Australia Pinewood Derby Race

Here are some cars from the “Wood and Wheels” race held in Australia (Maximum Velocity supplies the wheels and axles for the race). The photos were submitted by Matthew Webb.

Also, a Formula One Awana car built by Matthew:

From Pinewood Derby Times Volume 14, Issue 6

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Runoffs – When and Why to Run Them

Years ago, virtually every pinewood derby race used an elimination method (usually double elimination) for running a pinewood derby race. This method was relatively easy to implement and easy to understand, but did have issues including:

1. Slowest racers ran a few heats and were then eliminated (and likely lost interest in the event.

2. Possible unfair trophy assignment (third fastest car is eliminated early due to repeated pairing with the fastest two cars).

3. Cars did not always run on all lanes, so some cars had an advantage if they were assigned to a fast lane.

With the advent of Race Management software, many events have transitioned to a chart-based racing method, whereby all cars run the same number of heats, race in all lanes and are paired against a broad selection of other cars. These methods are much fairer, and are more accurate in assigning trophies.

But when using a chart-based method, the scoring method must be selected: time or points. I won’t get into a full comparison of time vs. points in this article.(1) Time-based scoring is certainly popular and is really the best choice for large events. But for smaller events, I prefer point-based scoring. I believe this method keeps the audience more engaged, keeps each heat exciting, and makes the finish order of each heat important.

But with point scoring, the final trophy assignment may not be accurate after the heats are complete. Like elimination methods, random heat assignments can result in the third fastest car being relegated to fourth place.(2) So, to ensure that trophies are assigned properly, another round for the fastest cars may be needed. Let’s look at when a second round is needed, and how many cars to select for the second round.

WHEN IS A SECOND ROUND REQUIRED?
To answer this question, we must first understand the terms “Perfect-N” and “Partial Perfect-N” (PPN) as they apply to race charts.

A Perfect-N race chart is one in which every car races the same number of times in each lane, and races against every other car the same number of times.

The simplest case is 4 cars on a four lane track, racing one time per lane. Each car races one time in each lane, and in each heat races against the other 3 cars. Other cases of Perfect-N charts will be described below.

A PPN chart is one in which each car races the same number of times in each lane, and heat assignment is optimized so that no one car races against any other car more or less than one time greater than the average.

An example of a PPN chart is one with 8 cars on a four lane track, racing one time per lane. Since the example car will need to race against 12 other cars (3 per heat), and since seven (the original 8 cars minus the example car) doesn’t divide into 12 evenly, the example car will race against 7 cars one time and 5 cars a second time.

For a four lane track, Perfect-N charts exist for the following numbers of cars(3):

4 – Yes
5 – Yes
6 – Yes – Bye required(4)
7 – Yes
8 – No
9 – No
10 – No
11 – No
12 – Yes – Bye required
13 – Yes

For all car counts greater than 13, only PPN charts exist.

When a race has a Perfect-N chart the race is perfectly fair and a run-off is not needed (except in the case of tie). But if the race has a PPN chart, it is possible that a trophy may be incorrectly assigned. In this case, a run-off race is required.

HOW MANY CARS SHOULD BE IN THE SECOND ROUND?
From the above discussion, the answer is clearly that a number must be selected that has a Perfect-N chart. In no case should a second round use a PPN chart.

Typically, we select the top seven cars, except when there are ties that would drive the number beyond seven. Then we select the top five or six cars.

IMPLEMENTATION / CONCLUSION
I grant that a time-based race is easier to implement, as the need for a second round is not necessary. But with a modern race management application, such as Grand Prix Race Manager, creating a second round is quite easy. In our race, we typically have the second round ready to go in two minutes from the completion of the final heat of round 1. Our emcee fills the time with a few kid-friendly jokes, so the excitement of the event continues during this slight delay. Then during the second round (seven cars typically take less than ten minutes), the excitement level (and sound level) reaches its peak.

If you are currently using a time-based method for your small race, consider switching to a point-based method. I believe you will generate greater interest and excitement, for just a few extra minutes of event time.

