Friday, October 02, 2015


(I am dedicating the Car Showcase this week to a car
built by Stephen Parks).

I was browsing your newsletter archives, and saw the article on the direct drive outlaw car that you built Volume 8, Issue 3

It was interesting to me because, as an engineering student, I competed in the ASME student design competition, and designed a "string transmission" for a transport device.

For last year's pinewood derby event at work, I wanted to make an electric car for the Outlaw class, and initially thought of using the same type of transmission. However, it has some issues. If the
wheels spin, then you may not have enough string to power all the way to the end, and if the wheels don't spin, then you probably should have used more power! Eventually I abandoned the idea of a string transmission, and decided to just use a gear drive. A co-worker races electric RC boats, and sourced a Lithium-Polymer battery. These batteries are expensive, but relatively light, and have almost no internal resistance. I found a few motors that looked to be a reasonable size, then built a dynamometer to test and compare them. This approach wasn't very consistent, so in the end I simply picked the motor that sounded and felt the strongest.

So far, this wasn't nearly complicated enough for me. I figured that this drag car ought to look like one, so I decided to hide the drive train, switches, etc. into a drag car model so that it would be a "sleeper". The model I chose was the Stone, Woods, and Cook Willys.

Model Box Photo

My Car

The start switch is hidden behind the grille. When it is race time, a pin fits through one of the holes in the grille and into the switch, and rests against the start post on the track. There is an arming switch underneath the car just in front of the rear bumper. There was also a cutoff switch underneath the car, so that when the car falls down onto the stop strip at the end of the track, the power is cut (well, that was the idea).

Quite a bit of work was required to transform a model kit that was intended to be stationary into a rolling, self-powered, self-guided vehicle. Here are photos of the chassis, showing the motor and gear layout. The silver rectangle is the battery pack. The gears are out of a broken DVD player.

Top of Chassis

Bottom of Chassis

I should mention that the track is not set up until the night before the day of the race (after the impound). So, testing is very difficult. But I did get the coordinator to allow a couple of practice runs. On the first run, the tires had too much traction and lifted the front end when they caught on a track joint, resulting in a
derail. But that run put enough graphite on the tires to reduce grip enough so that didn't happen again. The next run was 1.998 seconds, on 49 feet of BestTrack!

Video of a Run (WMV format)

On race day, the car got a lot of interest for looking good, though some thought that it was "just a plastic model." No one expected a two second run, and it was easily faster than the other Outlaws, all of which were gravity powered. The run times gradually increased, not because of the battery, but because of graphite buildup on the tires. Going fast was not a problem with this car, but getting it stopped was. I seriously underestimated the speed at the end of the track, and didn't have a good way to stop the car. At the end of the fourth run, one of the guides that keeps the rubber wheels from contacting the center rail broke, and the car could not stay on the track after that. I took the car out of the race instead of needlessly damaging it further.

This year I'll probably reuse the motor and battery, but forgo the fancy body in favor of a much more robust frame, and I'll build a stopping device to fit onto the end of the track. I may also switch to front wheel drive to eliminate the possibility of wheelies, and I can then clean the graphite off of the tires after each run to maximize traction and maintain consistent times.

Stephen Parks

From Pinewood Derby Times Volume 9, Issue 4

Subscribe to this Free Pinewood Derby E-newsletter

C)2015, Maximum Velocity, Inc. All rights reserved.

Maximum Velocity Pinewood Derby Car Plans and Supplies

Friday, September 25, 2015

The Best Pinewood Derby Rule

Although you can get away with using a cheap plastic ruler for an occasional pinewood derby car, having a nice, accurate rule (not ruler) is a must for any serious craftsman. But like any tool, there is a large variety of rules available on the market. Today, I want to share with you my favorite rule. In my opinion, this rule is a must have for pinewood derby enthusiasts.

The rule I am referring to is the Incra Six Inch Precision Bend Rule. Although this rule wasn't specifically designed for pinewood derby use, I have to believe that the designer was a pinewood derby parent.

Photo 1
Incra Six Inch Bend Rule

The obvious feature of the Incra Bend Rule is the shape. The rule is specifically designed to fit over the edge of a block or board in order to make precise measurement with ease. The rule is marked in 1/32 inch increments, and at each increment is a hole and a slot that allows insertion of a 5mm pencil (standard mechanical pencil size). These holes and slots eliminate the inaccuracy that comes with trying to make a pencil mark along the side of a regular ruler.

Photo 2
Making a Measurement

This feature in itself makes this a nice tool, but there's more. On one end of the Incra Bend Rule you will find measurements that are perpendicular to the rule. These are used to mark offsets from the edge of a block. For pinewood derby cars, the obvious use is marking axle locations, weight hole positions, car thickness, etc.

Photo 3
Marking a 1/8 inch Offset for Axle Holes

But this offset measurement feature is not just to make a tiny dot, but it can also be used for drawing horizontal lines. Just insert the pencil at the desired location, and slide the rule along the edge of the block. Sweet!

