Pinewood Derby Car Showcase – August 25, 2016

Tres Pooches – Bob Richardson

We have a family pinewood derby every year after the Cub Scout derby. This year I won a ribbon for the funniest car. The car also won 2nd in the men’s division. Lots of fun!

Luke’s Ride – Bob Richardson

Luke’s Ride was a fun car to build. It took first place at the Scout- O-Rama race in Santa Maria, California, on February 6th in the bandit class, which was open to adults and kids alike. Luke Skywalker was bought as an action figure and cut in half. The wheels were colored with an orange Sharpie pen. When my wife Carol saw the car, she said,”Where in the world did you find a figure that looks like our son Gene!”

King Boo – Justin Martin

Inspired from the character in the Mario Kart video game from Nintendo, King Boo took 2nd (by a very close margin) in our pack race. My son picked the design and helped sketch it on the block of wood and did most of the base paint work. He was too young to use the tools for the most part, and didn’t have the patience that was needed to make the car win just a few races. I didn’t have the greatest tools with which to work with, but it was all worth it to see the smile and excitement on his face as he won race after race. The car was the talk of the race.

To get the long nose on the front I had to re-drill the axle holes as far back on the car as possible. The Boo figurine was from a Burger King kid’s meal; I epoxied it in, hoping it wouldn’t fly off when it hit the stop at the bottom. The aluminum engine and plastic exhaust pipes were from toy cars. Because of the design of the car I could not get the center of gravity as far back as I wanted, but tried by drilling lots of holes and filling them with BB’s. If I could do it all over I might tweak a few things, but I can’t complain about the results — plus I got some great memories, pictures, and video.

From Pinewood Derby Times Volume 10, Issue 3

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(C)2016, Maximum Velocity, Inc. All rights reserved.

Maximum Velocity Pinewood Derby Car Plans and Supplies

Shop Talk – Making Weight Pockets

Mounting weights on pinewood derby cars can be done in many ways. The easiest way is to screw plates on the bottom of the car. The next simplest is to drill holes into the side, back or bottom of the car, and then insert lead or tungsten into the holes.

Another way to weight a car is with pockets in the bottom of the car. To create a very low-profile car and to focus the weight in one area, tungsten cubes are oftentimes used. These cubes are tightly packed and glued into pockets in the bottom of the car.

Although weight pockets can be made with more sophisticated machinery such as routers and mortising machines, they can also be made with a hand drill and a chisel. Today, I will share some tips to take the pain out of making pockets by hand.

Drilling
Before we start drilling, let’s cover some preliminary steps:

1. To make clean pockets, you must use a Brad Point or Forstner drill bit. These bits create relatively flat-bottomed holes with straight sides, which greatly reduce the amount of chiseling which will be required, and minimizes the risk of damaging the car.

2. Always make the pockets on the raw block. It is much easier to clamp, drill, and chisel into a block than it is to work on a shaped car. Also, if damage is done, then you can easily start again.

3. Select a drill bit that is properly sized for the work you are doing. If you are a making pocket to hold one row of 1/4 inch cubes, then a 1/4 inch drill bit is perfect. If you are making a pocket for multiple rows of cubes, then use a larger bit (3/8 or 7/16 inch).

4. After marking the perimeter of the pocket, clamp the block firmly to a work bench, or place it in a vise. Don’t try drilling into a block that is not firmly locked in place.

Now, let’s move on to the actual drilling. First we need to establish the depth of the pocket. With a hand drill, the easiest way is to wrap a piece of masking tape around the bit at the pocket depth. Then when drilling, you can stop when the masking tape reaches the wood.


Figure 1 – Masking Tape on Drill Bit (marking 1/4 inch of depth)

Start by drilling one hole at each corner of the pocket, making sure to stop at the masking tape. Then continue drilling holes around the perimeter of the pocket, and the interior of the pocket. The goal is to remove as much wood as possible with the drill bit.


