|
|
|
Fast Facts
Or "How do they always win?"
Being last got you down? Are they pulling out the calendar
to see fast your car is? Or do you just wonder why t-h-e-y always
seem to have the fastest car every year? After all, you all start with
the same kits, right? Well, they aren't using lucky wheels or charmed
pine. Its the time, patience and technique that goes into building the
car. If you don't make this investment then don't expect more than what
you put into it.
Let's state right here and now that its the fun of
working together, learning and the sportsmanship in racing that's really
important in the Pinewood Derby event. This should be a fun event
for all involved. If it isn't maybe you're doing something wrong.
There will be only one fastest car but that doesn't mean that everyone
else's effort was for nothing. Competition is a good thing. It builds
character, teaches us about our temperament and brings humility. Reading
this text will not make your car fast but using it can make you and your
car more competitive. So there!
We have witnessed 1000's of cars and races and have seen
some great looking cars that could barely roll to end of the track while
there have also been other cars that didn't get painted and the young
teary-eyed owner ended winning over all the other cars. But, there's several
common threads to most fast cars. The keys are:
 |
The builder followed the Rules
|
|
The car goes in a Straight line
|
|
It weighs the Maximum Weight
|
|
It has Minimum Wheel Friction
|
|
The car possesses a Minimum frontal profile
(it's skinny)
|
1. Understand and follow the rules. The fastest car can't
win if it never gets a chance to race.
2. Fast cars usually have a low profile that offers the least resistance
to the air-stream. Character figurines glued to the car and other excessive
trim can slow down a car, even if just a little. The aerodynamics of a
car can effect the car's performance but it is not the highest priority.
3. Axles. The "nail" axle out of the box will look pretty bright and shiny
but its appearance is deceiving. First, it will have at least two metal
webs that reach from the nail head to the shaft. These are small but will
ride next to the outer wheel surface. Use a fine mill-cut file to remove
these webs. Mount the axle in a drill motor or drill press and rev it
up to perform the filling tasks. Next, you'll find that axles are out-of-round
by as much as 2 to 5 thousandths of an inch. Again file them to make them
regular then use 400 grit wet-n-dry sandpaper with water or light oil
to polish them back out. Axles should be polished to provide a surface
for the wheel to roll without restriction. Use a good metal polish and
soft cloth for this step. I like the Wenol brand of polishes.
4. Weigh the car to the maximum, 5.00 ounces. The higher mass per volume
helps overcome drag and friction. If your scale isn't extremely accurate
provide an easy way to add or remove weight on race day. Try using wood
screws with washers under them you so can add or remove the washers as
necessary.
5. Try putting the weight towards the rear of the car. It won't make a
huge difference but then every little bit helps. The theory is that the
higher weight pushes the car for a longer period of time. On some tracks,
the track section joints can provide a significant jolt to the car. This
can make the car's front wheels jump up, maybe even enough to derail it.
So be careful about your weight distribution. I have seen most cars do
well with three 3/8" holes drilled from the side. Two behind the rear
axle and one in front of the rear axle. The 3/8" leads worms work well
here.
6. Insure that your car is tracking straight. A car that
bumps the lane guide more often gets slowed down more often. A "front-end
alignment" may be necessary. If your unit's rules permit, move the
axles closer to the end of the car body. A slot is fine for installing
the wheels but ensure your cuts are absolutely square to the car body.
New holes drilled into the body are good too but make sure they are also
drilled at the same distance from the bottom of the car. You will find
it handy to be able to remove the axle on occasion. It is more difficult
to repeatedly replace the axles or wheels on slotted axle mounts. They
just get too loose.
7. Use a good dry lubricant. Even though the Scout Shop doesn't sell it
anymore, the dry graphite seems to still work better than the white Teflon
compounds now available. Try them both and compare.
8. Insure your wheels roll smoothly and are not binding. A good test is
to spin each of your wheels with your finger and let them run to a stop.
It should take 20-30 seconds for well tuned and lubricated wheels to stop
completely. You may want to rub some dry graphite on the surface of the
car body where the inner wheel hub touches. You can't use washers so minimize
the friction of these rubbing surfaces. Another trick is to rub the entire
surface of the wheel with graphite too. Messy, but it doesn't hurt.
9. Never, never, never roll your competition pinewood car on the ground
or concrete. These rough and dirty surfaces can ruin the car's wheels,
axles and alignment.
10. Try different sets of wheels and axles. Some wheels tend to be faster
than others or roll without wobbling. You want to buy several sets and
test them for the best of four. The wheels are made by different companies
and even different molds at each company so there's lots of chances for
getting good and bad wheels.
11. Be careful of axle modifications. Reducing the diameter of the axles
can reduce the friction at the contact points and may increase
speed but it will increase the chance of damage, loss of alignment
and bending. This often happens when a car is dropped or even put down
too quickly.
12. Round adhesive labels can be used as wheel covers that will retain
lubricant but using too much can throw the wheels out of balance and actually
slow the car.
13. Don't ruin a good thing. Even with this (good?) advise, your car may
already be as fast as it can. Changes can sometimes work in the reverse
of best intentions. A pack pinewood winner will not want to change his
winning design but use these ideas for improving next year's design.
TOP
Pinewood SuperSite HOME
|