Photo 4
Drawing a Horizontal Line

Now the "pièce de résistance". Do you want to locate the center of your block? One half of the Incra Bend Rule is 3/4 inch wide, while the other is 7/8 inch wide. 7/8 inch is a familiar number - it is one-half of the width of a standard block. So to find the center of a block, lay the rule with the wide portion on the top or bottom of the block, and strike a line. Since blocks are not consistent, put the rule on the other side, and draw another line. "Voilà!" The center of the block will be between the two lines (or coincident with the two lines if the block is exactly 1-3/4 inches wide).

Photos 5 & 6
Finding the Center of the Block

I am confident that you will enjoy this rule as much as I do. This rule is available at some specialty wood stores, but to save you the trouble of tracking one down, Maximum Velocity is now offering the Incra 6 inch Precision Bend Rule. You can find it on our web site Here

From Pinewood Derby Times Volume 9, Issue 4

Subscribe to this Free Pinewood Derby E-newsletter

C)2015, Maximum Velocity, Inc. All rights reserved.

Maximum Velocity Pinewood Derby Car Plans and Supplies

Friday, September 18, 2015


Bi-Plane - Doug Kile

Last year I sent in a picture a picture of my John Deere Tractor. This Bi-Plane is what I made for this year. It legal to run with the wings removed.

Model T - Gary Trousdale

My son's pack has a siblings and parents category, so I decided to enter. As far as what design I would use, I had about 100 ideas flying around in my head. The Model T came about mostly because I knew no one else would do it, and I'm fairly sure I've never seen one before.

I downloaded a lot of pictures of old Model T cars and trucks and settled on the touring car design. The body is still the original wood block from the BSA kit, just cut up and re-arranged a bit. The running boards are brass strips from a hobby store, likewise the grill, mounted in foam core. The headlights, taillights and compression tank were from a jewelry and craft store. The brass front bumper had to come off due to weight. The canopy is paper, measured, cut, folded and painted over a wooden frame (again, the metal was too heavy). The seats are foam rubber with lacquered and painted tissue paper seat covers. The gear shift levers, horn, and windshield were fabricated pretty much from wire, Sculpey, sheet styrene and paint.

The car ran pretty slow, despite my grinding and polishing the axles. I don't think it was a question of air resistance as much as the wheels themselves were out of balance -- I put hub spokes made of painted toothpicks on them. Oh well, it looked really cool.

Valentine C-A-R - Galen Jordan

This car was made as a Valentine C-A-R (not card) for my wife since our race was on February 14. we originally did not intend to race it. but, we caved to peer pressure and let my daughter race it in the 11 and under open class without any preparation other than graphite. It took second place. It was a great day of racing for the whole family.

From Pinewood Derby Times Volume 9, Issue 3

Subscribe to this Free Pinewood Derby E-newsletter

C)2015, Maximum Velocity, Inc. All rights reserved.

Maximum Velocity Pinewood Derby Car Plans and Supplies

Friday, September 11, 2015

Measuring for Success

Making a pinewood derby car calls for a number of measurements, and marking several cut lines and drilling marks. Although this seems like a simple part of building the car, making accurate measurements quickly and repeatedly takes some practice, the knowledge of a few tips, and the proper tools.

Today, we'll focus on measurement tips; tools will be discussed in a future Shop Talk.


A typical measurement for a pinewood derby car is measuring off the bottom of the block for drilling weight holes in the side or back of the car. Let’s say you want to measure 7/16 inch off the bottom to locate a weight hole. Where do you start the measurement from? Typically, one would align the end of the ruler on the bottom of the block, and then make a mark at the 7/16 inch tick mark. This will work, but it is not necessarily accurate for several reasons. First, the end of the ruler (especially on an inexpensive ruler) is not precisely ground. Second, ruler ends are often a bit chewed up. Finally, it can be awkward to align and hold the end of a ruler on the edge of the block.

A more accurate technique is to align one of the inch marks (typically the 1 inch mark) with the edge of the block, then make the pencil mark at 1-7/16 inches. This will work for any measuring or marking task. But if you are measuring, make sure to subtract one inch to get the correct measurement.

Figure 1 - Making a 7/16 inch Measurement

Let’s say that you want a pinewood derby car to be 7/16 inch thick. Sounds easy; just measure 7/16 up the side, draw a line, and cut. But there are a couple of ways to do this, depending on the accuracy needed. If you don't need any significant amount of accuracy (e.g., a line is needed for a rough cut), then an easy way to draw the line is to measure at one spot on the block, then use your fingers to guide the drawing of the line. Just place the pencil at the marked location, place the tip of your middle finger along the side of the block, lock your fingers in place and draw.

Figure 2 - Finger Method

With a little practice, this will result in a reasonably accurate line. If you need to repeat the line (other side of the block, or a different block), just keep your fingers locked and keep drawing.

For a more accurate line, measure at two points on the block, place the pencil tip at one of the marks, slide a ruler against the pencil lead, align the ruler with the other mark, and then draw. If the ruler is firmly held in place, then this will result in a quite accurate line.

Figure 3 - Two Point Method.

