I sliced the pinewood derby block into 1/8 inch thick sheets on a table saw, then cut various profiles with the Glowforge and laminated the whole thing back together. Small dowels running laterally helped with alignment of the layers. The acrylic was snapped in via slots forward and rear.
That’s great! I love the idea of cutting the wood into 1/8th inch sheets.
I don’t know if they still permit this, but if they do: sharpen the tires. Rather than having flat tires (wide surface area touching the track), grind them down to blades. It will dramatically speed up the vehicle.
Also, fill those middle holes with metal (heavy screws or lead) so the car hits the maximum permitted weight. The better the car pushes down on the track, the faster it will go. [Just noticed your followup where you said you used weights. Good!]
@dr.krawetz@dhomburg : In addition to shaping the official wheels to minimize road contact, arrange for only one of the front wheels to actually touch the track. In my experience sufficient overall weight and fine tuning the wheels (and axles) is the key to a first-place finisher. The “penalty” for a hot car is lots of travel to regional race-offs. But that can be a fun experience—up until the point someone else has a faster car!
Yep, this car was set up as a single front wheel “rail rider” design.
Unfortunately, our Pack rules prohibit wheel shaping or I definitely would have.
I volunteered to set up the track the night before the races with several other dads, and of course we had to test the track. hee hee. Our car was consistently smoking the others (who ended up placing the next day) by 3-4 car lengths.
Unfortunately, I pushed it too far by thinking that we were riding the middle island too aggressively, and backing it off a bit. After the adjustment, there ended up being too little steering, and the raised wheel contacted the island some, bleeding off speed. The result was that we were coming in a car length behind cars we had beaten the night before. The adjustment was an almost immeasurable steering-axle turn.
The rules in our pack are that kids sand and paint. Kids or parents can build.
My older son did build his own cars from Bear rank forward, but the younger one is a Tiger (6 yrs). I still have to teach him bandsaw or Adobe illustrator. For my own sanity I wish we had a kids only build rule.
a 6yo using a bandsaw? holy crap. I would never do that.
I made a 2nd place finisher. I whittled my car down to shape. took a while.
my 2nd little brother from the big brother’s big sisters program was in cub scouts for a while. they had a build session for the cars. it was astonishing. we show up, there is a room full of equipment. kids picks a profile design. guy standing there cuts it. next station. a guy with a tool and die level jig drills the holes. I was amazed.
I asked about how this came about and was told that a kid years ago showed up with his car that he had painted by dipping i in a gallon of paint. (no father in the home) so the dads (many of whom worked at the ford plants here in louisville ) got together and created all of the jigs and patterns etc. so each and every kid would have at least a decent car. it was really something.
and the quality of those jigs… holy smokes. it literally was a pinewood derby racer factory that afternoon.