uh, oh. Cub Scout Pinewood Derby time is coming. Again.

[LCHIEN]

Eldest grandson graduated to Boy Scouts but the second just got his PWD kit and has some ideas already
At least he's requesting help more than a week before the race this time!
Its at least 4 weeks away.

Last years results:

[LCHIEN]

Grandson is 8 now, I showed him how a chuck works and the name of the chuck key, gave him strips of sandpaper explained fine and coarse grit progression and how to use google timer then turned him loose. one minute each four axles and four grits and polished 4 wheels and he said I just spent 20 minutes of my life doing this.

https://www.facebook.com/loring.chie...vQm1eqkt7uHxPy sdmkYowmBfLuYqrCJJWDHl?notif_id=1673202735093323&n otif_t=feedback_reaction_generic&ref=notif

Result of axle polishing - upper part is polished, lower part is original.


It may not seem like much but last year I observed the winning car sometimes beat the 2nd place car by ,010 seconds out of about 3 seconds or 0.3%

Little things like weighting your car to 5.000 ounces instead of settling for 4.995 makes a 0.1% difference in the potential energy at the start.

So if you do everything just right in sum you can get that 0.3% advantage. Do one bad thing and it can mess up the whole proposition.

[leehljp]

I just spent 20 minutes of my life doing this.

LOL!

After he wins,, I am sure he will say it was worth it!

[LCHIEN]

Showing off his multiplication table skills. I test him all the time against Alexa.
He wins easily.

[LCHIEN]

Tapered bodies this year challenging cut. Both practically the same shape.
I did mine on the taper jig and BT3 no blade guard 2.9 degree cut both sides VERY HAIRY.
Decided I did not want to do his that way.
We actually did my Grandsons on the bandsaw and cleaned it up on the belt sander. He did the cut with me helping guide some; he did the belt sanding. I had to touch it up a little at the end.

Lasered mine with Chinese characters for Happiness, Health, Wealth, prosperity, luck etc. being that it is Chinese New Year this week. Is an Mahogany hardwood inlay worth any points?

His mom helped him paint and made stencil for his. The drawing I made according to the description he gave me, although I suggested the taper dimensions. Still some decorations to do when he gets back here.


Now working on weighting...
I figured out how to take out precise amounts of weight by drilling away at the body underside based on computed density.

[capncarl]

I know it is called pinewood derby, but is the building materials limited to wood? Reason I asked was yrs. when slot cars were the rage they built some car bodies out of paper mache. Lots of fun and endless possibilities.

[LCHIEN]

I know it is called pinewood derby, but is the building materials limited to wood? Reason I asked was yrs. when slot cars were the rage they built some car bodies out of paper mache. Lots of fun and endless possibilities.

According to the official instructions, you must use the pinewood block they provide. However it says you can cut away (hollow out) as much as you want and add other materials of various types. So I figure I can cut away 100% and add other materials.

[capncarl]

Doesn’t make much sense to remove one material and replace it with another if doesn’t provide any benefits. The paper mache was fun to work with and could be molded from existing car and truck models.

[LCHIEN]

I wouldn't. Just start with what you want to use and if anyone asks where the wooden base is, say you hollowed it out completely and replaced it with whatever you used.

But Papier Mache is a additive process while woodworking is a subtractive process (remove everything that doesn't look like a car)

The last car started out with 3.9 oz block of wood cut down to .9 oz. and skeletonized to less than 0.7 oz, and added 3.8 oz of lead weights and 0.5 oz of wheels. Some people make recesses in the bottom of the car and pour molten lead in them.

[LCHIEN]

Meet "Shanghai'd" and "Swiss Cheese".

It says Health wealth Love happiness Serenity and Harmony


Entering these in the adult/family division.

Grandson's finished car? Sent him home and forget to take pic. Will get one.

[LCHIEN]

Grandson's car: Blazing Popcorn

[LCHIEN]

Race/competition is Saturday...

[nicer20]

Best of luck !!

[leehljp]

GREAT Looking race car and love the Popcorn! Waiting for the results!

[LCHIEN]

The Grandson won a trophy for 2nd place in speed, and an award for design " The car that was most not like a car for his Blazing Popcorn"

The family competition was tough and I did not place an award.

[twistsol]

The design award is well deserved. What was the time difference between first and second for speed?

[cwsmith]

Loring,

Congratulations on your grandson's efforts. I loved the popcorn idea, he is very clever and creative. Great looking entry!

CWS

[LCHIEN]

Quite a field



I had to run against 29 adult/family cars. For some reason the parents of the kids with fast cars also had really fast cars.

[LCHIEN]

The design award is well deserved. What was the time difference between first and second for speed?

The awards were based on average time - best 5 of 6 runs.
My grandson's car best 5 were 194 to 196 scale MPH, taking 7" car scaled to a 17+ foot average car.
I think the very best all came out to within a MPH of 195 or 196.
In terms of times the track was 42 feet long; my GS car ran 3.137 to 3.186 seconds. The winning cars ran 3.11 to 3.14 seconds best times. The timer had a resolution of .0001 second.

My 2 cars ran a disappointing 3.16 to 3.19 seconds.
They told me I can't run 2 cars next year (even though I put on e under my daughters name, I think they knew). The holey one I only started on it at Noon Wednesday and finished by midnight... I wanted to try they theory of really light on the front end but it didn't seem to help any.

FWIW here are the official results for his age group
So he missed 1st place by 5 milliseconds, that is 0.005 seconds.but he beat out third place by 5 milliseconds as well!

Here were the top winners in all ages groups times

[LCHIEN]

Screen captures from the live stream: The finish

Time results posted