Ok, I have a fair bit of expertise in this area (and the trophies to back it up!
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1) Unlike the "old" days, hobby shops now carry rough-cut forms of pinewood derby cars in several styles- f1, hot rod, etc. You can also find decal sets, molded ABS wheel ferrings, muffler pipes, etc.
2) Make a choice early on, either you want a car that looks cool or you want a car that goes like stink. You can probably do a bit of both and do well, but nothing beats taking the checkered IMHO.
Keep in mind though that its for you and your son to have fun together, my dad tended to get a bit overzealous with the "we're in it to win" attitude
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If you want to win, here are my go-fast secrets:
1. drag is your enemy, even though it looks like a little car, the same laws of physics apply. The all-time fastest body shape I've ever found was a simple wedge, actually a sliver is more fitting. My fastest car ever was no more than half an inch thick in the back, and the front was just thick enough not to splinter off when sanding.
2. get good at sanding. Once you have the wedge, make it as smooth as possible, then make it smoother. I went all the way to wet paper with mine, something rediculous like 600 grit. The pine was so smooth you'd think it was metal.
3. don't get crazy with the paint, use a high gloss that's durable but super smooth. I lost a race once cause I used a satin finish, which negates all the time you spend sanding btw.
4. Axles. These are the little 'nails' you use. Use a fine sandpaper and mount the axle in a power drill. Then spin the drill and polish that little nail as smooth as you can get it.
5. Wheels. As the others stated, you must tune these babies. Make sure the seem is made smooth and there are no burrs or anything from the molding process. You can use a somewhat smaller "axle" and smooth the hole in the wheel so that's as smooth as possible too.
6. Graphite is your friend. Graphite on the axles/wheel hubs will get 'em spinnin nice and easy, lowering that friction as much as possible. NOTE: years later I worked in a lab at Dupont and they make this teflon 'grease' that nascars use in their bearings and stuff. Its supposedly even more slippery than Graphite.
7. My fastest car ever: I cut tiny disks out of thin plastic and sealed the outside of my wheels. Before doing so however, I supplied a generous amount of graphite in the cavity. This basically acts like a continuous-lubricating graphite reservoir. The judges were worried, but I think thats more because they knew their sons were going to have trouble, hehehe.
8. No decals, stripes, labels, etc. All they do is slow you down.
9. As was said, go as heavy as possible, within the weight limits. From experience, do not count on the scale at the derby to be accurate. I was using a super accurate one at home and when I got to one race they said I was too heavy, so I had to scramble to try and adjust my car.
Here's my weighting secrets:
Believe it or not, lead will melt on your kitchen stove. I don't recommend using your wife's best teflon *** though
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In the back of your wedge, drill a hole right in the center of it about 3 inches long (or whatever it takes to get the weight right), through the rear of the wedge (not the bottom, you want the bottom to be as smooth as possible, just like the top). Tape two pieces of wood together and drill the same hole between the pieces. Pour the lead that you melted on the stove into the hole. Separate the wood pieces, and you have a very nice lead cyllinder to put in the back of your car. Use this to get close to your target weight but stay under just a bit.
Then, make two holes on either side of the main cyllander, these need to be shallow (1/2" deep maybe). These holes are how you fine-tune your weight. What I did was to use tiny lead splitshot for fishing and candle-wax. You fill the two shallow holes with melted candle wax and split shot. When you get to weigh-in, you can easily add/remove split shot to be right at the limit weight on whatever scale the judges are using. You can even whip out a candle and re-seal it on the spot if you need to.
Thats pretty much it. If you do the stuff above I can nearly guarantee victory.
...and yes, I'm at work, and very bored.
- Mark ('99 ACR)
