Derby Talk

There was talk about whether a boy should be allowed to win trophies for both Speed (Races) and Design (Best of Show) for the same car. The most typical way to limit cars to a single trophy is to exclude speed winners from design awards. Thus, if the best design wins a speed award, the first-place ...

For district races with 50 to 100 cars in the racing pit, stopping for 20 minutes between inspection and racing isn't practical. Judging during the racing creates some problems, too. (anonymity, boys and cars coming and going, etc.) Suggestions, anyone? The only regional derby I've been involved wi...

Balancing the weight between the two rear wheels would be a "2 wheeled disaster." A bit of a rough spot or touching the center rail and the front end pops up a bit and air catchs it and turns it over. You really need around an ounce of weight on the front to keep the car under control ......

Having a foam mounting may provide other benefits to dampening vertical movement of the weight. It seems that it would allow the weight to move backward a small amount as the car accelerates, thus storing some potential energy that would later be regained during the deceleration in the straightaway...

When looking at Michael Lastufka's DOE experiment data, I am not so fast to discount the effects of something I thought small, which was aerodynamics. In his first experiment to weed out factors to test, out of 11 factors, aerodynamics was in the top 5. It's been a while since I studied his data, b...

Our track raises the center strip to stop the car. The top of the raised strip is coated with non-skid material (the kind used on stairs in industrial settings), but the really fast cars still manage to hit the back stop (which is covered with foam). Anyway, I don't worry unless the decorations on a...

When a rigid car hits a small bump, its mass moves up. It requires energy to move the car up. Where does this energy come from? It comes from the car's kinetic energy (i.e., from its speed rolling down the track). And there is no mechanism to convert this energy back into forward-motion kinetic ener...

What a great design! Thanks for showing it to us! Weight was not an issue so we were able to use liquid acrylic to simulate the water. Once the acrylic hardened and the car was completed, it weighed over 12 ounces. You could modify this design pretty easily to keep the car under the typical 5-ounce ...

I would like understand friction better and maybe rid myself of mis-understanding. The friction formula? What is it? In physics, friction is abstracted as a constant (mu) times the force perpendicular to the surfaces. Thus: F[friction] = mu * F[perpendicular] The value of mu depends on the nature o...

I usually type up some notes every year and hand them out with the pwd cars but have found that most people need something visual to go be. At our "derby kick-off" meeting, I explain the construction process, and we send home a flier. The flier came from CSB, and includes drawings of each...

Some groups clarify the kit insert in their own published rules to specifically exclude lathe cutting. I believe that this is overly restrictive and contrary to the underlying goals of the PWD program. The playing field can be leveled with knowledge. Knowledge can be passed from parent to child. Fi...

Can someone please post a direct URL to this site's image gallery? Even with JavaScript and Flash enabled, the site doesn't work for me.

TIA