Pinewood Derby Times Newsletter Volume 12 Issue 7

Pinewood Derby Times
Volume 12, Issue 7
December 26, 2012
In this Edition:

- Editor's Notes

- Feature Article - Propeller Car Evolution

- Humor

- Product Showcase - Propeller Car 2

- Pinewood Derby Car Showcase

- Q&A

Editor's Notes

Reader Feedback

From Mark Robison:
"Thank you for sharing the Derby Guy's Paint Stand on Derby Talk and for carrying this product. I have a tip that I'd like to pass along about how to care for the tool and keep paint off the metal parts.

I can't tell you how much I enjoy using this paint stand or how many cars I've painted using this tool. However, the cleanup and removal of the paint that gets sprayed on the metal parts can be difficult to clean off with paint thinner.

So try this tip before painting a car. Rub petroleum jelly or Johnson's paste wax on the metal parts. When the car is dry and can be removed from the stand, wipe the tool down with a rag or paper towel. This method makes cleaning and care for the tool a whole lot easier."

You can find the Paint Stand Here.

MV Basic & Wedge Car Kits

If you are planning a race and are not required to use a specific kit type, our MV Basic or Wedge Car Kit are just what you need. These attractively priced kits are equipped with:

Quality Block - Unlike the blocks provided by some organizations, our blocks are soft, northwestern pine blocks, cut precisely to 7 inches long, 1-3/4 inches wide, and 1-1/4 inches tall. These dimensions, as well as the axle slots accurately duplicate the dimensions of standard pinewood derby blocks from BSA and PineCar.
Simple Axle Preparation - Don't worry about filing off flaws, or losing hub caps. Our Speed Axles have no burrs or crimp marks, and install without hub caps. With or without polishing, they are ready to go. We supply five, so you have a spare.
Quality Wheels - Forget cheap, out of round wheels. Our MV wheels are top-quality wheels. You will not be disappointed with the quality of these wheels.

So, if your organization does not mandate a particular kit type, consider our MV Basic Car Kits or MV Wedge Car Kits.

Inventory Clearance Sale We are clearing inventory on several items including car kits, car plan booklets, and pine blocks (plain, standard, and extended drilled). Click Here to find our clearance items. Don't miss out on the great prices.

Can We Help? If we can help you in any way with your pinewood derby project, or if you have any feedback regarding this newsletter, please contact us at: [email protected]

Feature Article

Propeller Car Evolution
By Randy Davis

(The third in a series of articles originally published November 26, 2003 and December 1, 2010)

Many organizations sponsor open competition races, some of which allow the use of powered cars. Whether your organization holds this type of race, or you are looking for a "crowd pleaser", the propeller car is a fairly simple way to get awesome speed from a pinewood derby car.

Propeller cars have come a long way since the first "Erector Set" version I built in 2001.

Figures 1 and 2 - Original Propeller Car
The Erector Set car is indestructible, but it carried too much weight to be fast.

Through various iterations, the propeller car was optimized with the version we sold from 2008 to 2012.

Figure 3 - Production Propeller Car
This car had fewer parts, was light-weight, and used a compact ducted fan to produce crowd-pleasing speed.

Capacitor Car
But in the spirit of continuous improvement, more speed had to be found. This was accomplished in a novel way by Rod Shampine, and documented in Volume 10, Issue 5. Instead of feeding the motor directly with a 9 volt battery, Rod used capacitors to feed power to the motor. This allowed the motor to run at a higher RPM (the battery limited the amps available to the motor), thus producing more speed.

My first version of the capacitor car is shown in Figures 4 and 5.

Figures 4 and 5 - Original Capacitor Car
The car is similar to Rod's design (but a bit more robust).¹ When the front switch is not in contact with the track's starting pin, the capacitors discharge to the fan and the battery is disconnected. After the capacitors are fully discharged, the car is fully inactive. When the car is placed on the track and the switch is depressed, the capacitors are disconnected from the fan, and the battery is connected to the capacitors. As long as the car sits at the starting gate for long enough, the capacitors will be fully charged for the run.

Propeller Car Ii
After some consideration, a few improvements to the capacitor car become obvious. First, removing the battery from the car reduces weight and increases the speed.² Next, the wiring and capacitors could be mounted under the car for a cleaner look. Finally, the ducted fan was mounted at the back (more for looks than speed). This upgraded capacitor car design is now available as a kit from Maximum Velocity in our "Propeller Car II" kit (see Figure 6).³

Figure 6 - Propeller Car II
The new Propeller Car is much faster than the previous version, is lighter weight, and has a sleeker design. The car is charged with a 9 volt battery using a power jack and plug (provided with the kit). The kit requires just a few common tools to assemble - no soldering is required.

Propeller Car Ii Performance
On a 32 foot track, the standard propeller car crosses the finish line in about 1.9 seconds. The Propeller Car II crosses the same distance in about 1.6 seconds. Not only is the capacitor version faster, but an added benefit is that it turns itself off, since the fan quits turning after the capacitors fully discharge. The links below have videos of the Propeller Car II racing against the original Propeller Car and a standard pinewood derby car. I think you will be able to figure out which is which!

