Survival Guide by decree


									                                 PACK 377
                 2006 PINEWOOD DERBY

SURVIVAL                                                   GUIDE
           Pinewood Derby Model Car Racing Rules and Hints
                      for Building a Better Car

The Pinewood Derby is one of the most popular events in Cub Scouting. Every year
more than a million boys and parents team up to carve, decorate, weigh, adjust, fret
over, and finally race a Pinewood Derby car.

                                 Welcome to the club!

    following “Survival Guide” outlines the basic steps needed to build a
    Pinewood car.

    OFFICIAL RULES for this year‟s Pack 377 Pinewood Derby can be found in
    Appendix “A”.

    the more advanced builders, Appendix “B” contains a list of Internet Sites
    that go into much, much more detail than this “Survival Guide”.

    those more interested in having FUN, Appendix “C” contains several
    diversions to keep you entertained up to race day.

                            COMPETITION MAKES LIFE FUN

   It is the intent of this “Survival Guide” to see that all of the Cub Scouts have access
        to the same knowledge. With the care and goodwill of all the members they will
        also have access to the same equipment needed to ensure fair competition.
        Simply put, the Cub Scout and his helper who use the knowledge and equipment
        to their best abilities will win and that is what a Pinewood Derby is all about.
        After all, the Pinewood Derby is a race and Cub Scouts are supposed to
        compete with each other.

                                       GOOD LUCK

                                     HAPPY RACING

                                  SURVIVAL GUIDE

     Read all of the steps completely before you start building your car. That way you
       will have a clear understanding of the purpose for each step.

     1) Check your car body for square axle grooves
       Square axle grooves will make the car run straight and stay off the sides of the
       track. You can check the squareness of the axle groove with a good carpenter's
       square. You need a 90-degree angle on the axle groove to the car body.


      You may move the axle groove location on the car, as you please, providing the
      following criteria are met:
      1) The original axel groove spacing is maintained
      2) The wheels do not protrude beyond the front or rear of the car
      3) The car does not exceed the maximum allowed length
      4) The car maintains the minimum clearance

2)    Pre-fit the axles in the car body
      Method No. 1: Using a hammer, pound an axle 3/8ths of an inch into the car
                       body at the exact spot where it will eventually be mounted. Then
                       carefully remove the axles with a pair of pliers. By doing this first
                       you ensure that the wheels can be mounted to the finished car
                       without damaging either the car or the wheels. This also helps to
                       see that the wheels will be mounted at a 90 degree angle to the
                       car. Insert and remove the nails very carefully so you do not
                       damage the nail heads.
      Method No. 2: Use a numbered drill bit and a drill press. The axels will vary
                       slightly in diameter. However, by using an accurate measuring
                       device, e.g. calipers, you will find that a #43 (0.089”) or a #44
                       (0.086”) drill bit will provide a very snug fit for the axel.

3)    Design the car body shape
      It has been found that the shape of the car body has very little effect on speed.
      Therefore, every Cub Scout should design as much of his car body as he can.

4)    Choose a color scheme and any decals
      The Boy Scout Shop and local hobby stores carry decals and paint. Let your Cub
      Scout pick out his favorite decals. Use of decals can add a lot to the appearance
      of the car and it gives the Cub the opportunity to add his personal touch to his car.

5)    Cut out the car body
      Once the Cub has designed his car shape, the helper needs to supervise the
      Cub‟s use of the saw. IT‟S ALWAYS SAFETY FIRST! Everyone wants a safe
      and accident-free derby project.

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6)   Properly sand the car body
     The secret to a shiny car body finish is to do the proper sanding, use sanding
     sealer, and use a good paint designed for wood models. Sand the car in 3 or 4
     stages. Use a finer grit sandpaper for each stage with the last stage being a very
     fine grit. You may wish to add weight to your car at this time to minimize the
     amount of refinishing work you will have to do later. Be aware that a good paint
     job with primer and two to three coats of paint will add as much as five grams of
     weight to your car.

7)   Apply sanding sealer
     The car should be coated several times with sanding sealer and allowed to dry
     between each coat. Between each coat of sanding sealer use a very fine grit
     sandpaper and lightly sand the car.

8)   Paint the car body
     Your official Boy Scout shop and local hobby stores will carry the paints needed to
     paint your car. Whether you choose brush or spray paints several light coats are
     better than a few heavy ones. Once you are satisfied with your paint job its time
     to add those special decals that give your car that personal touch. If you choose
     to wax your car after painting please be careful not to get to much wax in the area
     where the wheel hubs will contact the car. The graphite used to lubricate the
     axles and wheels may react with the wax.