Figure 2 – Drilling Holes

Chiseling
Now let’s look at chisels. Similar to selecting a drill bit, select a wood chisel that is appropriately sized. For a 1/4 inch wide pocket, use a 1/4 inch chisel. For larger pockets, a 1/2 inch chisel will work fine. Next, make sure the chisel is very sharp – a dull chisel will lead to a damaged car. Finally, be very careful with a chisel. NEVER, EVER pull a chisel towards you, or push a chisel towards your hand.(1) Treat the chisel like a knife and handle it accordingly.

Now with the block still clamped in place, hold the chisel vertically and press it down along the perimeter of the pocket – generally a hammer is not needed. Work around the pocket, squaring out the corners. Then, clean out any remaining wood in the interior of the
pocket. Two tricks:

1. When squaring corners, square along the grain of the wood first, then square across the grain, and,

2. Cut a small amount of material at a time – taking too much material can result in a damaged block.


Figure 3 – Chiseling

Test fit the weight into the pocket. If it doesn’t quite fit, then expand the pocket slightly with the chisel.


Figure 4 – Testing the Pocket

The bottom of the pocket will have tiny holes from the center tip of the drill bit. If the car will be thicker than the depth of these holes, then they can be left alone. But if the car will be just a little thicker than the depth of the pocket, from the bottom of the pocket fill the holes with some wood filler. Allow the filler to dry before slicing the car.

Now that the weight has been accommodated, you can shape and finish your car. Good luck with the race!

(1) Since Maximum Velocity began over 10 years ago, we have only experienced two significant accidents in our shop. One of the accidents occurred during a workshop for our local race. A father broke a chisel rule (Never push a chisel towards your hand) resulting in a decent sized gash on the palm of his hand.

From Pinewood Derby Times Volume 10, Issue 3

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(C)2016, Maximum Velocity, Inc. All rights reserved.

Maximum Velocity Pinewood Derby Car Plans and Supplies

Pinewood Derby Car Showcase – August 11, 2016

Silver Streak – David Smith

My grandson and I built this car for this year’s Cub Scout race. He won 1st place in his den and 1st overall in the pack. There is nothing very different from the standard wedge shape, except for the fact that careful planning and tweaking every detail pays off. I got the design idea from your site. The size and weight was the standard BSA specs. The paint was Rust-oleum silver and the navy blue and red stripes are cut from sheets of stick-on sign vinyl. This was our first year to win 1st place overall! Thank you for tips and supplies from your site.

Outlaw Cars – Elaine Morita


All our pinewood derby efforts culminated at the Oahu Makahiki Pinewood Derby this last Saturday. I made a Raptor kit for the Outlaw race. Joshua decided he wanted to be in the Outlaw race as well, so he made an extended Predator. It worked out great and he still was able to throw in some style.

Race results? Well there are 2 families (Nakano & Oshiro) who usually have the fastest speeds in the regular Cub races as well as the Outlaw race, so for our first Outlaw race, we are happy to have placed 4th & 5th out of 19 participants. We’ve always tried to find a winning combination of speed and “cool” designs. After all when the race is over, the cars (and memories) will be kept for a long time!

Thank you for your help and advice. The newsletters on your site have been helpful too. Also, I must thank you for your reliably quick shipping or Joshua would not have had time to make his entry. We were scrambling to get his done in a week!

Fishbone – Ralph & Keirsten Sharpe

This is the car I built this year with my granddaughter for her powder puff derby in Girl Scouts. We call it Fishbone. It is only 1/4 inch thick (less after sanding), weighs in at 5.0 with a balance point of 3/4 inch and is setup for rail riding. It has 3.9 ounces of tungsten cubes hidden inside. We used ultralight wheels and grooved axles. It was very fast. Nobody even came close to us. Our best time was 2.516 seconds on a 35 foot aluminum track. This is only our second car and she won grand champion again, two years in a row, using mostly your tips, your tools and your parts. We will be a customer for many more years as I have a new grandson who will be in the scouts too. Thanks for all the help.

From Pinewood Derby Times Volume 10, Issue 2

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Maximum Velocity Pinewood Derby Car Plans and Supplies

Cheater Bars – Do They Work?

