Gizmo

If anyone out there is interested in getting involved in the soap box derby, my son has outgrown both of his and he wants someone else to enjoy them. We have a stock division car and super stock car. The stock class car best was 4th and the super stock he finished 3rd. the young fellow that beat us in the semi's, went on to win. His dad was also a division winner back in the late 50's.

PhantomChaos

Oh.......I forgot to mention this.........


Everybody was using graphite to lubricate the axle/wheel area. We used 3 in 1 oil......really performed well!!!

HyperBaja

I took first in the troop my first year, and second 2 other years, and third the last year. Each time I beat everyone in my little group.

front was rounded off with a belt sander, then angled up to where the top of the block was (about 1.5" of the top of the block still there) Regardless to any superstition, the only year I had the car green, I did the best.

Now... On the rules. You cannot use oil based lubricants, but pile on the graphite.

mr_velocity

Graphite is the best lube, I found some in the lab that was much finer than the stuff bought in the stores. The rules for us say you can't modify the wheels, so a little polishing is it, but make sure you polish the surface that comes incontact with the axle. Just be careful not to melt the plastic. The biggest thing is the weight. This all about physics and stored energy. My 8 year old can tell you all about it although he'd say something like "hold a weight 6" above your foot and drop it. Then hold it 12" above your foot and drop it, which hurts more?" Same with the car, you want to move the mass farther up the track, storing more energy. You want the CG about 1/2" in front of the rear wheels to keep the front wheels tracking correctly. All things equal, all the cars will run exactly the same down the ramp, but the car with the mass farther back will keep accelerating at the point where the track starts to flatten out. It'll just run away from the other cars. All my cars have been basically the same shape, this shape has nothing to do with air flow, it has to do with where I want to place the mass. This car is far lighter, before adding weight, then all the previous cars. We were able to add just about 4 ounces just behind the rear wheels and keep the CG right. We'll see how it runs in Feb.

I've seen some really fast cars that were basically two wood rails from the front wheel to the rear wheels, then it was a wood block filled with lead. Extrememly fast but they have a hard time surviving the "crash" at the bottom of the track.

Ron P

Interesting theory. You'd think it would be more important to have the weigth equal on all four wheel in order to reduce friction.

It all sounds good but the time for that movement of weight to take effect is about a hundreth of a second. Maybe that's all it takes?

jrz

I have seen some close finishes, 1/100 of a second makes this more exciting.

BajaSquirt

Set your car up so that 1 front wheel rides 1mm above the track, not on it. 25% of your friction gone.

TopSpin80

when I was in scout my cars won 4 out of 5 years. My dad and I built them together and after most of the races our cars were so far ahead the other adults destroyed them making sure they were within the rules. I probably have some pictures of them, somewhere. The race we didn't was won by a car that had cheated by using mercury as their weighting system. as is sloshed around the car would gain many links, but to not disappoint the kid who had won, even though everyone knew the car had cheated the troop decided to let it go. So I ended up with 4 1st places and 1 second place. I learned how to run lathes and mills and did a lot of the work with dad's supervision. Dad of coarse designed the cars.

Boss272

We took first place twice. Make sure weight is on the money. Spray entire car with lemon pledge. Wipe off excess. Make sure axels get enough pledge. Car will be so fast that it is embarrassing. Good Luck. Have Fun. I know we did. We used the round weights looks like a lead pencil. Weight should be right behind the front wheels. Cars would go down the ramp neck and neck and as soon as they hit the straight away our car would shoot out ahead of the pack by about 2 feet.

bajabob38

I was wondering, Do you think there is any cheating taking place in these events.