Pinewood Derby
Pinewood Derby
open to all registered cub scouts of Pack 225

Fundamental equation of Pinewood Derby Car Design:

Kinetic Energy (speed) = Potential Energy - Lost Energy

Naughton and Bogenschutz boys

Mr. Marinelli at the start

Finish line with Monette & Naughton

Pack 225 Racing Team
Every Scout that participate is a winner and will receive a car holder trophy!
History:
The first Pinewood Derby was held in 1953 by Cub Scout Pack 280C of Manhatten Beach, California. The first reference to the Pinewood Derby in a Scout publication was in the October, 1954 issue of Boy's Life. The June, 1955 Program Helps listed "Wheels, Wings, and Things" as a theme. The Cub Scout Program Quarterly gave instructions for running the Pack Meeting Derby. The Supply Division's catalogs had kits available in a package of eight. Over 15 million kits were sold during the next 20 years. Today, over 80 million car kits have been sold.
Most Important Tip:
1. The boys and adult should make the car together as a project! It is not the intent that the parent shows the Scout the garage door then walk away; nor is it the intent that the boy play video games while the adult cuts and sands. Parents should shape with the power tools and then direct the rest of the action while showing the boy each step in building a car.

2. Have fun! After all, this is what it is all about.

3. Know the rules. Being disqualified can be very embarrassing.

4. Safety first. Lets not lose any fingers.

5. Always check your pinewood derby kit for any additional pack rules
Vehicle:
Axel, Wheels, and body must be used from kit provided by PACK 225 only.
(DO NOT get a kit from a hobby store or the Internet).
Banned Elements:
Wheel bearings, washers, and bushing are prohibited.
The car shall not ride on springs or shocks.
The car must be free-wheeling with no starting devices or motors.
Inspections:
Each car must pass inspection by the official Inspection Committee before it may be allowed to compete. If at registration, a car does not pass inspection, the owner will be informed of the reason for failure, and  will be given time within the official weight-in period to make any adjustment. 
The inspectors have the right to disqualify those cars that do not meet these specifications. (Except outlaw class).
After final approval, cars will not be re-inspected and will be turned in on inspection day.
Details:
Cars (except those entered in the outlaw class) must meet the following specifications.
Note: Check the kit block before you start to make sure that it does not exceed any of the requirements.
Width not to exceed 2 3/4"
Length not to exceed 7"
Weight not to exceed 6 Oz (No Negotiating)
Height not to exceed 4 inches
Min Under-Car Clearance 3/8"

Details such as steering wheel, driver, decals, painting and interior detail are permissible as long as these details do not exceed the maximum length, width and weight specifications. (Any details that are not hand carved might negatively affect designer award decisions, but will NOT disqualify car from racing).
No loose materials of any kind are permitted on car. Any attachments must be secured, but it must not extend the car beyond the dimensions given.
The car must be made in the same calendar year of the derby. If a car has raced in a previous year, or was built in a previous year, it does not qualify.
The car may be hollowed out and built up to maximum weight using additional materials (such as weights), provided such materials are securely built into the body.
On the underside of your car, mark your first and last name, rank and your Den number
Wheels:
There shall be no shaving of axels or wheels (minimum de-burring only).
Wheels may be sanded slightly to remove burrs.  Wheels are not allowed to be sanded to a razor sharp edge; finish sanding is allowed as long as the width of the wheel is not altered.
No lubricating oil or any other liquid substance may be used. Axel may be lubricated with powdered graphite or dry silicone.
Car Judging:
Fastest Car/Speed

Originality/Design: Was the design the idea of the artist himself? How much creative thought went into the design.

Craftsmanship: (The skill the workman showed in cutting, carving, sanding and detailing the car.) Did the owner make the car's extra ornaments or were they something bought and attached?

Color/Paint Job and Appearance: What is the outward appearance? Is the painting of the car appealing? Are the colors and paint even all over? Is the appearance pleasing to the eye?
Outlaw Class:
Outlaw class os for any parent, sibling, relative or friend of any scout that might have missed one of the rules. There is no award, only bragging rights

Designing Tips:

Have your son draw a design on paper, then cut it out and use it as a template. Graph paper makes it easier to draw. Draw a side and top view on the paper by tracing around the block of wood. Have your son draw a design on paper, then cut it out and use it as a template. Graph paper makes it easier to draw. Draw a side and top view on the paper by tracing around the block of wood.
Keep the car the full seven inches. This has to do with the physics of velocity and length of travel of the weights.
Use the full 2 ¾ inches (outside wheel to outside wheel) that the rules state. This will allow the wheels to travel farther before hitting the center strip.
Leave a lot of wood in the back so there is a place to install weights.
Use the grove closest to the end of the block of wood as the rear axle.
Do not make the front of the car pointed because it makes it difficult to set it up against the starting dowels.
Use your imagination! Be creative! Shape has the least to do with winning. A beaver driving a log or a pickup truck is more interesting that a wedge - and will be just as fast! The aerodynamics of a small block of wood doesn’t mean much in thirty feet.

