W h e n

Transcription

W h e n

When 2nd p lace just isn’t g ood en ough…
WWW. DERBYMON KEY. COM
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© Copyright 2009 Derby Monkey Garage
Introduction ……………………………………..
3
Tip 1: Do Your Homework …………………..
5
Tip 2: Aerodynamic Body Design …………
12
Tip 3: Extended Wheelbase ………………..
14
Tip 4: Lightweight Wheels ………………….
15
Tip 5: Raising One Front Wheel …………..
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Tip 6: Polis, Polish, Polish… ……………….. 18
Tip 7: Center of Gravity Placement ………
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Tip 8: Rail Riding ………………………………. 23
Tip 9: Canting the Rear Wheels …………..
27
Tip 10: Lube, Lube, Lube… …………………. 29
Tip 11: Testing ………………………………….
31
Tip 12: Can’t Touch This …………………….
32
Conclusion ……………………………………….. 34
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What this book is:
The Pinewood Speed Shop has interviewed the top Pinewood Derby car
builders across the nation and asked them to make a list of their most
important speed factors. We then compiled a list consisting the 12
most discussed items. These are the factors that the majority of the
builders stress as being a very important part of building a super fast
car.
This eBook contains these speed tips along with a thorough
explanation of each. Detailed information and diagrams shows how
you can apply these factors to your or your son's Pinewood Derby car
and blow the doors off the competition.
It’s important to note that car builders often have different opinions
when it comes to Pinewood Derby speed techniques. There is usually
more than one way to do things that may, or may not, achieve the
same results. This eBook concentrates on the methods that are the
most subscribed to and will no doubt work well for you.
What this book is not:
This book was written on the assumption that the reader has at least a
basic understanding of how to build a Pinewood Derby car. This book
is not designed to be a detailed and complete builder’s guide for those
who have absolutely no building skills or Pinewood Derby car
knowledge. It is not an absolute, all inclusive, guide to Pinewood
Derby cars. If you need a complete pinewood derby builder’s bible
then you should consider one of the many available Pinewood Derby
manuals here.
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This manual and other races:
As the popularity of the pinewood derby grew, other organizations
adopted the concept. Pinewood derby is a registered trademark of the
BSA, so most use different names. Each derby has slightly different
rules for making and racing their cars.
While this book was written specifically for Pinewood derby cars, most
of the information will also apply to the other forms of wood car
racing. The other racing organizations include:
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Awana has the Awana Grand Prix.
Christian Service Brigade uses the name Shape N Race Derby.
Royal Ambassadors have RA Racers.
Royal Rangers use a different kit with screw axles and dowel rod
axle supports.
Scouts Canada has the kub kar rally for Cub Scouts and beaver
buggies for Beaver Scouts.
YMCA chule cars use the same kit as the Royal Rangers.
There are also several national and regional Pinewood Derby racing
leagues. These leagues allow builders of all ages and skill levels to
compete.
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Woodcar Independent Racing League
Pinewood Derby Racing League
Pinewood Derby Drag Racing League
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Professional derby car builders agree that the very
first thing that you should do is research… do your
homework. Too many times a new car builder will
wait until a short time before the race to start the
building process. This is usually the kiss of death
(There are many kisses of death in Pinewood
Derby car building. This book will help you avoid
most of those). They now don’t have time to
properly research what they need to do so they
just slam the car together as best they can. Then, they wonder why
their car was beaten so badly on race day.
Its very important to get an early enough start so that you can fully
research the pack rules, the district rules, how the races are
conducted, who qualifies for the district derby, speed tips that fit
within your rules, pinewood derby forums, etc.
Know the Rules
Make absolutely certain that you fully understand the rules. There are
many sets of rules on the internet with certain important variation so
don’t go by some set of rules that you found. Get your pack rules.
Some packs will permit broad modifications to the wheels and axles.
Some packs may only allow minor modifications. There is utterly
nothing more disappointing than seeing your son’s car disqualified at
check-in because you didn’t carefully follow the rules.
Some pack and district Pinewood Derbies have different race divisions
or classes, such as “Stock”, “Modified”, “Outlaw” and “Open”. Cars in
the Stock class usually must follow the basic rules with no deviations,
often allowing little or no modifications at all. Modified and Outlaw
class rules usually allow much more flexibility in the building of the
car. The open classes are usually for the scouts family members who
wish to race a car. This is a great class for dad.
Find out who your Derby committee chairman is. Ask him for a set of
the rules before well before you begin building the car. Then get to
know him. Converse with him and offer him your assistance. Offer to
help him set up the day before the race. What you’re doing here is
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establishing valuable “goodwill” with the chairman. This will allow you
to more comfortably ask for rule clarifications down the road. This
new friendship may also provide helpful should there be any future
rule disputes involving your car.
If at any point you are unsure whether a particular trick is legal, ask
the derby chairman for clarification before you make that modification.
