Pinewood Derby Car Showcase – May 25, 2017

Delorean – Daniel Stalzer

This car was created after my son saw “Back to the Future”. He wanted a car that was fast and would “travel through time”. I made two of the cars, one for each of my sons. The cars won creativity and speed awards.

The only thing I did to help was painting the car, helping with tools, and installing the wires. Unfortunately the 2nd car was destroyed during the younger boy’s play time.

Arrow – Aaron Shain and Jim White

My grandson (Aaron Shain) and I built this car for his 2012 RA (Royal Racers) event here in Kentucky. “The Arrow”, as he calls the car, has a carbon fiber rod down the car center for extra strength. We hope it hits a “Bull’s Eye” at the races. (The hole in the side is for final adjustment of the car weight using tungsten putty when the wheels are changed for different races.)

From Pinewood Derby Times Volume 11, Issue 9
Subscribe to this Free Pinewood Derby E-newsletter
(C)2017, Maximum Velocity, Inc. All rights reserved.
Maximum Velocity Pinewood Derby Car Plans and Supplies

21st Century Changes Pinewood Derby Racing

During the pinewood derby season I receive many calls asking for assistance in selecting products for an upcoming pinewood derby race. Quite often the customer will state something like, “Wow, there sure is a lot to choose from. When I did this back in 19xx there wasn’t anything available”.

There certainly are a lot of products to choose from today. Whether it is tools, weight, software, tracks, etc., the pinewood market really exploded during the first decade of the 21st century. Sifting through all of the new offerings, I believe there are several key products and technologies that created a step change in competitiveness and in race management. Let’s take a look at these key developments and how they have made a huge impact on pinewood derby racing.(1)

Internet Retailing – 2000
Although not specifically related to pinewood derby racing the introduction of e-commerce, opened up the opportunity to offer a wide variety of pinewood derby products directly to the user. Maximum Velocity began selling on the Internet at the end of 1999. Prior to that (to the best of my recollection), there was one mail order company (Hodges Hobby House) offering an assortment of products, and another company (Winning Edge) offering a speed tip booklet. By the end of 2001, there were a few additional companies offering a broad assortment of products. Now there are numerous companies offering either a wide or a unique selection of products. Regardless of the new products that have been developed, if it were not for Internet retailing, the pinewood derby builder would continue to have only a limited selection of products.

Tungsten Weight – 2001
I believe Maximum Velocity was the first retailer to offer tungsten weight for pinewood derby building. The first product was a tapered tungsten cylinder, which was actually a golf putter weight. There is an interesting story behind these weights.

In 2000, I received a call from a tungsten sales rep (who was also a pinewood derby dad), asking if we had considered offering tungsten. He had used tungsten for his son’s car, and thought that it worked great. At the end of the conversion, the sales rep offered to send me some samples. When I received the samples (an oddball set of parts), the only part that seemed interesting was a tapered tungsten cylinder (the thought of having custom made tungsten parts did not seem reasonable at the time). When I asked the sales rep about buying some, he stated that he didn’t mean to send me that part, as it was a proprietary part from a particular customer. Oh well.

But the part intrigued me, so I went looking on the Internet. The sales rep had indicated that they sold parts to golf club manufacturers, so I specifically looked at golf club dealers. Amazingly, a Ping putter was shown on a particular site, and it looked like the putter used the tapered tungsten cylinders for weighting. Ping is based in our area (Phoenix, Arizona), and I happened to know a manager at Ping, so I showed him the part and explained that I wanted to offer the part for pinewood derby racing. He said, “No problem, we will sell them to you.” So, for the next several years, we purchased the cylinders from Ping.

Now, the use of tungsten for pinewood derby racing is quite common. It allows for much more effective weight placement, and for extremely low-profile cars. Not only are cars more unique today, but the weight placement and aerodynamics have greatly improved performance.

Specialty Tools – 2002
Prior to 2002, the only readily available pinewood derby tool was the wheel mandrel. But then in the summer of 2002, Bill Launius contacted Maximum Velocity regarding a prototype tool he had invented, the Pro- Hub Tool. That tool was introduced in September 2002, and was quickly followed by the Pro-Body Tool and Pro-Axle Press. More tools followed, and now there is a broad selection of pinewood derby tools available from DerbyWorx. We also have a few of our own unique tools such as Axle Extraction pliers, and the Axle Install Support.

Now that these tools have been available for many years, it would be difficult to make a competitive car without the tools. Just like other types of technology, we have become accustomed to having the right tools for the job. By simplifying the building of accurate cars, pinewood derby specialty tools have increased the competitiveness of all pinewood derby races.

Race Computerization – 2002
Although some software packages were available before 2002, in that year Lisano Enterprises introduced Grand Prix Race Manager (GPRM). With the ability to create “perfect-n” and “partial perfect-n schedules”, this package helped to convert many race leaders away from elimination-style racing. Coupled with certificates, sound effects, and many other features, GPRM dramatically improved the quality, accuracy, and entertainment value of pinewood derby racing.