An even more accurate way to draw horizontal lines will be discussed in the next Shop Talk.

Oftentimes a horizontal line is needed down the dead center of the block. This is useful when drilling weight holes on the bottom of the block. Either of the previously mentioned methods can be used, however, since blocks are not always exactly 1-3/4 inches wide, another method can be used to get more accuracy.

Using the Two Point Method, instead of measuring 7/8 inch from one side of the block, place one of the inch marks on the ruler at the approximate center of the block. We'll use the 3 inch mark on a 6 inch ruler, but it can be any inch mark. Then adjust the ruler so that the 2 and 4 inch marks extend off the block the same distance. Make a pencil mark at the 3 inch mark, which will be the center of the block.

Figure 4 - Locating the Center

Repeat this technique at another spot on the block, and then connect the two marks.

From Pinewood Derby Times Volume 9, Issue 2

Subscribe to this Free Pinewood Derby E-newsletter

(C)2015, Maximum Velocity, Inc. All rights reserved.

Maximum Velocity Pinewood Derby Car Plans and Supplies

Thursday, September 03, 2015


iPod Jeep - Jeff Jouett

This was my oldest son Jack's final Pinewood Derby and he wanted something different. The result is the red car. It did play, though not loud enough unless you were right next to it.

Darth Vader - Dan Blythe

Attached is our Darth Vader car my seven year old and I created. I have experimented over the years with paint and making my own decals using pictures off of the Internet, magazines, etc. I give them some special backgrounds and highlights on the computer and then print them on adhesive backed label paper.

The boys pick out the theme, help with the painting, and pick from a variety of decals and where they want them placed on the car. I put it all together with them and teach them some speed tricks along the way.

Music on Wheels - Bruce Edney

My eight year old granddaughter inspired me when she asked me to make a "guitar" pinewood derby car. She sketched a concept and I designed the car based on my old Martin Ukulele that I had on my shelf since high school. The car's Ukulele is a one-third scale model using Myrtlewood and Purpleheart. The strings are mono-filament fish leader. The frets and tuning knobs are brass rod. I finished off the design with piano music copied from a music book and glued to the car body. She named the car, appropriately, "Music on Wheels". The car won first place in the "Show" class at WIRL in November 2008.

From Pinewood Derby Times Volume 9, Issue 2

Subscribe to this Free Pinewood Derby E-newsletter

(C)2015, Maximum Velocity, Inc. All rights reserved.

Maximum Velocity Pinewood Derby Car Plans and Supplies

Thursday, August 27, 2015

Outlaw Race is a Winner

At last year's derby we had so many families hanging out after the race having a good time that we thought next year we'd add an "Outlaw Race" open to anyone. The only rules were that the car had to fit on the track, not damage it, and not interfere with any other racer.

We had a great turnout with all kinds of outlaw cars. We had brother racing sister, parents vs. kids, grandparents vs. grandkids, and Cubmaster vs. everyone! Everyone was very pleased with all the competition and are anxiously waiting for next year’s race.

I entered my car, the 10 ounce "Dragonator". The car beat other cars that weighed 2 pounds or more!! And after all the years of helping my own son build cars, this was the first time we'd won anything. Needless to say my boy was a bit jealous of my Outlaw trophy which is proudly displayed in my game room.

For next year's Outlaw race the gauntlet has been laid down and challenges made from all.

Thanks for putting on a great site with good information.

Rick Wold
Pack 457, Covina, CA

From Pinewood Derby Times Volume 9, Issue 1

Subscribe to this Free Pinewood Derby E-newsletter

(C)2015, Maximum Velocity, Inc. All rights reserved.

Maximum Velocity Pinewood Derby Car Plans and Supplies

Thursday, August 20, 2015


Speed Racer - Mike McBride

I have dozens of cars, some built for speed some just to look at. This car was designed after the Speed Racer Mach 5. It has not been raced yet. It is wider than BSA specs, but will be raced in a modified class that we do with our church's men's group every year.

Winged Rail - Rick Ellis

This car raced in our church's 2009 Awana Grand Prix. It got the award for best workmanship and finished fourth for speed in the Open Division. It weighed exactly 5.00 ounces on the entry scale and has three wheelson the ground. This was my second derby. I took first in the Open Division last year and second overall. I don't mind finishing fourth as I helped build the other three cars.

Commodore Outlaw - Bill Klingler

This car is radio controlled, and will cover the track in a bit over a second. I can run it fast or slow. I can also throw it into reverse and back it up the track. It's great fun to stop it on the track, wait for a gravity car to pass, and then do a burn-out and pass the other car.

The electronics are from the Losi Mini-T RC car. The motor is an upgraded one over the one that comes with the Mini-T, and the drivetrain is built from slot car parts. It uses a 7.2V Nickel Metal hydride battery. The body is from a car kit.

From Pinewood Derby Times Volume 9, Issue 1

Subscribe to this Free Pinewood Derby E-newsletter

(C)2015, Maximum Velocity, Inc. All rights reserved.

Maximum Velocity Pinewood Derby Car Plans and Supplies