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Post by downhour on Jan 18, 2013 9:12:54 GMT -6
My son had his Pinewood Derby Race last night. Through the 1st 6 races, he averaged a speed of 191.6 MPH, 4MPH ahead of anyone else in the Pack. In the Finals, his speed was an average of 185.7MPH. The other cars speeds did not change. He dropped from 1st in his Den and in the Pack, to 3rd in his Den and 4th in the Pack, missing the cut for District. These races were all done on the same track, with 1 run on each lane. Can anyone explain what would cause a car to suddenly have a drop off in speed that significant? I am having a hard time explaining it to him. Last year he was 3rd in the District and his car from this year is was faster than his car from last year breaking our track record, he set last year.
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Post by Murph on Jan 18, 2013 10:22:23 GMT -6
Hi Downhour, Thanks for your inquiry. There could be several reasons for your Scout's car loosing speed.
- Increased friction due to graphite loss - Foreign material got into wheel bore/axle interface - Car alignment changed during the race
I would suspect one or a combination of these entities contributed to the loss in performance over time.
Let us know if you need anymore insight! Thanks! Murph
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Post by renner on Jan 18, 2013 22:25:01 GMT -6
All the cars we built had this exact same problem. My suspicion is that we polished the axles TOO much. There's no surface irregularities on the axle for the graphite to hold on to and it works itself out too soon. So we are going to try doing the axle prep a little different this year.
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