Aluminum Tracks – 2002

Source: besttrack.com

Prior to 2002, an aluminum track surface was only available by covering a wooden track with aluminum plating. But this changed when BestTrack introduced an all-aluminum track in mid-2002. Piantedosi (now Microwizard), followed soon after with an all-aluminum version of their Freedom track. Now aluminum tracks are much more prevalent than wooden tracks.

The common use of aluminum tracks has resulted in faster times (for a given track length) and generally tighter races. This adds to the excitement of the event, and has further increased the number of organizations that hold pinewood derby events.

Rail Riding Technique – 2008
Although the Rail Rider alignment technique(2) was developed by Jay Wiles several years ago, it became popularized in 2008 with the introduction of the DerbyWorx Pro-Rail Rider Tool, and eventually the Pro-Axle Bender.  The Rail Rider technique greatly improves the consistency and performance of pinewood derby cars. Because it is relatively easy to implement, the Rail Rider technique is now commonly used not only in the highly-competitive adult race leagues, but in most pinewood derby races. No other technique has so quickly become a standard that is virtually required to have a competitive car.

New BSA Wheels – 2009A major step forward for Cub Scout pinewood derby builders was the introduction of the improved BSA wheel in 2009. By using internal injection, this wheel did away with the mold mark on the tread, reduced the weight, and improved the accuracy of the wheel. This served to improve the competitiveness of Cub Scout Pinewood Derbies. Now there are fewer cars which don’t cross the finish line, and races tend to be much closer, increasing audience interest.

Not involved in a BSA-sponsored derby? In 2010, Maximum Velocity introduced a highly accurate light-weight wheel for their MV Car kit. This wheel also uses internal injection to eliminate the mold mark and improve concentricity. In races using this kit, cars are much faster and are much closer at the finish line.

Conclusion
Certainly, the first decade of the 21st century significantly changed pinewood derby racing. I for one am anxious to see what the current decade will bring. Hopefully it will be as exciting as the first decade, and pinewood derby racing will continue to grow in popularity and excitement.

(1) This is my list of pinewood derby step changes. If you have one or more additional items that that you believe are 21st century step changes, please send me your input and I’ll collect and publish them in a future newsletter.

(2) If you are not familiar with the Rail Rider technique, please Click Here.You can find the Pro-Rail Rider and Pro-Axle Bender tools Here.

From Pinewood Derby Times Volume 11, Issue 9
Subscribe to this Free Pinewood Derby E-newsletter
(C)2017, Maximum Velocity, Inc. All rights reserved.
Maximum Velocity Pinewood Derby Car Plans and Supplies

Pinewood Derby Car Showcase – May 12, 2017

Today’s special: Cars with tungsten canopies

Spiderman-mobile – Robert Stevens

Last year my son participated in his first pinewood derby and won the grand championship for his pack. This year was his second pinewood derby and his second grand championship for his pack. We took the Predator design and turned it in to the Spiderman-mobile. We implemented the rail-riding alignment technique using the Pro-Rail Rider tool. Thank you for all that you do to help boys have success with the pinewood derby. It has really helped build my son’s confidence and esteem.

Predator – Michael Tances

I raced this car in the adult class in 2010. The car won all the races and had faster times than the pack winner. It is completely stock and is exactly 5 ounces. I’m 64 years old and still like to win!

Race for the Cure – Kimberly Paul

This car took first place in the open division at our pack here in Tulsa. The car ran really well thanks to the tungsten canopy purchased through Maximum Velocity.

Vaccinator – Stephen Davis

This car was raced in an Outlaw division a few years back.  It easily took first place.  It has needle axle wheels and a very aggressive COG.

From Pinewood Derby Times Volume 11, Issue 8
Subscribe to this Free Pinewood Derby E-newsletter
(C)2017, Maximum Velocity, Inc. All rights reserved.
Maximum Velocity Pinewood Derby Car Plans and Supplies

The Making of the MV Wheel

For several years, Maximum Velocity has been offering a bulk car kit similar to kits offered by BSA, PineCar, et al. When we first introduced the kits, we used PineCar-brand wheels. But in the spring of 2010 we decided that the time had come to have our own “MV” wheels. Thus, we entered the world of plastic injection molding.

We decided that if we were going to have a wheel made, it had to be very high quality. So we chose the best characteristics from the various wheels on the market:

  • Internal, three gate injection: Improves wheel accuracy (no mold mark on the tread surface),
  • Hard plastic (actually styrene): Less flexibility to improve performance,
  • Solid sidewall: Results in a stronger and more accurate wheel,
  • Light weight: Lighter wheels are faster,
  • Clean transition from tread to sidewall: No tread marks on the edge of the wheel.

The end result is shown in Figure 1.


