Mousetrap Vehicle C

[Danny Smith]

This link gives an example of a compound lever system in action:
http://www.youtube.com/watch?v=RG7rm5iZYEs

For people who are using threaded rods for breaks, what do you use to hold the axles? I havent found anything that the threads wont chew up (soft balsa certainly doesnt work) and any metal tubes i use catch the threads. what have others been using?

[illusionist]

Thanks for the link.

And as explained previously in the forum, using Lego pieces with holes in them works nicely, and I have also found success using metal tubes with the edges sanded down. Also, try putting a nut at the each end of the threaded axle to prevent it from moving left to right. But, just take a look a couple pages before in this forum

[winneratlife]

This link gives an example of a compound lever system in action:
http://www.youtube.com/watch?v=RG7rm5iZYEs

Wait...what exactly is the merit of such a system?

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

Nope:

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.

^What I've been doing a very poor job of explaining the entire time, simply because for the life of me I couldn't pull the word "torque" out of my brain^

[bwy]

From what I've seen by tweaking my own vehicle, you have to compromise between a thick axle and a shorter rod since the thicker axle needs more string. For my car, I went with a long rod and a thick axle because the shorter rod didn't seem to help as much as a thicker axle did.
For those cars with smaller wheels, I'm guessing they also had to have thinner axles. The advantage they had was that their cars weighed a lot less and, as mentioned above, took less torque to get going. Unfortunately, poor schools like mine have no money to get the custom wheels from kits and usually have to settle for CDs.
It looks like that mousetrap car took a lot of tweaking. It's a good idea to try out different combinations of thick axles and long rods or thin axles and short rods to see which works best.
I don't think replacing mousetraps too often is necessary. It probably makes about a.1 s difference for 100 runs

[illusionist]

Is it worth trying to add a gear system to speed up the vehicle? For example by winding the string on an axle that is connected to the driving axle by gears?

[bwy]

Is it worth trying to add a gear system to speed up the vehicle? For example by winding the string on an axle that is connected to the driving axle by gears?

That was actually the first thing I did when I started this event last year. I thought I'd have a huge advantage, but it turned out that it slowed my vehicle down. I guess it was something to do with the friction.

About sighting systems again (sorry): for the people using removable ones, how do you make sure that when you put it back, you put it back in the exact same spot? I was thinking about just making some marks with a pen or something, but I'm not sure how accurate that would be...

[winneratlife]

Is it worth trying to add a gear system to speed up the vehicle? For example by winding the string on an axle that is connected to the driving axle by gears?

That was actually the first thing I did when I started this event last year. I thought I'd have a huge advantage, but it turned out that it slowed my vehicle down. I guess it was something to do with the friction.

About sighting systems again (sorry): for the people using removable ones, how do you make sure that when you put it back, you put it back in the exact same spot? I was thinking about just making some marks with a pen or something, but I'm not sure how accurate that would be...

Also, everytime you transfer energy, you lose some.

There's probably some sort of clip in you could use, like 2 things that lock together only one way? Don't know, I don't use sighting.

[Paradox21]

About sighting systems again (sorry): for the people using removable ones, how do you make sure that when you put it back, you put it back in the exact same spot? I was thinking about just making some marks with a pen or something, but I'm not sure how accurate that would be...

Yeah, I use an interlocking system so that there is only 1 place the scope fits into the vehicle.

[austinfhs]

How would you set up a scoping system? Like where would you point scope and what would you set up on the other end? So far, I've been winging it, meaning I'm just guessing where to start from and I'm getting pretty close, but I'm hoping to get gold in this event (at least at regionals!) so it should probably be as accurate as possible, haha

[packer-backer91]

Is it worth trying to add a gear system to speed up the vehicle? For example by winding the string on an axle that is connected to the driving axle by gears?

That was actually the first thing I did when I started this event last year. I thought I'd have a huge advantage, but it turned out that it slowed my vehicle down. I guess it was something to do with the friction.

Last year I used multiple gears to get the 'most' out of the mousetraps as possible, yes jumping the gears you do lose some energy, I went through hundreds, literally hundreds of different combinations, to find one that was optimum. Yes there is some energy loss but that being said one of the tests that were done to even test the merit of the gearing we had was to put all the wraps on one gear in which the vehicle was extremely slow. I don’t know for sure how anyone else had their wraps set up if they used a gearing system but what I came up with was very complicated. Think this over logically where you would require more power and other places that you can skimp on power and I still believe a gearing system is still a valid tool to incorporate if you have a lot of time and patience to find the exact optimal set up.