The track was
set up first with a lane timer that measures to .001 of a second. For each test, the cars made at least 5 runs. I took out the high and low times
and then averaged the rest. All
tests were run in the same lane of the track. I only want to test modifications
that will be legal in Cub Scout races.
(See the official rules from the Pinewood Derby Kit.)
Test 1: Baseline:
I tested three cars with no modifications other than adding weight
to make them all 5 ounces each to find a baseline time. We poked screws in the sides of
the cars to balance them. We
had the weight in the center of the cars for all the baseline tests.
Test 2: Stress:
Next we ran one car 50 times to see if the parts would wear in and
go faster, or wear out and go slower. Blank chart
Test 3: Graphite Baseline: We put graphite on
the axles of the three cars and timed them to get a baseline time with
Test 4: Graphite Stress:
For this test, we put a lot of graphite on the axles of one car and
ran it 50 times to see if the car would run faster after a few races.
Test 5: Weight & Axle Location:
We raced a car with the weight (center of balance) closer to the
front and then closer to the back. Then
we raced the car with the axles more toward the front and again more
toward the back. Blank chart
Test 6: Aerodynamics:
We cut a slot in the top of a car and put in a 3x5 index card to
see if the wind would slow down the car.
Then, we cut the front of the car into a point to see if the car
would go faster.
Test 7: Wheels:
We put the wheels in a drill and sanded them to make sure they were
smooth and round. Then, we
waxed the wheels to make them slippery.
We pushed in the axles more so they would only stick out 1/16 of an
inch. Then we pushed the
axles in more to about 1/32 of an inch.
Test 8: Alignment:
We rolled one of the cars on a table. Instead of going straight, it
turned about 3 inches in 3 or 4 feet.
We timed that car several times, then adjusted the axles so the car
rolled straight on the table. Then
we timed the car several more times.
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