(1) For a comparison of these two methods, please refer to:
Points or Times: Which Method Should I Use?

(2) For example, if the third fastest car races the two fastest cars resulting in two second place finishes, and the fourth fastest car only races against one of the top three cars resulting in one second place finish, then the fourth fastest car would be incorrectly assigned the third place trophy.

(3) If you have a track with more or less than four lanes, you can use Grand Prix Race Manager (GPRM) to determine the Perfect-N charts.

(4) A phantom car is inserted into the schedule. When it races, the lane is left empty. GPRM automatically takes care of byes.

From Pinewood Derby Times Volume 14, Issue 6

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Shop Talk: “Frame and Skin” Car Construction

By James White

I would like to share the “Frame and Skin” car construction method used by my grandson (Aaron Shain) and myself for pinewood derby car building.

We start with a normal pinewood derby block with drilled axle holes. After cutting out the profile we want, we remove all material except the frame of our car, and then we apply a rock hard varnish to the areas where the wheel hubs will rub the frame.


Figure 1 – Frame of Car
(An additional support piece was added over the front axle holes)

Next we build side extenders to be glued to the frame sides.


Figure 2 – Side Extenders

We then add a carbon fiber rod for stiffness down the car center and glue a 1/64 inch thick model plywood bottom skin onto the frame.


Figure 3 – Carbon Fiber Rod, and Bottom Skin

Tungsten weight is then added into the two rear pockets (not shown in photos). We target 4.85 ounces with all parts included. Tungsten putty is used as trim weight after the car is complete. The putty is placed into 1/8 inch holes drilled into the bottom of the car between the two rear axles.

Next, a 1/64 inch thick top body skin is cut out and glued to the frame.


Figure 4 – Top Skin


Figure 5 – Top Skin Installed

Fender tops are placed over the wheel wells (if desired). At this point, we install the prepped wheels and axles to do some tuning and testing.


Figure 6 – Fender Tops

After a paint job is applied, we are ready to race!


Figure 7 – Finished Car
(Photo is of a sister car, so the wheels are different)

From Pinewood Derby Times Volume 14, Issue 5

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Pinewood Derby Car Showcase – November 28, 2014

Iron Man – Randy Davis


I built this car as a prototype for a CNC machined car, but the shop I was going to use closed down. Oh well. I still had the prototype, so I entered it in our local Outlaw race and it took 1st Place in speed and 3rd Place in design. I used some X-Lite Outlaw wheels that were machined from Turcite-X. The wheel color doesn’t really match the car color, but the wheels certainly draw attention to the car.

Olaf – Richard Larson

Olaf ran in our local race as well, and took 2nd Place in design and speed. Every year, Richard builds great looking cars. Here are links to a few of his previous cars:

‘Mater

Red

Finn McMissile

From Pinewood Derby Times Volume 14, Issue 4

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Rail-Riding – Getting that Extra Speed

By Randy Davis

If you have spent any time on the Internet researching pinewood derby racing, you will have ran across the term “rail-riding”. This alignment technique had been used for many years by a select few, but became popular around 2008.(1) The Pro-Rail Rider Tool, the Pro-Axle Bender and other tools were introduced soon after to facilitate the implementation of this technique.

But with all of the tools, videos, and documentation available, I still get many calls from confused car builders about rail-riding. Therefore, the intent of today’s article is to organize the many facets of rail-riding in such a way that clarity can be attained.

WHAT IS RAIL RIDING
When a pinewood derby car rolls down the track, it will contact the center guide rail.(2) Each time a wheel contacts the rail, some performance will be lost. Moreover, when a rear wheel contacts the rail, even more performance is lost since the rear wheels carry the majority of the car’s weight.

So, the fastest car (all other factors being equal) is one that never touches a guide rail. It would seem then that setting the cars alignment to go straight would be the best bet. This might work if the track was perfectly smooth and level, but we all know that is a pipe dream. All tracks will lean one way or another (and some lean both ways alternately by track section). So, a car that is set to run straight will follow the lean of the track, resulting in contact with one or both wheels on one side of the car.(3) In addition, if the car is a three-wheeler (with a raised, non-spinning wheel) and the raised wheel contacts the rail, the advantage of the raised wheel is lost.