Official BSA Rules
A very basic set of “Official Rules” are provided
in the car kits. Some packs will simply ask you
to follow these fundamental rules:
Width: 2-3/4"
Length: 7"
The Official BSA
Pinewood Derby Kit
Weight: Not over 5 Ounces
Width between wheels: 1-3/4"
Bottom clearance between can and track: 3/8"
Wheel bearings, washers, and bushings are prohibited. The car cannot
ride on springs.
Only official wheels and axles are permitted. Only dry lubricant is
permitted.
An example of a particular set of District rules are as follows:
OKEE-TUKLO DISTRICT PINEWOOD DERBY STANDING RULES
1. LENGTH, WIDTH, HEIGHT, & CLEARANCE
a. Maximum overall width (including wheels, axles or other
parts) shall not exceed 2-3/4".
b. Minimum width between wheels shall be 1-3/4" so the car will
clear the center guide strip.
c. Maximum height shall not exceed 4-1/2" in order to clear the
race timer.
d. Minimum clearance between bottom of car and track shall be
3/8" so the car will clear the center guide strip.
e. Maximum length shall not exceed 7".
2. WEIGHT AND APPEARNCE
a. Weight shall not exceed 5 ounces. The readings of the Official
Race Scale will be considered final. The car may be hollowed
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out and built up to the maximum weight by the addition of
wood or metal only, provide it is securely built into the body
or firmly affixed to it. No loose materials of any kind are
permitted in or on the car. The bottom of the car must be
smooth in order not to damage the car stoppage area.
b. Mercury or other liquids shall not be used for adding weight.
Mercury is a potential health hazard.
c. Details such as steering wheel, driver, spoiler, decals, painting
and interior details are permissible as long as these details do
not cause the car to exceed the maximum length, width,
height, and clearance specifications.
d. Cars with wet paint will not be accepted.
3. WHEELS AND AXLES
a. Only the official Scout Grand Prix wheels and axles can be
used. Wheels must have "Official B.S.A." stamped on the
inside of the wheel rim.
b. Wheels can be sanded to remove surface imperfections, but
the surface that touches the track must be left flat and at
least 1/4 wide".
c. Wheel bearings, washers or bushings are prohibited.
d. The car shall not ride on any type of springs.
e. The car must be free-wheeling with no starting device or other
propulsion.
f. The wheel base location of the car may be adjusted as long as
you still meet the maximum length, width, height, and
clearance specifications.
g. Hubcaps or similar items used to keep the wheels lubricated
are prohibited.
h. Spoke Wheels and/or modified wheels are prohibited.
4. LUBRICATION
a. Only dry powdered lubricants, such as graphite, may be used.
Regular oils and silicone sprays may often soften the plastic
wheels.
b. Cars must be lubricated before registration. No further
lubricants will be permitted.
5. GROUND RULES
a. The race is open to all Cub Scouts and Webelos Scouts
registered in the OKEE-TUKLO DISTRICT. The Open Division
bracket is open to registered Cub or Boy Scouts from the
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OKEETUKLO DISTRICT, any family members of these Scouts,
Scout leaders from the OKEETUKLO DISTRICT, and race
officials. Only one Open Division entry per participant.
b. Cars must have been made for this race with all the work on
all the parts being done since the completion of last years
race. Cars made for previous derby are not permitted.
c. After meeting weight and inspection requirements the cars are
registered with your car number being attached to the back of
your car. It will then be placed on the table by a race official
for competition. No car can be handled by the boy, leader,
and/or parent after registration unless they have permission
from the chairperson.
d. Cars will be placed in divisions by scout rank for competition.
(Tiger, Wolf, Bear, Webelos I, Webelos II, and Open Division)
e. All cars will race three times (once in each lane) against other
cars of the same division with the times being recorded.
Partial Perfect (N) race charts generated using a computer
program developed by Stan Pope and Cory Young will be used
for lane assignments. The charts can be obtained on the
internet at http://members.aol.com/StanDCmr/ppngen.html
f. Overall winners for each scout rank and Open Division will be
based upon the total of the three race times recorded with
the lowest time being ranked first.
g. If a car jumps off the track prior to the timer, loses an axle, or
breaks a wheel it can be repaired if possible and rerun by
itself on the same lane after all the races for that rank are
completed. If they choose to rerun then the original time
must be replaced by the rerun time. If the car cannot be
repaired, the car must forfeit from the competition. The car
must be repaired within 5 minutes or by the time the car is
called for it's next race, whichever is longer. If a car jumps
from the track loses an axle, or breaks a wheel a second time
it must forfeit from the competition.
h. If a car (or parts of it) leaves its lane and interferes with
another car, the car interfered with has the option to rerun by
itself on the same lane after all the races for the rank
completed. If they choose to rerun then the original time
must be replaced by the rerun time.
i. Only Race Officials and Scouts involved in the current heat(s)
are permitted in the track area.
j. Cars racing in the Open Division must meet all the above
requirements except section 5 (b).