9)   Remove burrs and polish axles
     The single most important parts of a pinewood car when it comes to speed are the
     axles. Most of the drag generated during the race is caused by friction between
     the wheels and axles so pay very close attention here. The car with the fastest
     axles should always win the race. The axles that come with the kit will need a lot
     of finishing work to run fast. At the very least, they need to have the burrs
     removed and then polished mirror bright. The axles can be mounted in a drill or
     dremel tool and a metal file used to remove all burrs. After removing the burrs
     polish the axle as smooth as possible. Everyone in the race will try to remove
     burrs and polish axles so it takes a lot of extra work to have the fastest axles.
     Polish your axles till they are mirror bright and make doubly sure all burrs are

10) Remove burrs and polish wheels
    Using very fine sandpaper remove all burrs on the wheels‟ outside surface.
    Visually check the inside of the hub where the axle fits through the wheel, if you
    see any burrs they can usually be removed with a small nail. Next make sure the
    bottoms of the wheels are flat and the wheels are perfectly round in shape. If
    they are not you will need to use a wheel mandrel mounted in a drill or Dremel
    Tool and sand off any uneven wheel material. After you are satisfied with the
    shape of your wheels it is time to polish the wheels with very fine emery cloth or

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     sandpaper while the wheel is spinning. The ideal wheel is as smooth and
     burr-free as possible to reduce drag between the wheel and the track. Altering
     wheel shape is not allowed.

11) Pre-lube the wheel hubs with graphite
    Use only fine-grain graphite powder or the newer style “white graphite” that is
    available at the scout store. Lubricant is a very important and often overlooked
    part of pinewood car racing. The only lubricant you should use for a pinewood car
    is graphite powder because oils and Vaseline will react to the plastic wheels and
    actually melt them. You need to „BURN‟ graphite on the axles and insides of the
    wheel hubs before you permanently mount them on the car. Place each wheel on
    an axle and then mount the axle in a drill motor. Next, put some graphite inside
    the hub and run the drill. The spinning axle will rub or burn the graphite onto the
    surface of the plastic inside the wheel hub. After the burning-in process the wheel
    and axle should be kept together as a pair. Also, try to spin the wheels in the
    direction they will be turning after they are mounted on the car. Next, use your
    finger to rub some graphite on the car body where the wheel hub touches the side
    of the car. During the race the car body and the wheel hub come in contact with
    each other. Placing graphite here reduces this friction.

12) Install proper amount of weight
    Maximum weight is five ounces or 141 grams - this rule will be strictly enforced.
    All members are encouraged to have their cars weighed before the actual race
    day. If you wait till race day to have your car weighed you risk having your car
    damaged at the last moment and not being able to be an effective competitor.
    Where do you place the weight? The general consensus is to have the weight
    towards the rear of the car because it falls a longer distance. This will give it a
    little longer boost and help to increase car speed. Actual car design will usually
    have an influence on weight placement and you may wish to keep this in mind
    when designing your car. Never place weights directly on the bottom of the cars.
    It will drag on the track.

13) Install axles and wheels
    Great care must be taken to install each wheel and axle as straight as possible.
    Carefully place your car on a soft surface so you don‟t mar your paint job. Then,
    attach your paired axles and wheels onto the car. Leave approximately 1/32nd of
    an inch between the wheel hub and the car body so the wheel will not drag on the
    car body. The wheels need to be mounted so they point straight ahead which will
    make the car roll straight and not rub the sides of the track.

14) Check for straight wheel alignment, and that all wheels turn freely
    This step is the final one before the axles are glued in place. This will be your last
    chance to make any wheel changes you deem necessary. If it is at all possible
    you should trial run your car on a flat surface to see if it runs straight, any
    corrections that are needed can be made at this time.

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15) Glue the axles in the car body axle grooves
    This step is an option that many people choose not to do. If your car has very
    tight fitting axle grooves, use of little or no glue would allow you to make
    adjustments or emergency repairs on race day. If you have any play at all in the
    axle grooves the axles must be glued in or the wheels will not stay in position.
    The rougher your race track is, the harder it is to keep the axles in place without

16) Re-check the car's weight
    If it is at all possible, have your car's weight checked again after final assembly.
    While we want our cars to weigh as close to five ounces as possible coming to the
    race with a car that is too heavy could spoil all of your hard work.

17) Lubricate again with graphite
    After you are fully satisfied with your race car's appearance, weight, and tracking it
    is time to graphite your wheels again. Remember, a little graphite goes a long
    way so apply it sparingly or your perfect paint job will end up being a dull gray

18) Remember the BIG SEVEN:

     1.   HAVE FUN!

     2.   Make sure that the axle grooves are square in the car block.

     3.   Properly finish axles and wheels.

     4.   Mount wheels and axles at a 90-degree angle for straight wheel alignment.

     5.   Make sure your car weights as close to five ounces as possible.

     6.   Lubricate your wheels with graphite powder.

     7.   HAVE FUN!

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