How can we compensate for this? Recognizing that the least amount of loss occurs when the lightest loaded wheel (a front wheel) contacts a rail, if we could set the car’s alignment so that a dominant front wheel is the only wheel that contacts the rail (the non-raised wheel for three-wheel cars; your choice of wheels for a four-wheel car), we would achieve the least guide rail losses. This is the basis of rail-riding.

Read the entire article on Rail-Riding Here

From Pinewood Derby Times Volume 14, Issue 4

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Pinewood Derby Car Showcase – November 14, 2014

Speed Racer – Nick Fish


This Bear pinewood derby car was built by Nick Fish and his Dad. We love Speed Racer, so we did our interpretation of Speed’s Mach 5. It won the den and took first place in the pack without losing a race. District competition was a lot tougher with a 5th place finish. The car is a modified Wing design using a 3.5 oz. tungsten canopy, tungsten putty for the final weight adjustment, raised front wheel, polished/grooved axles, aero underbody, and custom graphics.

The Reaper – Jason Otis


My pack’s Pinewood Derby Bandit/Open Class is pretty competitive every year, to the point where we had to create a class just for the parents. I got tired of coming in second, so I put this thing together a couple of years ago.

The main body is from an original BSA Pinewood Derby Kit, and the fan shroud was carved from three pieces of glued-together 2 X 4s.

Specs & Info:
Propulsion: 55mm 8-Blade 60K RPM ducted fan (19oz thrust)
Power: 3-Cell 11.1 Li-Po Battery
Best Track Times: 32-Foot Track-1.111 sec, 38-Foot track: 1.267 sec

From Pinewood Derby Times Volume 14, Issue 3

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Pinewood Derby Awards

By Randy Davis

Should every child entering a pinewood derby race get an award? Or should only the top cars for design and speed be given a trophy? How about a compromise? The answer to these questions will likely vary from person to person, and depends a lot on your philosophy of raising children.

I am not a child psychologist, so I can’t argue the theory that underlies awarding children. But I am a parent that cares about my children. Before they leave our home, I want to give them a solid understanding of how they should behave and what they should expect to encounter in the world.

I do not believe that every child should be equally rewarded, that is, no winners and no losers. This is certainly not the way the world operates, and teaching a child this perspective will not prepare them for reality. In my opinion children need to understand that sometimes you win, and sometimes you lose, and greater effort leads to greater opportunities for winning. Learning how to deal with losing (and winning) builds character and maturity. So I believe that trophies for the fastest cars and best designs are certainly appropriate.

NON-TROPHY AWARDS
But on the other hand, I think providing a larger variety of awards can be a great encouragement for kids. These can be certificates for: “Best Paint Job”, “Car Most Likely Built By a Kid”, “Silliest”, “Funniest”, “Most Aerodynamic”, etc. If you are interested in providing these types of certificates, many free downloads are available on the web. Just search for “pinewood derby certificates”.

Be careful with these type of awards. If you decide that every participant will get one, then it will be a big challenge to make sure that the number of certificates match the number of entrants, and that the awards are given out appropriately. Again, I don’t believe it is necessary for every entrant to receive an award of this type. But
that leads to…

PARTICIPATION AWARDS
Providing all entrants with a ribbon (or alternate) for participating is certainly appropriate. I am still amazed how much my kids like those ribbons. Even when they won a trophy, they would drape the participation ribbon over the trophy.

Participation awards can be more elaborate. Stan Pope has provided a neat idea for providing a mounting plaque for every car. The plaque has the date of the race and group name/number.

Certainly other participation awards such as pins, patches, etc. can also be used. In recent years we have gotten away from ribbons and have been giving each participant a “Hot Wheels” car. My wife watches the ads and picks them up for less than $1.00 each. These are a bit more expensive than ribbons or patches, but the kids really like them (a lot of trading goes on after the race).

