pinewood derby cars

[schloff]

I am about to take my boy to the shop and design his car. Anybody have creatice design ideas that we might pillage?

I've done the wing car, the flat car, the bubble car, heavy car, light car, and nothing has worked worth a [excrement].

They look cool, but that's about all. Judges are impressed, but I'd like him to have a decent racer this year.

Any ideas about styling that we can incorporate?

Thanks

Dan

[Black wallnut]

Styling has nothing to do with speed. Speed is a function of wheels, axles, lube (graphite), and balance.

[schloff]

Correct. I meant that as another question. I get too caught up in my own thoughts that I can be too vague at times.

Sorry.

[Black wallnut]

Thought you already knew that but post just in case it was not known. One of the coolest I've seen was a cabover pickup truck.

[Uncle Cracker]

I've done the wing car, the flat car, the bubble car, heavy car, light car, and nothing has worked worth a [excrement].

Maybe it's time to do the jet-powered car...

[JSUPreston]

Last year, my older son declared he was not participating. At the very last minute, he decided he wanted to race. So, SWMBO and he literally lubed the axles, put the wheels and axles on and weighed it down so that it was 4.9/5.0 oz. Basically, a block with wheels and weights.

He placed 2nd in his den, which was the largest den in the Pack last year. He did the same this year with Raingutter Regatta, and won his den and I believe 2nd overall.

We had one child my first year as Cubmaster that brought in the best looking car we've ever had to race. It was one of the Lowe's kits and weighed at least double what everyone elses did. Out timer software allowed me to flag him so that his times wouldn't count, but would still allow him to race. In all 3 of his heats, he placed dead last. We all thought he would stink up the show because of the weight.

I've heard it said that aerodynamics come into play, which is why the wedge or flat cars work so well. In my experience, that's a bunch of hooey. Axle and wheel prep, with good weight placement seems to be the best, as well as making sure the car tracks good. One thing that does seem to help is to make sure one of the front wheels is just barely off the track. 3 wheels=less drag, but you've got to make sure the car tracks properly.

[Knottscott]

One trick I learned that has nothing to do with actual speed but helps with a good start, is to angle the nose of the car from the bottom up just in front of the axle to the tip. Depending on the setup of the starting bar, the angle on the nose helps get the car rolling as soon as the holding pins begin to rotate out of the way.

[JSUPreston]

Knott, you've given me a new strategy to try. Since I assemble the track every year, I am very familiar with how my Pack's track works, and this is a good idea.

[crybdr]

We ran a grown-up Pinewood Derby at work a couple of years ago. I work for a product design firm with many engineers - so...serious engineering principles were brought to bear.

The winning car (mine - ) was the simple wedge. I spent a lot of time making sure the axles were free of burrs and highly polished (I even went so far as to polish them in the direction of rotation for each wheel - probably more voodoo than actual measurable benefit). There were other cars that had been optimized via computational fluid dynamics with the body subsequently machined to shape - but the standard wedge still came out on top.

Maximizing weight is key, as well as FREELY spinning wheels (take a #2 pencil and 'color' every surface of the axle and wheel that come in contact). Plus, the straighter the car travels, the less time the wheels spend rubbing on the edges of the track. Don't assume the axle slots in the pinewood block are square.

Good Luck! I still love building these cars - we've got another grown-up derby coming up later this year.

[iceman61]

Visit this site if you want see some tips on designs or what it takes to be as fast as you can.

Allot of guys that make cool looking cars still use the "flat 1/4" thick car" as a base the use balsa wood over it to carve their car body out of. If you want a fast car I'd stick with a thinner car. If rules let you have only 3 wheels touching, try out the railriding approach. You will never get a car to stay off the rail in 32-42 feet. I swear by railriding & my son has allot of trophies to prove it. These aren't all that pretty but they won alot of races this year.

[cwsmith]

This is a bit old, as my son is presently 40! But the car was a winner with a couple of first place wins in the pack and then a second place win in the final.

No tools at the time except my old RAS and some hand power tools. We drilled the pin (axle) holes in the block first, using a Portalign drill guide and then shaped the body with a rasp and then some hand sanding.

The pins were put in the hand drill and polished. The wheels were deburred and we used plastic-compatible oil (model train lubricant). The weights were added to one or two holes bored in the bottom and then taped over and painted like the body. Paint was Testors metal flake, and the little wind screen was a piece of plastic divider from one of the little hardware drawers. Pins and wheels were mounted last.

I took these photos a couple of years ago, when we discovered it in the old desk. My grandson now has it.