Operator Error

Operator Error

The backlash discussion posted previously was inspired by the comments posted on a hobby website I frequent. The commentator was of the opinion that a transmission with lots of “slop” was sure to fail — even with only a 6.5 horsepower motor driving it. The transmission is only operated in forward or reverse; it cannot be shifted while the vehicle is in motion. I ended up taking mine apart, measuring the gears, and calculating the life expectancy to put other group members at ease.

I do not doubt that a determined idiot could destroy this little unit quite easily. Bigger, better, and much more robust devices have failed at the hands of those who chose not to read the instructions. We used to joke that if you sent a bowling ball down into a mine, it would be battered into a cube by lunch.

We once had the opportunity to make transaxle gears and dog clutches for a famous Indy Car racing team. This was in the 1990s before transaxles and eventually the complete car became single-vendor sourced. The opportunity came our way because we had successfully “fixed” the short service life of some offshore powerboat racing gears.

Applying the same techniques to these well-established Indy Car components was equally successful — i.e., for two-thirds of the team. The veteran drivers, both legendary race winners, could easily get complete 500 mile races out of the previously temperamental bits. Their “fan favorite” understudy, however, continued to transform nice shiny parts into shrapnel with a single downshift.

You could see the difference in “duty cycle” on the telemetry screen during test sessions. The engine rpm barely varied for the legends. The “local hero” — no matter how popular or well-funded — had lots of abrupt changes in those rev curves. I often thought he and his “rough rider” contemporaries motivated the invention of the electronic shift racing transmission just so the poor transaxle technician could have the occasional day off.

Categories: Gear Talk With Chuck

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Charles D. Schultz

Charles D. Schultz is President of Beyta Gear Service and one of Gear Technology's technical editors.

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