The secret?? Weight in the nose, and powdered graphite on the Axles. Never came in less than 2nd.
way to go!
Actually the reverse. Weight in the tail.... as far back as you can get it. Wheels as far apart front to back as possible. Wedge shape.
Turn the axles with a file and drill. Ream the wheel holes and coat with graphite. Run the wheels in on an a specific axle for 5 minutes while adding more graphite.
Pack Winner and District winner for 3 consecutive years
Weight at 75% of balance point to the high (rear) and polished wheels with graphite - made regional.
Shape of the car actually impacts the speed very little. Had one care place 2nd that was an block shape - not even a wedge.
Won New England Regionals w/ opposite approach. Weight as far back as possible to increase the “drop” one axle raised others graphited w/ weight balance across the 3 axles. Flip the block around to make the long nose. Wheels were modified on a lathe to be round and to remove mass on the inside of the tread so they spin up faster due to lower moment of inertia. Axle nails are highly polished w/ burr from nail to nail head removed w/ a file. polish inside of wheel too. graphite the H**L out of it. most importantly get a 12’ board raised just enough to make car roll, the simply turn the axles just a bit till car runs straight w/ a lane guide.
Actually, you are better off placing your weight closer to the back. You want the weight as high as it can be from the floor at the beginning without causing instability to the front of the car. The farther the weight has to fall to get to ground level, the more acceleration you achieve.
Before putting graphite on the axles, chuck the axle into a power drill and polish it with very fine sandpaper to eliminate any ridges or imperfections left by the manufacturing process. You should also sand the underside of the nail head into a bell or cone shape to minimize the contact between the tire and the head of the nail.
I have a room full of trophies to support the efficacy of my process. :-)