FRICTION IS YOUR ENEMY ! TRY THESE TRICKS

Debur the wheels.  Take off the flashing and seam that was produced when the wheel was molded with a 600 grit or better sandpaper - inside as well as out.
Sand any bumps off the wheel.  Metal polish will restore the gloss.  Be careful no to break any rules regarding wheel modification.  Don’t sand too much or you will create a flat spot.  Sand by hand - not in the drill.  Heat from the high speed of a drill will damage the plastic wheel.
Polish the axles.  First with a 400 grit if you have a really bad spot.  Then a 600 grit, and then a jewelers rouge.  Finish off with a chrome/metal polish.
Have only three wheels touching the track.  Raise a front one slightly.  There is less friction with 3 wheels rolling rather than 4.
The head of the axle should be tapered about 15 degrees so it rubs against the wheel less.
Wax the wheels with furniture polish.  Make sure the polish does not contain solvent of any sort.

LUBE JOBS

Use graphite only.  Oil damages the paint and collects dust and is not allowed in the rules.
Break in the wheels by spinning them with lots of graphite.
Right before you check-in, fill the wheel 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!
Put a drop of white glue where the axle goes into the car body and put powdered graphite there.  That causes less friction if the wheel should rub against the car body.
After polishing the axles, dump the axles and wheels in a ziplock bag with a little graphite and shake them for a few days prior to the race.

IT’S TIME TO GO STRAIGHT !

You can try putting the axle in at a downward (5-10 degrees) angle.  This provides two benefits:  First, only the inside edge of the wheel is in contact with the track.  (This seems to make the car go straighter with less wobble.) Second, the wheel rides to the outside of the axle and doesn’t come in contact with the body.
Axles must be square to the body of the car.  Don’t trust the slots, check it!  If you have one, use a drill press to ensure all axles are straight.  One of the front and two of the back should be measured to be the same height.
After pressing in the axles, test the car for crooked wheels… roll it on the floor.  If the wheels are on straight, the car should roll 8-10 feet in a fairly straight line.
Should the car turn left or right, you need to tinker with the axle placement without removing them from the body, until it rolls straight.
Do not put the axles in at the top of the groove.  Put them in at the middle.  This lifts the car off the track a bit more and reduces the chance of rubbing the center strip.
Glue the axles in place.  Nothing is worse than having a wheel fall off as you cross the finish line.
Once you match a wheel and axle together with graphite, keep them together.  They wear into each other as a matched set.

THE FINISH

Buy a gloss finish for the car.  It’s worth it.  After all that work, this is the final touch.  The more coats you put on, the shinier your car will be.  Be sure the paint is dry before putting on the gloss coat.  Some gloss products may be incompatible with the paint.
Sand in the direction of the grain when smoothing and against the grain when shaping.
Use a sandable primer or wood sealer.  White is for light colors and gray for dark colors.
Water based paints dry quicker (1 hour) than oil based paints (24 hours).
Children LOVE decals.  The more… the better!

WEIGH IN

Get the weight as close to the 6 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.
Everyone has an opinion on where to put the weight.  Many believe 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 1 to 1 ½  inches in front of the rear wheels.  But be careful not to put too much in the rear or you’ll pop a wheelie!
What kind of weight?  Melted lead is dangerous and unnecessary.  Tubular weights can be sunk in the sides.  Flat weights, like those sold at hobby and 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.  No movable weights or mercury are allowed.
Past contestants have used round weights found at hobby shops to form “tail pipes” or “jet engines”. They stick out of the back of the car and can be painted to match.  Another plus is that the weights are as far back as possible.
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.

RACE DAY - BE PREPARED

Have extra axles and wheels on hand.  You never know when your car may be the one dropped by your son as he shows off his handiwork.
Have a derby tool kit handy.  It should include superglue, sandpaper, a drill, extra screws for your weights, extra weights, a small screwdriver.  You may not use it, but it will make you the most popular person at the event!
Transport your car in a shoebox.  Dropped cars are common.
Add LOTS of graphite just before check-in.
Explain to your son that running the car along the floor prior to the race may cause it to lose!