The key to winning these events is to hit the ground running. To get maximum purchase on the track at launch, these racers carry tires like large, treadless, under inflated (5 psi) balloons that deform, or flatten, as much as 50% under the enormous initial acceleration. As the race progresses, the car levels somewhat and the tires revert to fat doughnuts. The more rpms at launch, the more the tires will squat and the faster the car will accelerate. But too much power and too many rpms, and the tires lose traction, spin, and expand prematurely. Result: losing the race and maybe the engine as well.

To monitor tire behavior, Nordell mounted one of Baumer Electric’s self-contained analog output laser prox sensors on the car’s rear frame to measure the distance between the bottom of the frame and the ground during launch. The OADM 20 pager-sized prox is a line rather than a point laser device (to compensate for irregularities in the track surface). It accurately measures distances down to 0.01 mm, and reports to a data logger throughout the race on how much and when the tires compress or expand. It also notes any spikes in tire diameter that indicate spin. Nordell uses the information, along with that provided by a 32-channel data logger and a PLC monitoring various motor and transmission functions, to fine-tune the car’s performance.

The Class 3 laser works fine in bright light, and a unique design that flips the receiving element’s orientation makes for a crisp, well-defined signal. And rather than measuring only the distance between two points, the sensor offers multipoint linearization that averages distance over multiple measuring points for unmatched accuracy. Price? $1300.

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