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Carson
Carson SuperDork
4/15/09 6:57 p.m.

I've heard, from a physics professor, that you want to place the lead weight higher in the car therefore increasing it's potential energy so it'll go faster. Makes sense from the potential energy stand point, I don't know if it would go any faster though, haha. I don't know if he was joking or not, haha he was like that as most physics profs are.

1slowcrx
1slowcrx HalfDork
4/15/09 7:29 p.m.

hehehe, I've used ProEngineer to design the most bad ass pinewood derby car you could ever dream of!!

It's ugly as sin but fast as anything I've seen. It's at my parents house but I'll see if I can't find a picture around here somewhere.

Think, ice cream cone... pointy end first.

nocarbud
nocarbud New Reader
4/15/09 9:17 p.m.

I found an ad in the back of Boy's Life magazine on how to build a winning pinewood derby car. It was like a "Tune To Win" for p-wood cars. I used my dad's lathe to turn down the wheels and I knife edged the wheels... made for a lot less rolling resistance. I also polished and notched the axles to reduce drag.
I tested the setup by spinning the wheel with my fingers and timing how long it would spin. my baseline from the out of box setup was around 15 seconds... my polished setup would spin for almost a minute longer. Still looking for the cars to snap the pics.

Keith Tanner
Keith Tanner MegaDork
4/15/09 9:38 p.m.
Carson wrote: I've heard, from a physics professor, that you want to place the lead weight higher in the car therefore increasing it's potential energy so it'll go faster. Makes sense from the potential energy stand point, I don't know if it would go any faster though, haha. I don't know if he was joking or not, haha he was like that as most physics profs are.

It'll have more potential energy at the beginning of the race, but there will also be more potential at the end. The total energy available should be the same - the weight is still moving down by the same amount, whether it's placed high or low in the car. Right?

Unless, of course, you find some way to have the weight fall inside the car and drive the wheels through a hidden mechanism.

Osterkraut
Osterkraut UberDork
4/15/09 9:52 p.m.

This topic is relevant to tonight's South Park!

SkinnyG
SkinnyG UltraDork
4/15/09 10:20 p.m.

What, Keith, no mention of this awesomeness??

Keith Tanner
Keith Tanner MegaDork
4/16/09 11:27 a.m.

I figured it would be rude to bring that up again :) For those who don't recall, that's a model of my Locost, built by the son of one of my autocross buddies. It blew my mind when he sent me pictures, it was a complete surpise.

sachilles
sachilles UltraDork
4/16/09 11:50 a.m.

Great timing. South Park just did a new episode last night involving pinewood derby cars. Worth a watch for nostalgia.

slantvaliant
slantvaliant UltraDork
4/16/09 1:07 p.m.

The definitive Pinewood Derby movie: Down and Derby

Way too close to home.

Edit: A place for real PWD geeks: Derby Talk

Curmudgeon
Curmudgeon MegaDork
4/16/09 1:42 p.m.
nocarbud wrote: I found an ad in the back of Boy's Life magazine on how to build a winning pinewood derby car. It was like a "Tune To Win" for p-wood cars. I used my dad's lathe to turn down the wheels and I knife edged the wheels... made for a lot less rolling resistance. I also polished and notched the axles to reduce drag. I tested the setup by spinning the wheel with my fingers and timing how long it would spin. my baseline from the out of box setup was around 15 seconds... my polished setup would spin for almost a minute longer. Still looking for the cars to snap the pics.

We did a lot of that kind of thing when my brother and I were Boy Scouts. The local judges frowned terribly on notching and knife edging. We used to get these blue nails which would quickly show any attempts at monkey business. But when there's a will, there's a way. My dad would show us what to do but we had to do it.

Couldn't notch the nails without getting caught but we would chuck them in a drill and use polishing compound to smooth out the nail's shank. The back of the nail's head usually had two small 'flash' ridges, those would go. Then we would chamfer the edges of the holes in the wheels. The wooden 'axles' had the holes for the nails predrilled in a press so they'd go in dead straight and the ends of those same axles were carefully sanded with very fine paper to remove ridges etc. Lock lube graphite worked great on the axles too.

The wheels were skinny, not anything like the ones used now. You couldn't do anything like grinding, knife edging etc but if you got a soft lead pencil you could rub it along the inside edge to cut down on drag when the wheels touched the wooden guide strip.

Yeah, we did pretty well with our cars.

sachilles
sachilles UltraDork
4/16/09 2:08 p.m.

Just curious....do they do a Dad's pinewood derby...seems like it might be a smart thing.

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