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k. Cars entered in the Okee Tuklo District pinewood derby race
must be the car that won at the pack level. New cars will not
be allowed.
6. INSPECTION AND DISPUTES
a. Each car must pass inspection by the Official Inspection Team
before it may compete. The inspection team has the right to
disqualify those cars, which do not meet these rules. Car
owners will be informed of the violations and given an
opportunity to modify the car to meet these rules.
b. Any participant (including the parent of the participant) has
the right of appeal to the Race Committee for an
interpretation of these rules. The Race Committee, by
majority vote, will be the final judge of these rules. In case of
a tie vote, the decision of the Race Committee Chairperson
will be final.
c. GOOD SPORTSMANSHIP AND BEHAVIOR IS EXPECTED.
Ungentlemanly or unsportsmanlike conduct by any participant
or member of the audience will be grounds for expulsion from
the competition and/ or grounds.
The above rules are the custom set of regulations for one particular
scout pack. You must check your local rules.
Know the Track
You must find out what type of track
you’ll be racing on. Pinewood Derby
tracks come in a baffling assortment of
designs and styles but most stick to a
few basic parameters:
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The starting gate is affixed to the
top of a 4-foot, or higher, slope.
Track lengths range from 32 to 48
feet.
The number of lanes basically
ranges from 2 to 6.
The cars either ride along a center
rail or within a lane.
This is a popular aluminum track and
timer from Best Track.
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Tracks are generally made from wood or aluminum, and separate into
smaller sections for easy transport and storage. Aluminum tracks are
typically longer and smoother than wood tracks and offer a faster race.
A wood surfaced track can be just polished wood or can be faced with
Formica, Masonite, or aluminum. The curve usually constitutes about a
third of the total length with a straight, flat section of track and a
braking area beyond the finish line making up the rest of the distance.
It is very important that know what type of track you have because
this will affect how you build and align your car.
Communicate with Other Car Builders
Most first time car builders feel like they’re alone on an island with no
help or direction from someone more experienced. Occasionally, you
can get help from another scout dad. They are often eager to help but
will sometimes hold back on some of their tried and proven speed tips.
Pinewood Derby blogs and forums are the best place to communicate
with experienced builders. These blogs and forums are packed full of
archived information and can be a tremendous resource for the new
builder as well as the old pros.
Pinewood Derby Blogs & Forums
Fast Pinewood Derby Tips – www.FastPinewoodDerbyTips.com
Derby Talk – www.DerbyTalk.com
DerbyWorx Forum – www.pinewoodp.proboards.com
PDDR Forum – www.P-D-D-R.com
PWDRacing Forum – www.PWDRacing.proboards.com
Plan Ahead
Part of your homework is to establish a calendar in
order to plan the stages of building and testing you
new Pinewood Derby car. Make sure that you allow
sufficient time to build your car the right way. If you
wait until the last minute, you will be severely
limited in what you can do. Even if you learn some
speed tricks from the blogs, you’ll have little time to
implement them.
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Serious car builders start this project at least two months in advance.
The Pinewood Speed Shop allocates 3 months for the building of a new
car for a particular race.
If you want to have a super cool paint job then you must factor in the
drying time of the paint between coats. The rushing of the paint job
will often spell disaster.
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There is a huge controversy regarding the importance of aerodynamics
and Pinewood Derby racing. The majority of the experts that we
questioned are convinced that having an aerodynamic car creates a
huge speed advantage.
The Derby Monkey Garage builds all of its “Xtreme Speed Series” cars
with a very low profile body. This creates an extremely aerodynamic
car that cuts through the wind with ease as it races down the track. A
low profile car also reduces the wood weight of the car allowing an
experienced builder to place the weights exactly where its need in
order to place the center of gravity in the optimum location.
A Pinewood Derby car should be
designed to move as little air as
possible as it speeds down the track.
Comparing two cars with identical
characteristics, except that one car
has better aerodynamics, the car
with good aerodynamics will have a
competitive advantage. Pinewood
Derby races are often won, and lost,
by only a thousandth of a second so
every little bit of speed increase is
worth the effort.
Car 2 is much more aerodynamically
sound than car 1.
Your young scout may have already
drawn or envisioned this super cool looking car that he wants you to
build. Before it’s too late, you should discuss this idea with him. The
best looking cars are seldom the fastest cars.
But also remember, the Pinewood Derby experience is for the father
and son to work together. If it means more to him to have the car
design he wants then build it. You can always build your own car and
enter it in the open class.
Follow these important factors while planning and building your car in
order to make it as aerodynamic as possible.
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1. Design a car body that is as low-profile as possible, replacing
the wood weight with weight… preferably tungsten.
2. Round and smooth all edges of the car.
3. Do not ad accessories such as drivers, flags, engines,
spoilers, etc. These only act like parachutes slowing the car
down.
