ddunn.org
Duane, Dawn,
Sam, Nick, and Mike
(Jessy and Jenny)

Home Up Boating Music

 

 

3/19 to 3/24/2005

Pinewood Derby
A good night for the Dunn boys at the track.

3/19 - 3/20/2005
It's been derby week for scouts Nick and Mike.  We spent the previous weekend cutting, sanding, drilling and painting the cars for the Cub Scouts Pack 633 Pinewood Derby.  Both cars were cut the same on the table saw, then with some time using a coarse grit paper in the belt sander the two different shapes were formed.  Nicks got an additional cutout in the middle removing as much weight as possible so we could add it back with lead on the rear of the car.  This was followed by drilling 3/8" holes in the body and gluing in slugs of tungsten (heavier than lead) to get the cars as close as possible to the allowed 5.0 ounces of weight.

Nick's car received 5 coats of metallic purple paint from a balky spray can, while Mike's was wrapped in a flame 'skin' that is applied like a decal using a sponge.  Once that was done it received a overcoat of clear poly.

Then we added the details, Mike's blacked out canopy, and Nick's jet engines made of lead spray painted with copper paint.  Finally the finishing rub on decals were applied.

3/22/2005
Tonight is the weigh in and tech inspection.  We spent the dinner hour de-burring and polishing the nail axles, and drilling the rim area of the wheels (a feature of last years winning car) and sanding their surfaces smooth.    This takes quite a while as we had to drill 6 holes in all eight wheels.  Then we mounted the wheels, lubed with graphite, and were off to the inspection. 

On arriving we were informed that this year drilled wheels would not be allowed.  No one had informed anyone of this rule before hand, but we were now faced with replacing all 8 wheels on the two cars.  We found 4 additional spare wheels, and pulled 4 more old wheels of the spare 'play' cars the pack has.  Dawn rushed to the gym with the sandpaper and drill so we could do our best to prep these wheels. 

Finally we have them all on, but the nails went in too easy the second time.  Of course, now Nick's car is overweight.  After some additional drilling on the bottom and trimming of the lead 'jet' engines we finally got the scale to display '5.0'.  Mikes is light, at only 4.8 ounces.  We added some weight with double stick tape to get to 4.9 and will just hope it holds.  His canopy also popped loose so we had to re-glue and trust that it's dry and ready on Thursday as the car is now wrapped and stored in the quarantine box.

3/24/2005
Derby night is here.  Dawn is in charge as I'm off doing Maundy Thursday services.  She is the quarantine parent who has to keep 37 kids hands off their cars until the competition races are done.  The racing is done by age group (Den) starting with the first graders in Mike's Tiger Cubs den. 

It's a small group of only 3 kids and Mike's car wins every race by a substantial margin.  It's back to the quarantine area for his car as the champion of his age group. 

Nick races later in the 4th grade Weblos 1 den.  This is a group of 10 kids and through the course of many runs Nick is the champion of that den.  So far the Dunn boys are doing good.

Once all 5 dens are done and have a champion it's time for the finals to determine the winner.  Dawn re-lubed the axles as allowed under the rules, but didn't check the tightness of what were already axels that had been removed once before. 

In the first race it's Mike vs. Nick (the track only has 4 lanes and there are 5 cars so they had to run various elimination runs).  Nicks car now has a shimmy as it goes down the track due to slightly loose front wheels.  Mike wins by the narrowest of margins. 

Nick continues to race, finally loosing twice and finishing in third place over all. 

Mike races all the others as well, and finishes the night as the Grand Champion of the pack 633 - 2005 Pinewood Derby. 

His car never lost a race the entire evening.  There are no "x's" on his number 63 sticker.

All 5 den champions get a trophy and Mike has the bragging rights for the next year.

Update 2007:
Now that we are past cub scouts I can reveal the secret to these cars success. 

Based on my observations during our first derby I came up with a theory of how to get just enough of an edge to win races.  Using the table saw I cut a 1/2" deep 1" wide channel down the center of the bottom of each car.  This is entirely within the rules as the front is still a straight surface without any indents.  As the starting pin the car sets against is rolled forward flush to the track to start the race a car with this groove releases just a fraction of a second sooner than a car without it.

Looks like my theory worked out pretty good.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


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