Mousetrap Vehicle C

[austinfhs]

Hmmm it seems like accuracy is a little less crucial (well it seems easier now, since we have a lot of compensation with the cup) and time is more important Better cut down a bunch of time then. I think the kit that ordered (I'm stealing parts from it) has hollow rods, so that's good.

[illusionist]

There are kits? I'll look into the designs of some of those kits. But yeah, speed is quite important... I believe every second is 10 points?

[austinfhs]

We've always purchased kits/parts from here: http://www.docfizzix.com/

Every second is 1 pt at regionals; 2 at states; 4 at nationals.
I'm just saying that time is more important because it seems like everyone is getting near perfect accuracy.

[illusionist]

My vehicle is barely moving today... I have no idea what happened, and all the wheels look pretty smooth and free. Could it be that I need to replace my mousetraps? If so, how often would you guys suggest replacing them? And should I replace them with new ones the day before competition?

[robotman]

I have been using the same mousetraps for about 4 years (started with them as a trial in middle school) aand am planning on changing them in a week or so. so I don't have much on how often you should change.
However I wouldn't suggest changing your mousetraps the day before a comp as it could screw up your data by having that extra power

[Danny Smith]

It seems in general, that there can only be a set amount of energy that can be used over the course of the run. So while thicker axles may give you more torque, you need a longer arm which gives you less torque. if you make the arm short and the axles thick, you will need a giant wheel to travel the distance in very few turns. So a long arm and small wheels vs. a short arm and big wheels, the only thing that makes those different would be weight, because that determines how fast you can go. right? i had been using a design with a short arm and wheels the size of records. but im now thinking of changing my design to the more conventional long arm, little wheels. have people found that one is superior to another, or is it pretty much a matter of preferance?

[riley404]

I didn't watch for very long, but the fastest car I saw at nationals last year had wheels smaller than CDs. I think it might have won 6th place http://scioly.org/wiki/The_Best_of_2010#6th_Place_2. The car that won last year had tiny wheels (image below). Since the distance is smaller this year, I think smaller wheels might give better times,

Does anyone know if the axle with one wheel on the Solon car that won last year had any function?
It doesn't look like it is attached to a mousetrap, so is it the braking mechanism? I tried to design something similar last year that had everything (brakes and mousetrap) on one axle, and one mousetrap pulling each way, but it didn't work very well.

My car had back wheels made of gallon ice cream lids last year http://gallery.scioly.org/data/media/40 ... G_4325.jpg and it got around 16 seconds. I think small wheels + long arm is usually faster but I have no real evidence other than the fact that smaller wheels take a lot less torque to get moving.

[Danny Smith]

Smaller wheels do infact take less torque to get moving. however, if you want smaller wheels, you need a longer arm. and the torque you gain from using smaller wheels is lost in the long arm. last year i had a vehicle with one big wheel that was the drive wheel and brake. it got around nine seconds, but wasn't very accurate.

[austinfhs]

The distance is much shorter this year actually, so the turn (from going forward to backward) actually takes up almost 1/3 of my time. I think that smaller wheels, and then less torque need, would make this turn much faster, right?

[illusionist]

Small wheels should make the turn time shorter due to the fact that they need less torque.

Could someone please explain the compound lever system used above? I don't seem to understand how it works.