RACHEL’S, SARAH’S AND big
DAVE’S
AWANA
GRAND PRIX TIPS – 1999 Revised for 2000
What follows are the
design philosophies around which we built our Awana Grand Prix Cars. They are not proven to be right, just the
way we did it. They are listed in what
we think is their relative order of importance. Most important first.
Therefore use at your discretion, and most of all…have fun!
1.
It’s all about
friction. Friction between the wheel
and the axle. Friction between the
wheel and the car body. Friction between
the wheel and the track. So first of
all make sure you have good wheels and axles.
Look through the kit. If the
axles are not round and straight, buy another kit of parts. Make sure when the axles were stamped out
that the dies lined up. There should be
a nice crisp corner where the head meets the round part of the axle, and it
should be relatively smooth. If you
have 4 axles that pass the visual test proceed to polish them. To do this mount the axles in a drill and
spin them at high speed. Cut a strip of
1000 grit emery cloth or wet and dry sandpaper (available at auto stores that
sell painting supplies – 1000 grit wet and dry is used to sand out lacquer
paint jobs on cars) about 3/8ths of an inch wide and the length of the sheet. Curl it around your spinning nail and use
your fingers to pinch down on the nail.
Move the sandpaper up and down and around. Push it into the head of the nail. Polish and polish and polish that nail. Till you can see yourself in it.
You can also add a little light oil, like WD-40 to the wet and dry to
make it polish even smoother. Do about
3 to 5 minutes of polishing per nail.
More if you really want. Now
check your wheels. They should be real
smooth and round and concentric. Pick
good ones. If there is just a little
flash from the injection molder then cut it off with a really sharp razor knife
or razor blade. If the wheel has a lot
of problems, just like the nail-axles, get another. To control the friction where the wheel contacts the center
strip, I put a very slight (like 30 degree) bevel on the inside of the
wheel. You will have to be creative to
do this squarely. Maybe a drill press,
probably a lathe. If you can’t bevel it
absolutely perfectly, I think they are better left alone. (This last tip was not allowed by year 2000
rules.)
2.
Now for
Lubricant. We think dry lock cylinder
graphite is best. One of the PHd’s at
work said half graphite and half moly-di-sulphide would be best. Well it took me a year to find that stuff
and it was like putting honey on my axles.
My car stuck to the ramp! So we
use only Graphite in the Erce pits! Be
aware however that the Doanne/Markovich alliance use WD-40 to good
results. We use a little spatula to
flood the wheel axle hole with graphite, smear it around on the car body where
the wheel hub rubs, and then dip the axle in it when we assemble the car. I think you are getting the idea, lots of
graphite. Everywhere. You should have a great mess when you are
done. We graphite over a sheet of
aluminum foil so that we capture most of the mess.
3.
Weight is the
engine. You are allowed 5 ounces and
should use every hundredth of an ounce.
Think of it as allowing 5 cylinders in your engine, if you only show up
with 4 you will be at a disadvantage.
We think this is true because wheel friction does not scale linearly
with weight, but the potential energy does.
We weigh our cars to 5.000 ounces now that we know Kevin’s scale is a
good one. The post office lets you
check on their scale if they are not busy, and once you have a 5 ounce car,
well you have a standard for next year and can make your own scale.
4.
Put that weight in
the back of the car. Sarah and my car
(1999 cars) had about 4.5 oz of weight on the back wheels and about 0.5 oz on
the front wheels for weight distribution.
We have stayed on Kevin’s torture track in 1999! Too little weight on the font and you are
going to leave the track at that first dip.
Rachel was more conservative and moved her weight forward and put 1.25
oz on the front and 3.75 on the back for distribution. (Note these numbers were arrived at by
holding the car level and weighing the front wheels only. Then holding the front and weighing the rear
wheels. The actual amount of lead or
steel used is about 3 oz.) This weight
distribution does two things, it gives you a little more potential energy when
you start, because the back of the car is about an inch and one half higher
than the front of the car; and it makes the car rub off less speed in friction
when the front hits the center strip.
Kevin’s course is a long one and no one I’ve seen has gone straight down
it without touching the center guide strip.
If you car is light in the nose then it steers itself down easier. This really changed in 2000 with Kevin’s
mighty dip! Both Sarah and Rachel’s
cars left the track. They turned them
around and went down heavy end first (rearward) for the rest of the races. They stayed on the track and Don said the
times were actually a little faster. So
we think that a near 50% front, 50% rear weight distribution is best when Kevin
throws in the big dips. The bigger the
dip, the more the weight must be forward.
5.
Make the car as long
as the rules allow and put the wheels as far forward and back as the rules
allow. This is that steering thing
again. Longer wheelbase = easier to
steer and more stable too. Although
Cindy’s cabooses are always short and they are real fast. So go figure!
6.
Go down on three
wheels instead of four. We tried this
for the first time in 1999 and think it helps a little. Basically one of our axle holes is drilled
0.025 of an inch higher than the other three so only three wheels touch the
track. This keeps us from wasting
energy on turning 4 wheels. Again, we
think the friction term doesn’t scale linearly. Also the other three axles shafts must be square with the block
of wood. No toe in or toe out. That will scuff off energy. I think a little positive camber, like 0.75
degree would help, but I haven’t tried this yet. This would help to make the
wheel rub against the nail head, which is smoother than the car body. Might help a wee little bit. Year 2000 rules didn’t allow the power tools
that made this kind of accuracy possible, so good luck with your methods with
the hand drill. Because of the changes
in tip #4 (50%-50%) weight distribution, you can no longer go down on 3 wheels
or you will plow to the left or right, so you want all your wheels square and
level with the even weight distribution approach.
7.
Air friction and
frontal area. We don’t think this
matters a lot. I make my cars as squat
as possible for stability and low air friction. Rachel made her’s almost the height of the block in the
back. Both worked in 1999.
8.
ADD MORE GRAPHITE!
15.
16. There we made it to 16 points and over two pages with Andrew’s
help. So think about next year, dream
those dreams, have some fun, make some practice cars, thank Kevin, and most of
all thank the Lord for making us and giving us the chance to be His. And that is what is important! No Grand Prix win can compare with what
awaits us in Heaven! Hope these tips
help. Now you know all we know! Look forward to next year! My sincere thanks to all who prayed and are
praying for my recovery. I appreciate
you more than I can describe. My
presence here this year was a gift from God! I thank Him beyond compare for his
gracious mercy, love and care!
God Bless, Rachel, Sarah and big Dave, Andrew too!