Monday, March 12, 2007

Pinewood Derby

Over the past couple of months Samuel and I have had the opportunity to build a Pinewood Derby car for Cub Scouts. I had promised myself that I'd make sure Samuel had plenty of help building a car, and make sure we could make it as speedy as possible.

He got his kit from the Scouts and Samuel drew several designs for the car. After going over the designs with him he decided on a shape and we cut it out. Samuel handled the bulk of the sanding and I cleaned and shaped areas that were difficult for him.

Painting was fun. It was Samuel's first time using spray paint, so needless to say we painted - sanded it all off - painted - sanded - painted - sanded. You get the idea. He finally got the hang of it and he settled on a red car with a black bottom. I thought it looked really good. We added pin-striping from the auto-parts store and a number from the original kit.

I took charge of the wheels and axles. I figured if there was to be a major contributing factor to the outcome of any of these races the wheels and axles were going to be a major link. The kit comes with four nails that are used for the axles. I carefully cleaned the burring and flashing from them and smoothed them out - finally using 1500 grit sand paper. I also beveled the heads slightly. The wheels, just plastic, came with mold marks and flashing from the manufacturing process. I cleaned those up as well.

Mounting wheels and axles turned out to be a bit trial and error and a lot of guess work at first, but I finally managed to get them in straight. The car held a good straight line and the wheels didn't wobble or pull in or out on the axle. I applied graphite to the wheels, axles and anywhere else I thought might be a contact point.

My other job was adding weight to the car. The maximum weight is 5 ounces. Not wanting to go over I settled on 4.8 ounces and hoped the scales used at the race wouldn't weigh heavier than mine.

Race #1

We took our car to the race. Weighed in at 4.8 ounces as I had hoped. I made sure everything was still straight on the car and Samuel and I checked it in.

Samuel won both of his races at the Pack Race and was 2nd place in the Tiger Cubs and tied for 3rd for all the divisions. I was thrilled, he was happy, but he came into this race knowing that he would have a fast car, and really expected to do well. He obviously had some confidence in our design and building skills. His first run down the track took 2.67 seconds. His second run was a bit faster at 2.65 seconds.

A nice surprise was getting 3rd place in Best of Show! As many times as we had sanded and painted, we really didn't expect much in terms of looks. We were just proud to get a decent coat of paint on it. The pinstripes must have been just the trick.

Race #2

This was the District Race. Unfortunately I didn't get to attend this one, but Tina filled in for me and they headed out for the race early this past Saturday morning. Samuel won 4 of 8 heats, and had an average time of 2.327 seconds - his best time was 2.310 seconds. The average scale speed was 212.5mph, his fastest was 214mph. Speedy!!!

The final results put Samuel in 5th place. He was only 0.343 seconds from the 1st place car. I was thrilled! For a couple of first timers building a Pinewood Derby car I think we did pretty good. We didn't have a lot of tools, or any way to test the car. With the exception of cutting out the car at the pack meeting on the band saw, everything we did was by hand or with small hand tools. Neither of us really qualify as "highly competitive" either. We just wanted to have a good time! We have the car on display here at home now, and we can hardly wait until next year.

If you've got a boy that's Cub Scout age, you should really get involved - even if only for the Pinewood Derby. It's a lot of fun for a Dad and Son!


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