The Tuned Racer - Derby Tech - February, 1986

by Ken Rogers


(Reprint from Dec 77 Derby News)

Did you ever, wonder why some people run faster than other people? It is not strength. The harmony of muscles working in unison is the fact of human speed. If muscles tend to work against each other, people say you are a little clumsy. The same fact is true in building a fast racer. All facts being equal between two identical racers, the racer with the best beat of the track down the hill will win.

Some racers may only get the "beat" for 5 to 10 seconds, when going down the hill, but longer it can be held, the better the racer will win. Some racers get an early "beat", while other can finish good ... a later "beat". Some tracks are not long enough to allow some racers to reach their "beat".

A musical strobe meter can measure the vibrations of each axle spindle. The changing of lead strips along each axle can change the vibrations at axle spindles. (Example: E sharp to G flat) The higher up the scale, the later the racer will get the "beat". The "Beat" is different on different tracks. The most one can hope for is out 15 seconds of peak harmony. The matched set of four spindles can be obtained by lead strips taped to the axles at different points. Tuning forks can be placed in the racer and tuned to the same vibrations of the axle spindles and this will amplify the length of the "beat". The tests of not harmonizing the spindles in our test racer is as follows after 20 test runs tuned & untuned.

Untuned 940 ft. track 27.2 average speed.

Tuned 940 ft, track 27.0 average speed.

The following sketch will show how a sound wave of spindles should be to work together:

 


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