4. Fill holes and pockets with body putty, wood filler, bondo,
glue or foam sealer. The easiest body filler to work with is
Monkey Mud
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Car #1 has a standard wheelbase of 4 3/8”
while Car #2 has an extended wheelbase
wheel base as much as possible.
Your pack’s Pinewood Derby
rules will have a lot to do
with this one. In your
“Homework” stage, you
determined if you are
permitted to modify your
wheel base. Some rules
allow you modify your
wheelbase as long as the
car, including the wheels,
does not violate the 7 inch
maximum length rule. If you
can, you must extend the
The standard wheelbase on the
block from the BSA Kit is 4 3/8
inches. This short wheelbase
decreases the stability of the car.
This instability will cause the car
to bounce back and forth, left to
right, slamming itself against the
center rail. This action takes off a
tremendous amount of speed.
You want you car to be a stable as
possible with very little side to
side action. An extended wheel
base is the only way to increase
the stability of your car. So,
move the front wheels as far
forward and the rear wheels as far
backwards as you can without
exceeding the 7” length rule.
The top body has the standard axle
slots at about 4 3/8” apart. The axle
slots on the bottom body have been
extended to the maximum
wheelbase. For a standard BSA kit
block, the new axle slots, or wholes,
will be place at 5/8” from each end
of the car body. Make sure that the
overall length of the finished car
does not exceed the 7” restriction.
The old axle slots may then be filled
in w ith wood filler or body putty.
This will force you to re-cut your
axle grooves or drill a whole new
set of axle holes.
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Notice the inside of each DerbyWorx BSA
wheel has been machined to remove plastic
and reduce weight.
Stock wheel reduced to 3.3g
Just like in Tip 3, your pack’s
Pinewood Derby rules will have
a lot to do with this one.
Again, in your “Homework”
stage, you determined what
modifications you are
permitted to perform on your
car. You especially want to
know what wheel modifications
are allowed. It is imperative
that your wheels are as
lightweight as possible.
Weight can be reduced by
sanding or machining excess
plastic away from the outside
and the inside of the wheels.
The huge advantage of
lightweight wheels is due to
the reduced start-up inertia.
In other words, the wheels are
easier to start rolling. This
allows the car to reach its
maximum speed sooner than a
car with standard wheels.
The huge speed advantage of lightweight
DerbyWorx wheels is due to the reduced
start-up inertia. Get them here
You can perform some of the
modifications your self with
the proper tools. The Derby
Worx Pro Wheel Shaver and
Pro Hub Tool allow you to
remove some plastic as well as
true the wheel circumference
and reduce wheel hub to body
friction.
However, in order to properly perform some of the most beneficial
wheel modifications you must be highly skilled and have the proper
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equipment. A micro-lathe or CNC is required to accurately machine
the wheels interior. This will remove a lot of unneeded plastic and
drastically reduce weight. You can decrease the stock weight of 3.6
grams per wheel all the way down to only 1.0 grams.
Unless you have the equipment and are somewhat of a master
craftsman it is highly recommended that you purchase a set of official
BSA wheels that have been professionally modified by an experienced
machine shop like Derby Worx.
The Fastest Pinewood Derby Wheels
The Derby Worx Ultra-Lite Wheels are official BSA wheels which are
precision CNC machined with True Track Tread and reduced in weight
from 3.5 grams to only 1.0 grams each. Extensive testing has proven
that these are the fastest BSA wheels available. These wheels can be
raced without any additional preparation.
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Installing one of the front axles so that it
lifts the wheel off the track is beneficial in
several ways…
First of all, by only having three wheels on
the track, the start-up inertia required to
get the car moving is reduced by 25%...
this is huge.
Secondly, it simplifies the process of
aligning your car since the raised wheel
needs no adjustment. Finally, if you’re
going to create a Rail Rider, as we will
soon discuss, you must raise one front
wheel… usually the right front.
The best way to raise a front wheel is to
simply drill one front axle hole higher than
the others. It doesn’t take much. From
1/32 to 1/16” is plenty.
I mages Courtes y of DerbyWorx
Another way is to bend one of the front
axles upward to lift that wheel off the track.
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While racing down the track, the inside of the wheel hubs rub against
the axles. This creates a huge amount of friction that even the best
lubrication cannot eliminate. So, it is crucial that you polish the axels
and the wheels hubs extremely well.
Axles
The purpose of this step is to create a shiny finish on the axle shaft
and the inside of the axle head. Anywhere the wheel rubs on the axle
must be highly polished in order to reduce friction.
Most folks will tell you to polish you axles with sand paper up to about
2500 grit. That’s fine for those who want to finish in second place.
The axles need to have a near mirror finish in order to eliminate as
much friction as possible. To achieve this, you must polish your axles
with the use of sandpaper all the way up to 12,000 grit and then finish
them off with a polishing compound and polishing cloth.