Many years ago, the predominant commercially available track was equipped with a simple starting mechanism. The starting pins were attached to a board which was held in place by rubber bands. To start the race, the operator would rotate the board. Thus, the speed of the operator’s movement determined the speed at which the pins would drop. Of course, this speed varied from heat to heat.


Figure 1 – Vintage Starting Gate
Source: blog.robinsonmaites.com

It wasn’t long before some clever derby car builders realized that by having the car contact the starting pin at a higher point, the car would start more quickly. In fact, this advantage would be significant whenever the operator rotated the board slowly. So, the “Cheater Bar” (also known as a “Spoiler”) was born.

Today, starting gates are spring loaded. So, the pins fall rapidly, with a consistent speed, and the speed of the operators hand is not a factor. However, the Cheater Bar concept has continued to be viewed as a way to gain an advantage. In fact, many races ban cars which have a starting pin contact point higher than a set value.

Considering that most racers will run on tracks with spring-loaded gates, and the pins on these gates drop very rapidly, is there any benefit to a Cheater Bar? Let’s find out.

IMPLEMENTATION OF A CHEATER BAR
A cheater bar is normally a metallic attachment to the front of a car that causes the car to contact the starting pin at a higher than normal location. This can be implemented in several ways. One way is to form the bar out of a piece of coat hanger wire.


Figure 2 – Cheater Bar
(Opaque material removed for clarity)

Note the notched front end on the car. This is necessary to ensure that the car only contacts the pin on the bar. Also, the Cheater Bar in the above photo is missing a vital piece. In order for the bar to trip the sensor on an electronic finish line, some opaque material (usually tape) would be wrapped around the bar.

A similar technique is to design the car with the wood creating a high front end (see Figure 3).


Figure 3 – High Nose Car

Although the High Nose will provide the same theoretically fast start as a Cheater Bar, the aerodynamics will be somewhat compromised.

EXPERIMENT SETUP
For this experiment a Cheater Bar was implemented in a different way. To minimize the number of factors that could affect the results, an adjustable Cheater Bar was attached to a car. The Cheater Bar was fashioned out of a piece of aluminum plate, two pieces of coat hanger wire, and a small segment of rubber tubing. The metal plate was held in place by rubber tubing, so it could be slid up or down. During the experiment, nothing was changed on the car except for the height of the metal plate.


Figure 4 – Cheater Bar at High Position


Figure 5 – Cheater Bar at Low Position

The car was equipped as follows:

– Extended wheelbase wedge car
– Rear weighted to 5 ounces
– Three wheels on the ground
– Alignment set to rail ride
– Pro-Stock Wheels and BSA Speed Axles
– Krytox 100 lube

Tests were run on a thirty-two foot Aluminum Freedom Track. The car was staged identically for each run. Five runs were made with the Cheater Bar set at 1-1/2 inches above the track (maximum for the starting pin). Then five runs were made with the bar set at 13/16 inch (low as possible on the car). These tests were then repeated, for a total of ten runs per configuration.

EXPERIMENT RESULTS
The results were as follows:

High Position – 2.556 seconds average, Standard Deviation at .0037

Low Position – 2.555 seconds average, Standard Deviation at .0030

Thus, the experiment shows that the position of the Cheater Bar did not affect the heat times. (The one-thousandth deviation in average times was well within the Standard Deviation of the data).

CONCLUSION
So, if you will be competing in a race that will be run on a track with a spring-loaded starting gate, don’t bother with a Cheater Bar. It won’t give you any advantage, and may cause your car to receive greater scrutiny or to be disqualified.

On the other hand, if you are in charge of a race that will be run on a track with a spring-loaded gate, then don’t worry if a car has a Cheater Bar. It won’t provide any advantage.

From Pinewood Derby Times Volume 10, Issue 2

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(C)2016, Maximum Velocity, Inc. All rights reserved.

Maximum Velocity Pinewood Derby Car Plans and Supplies