steering would be difficult to introduce to the current Dallara chassis, according to Mactaggart, because of a unit's size. It's basically an electric server that fits under the steering column and is tied to a hydraulic system.
"It would be difficult to install in these cars without compromising the drives' safety in terms of their legs," he said. "We would have to completely re-engineer what we have."
Already, an electric server powers the pneumatic paddle shift system, which replaced the six-speed sequential shift gearbox.
The paddle shift system eliminates the need for the driver to remove their right hand from the steering wheel to shift gears. Paddles are located on the back of the steering wheel, with the right paddle moving up gears and the left paddle moving down gears. IndyCar.com