For best results, the Derby Monkey highly recommends the use of the
Ultimate Axle Polishing Kit order to get your axles where they need to
be to increase your chances of victory.
Another option is to purchase a set of official BSA axles that have been
professionally modified by an experienced machine shop like Derby
Worx. These prefinished Derby Worx Axles are finished up to 3200
grit. Then you can just finish up the polishing process with the finer
grit sandpaper. First make sure that your race rules will permit this.
Complete BSA Axle Preparation
1. Straighten axle with the Pro Axle Press.
2. Chuck the axle in a drill press or any electric drill.
3. While the axle is spinning, use a thin flat file to grind off the
crimp marks near the axle head.
4. The polishing process will begin with a ¼” a strip of 400 grit
wet/dry paper. Dip the paper in water and sand the nail and
the inside of the nail head while the axle is spinning.
5. Allow the sandpaper to make firm contact with the axle shaft
for 10 to 15 seconds.
6. Switch to the next grit strip of dampened wet/dry sandpaper.
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6. Continue this process until all grits of sandpaper are used
ending with the 12,000 grit paper.
7. Finally, apply the special axle polishing compound with a ¼”
section of polishing cloth. Polish the axle shaft for about 30
seconds. Make sure to polish the inside portion of the axle
head.
8. Remove all polishing compound using a clean, soft cloth.
9. Place the axles in denatured alcohol for about one hour in
order make sure all polish residue is removed.
Wheel Hubs
Now, you must polish the inside of the wheel hubs. The only good way
to do this is with the Derby Worx Pro Bore Polisher. Most folks will tell
you to simple use the Micro-Surface Micro-Gloss for this. However,
most do not mention that you must take it to the next step and finish
this process by applying the Micro-Surface Micro-Finish compound.
Polish with equal outcomes would be the Monkey Spit Wheel Bore
Polish.
Preparation
1. Clamp the hand drill to a work surface using the clamp. Do
not use a Dremel-type tool as the RPM is too high.
2. Insert the solid shaft of the Pro Bore Polisher into the chuck of
the drill.
3. Cut a piece of pipe cleaner 1-1/4” long.
4. Slide the pipe cleaner between the two prongs of the tool.
Make sure that the pipe cleaner is centered between the
prongs.
Caution - Some polish may be thrown when the drill is running, so
wear eye protection, old clothes, and cover any sensitive equipment
on either side of the pipe cleaner.
Polishing
1. Apply a small amount of Monkey Spit 1 Wheel Bore Polish to
the pipe cleaner. Spread the polish onto the entire pipe
cleaner surface.
2. Slide a wheel onto the pipe cleaner and over the tool.
3. Hold the wheel and start the drill on a slow to medium speed.
4. Move the wheel back and forth on the tool for 5 to 10
seconds.
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5. Slide the wheel off the tool onto the pipe cleaner and polish
for an additional 5 seconds.
6. Remove the wheel and stop the drill.
7. Repeat steps 5 to 10 for the other wheels.
8. Use a new pipe cleaner and repeat the above steps using
Monkey Snot 2 Wheel Bore Polish.
Important - Do not slide the wheel onto the Pro-Bore Polisher while
the drill is running.
Clean-Up
1. Wash the wheels in water, using a clean portion of the pipe
cleaner to scrub inside the bore.
2. Dry the wheels. A dry portion of pipe cleaner can be used to
dry inside the wheel bore
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What is Center of Gravity?
The center of gravity of your
pinewood derby car is the distance
that the balance point of the car is
in front of the rear axles. This is
sometimes referred to as the
center of mass, COM or COG.
Many people simply tell you to just
“put the weight in the back”.
While that is true, there is a lot
more involved in this process.
Proper placement of the COG is
crucial in order to have a fast car
The COG is the distance that the
balance point of the car is in front
of the rear axles. This is
sometimes referred to as the center
of mass or COM.
The exact location of the COG of your car can be determined as
follows:
1.
2.
3.
4.
5.
6.
Set a ruler on its edge on a flat and level surface.
Carefully lay the car across the ruler.
Move the car back and forth until it balances on the ruler.
This balance point is the COG.
Measure the distance from the COG to the rear axles.
This distance is how we express the COG location on a Pinewood
Derby car.
The perfect tool for locating the COG is with the aid of the Derby
Monkey’s exclusive COG Quick Ref.
Where Do You Want Your COG?
There are many different opinions regarding where the exact location
of the COG should be. However, every one aggress that you want it
close to the rear of the car. Most publications recommend a COG of 1”
to 1½” in front of the rear axles. Most experts agree that this is too
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far forward. The faster cars seem to be built with a COG of a less than
1”.
The Derby Monkey Garage builds its cars with a COG of ¾” in front of
the rear axles. Some builders even go with shorter COGs.