Video 1 - Propeller Car vs. Propeller Car II
(propcar2vs1.avi, 3.4MB)

Video 2 - Propeller Car vs. Standard Car
(propcar2.avi, 4.4MB)
Conclusion
So, if you want to blow away the competition in a real race, or just have a fun car to demonstrate at your event, consider the Propeller Car II from Maximum Velocity.

¹For more information on the design of a capacitor propeller car, Click Here.

²On a gravity powered car, more weight generally provides more speed. But on a powered car, lighter weight is better as this allows faster acceleration.

³The Propeller Car 2 is available Here.

Humor

Some young children were sitting in a circle with their teacher. She was going around in turn asking them all questions.

"Davy, what noise does a cow make?"

"It goes 'moo.'"

"Alice, what noise does a cat make?"

"It goes 'meow.'"

"Jamie, what sound does a lamb make?"

"It goes 'baaa.'"

"Jennifer, what sound does a mouse make?"

"Errr..., it goes... 'click!'"

Product Showcase

Car Showcase

Today we have a selection of ducted fan cars.

Red Bull - Travis Burkhardt

I added substantially more efficiency with the addition of a thrust tube. A Red Bull can is a perfect fit for the 40mm fan unit, 9V battery, front nose switch included. Total car weight of 5.0 ounces and all dimensions, axles, and wheels stayed within BSA standard rules. First Place finish and track record at 2.2 seconds.

Batmobile - Brian Amato

I decided to go for both form and function with my version of the propeller car kit. Of course I won the parent's outlaw race!!!

Blown Away - Dennis Bjorn

I wanted to build a ducted fan car that didn't show all the components. So I built "Blown Away". The capacitors are inside the body. The car weighs 3.6 ounces. Running on a 35 foot Best Track my best time was 1.56 sec at 315 mph (scale speed).

Outlaw - Mike Henkelman

The "Outlaw" car was built for demonstration heats in the upcoming pinewood derby season. It features a ducted fan jet engine with a functional hood scoop, eight side air scoops, a mesh windshield (air scoop), and lithium polymer 11.1 volt batteries.

Share Your Car With Our Readers
Do you have a car you would like to "show off" to our readers? If so, send us a photo of your car along with a brief description of any special features. Also, please include your full name. If selected, we will include the photo and description in this newsletter.Please e-mail photos to:
[email protected].

Photos must be sent by e-mail in JPG format (minimum size of 640x480, maximum size of 1280 x 960). Please shoot photos from the front left of the car, similar to the orientation of this car:

For better focus, keep the camera four or five feet away from the car, and then use the camera's zoom to fill the frame with the car.

Send only one photo per car, unless an additional photo is needed to adequately show a feature. Also, only one car per subscriber per year please. Thanks!

Q&A

I have a pinewood derby car that my oldest son used about 6 years ago to win his rank, pack, and district. The car was extremely fast and I would like to use the wheels and axles on my youngest son's car this year. The car has just been sitting, and has not been played with like some of our cars. Do you think this would work, and if so would I need to do anything above and beyond the usual prep?

Congratulations on the fast car.

Does the car use BSA wheels and axles? If so, then I suggest going with new wheels. In 2009, the wheel molds were changed. The new wheels are lighter in weight and more accurate, so they tend to be quite a bit faster than the older wheels.

We are wanting to do a Big Rig Truck race. We are looking for some rules of some sort. Can you help.

The only rules I could find were these. Note the section on Big Rig Racing.

www.scoutingpages.org/us/tx/pack38/pdf/Pack 38 Pinewood Derby Rules 2008.pdf
(copy and paste into web browser)

By the way, here is an article I wrote about the BSA Big Rig kit.

Do You Have Questions that Need Answers? Do you have a pinewood derby-related question? If so, send your question to: [email protected]. We answer all questions by e-mail, but not every question will appear in the Q&A section of the newsletter.

Back Issues

Are you a new subscriber, or have you missed some of the previous newsletters? Don't miss out! All of the issues for Volume 5 through Volume 11 are posted on our web site and can be found using our Newsletter Index.

Issues from Volumes 1 to 4 are available in four formatted documents, ready for immediate download. To find out more, Click Here.

Newsletter Contributions

We welcome your contributions! If you would like to contribute an article, a web site review, or a speed tip, please send it to: [email protected].

Please read our submission policy.

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The Pinewood Derby Times is a free e-newsletter focused on the Pinewood Derby. It is published biweekly from October through March.

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Randy Davis, Editor, Pinewood Derby Times
E-Mail: [email protected]
Copyright ©2012, Randy Davis. All rights reserved. Please do not reprint or place this newsletter on your web site without explicit permission. However, if you like this newsletter we grant permission, and encourage you to e-mail it to a friend.

The author disclaims any personal loss or liability caused by utilization of any information presented in this newsletter.

The Pinewood Derby Times is not specific to, and is not affiliated with the Boy Scouts, YMCA, Awana, or any other organization .

®Maximum Velocity! is a registered trademark of Maximum Velocity! Pinewood Derby Products.
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