h a l f b a k e r yFlaky rehab
add, search, annotate, link, view, overview, recent, by name, random
news, help, about, links, report a problem
browse anonymously,
or get an account
and write.
register,
|
|
|
Please log in.
Before you can vote, you need to register.
Please log in or create an account.
|
The Pinewood Derby (linked) is an elegantly simple race contest in which Scouts make little gravity powered cars using a standard kit. There are weight constraints. Elements not in the kit (except for decorative elements) are prohibited. Most modifications have to do with maximizing weight (and so
potential gravitational energy) and minimizing wheel friction.
How to win using unorthodox methods, but stay within the rules? I propose a Pinewood Derby car might be built in the form of a very tall tower with a pyramidal base. Three wheels are at the base with the fourth at the tower tip. This car towers over its competitors. After rolling down the initial slope, it topples forwards onto the track but continues to roll. The three wheels minimize initial friction down the track (as compared to four) and the fall forwards puts the nose ahead of competitors and so across the finish line first.
Outrage and much consulting of rules ensues. Ultimately Bung Jr is crowned Pope of Pinewood - the second step towards World Domination!
Pinewood Derby rules
http://en.wikipedia...wiki/Pinewood_derby
[bungston, Jun 25 2010]
[link]
|
| |
[+] for Dick-Dastardly Wacky-Races cheating, [-] for lack of inappropriate, haigly inadvisable and recklessly dangerous use of pyrotechnics and/or explosives. |
|
| |
I learned from experience that the way to win is through a combination of aerodynamics and gimbal lubricant on the axles. |
|
| |
AA buckshot would have given you more mass. An you don't need veneer; save the turnings from drilling the holes, mix them with PVA, backfill the drillings with them, polish and varnish. |
|
| |
There is a cap on mass. But conformational changes to tap an increased starting potential energy are not something the rule book has considered. |
|
| |
there are two considerations here: The added
energy given by the higher weight and the increasing
nose length. A shorter car with a higher center of
gravity where the center of gravity can drop driving
the wheels would be another version. |
|
| |
Cool.
The imapct of the apex could shoot out a length of dowel as well. I think that a little creative bending of the rules should be encouraged. |
|
| |
I wonder if having a magnet in your car is forbidden |
|
| |
Is there some chance that the fall would end with a bounce that would flop the car off the track? |
|
| |
/end with a bounce/
Yes. Also I can envision a very tall / long car having the midsection bottom out on impact, losing momentum to friction. So despite my initial inclination this car should probably not be a meter tall. Tall enough to tip forward but no taller. Re shock absorbers: I envision the single apex wheel cradled in thick lathed curls of pinewood which absorb the impact in the manner of a bow and arrow. In fact the body of the car could be also made of a single curl of lathed pine, twisting up and around the otherwise unaesthetic stickish body. |
|
| |
I like the dowel shooting aspect as well: this could be strictly mechanical using only parts from the Pinewood kit (ie all wood) and if done well might put to use some of the shock of impact. |
|
| |
Sorry, but the physics here is a little dodgy, you see the tower falling forward, wouldn't really, it would rotate the car around it's center of mass, so as the tower fell forward the wheels would roll backward. You would be starting with a higher potential energy, but you will only gain from that if the impact is lossless. The basic design also suffers bad aerodynamics, so I'm on the fence with this one. |
|
| |