How fast your car goes on the first flat part of the track is based on
the distance that the COG of the car actually travels before it reaches
the curved part of the track. The weight mass of car with the COG in
front will not have traveled as far when it reaches the curved section
as the weight mass of a car with the COG in the rear. The farther the
weight mass travels the more speed the car picks up on the first
section of track.
Your COM should also be very low in the car. The lower the COM the
more stable the car will be. That’s why tungsten plates attached to
the bottom of the body can help create a very fast car.
Position the weights in you car so that you have the optimum COG.
Tungsten is the best weighting material because of its density. This
allows you much more flexibility in controlling your COG.
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Most instructions manuals will have you to align your car so that it
rolls perfectly strait with absolutely no deviation for at least six feet.
The theory, or myth, is that if the car rolls strait down the track it will
not make contact with, and rub against, the center guide strip.
Believing that the breaking effect caused by rubbing the rail will slow
the car down many builder insist on a perfect strait running car. The
only problem is this adjusting technique is doomed from the start.
Experts agree that controlled
rail riding will produce a much
faster car. Yes, that’s right; if
your car consistently rubs
against the rail all the way
down the track it will be
faster. Here’s why: since it is
nearly impossible to have a
track that will allow a perfectly
Notice the left front wheel of the car in photo
aligned car to run straight and
1is not yet touching the rail. Photo 2 shows
not hit the rail. Invariably, any
that the car has migrated toward the rail and
car will drift into the rail
the left front is now riding against the rail.
causing it to bounce back
toward the other side. This generates a side to side movement,
causing the car to repeatedly slam into the rail. This is a huge enemy
of a speedster. Therefore, knowing that you will certainly be hitting the
rail (evidenced by almost every video of a fast car that you study in
slow motion) why not bias the car to hit the rail on the front dominant
wheel side, as opposed to the raised wheel side, which incidentally is
yet another kiss of death.
Now, the real trick is to determine how much bias towards the center
rail to create. According to most of the experts the optimal is about 1"
to the rail over a 4' tuning board. Some say 1” for every 6’ of tuning
board.
In order to force the car to drift toward the rail is to cant, or bend, the
front axle about 1.5 degrees. You can place the axle in a vise and
bend it with your fingers but it is highly recommended to use the
Derby Worx Pro Axle Press and Rail Rider Tool.
23
How to Do It
1. You want the bend in the front dominant axle, the side that touches
the track, to be just inside the wood body so that the hub will never
ride on the bend, only the straight part that resulted from the bend.
2. Determine your space and mark accordingly with a sharpie: Try
putting the axle through the wheel and inserting it into a practice
scrap with a drill hole slightly bored out so that insertion and removal
is easy. Use a gap tool or credit card
or whatever else you use to assure
Extra Tip: On marking the axle
consistent wheel spacing, to get the
head- try cutting a groove in the
distance from the body to the edge of
axle head with a Dremel tool &
cut-off wheel. Create a slot like
the inner nail head. You can measure
a flat head screw. You can place
it with a caliper or you can just
a 6:00 dot on one end of the
eyeball it. Once you have figured out
slot. The dot will serve as a
where you want the "bend" to be,
reference point and you will use
mark that spot with a black sharpie.
the slot for easy turning &
tuning your steer with a
screwdriver.
Here is where you can get creative.
Knowing that you want a consistent
bend and that you also don't want to
The Derby Monkey has an Axle
Head Groove Kit for this purpose scar either the axle head or the shaft
with your bending methodology, you
need to be very careful and go slowly.
1. Derby Worx Axle Press and Rail Rider Tool Method:
A. Insert an axle into the Pro Axle Press at the location of your
sharpie mark or with the axle head extended out about ½”.
B. Turn the axle so that the head dot is located at the 6:00
position… or position you axle head groove in the vertical
position.
C. Place the 1.5 side of the Derby Worx Pro Rail Rider Tool over
the top of the axle press and rest on the axle shaft in the
groove on the tool.
D. Press the axle head against the Pro Rail Rider Tool.
E. Keep your dot in the 6:00 position.
F. Hold the assembly with one hand and gently place it on a solid
surface.
G. Gently tap the top of the tool two to three times. This will
accurately bend the axle to 1.5 degrees.
24
2. File on Wood Block Method:
A. Mark the spot at which you want the bend.
B. Lay the axle on a piece of clean soft wood.
C. Align your steel file perpendicular to the axle over the mark
and press down with your thumb until you get the desired
bend.
D. Be careful to not scratch any area where the wheel rides the
axle and also not to damage the head with pressure.
Make it Ride to the Rail
1. After applying lubrication to the wheels and axles, install them
with the location dot of the dominant front axle at the 12:00
position... or position your axle head groove in the vertical
position.
2. You will need to make some type of tuning board. This can
easily be made with any 8” wide board that is 4 or 6 feet long.
Mark a strait line all the way down the length of the board. Prop
one end up about 3”. Level the tuning board as well as possible.