CONCLUSION
I realize this article is a bit short, but of course my experience is limited to the races sponsored by our organization. So, I would like to get your input on this topic. If your group has a method of providing awards that works well or is unique in some way, please send me a description. I will try to include your comments in a future newsletter. You can send your comments to:
info@maximum-velocity.com.

From Pinewood Derby Times Volume 14, Issue 3
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Pinewood Derby Car Showcase – October 31, 2014

Today’s cars are owned by Darren Stark.

“I started a collection of pinewood derby cars and now have close to eighty. Sixty-five to seventy of them I personally built with family and friends. The photos below show a few of my favorites.

My son and I go to several races every year and display our cars with Todd Paxson. Todd is a friend of mine whos cars were used to make the movie “Down and Derby”. He is the one who convinced me to display my cars rather than keep them in a box. My son and I get such a kick out of watching people’s reactions to our cars and helping others figure out how they can make their ideas come to life. I hope you like them as much as we do

Editor’s Note: Todd Paxson’s display was featured in
Volume 6, Issue 14.

From Pinewood Derby Times Volume 14, Issue 2

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Creating Accurate Pinewood Derby Axle Slots

By Randy Davis

Most brands of pinewood derby kits come with slots on one side of the block into which the axles are pressed. These pre-made slots generally work well, but there are occasions when the car builder would like to cut new axle slots. These include when:

1. The existing slots are defective.
2. The builder wishes to change the wheelbase by cutting new slots on the opposite side of the block.
3. The builder wishes to build two cars from one block by cutting new slots on the opposite side of the block.

Previously, cutting new slots was a bit tricky. Usually, a hacksaw was equipped with two blades, and then the builder carefully cut new slots by following a pencil line. Obviously, errors were common: cutting a slanted line or cutting too deep were common issues.

But now, a new tool is available to solve these issues and greatly simplify the process of cutting new slots.

PRO-BODY SLOTTER FROM DERBYWORX
DerbyWorx recently introduced the Pro-Body Slotter. Similar to the Pro-Body Tool for drilling accurate axle holes, the Pro-Body Slotter is a cutting guide for cutting axle slots.


Figure 1 – Pro-Body Slotter

The tool fits over a standard pinewood derby block, and is held in place with a set screw (a clamp would interfere with sawing). Index marks on the tool are aligned with a pencil mark on the block which identifies the desired location of the new slot.


Figure 2 – Pro-Body Slotter Parts


Figure 3 – Pro-Body Slotter Parts

As mentioned before, two hacksaw blades are mounted on a hacksaw frame (one blade is mounted with the teeth forward and the other with the teeth reversed. The blades are then placed into the slot in the tool, and the cut is made.

After the first cut is complete, the tool is loosened, moved to the next slot position, reattached, and then the second cut is made.


Figure 4 – Pro-Body Slotter in Use

The index screw will leave two indents in the block, one per slot. These marks are filled with wood filler before sanding and painting. Note that the marks will be located behind the wheels, so they are not obvious.

TIPS
Here are a few tips for using the Pro-Body Slotter.

1. Use the Pro-Body Slotter on the pinewood derby block before cutting or shaping the block.

2. When placing the tool onto the block, orient the set screw on the side of the block opposite the pencil marks.

3. Keep the set screw on the same side of the block for both cuts.

4. Use even, gentle forward and back sawing strokes.

5. Make sure to stop when the saw blades reach the bottom of the tool.

6. For an extended wheelbase, position the slots at 5/8 inch (actually I prefer 11/16 inch) from each end of the block.

7. After cutting the slots, use a Pro-Axle Guide to insert a spare axle into each slot position, then twist and pull it out with a pair of pliers.

8. When painting, either mask off the axle slots, insert a spare set of axles into the axle slots, or better yet, use a Paint Stand.(1)

CONCLUSION
Using the Pro-Body Slotter makes creating accurate axle slots a simple process. The Pro-Body Slotter is available from many on-line vendors including Maximum Velocity. You can find the tool Here. A video from DerbyWorx on using the Pro-Body Slotter is available Here.

(1) The Paint Stand is available from Maximum Velocity Here.

From Pinewood Derby Times Volume 14, Issue 2

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