Mousetrap Vehicle C

[ChrisYim]

which method for mousetrap vehicle do you think works best? method 1 or method 3?

[franklinknights]

which method for mousetrap vehicle do you think works best? method 1 or method 2?

i use method one yim. bring it on

[winneratlife]

which method for mousetrap vehicle do you think works best? method 1 or method 2?

i use method one yim. bring it on

Assuming that no one has edited the wiki since I redid it, method 3.

[bwy]

Take a look at this.

I'm not too sure one the idea of having using string as a brake especially for this event. String never will spool exactly as you want it to, even if you have threads to guide the string as it transitions from on axel to the next there in a large uncertainty if that will happen exactly the same each run thus distances may be different from run to run. This does make for a simple to make and ok brake, but from my opinion using the wing nut idea which produces better/more consistent results. That’s not to say that the string idea is terrible, if you can make it perform well than go with it. The wing nut design has one flaw that being you have to start with the brake to be locked or almost locked to make the brake work right.

I agree; I have always used something like a wingnut for events like this. But I thought I would link to a page with several options.

I used a different design than those listed that was a lot simpler: I attached some light, plastic gears to my axles and the mousetrap bar so that when the bar came down, the gears caught and stopped the car. With this design, there's no coasting but it's easy and accurate.

On a different note: this year in 5b. and 3g. the rules make it obvious that you should put your fixed point of reference at the back of the car, so that the car has to travel the least distance because the fixed point no longer starts at the line: because of the rule change, the point starts as far back as the car is long, right? I'm wondering if anyone's also considered making a very light extension kind of bar to the car so that it actually does take up the maximum 1 m length, placing the point at the end of it, and thus reducing the distance it has to travel as much as possible.

[packer-backer91]

On a different note: this year in 5b. and 3g. the rules make it obvious that you should put your fixed point of reference at the back of the car, so that the car has to travel the least distance because the fixed point no longer starts at the line: because of the rule change, the point starts as far back as the car is long, right? I'm wondering if anyone's also considered making a very light extension kind of bar to the car so that it actually does take up the maximum 1 m length, placing the point at the end of it, and thus reducing the distance it has to travel as much as possible.

That sounds interesting to use all of the 1m box, strictly going by the wording of the rules [as your post says] it makes sense that having a small frame and a long pointer that sticks out the back sounds all good. The problem is that it comes down to one of the SO general rules where you should not attempt to use the rules to give you an unfair advantage over any other team which in my opinion your design defeats the spirit of the event so I don't think it should be allowed. No rules are completely sound so there will always be some room to use the rules to get an unfair advantage. I will use last years rules as an example if you went only by the wording then you could have added ANYTHING to your mousetraps because there are two lines in the rules that go against each other [I'm talking about the line that read mousetrap should be "unmodified" but explained that unmodified means that all things have to stay in place and function as intended but things may be added which is in direct opposition of the meaning unmodified]. So the rules allow you to add an extra spring to the mousetrap [which is illegal] because this allows the trap to function as intended and yet that is not allowed because in doing so you are getting an unfair advantage over any team that did not interpret the rules as such. Ask for a clarification first would be a good choice when ever you want to stretch the rules as much as you can.

[Paradox21]

I'm sorry, but I do not think it is cheating at all. It is definitely illegal to add things to your mousetraps to make them stiffer, or try to wind them around an extra time (which is really difficult), as was explained in a rule clarification last year. Part of engineering is about building to the limits of your parameters. Adding in a long arm bar will add in some extra challenges to get it to work properly, these additional challenges in turn pay off with less total distance that must be travelled. It is not an unfair advantage; it is more like an advanced technique. bwy was not the only one to think of the idea, the Mousetrap people here at my school thought of it too and I'm sure many others have thought of it. There really is nothing unfair about it, just a good idea.

[bwy]

I was thinking about it and taking up a whole meter seems a bit of a stretch-- the problem is that the length with amplify any slight swing in the vehicle's direction, which would add some points to the distance score, though that could be fixed. I'm definitely not above adding a little bit of extra length, as parallax says. After all, packer-backer, it could be interpreted as "unfair" that people with longer cars or that put their reference points at the back of the car have to travel less distance.

I'm also wondering about 5a. because I haven't found anything that clarifies this: does the whole cup have to cross the line, or only the rim of the cup closest to the tape? It's kind of trivial, but the cup is about 10 cm long.
This year, it seems, they've emphasized that the lane bonus counts even if you cross the 4m line behind the start line. Last year the proctor at state and regionals didn't award the bonus in those cases, which really messed up some teams.

[packer-backer91]

I'm sorry, but I do not think it is cheating at all. It is definitely illegal to add things to your mousetraps to make them stiffer, or try to wind them around an extra time (which is really difficult), as was explained in a rule clarification last year. Part of engineering is about building to the limits of your parameters. Adding in a long arm bar will add in some extra challenges to get it to work properly, these additional challenges in turn pay off with less total distance that must be travelled. It is not an unfair advantage; it is more like an advanced technique. bwy was not the only one to think of the idea, the Mousetrap people here at my school thought of it too and I'm sure many others have thought of it. There really is nothing unfair about it, just a good idea.

I just wanted to use the modification of the spring as an example where the rules dont say you cant do something doesn't means it was alright to do it [reason for the clarifiction to close the loop hole]. I see your point about using the 1m box to its fullest, actually if I was in the event I would probably use it myself. What I meant as unfair was that not all vehicles full length of the track but you are defiantly correct about not being unfair because not every vehicle will not have to go the same distance [depending on the length]. That was at first I thought it’s unfair that was because potentially some vehicles will have to go only 6m back [if pointer is at +2m when reverse then to the -4m line to finish] and the really small vehicles have to go back a greater distance [was why I thought was unfair]. I understand your point now that you are just using all of what you are allowed, especially if its unspecified that the pointer must be at the starting line. With that being said it really good idea to add a bar to make use of almost the entirety of the 1m box.

Times this year should be much quicker than last year even the vehicle I had could get around 10 seconds because I would not need to rely on traveling back as much with now power. I don’t know how much the cup will slide either so potentially if one would to accurate to a high speed stop and reverse the cup will want to keep moving forward some. If I understand the rules there are two measurements so how much the cup will slide is a valid variable that should be tested some or even that this side is also dependent of the floor.

[Flavorflav]

I just wanted to use the modification of the spring as an example where the rules dont say you cant do something doesn't means it was alright to do it [reason for the clarifiction to close the loop hole]

But the rules did say so. Your spring would be adding kinetic energy, which was banned by 3.c.

[winneratlife]

I'm sorry, but I do not think it is cheating at all. It is definitely illegal to add things to your mousetraps to make them stiffer, or try to wind them around an extra time (which is really difficult), as was explained in a rule clarification last year. Part of engineering is about building to the limits of your parameters. Adding in a long arm bar will add in some extra challenges to get it to work properly, these additional challenges in turn pay off with less total distance that must be travelled. It is not an unfair advantage; it is more like an advanced technique. bwy was not the only one to think of the idea, the Mousetrap people here at my school thought of it too and I'm sure many others have thought of it. There really is nothing unfair about it, just a good idea.

Agreed. When I first read the rules, adding a bar to the end to hold your point was the first thing I thought of. At most it would shave like...a second off your time though, so it's not exactly a massive advantage.

But yes, it changes the balance and amplifies paths that are off.