3. Place the car at the top of the tuning board straddling the line
and point perfectly strait down the board.
4. Roll the car down the tuning board
and observe which way the car
drifts and by how much.
5. Your goal is to have the car’s
dominant front wheel drift toward
the center line at about 1” over a
4’ distance. Some cars run better
being set up less aggressive while
others perform best being more
aggressive.
6. To make adjustments to the drift,
slight turn the axle with pliers or
your axle head screwdriver.
To make adjustments to the
drift, slight turn the axle with
7. Continue testing and tuning until
pliers or your axle head
you achieve the desired results.
screwdriver
8. As soon as you achieve the
desired results, glue the axles in
place so that your adjustment will not change.
25
If you decide to build a rail rider and experiment with t he degree of
migration to the center rail, experts also highly recommend narrowing
the front wheel spacing less than the rear. You may want to start
around 1/16”. One way to do this is to simply sand off 1/16” on the
front side of the body where the dominant front wheel is attached.
26
OK, so you already know that friction is
enemy number one to the Pinewood
Derby car builder. One troublesome
point source of friction is where the
wheel hub rubs against the car body.
During the race, the wheels tend to
migrate back and forth on the axle
The rear axles are bent up so
shaft and make contact with the car
that the top of the wheels lean
body. Occasionally, a wheel will
in toward the car body. This
migrate into the body and stay there
will force the wheels to
migrate out and away from the creating a braking effect all the way
down the track. There are several
body decreasing friction.
techniques, some are not legal, to
reduce the friction of this rubbing.
Many experts agree that its best if the wheel hubs never touch the
body at all. The only way to accomplish this is to cant both rear axles.
We want to bend both rear axles up so that the wheels migrate toward
the inside of the axle head and not the car body. It is true that this
process simply shifts the wheel friction from the car body to the axle
head however, the amount of friction is greatly reduced.
You can bend the rear axles using the same methods discussed above
in the Rail Riding section using Derby Worx Axle Press and Rail Rider
Tool. Depending on who you talk to, the amount of rear axle canting
should be from 1.5 to 2.5 degrees. The Derby Monkey uses 1.5 to
2.00 degrees canting on its cars.
After applying lubrication to the wheels and axles, install them with the
location dot of both rear axles at the 12:00 position... or position your
axle head groove in the vertical position. Look at the car from the rear
and make sure that the tops of the wheels are leaning in toward the
body.
Gently roll your car on a flat surface and concentrate on the rear wheel
hubs. If the hubs migrate toward the body and rub against it, then
slight turn the axle with pliers of an axle head screwdriver. Continue
27
to test and adjust until the wheels migrate out and against the axle
head. Perform this with the car rolling forward and backward.
Try to make sure that each rear wheel is parallel to the car body… at
least as close as possible.
28
During the race the wheel hubs will rub on the axles. This unwanted
friction contact cannot be avoided. However, if you have properly
repaired and polished your axles and hub bores then this friction is
reduced. But even that is not enough.
We must thoroughly lubricate all friction points before putting on the
wheels. Your scout rules will probably require that you use a dry lube.
If so, use quality graphite, such as Monkey Dust or Hob-E-Lube. If, on
the other hand, your rules allow for the use of oil then you should
consider taking advantage of that by using a super lubricant like NyOil
or Krytox.
Krytox
The Derby Monkey Garage uses DuPont Krytox® GPL 100 whenever oil
is allowed and sometimes when its not. This is a highly-refined
synthetic thin-film lubricant with an ultra-low viscosity. When this stuff
is properly applied it equals or outperforms any dry lubricant on the
market including graphite. Krytox is much easier and faster to apply
than graphite.
It is also almost undetectable by derby officials. As a matter of fact,
Pinewood Derbies should adopt a Krytox only policy. When properly
applied, Krytox is much cleaner and leaves no trace on the tracks.
This stuff is also perfect for your nice paint job. Graphite will stain and
ruin a light color paint job but Krytox will not.
Monkey Dust
Monkey Dust is a unique formula of natural and pure industrial grade
graphite powders that create an extremely low coefficient of friction.
The graphite particles that make up Monkey Dust are milled to a
minute 325 mesh which makes it the silkiest graphite on the market.
Hob-E-Lube
Hob-E-Lube consists of a fine, specially ground formula fortified with
Molybdenum. The Molybdenum additive has a very low coefficient of
29
friction and when mixed in the proper proportions boost the lubricating
effects of the graphite. Many tests have proven Hob-E-Lube to be the
best available.
How to Properly Use Graphite
With graphite, too much is never enough. Forget what your mother
told you… you can be as wasteful as you want. This stuff is not
expensive. Using too little graphite is another kiss of death.
It is very important that you first treat the axles with graphite. This is
an often overlooked procedure and most experts agree that this is an
extremely important process. The graphite must be properly worked
into the axle. No matter how fine you polish the axle shaft there will
still be microscopic scratches that will ad fiction. By working in the
graphite, it fills the minute scratches and helps protect against this
unwanted abrasion. The Derby Monkey Axle Treating Cradle is an
excellent tool for thoroughly treating axles.