Figure 1 – MV Wheel Design

The next step was to find a molding company that would work with us to get a high quality wheel. We were fortunate to find a company (MoldWorx1) in our area that was interested in the project. Then came the education; I learned that injection molding consisted of four phases:

  • Part Design Phase
  • Mold Design Phase
  • Mold Creation Phase
  • Injection Molding Phase

Part Design Phase
The design phase consists of creating a 3D model of the part to be molded. During this phase, the design of the part is usually adjusted to allow for manufacturability. The end result is a 3D model of the part, agreed upon by both the customer and the molding company.


Figure 2 – Blueprint of 3D Model

Mold Design Phase
Next, the mold itself must be designed. This is where the injection method and the runner system must be decided upon. “Runners” are the paths for the molten plastic to get into the mold cavities (and the resulting waste product – see Figure 3). If you have ever built a plastic model, then you will recognize the waste plastic connecting the various parts as the runners.


Figure 3 – Runners on MV Car Parts

The runner system shown in Figure 3 would be used on wheels that have the mold injection point on the tread of the wheel (like old BSA wheels and PineCar wheels). To have the injection point on the interior of the wheel requires a more sophisticated runner system (see Figure 4). In this mold, when the wheels are released they are automatically freed from the runners. The only sign of the runners are the three small dimples on the interior of the wheel. Although this method generates more waste plastic, the three gate system results in the most round wheel (least runout) available from injection molding.


Figure 4 – Runners on MV Wheels

The final mold design is in two parts (A and B), and is shown in Figures 5 and 6.


Figure 5 – Side “A” of Mold
 


Figure 6 – Side “B” of Mold

Mold Creation Phase
Next, the mold must be manufactured. This is the most costly part of injection molding as the mold must be precision machined so that it functions properly and produces high quality parts. Most of the mold is fashioned on a computer driven (CNC) milling machine. However, much of the detail in the mold cavities is too fine for the CNC. This fine detail is fashioned using custom made graphite electrodes. When high voltage is applied, the electrodes etch the desired detail into the mold cavity. The electrodes self-destruct so many of them are required. For the eight-cavity, MV wheel mold, eighty electrodes were used.

Injection Molding Phase
Finally, it is time to make the parts on the injection molding machine. The machine has several sections, shown in Figures 7 through 9.


Figure 7 – Plastic Pellets in Hopper

The hopper holds the styrene pellets. The white pellets are the base plastic, while the black pellets are added to adjust the color.


Figure 8 – Heating Section

The pellets are fed into the heating section, where they reach the proper temperature for injection into the mold.


Figure 9 – Molding Section

The mold halves are pressed together, injected with plastic, cooled with water, and then pulled apart. The parts are then ejected and fall into a bin below. The runners are grasped by a robotic arm (partially seen at the top of the photo), lifted out, and dropped into a grinder. A portion of the ground up runner is fed back into the pellet hopper. The rest is discarded.

The cycle time of the mold machine affects both the quality and cost of the part. The major step that affects the cycle time of plastic injection molding is cooling the part area – the better the cooling system, the quicker the material will “set”. This also happens to be one of the most expensive areas of a mold. Typically, more dollars spent on the cooling system results in a faster cycle time and a lower part cost.2

When the cycle is slow, the parts cool down while still in the mold so that they are fully hardened when they are ejected. This achieves the highest quality part, but the longer cycle time means that the machine must be run for a longer period of time to finish the production run (higher cost). On the other hand, if the cycle time is faster, the cost is lower but the parts are still malleable when ejected. This can cause slightly warped parts.3 So, quality and cost must be balanced to achieve the best cycle time for the part being molded. For the MV wheels, the cycle time was set such that the parts were adequately cooled before ejection from the mold.

Final Product
The final result of this project was the MV wheel shown in Figure 10. These wheels have a lower variance than most pinewood derby wheels.


Figure 10 – MV Wheels

The MV Wheel specifications are:

  • Wheel Diameter – 1.192 inches
  • Wheel Tread Width – 0.319 inch
  • Wheel Bore Diameter – 0.095 inch
  • Wheel Weight – 2.4 grams

These wheels are included in our Basic Car Kits or they can be purchased in Bulk or as a Weight-Reduced Speed Wheel.

1Visit the MoldWorx web site at: www.moldworx.com

2As an example, MoldWorx told me that they saw a 128 cavity mold run at a 5-6 second cycle time (very fast). But the customer likely spent $750,000 for that mold.

3This is a major reason why there is so much variance in most pinewood derby wheels, even within a given mold number. If the cycle time is a little too fast (which is very common, as lower cost is the main objective for most companies), the wheels will still be soft when ejected, leading to a slight warpage.

From Pinewood Derby Times Volume 11, Issue 8
Subscribe to this Free Pinewood Derby E-newsletter
(C)2017, Maximum Velocity, Inc. All rights reserved.
Maximum Velocity Pinewood Derby Car Plans and Supplies