Design Tips

Design Tips

Body:

  1. Draw a side and top view on graph paper, and then cut this out of the paper. These can then be used as templates by tracing these outlines onto the block of wood.
  2. Keep the car a full 7 inches. It has to do with the physics of velocity and length of travel of the weights.
  3. Use the full 2 3/4 inches (outside wheel to outside wheel) that the rules give you. This will allow the wheels to travel farther before hitting the center strip.
  4. Leave a lot of wood in the back to put in the weights; the further back the weights go on the car the better.
  5. Use the groove closest to the end of the block of wood as the rear axle.
  6. Do not make the front of the car pointed. It is hard to set up against the starting dowels.
  7. Use your imagination. Be creative. Shape has the least to do with winning. A beaver driving a log or even a pickup truck is more interesting than a wedge and will be just as fast. The aerodynamics of a small block of wood doesn't mean much in thirty feet.

Wheels & Axels:

  1. Other than the good polishing of the axles, dump the axles and wheels in a ziplock bag with some graphite and shake them for a few days prior to the race. That way the wheel and the axles are as slick as can be.
  2. Break in the wheels by spinning them with lots of graphite.
  3. Right before check-in, fill the wheels wells with graphite and cover with stickers like a hub cap. You can paint the 1 inch stickers in a contrasting color. It looks great!
  4. Put a small drop of white glue where the axle goes into the car body and put powdered graphite on it there. That causes less friction if the wheel should rub against the car body.

Weight:

  1. Get the weight as close to the 5 ounce limit as possible. Add the last little bit of weight with lead tape from the golf shop. This can be trimmed with scissors at the last minute. Remember, the official scale may not weigh the same as yours.
  2. Everyone has an opinion on where to put the weight. My belief is that the weight needs to be predominantly in the rear so that gravity can act upon the weight further up the incline and for a longer period of time. A car with more weight to the rear generally grabs more speed down the slope. Many suggest having the center of gravity at 1 to 1 1/2 inches in front of the rear wheels. But be careful not to put too much in the rear or you'll pop a wheelie.
  3. What kind of weight? I think the melted lead is dangerous and unnecessary. Tubular weights can be sunk in the sides; flat weights, like those sold at hobby & council stores can be attached to the car bottom if it is carved in a bit. Incremental weights (with pre-marked grooves) are easier to snap off into the size you need. Some folks just use BB's, nuts & bolts, etc., but these must be glued so that they can not move. No movable weights or mercury are allowed.
  4. I like the round weights found at the hobby shops and craft stores. This allows us to stick the weights out the back of the car. We paint them and tell everyone that they are jet engines or tail pipes. What they really do is allow us to get the weights as far back as possible.
  5. Keep the weight low on the car and in the center (Left/Right of the car). Put the weight just in front or behind the rear wheels for less wheel chatter.