Treating the Wheels
Extra Tip: When inserting the
axle, make sure that the axle
tip does not rub against the
inside of the hub wall. This
will place scratches on the
surface that you have worked
so hard to polish. These new
scratches will create unwanted
friction.
You can’t just squirt a little graphite in
the hub and that’s it. You must pack
the graphite tightly in the hub until the
hub is completely packed full of
graphite. Again, don’t worry about
being wasteful.
After the hub is packed, carefully insert
the axle in the wheel. A lot of the
graphite will be pushed out of the other
side of the hub but that’s OK. Spin the
wheel several times on the axle to help
Extra Tip: Keep your
seat the graphite. Graphite has a breakgraphite and lubed car in a
in period of 4 to 6 runs so always spin
dry place. High humidity will
the wheels multiple times. Then mount
actually dampen the graphite
causing it to gunk-up and
the wheel and axle on the car. Be
decrease your speed.
careful so that you don’t get graphite on
your nice paint job.
Now, roll the car back and forth on a clean flat surface. If you have a
test track, make 3 or 4 practice runs. This further helps to seat the
30
graphite. Then remove the wheels and start the wheel treatment
process all over again.
Extra Tip: Other parts to
consider lubing with graphite
are:
 The car body where the
hub rubs
 The inside of the wheel hub
 The inside of the wheel
edge
 The wheel surface
Every little bit helps.
After the last wheel lube, you car will
need what is comparable with 5
practice runs to break-in the graphite.
Wipe the car down and remove as
much loose graphite as possible from
the body and outsides of the wheels so
that it won’t get on the track. Then put
the car away and don’t touch until
check-in time.
31
There is absolutely no doubt that having the ability to test your
Pinewood derby car is an advantage of gargantuan size. The only
problem is that unless you have a friend with a test track and timer,
you have to buy one. The Best Track single lane test track and timer
is the ideal tool for testing and timing.
Having a quality test track and timer allows you to make adjustments
to your car and check the run times. You can quickly determine which
adjustments are good and which are not.
Keeping a journal of your adjustments and times are extremely
valuable. If you have a winning car this year then you know what test
times you need for next year’s car to be competitive.
32
This is a very important factor that you should really discuss with your
young scout well before the car is finished. All too often, some scout
will impatiently decide to start playing with their car on the floor before
the race. This is disastrous. The car will lose graphite, get knocked out
of alignment, pick up dust, or even worse… get broke.
You should explain that this Pinewood derby car is a fine tuned
instrument and that any unnecessary handling can easily slow the car
down. There will be plenty of time to play with the car after the race.
Handle the finished car as if it were a fragile heirloom. Derby Monke y
has a few great car carriers that will protect the car until it’s officially
checked in.
33
The Derby Monkey truly hopes that this manual has been of some help
to you. For more information please visit the Derby Monkey website
and the Fast Pinewood Derby Tips blog.
The History of the Pinewood Derby
The first Pinewood Derby ever held took place in 1953. Pack 280C of
Manhattan Beach, California gathered at the Manhattan Beach
Clubhouse and made Cub Scout history.
Cubmaster Don Murphy had been looking for an activity that his 10
year old son, Don, could participate in after being too young for a soap
box derby. Remembering the cars and airplanes he used to carve as a
child he decided his Cub Scouts could work with their fathers and
carve their own race cars. He felt this activity would foster a closer
father-son relationship and good sportsmanship through competition.
Murphy approached his Cub Scout committee who eagerly took on the
project. A car and track design was quickly worked out. The racing kit
consisted of a block of pine wood, two wood axles, four nails, and four
wheels. The track was 32 feet long with a declining four foot down
ramp for the gravity propelled cars. The electric finish line was built
with door bell coils powered by batteries to signify the winner.
The first race day was set for Friday May 15, 1953. Contestants raced
in three classes: Class A: 10 years old, Class B: 9 years old, and Class
C: 8 years old. The race was a hit from the second the first group of
cars started down the track. News of the Pinewood Derby quickly
spread. A city wide Pinewood Derby was sponsored by the Herald
Express newspaper and the Los Angeles City Recreation and Parks
department in 1954. When word reached the national office of the Boy
Scouts of America they decided to promote the race nationwide. A race
car kit was even included in the Boy Scouts of America's supply
catalog.
Today most of the rules and regulations of the Pinewood Derby remain
the same. Cub Scouts and their parents look forward to the race each
34
year. Don Murphy, the father of the Pinewood Derby, still takes great
pride in the event he started over 50 years ago. A regulation Pinewood
Derby track can be found in the National Scouting Museum where
visitors can race their own cars or a car provided by the museum.
Source: National Scouting Museum
35

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Transcription

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