anyone else done mousetrap cars for physics?
heres my design so far(minus all teh materials) in inventor
the square up front is the mousetrap which will have a lever arm attached to pull on the "cvt" on the intermediate axle this will give me variable speeds not just one. and then another pulley that goes back to the main axle. the wheels will be made out of desktop and laptop harddrive disks cnc'd out. i have the intermediate axle because my teacher has restrictive size requirements. the frame will be made out of foam board then covered in fiberglass and if i feel like it carbon fiber for looks. the 1/8th" shafts will be riding on tiny little open bearings for minimum rolling resistance. the grading as i remember it is the total distance travalled/time for the first 5m.
Nice.
We also have to make a mousetrap car for the physics olympics. My friend and I are doing a collaboration and we’re making that, a joule car, the toothpick bridge, and a rube goldberg. I might also do the paper tower and the slow bicycle race.
We’re also using pulleys to get the maximum distance out of it, since the competition is for distance.
Do you have to go for maximum speed, and what materials have you considered for the axles?
the ranking criteria is the highest # of total distance divided by time it took to complete the first 5 meters. as far as axles go i don’t really know steel is to heavy even that miniscule amount. but other things might bend. i’ll probably end up with some sort of plastic.that way the only metal things are bearings and the wheels.
my theory for the grade is be in a quick acceleration gear for the first 5 meters then “shift” to a hard long pull for the rest of the trial. that way i’ll end up with a fast car that goes aways.
pretty sweet…just make sure when you do the “gearing” of your car that its not so much as to not allow the car to move…it requires some trial and error
Does anyone else find it amusing how we spend six weeks designing a 130+ pound robot, and then in school we’re assigned to create a little mousetrap car? :rolleyes:
Nice, for our mousetrap and joule car, we’re actually using carbon fiber axles. Balsa wood body because it’s easy to work with and cheap. Our grading is easier. It just has to travel 5 m, and then the competition is for distance after that.
We were considering using a CVT, but a regular pulley would allow it to travel farther and it’s easier to lathe. We don’t need to pay too close of attention to it when winding it. Are you going to use string, or some kind of belt?
it’ll be string and i may use carbon fiber for the axles that sounds like a good idea. pulleys would cause alot of unnecessary drag. it’ll be fishingline
this works very well it gave me a 1/3 better distans this let me own rees
as for gearin i just put a cone on the drive shath the move the line to along to (programing) the car
yes… minus programming, minus electrical, minus crate requirement (unless you guys got the project asssigned with a size maximum), minus sponsorship (unless you really don’t have the scrap in your garage or a KNEX set or something of that sort), minus the need for an r&D group, minus basically the team… yeah… its amusing to build a little mousetrap car after being in FIRST, but its FUN!
I’m soo sick of mousetrap powered anything. Right now i’m working on a 4"x6"8" mousetrap powered car for a class that has to drive up a ramp, maneuver over a 6" gap, press a button on one of the walls of the gap, drive down another ramp and stop on a line at the bottom.
Btw. I don’t know if its legal in your competition, but if you take the mousetrap apart and just use the spring, you can extract alot more energy from it because you can rotate it further. The stock setup goes only 180 degrees. I’ve found that they will go at least a full rotation without yeilding. That gives you 4x the available potential energy.
I’ve found that when you use a mousetrap over and over, the U-bars that hold the spring in tend to pull out… ruining the mousetrap. If you could get a (legal) setup like that, you’d blow away the competition!
So, no one has mentioned one of the best mouse trap techniques ever…
Think about the force vector…and the direction the spring bar is traveling… and the direction the string is traveling.
For ease of design, you might want to keep the string perpindicular to the travel of the spring bar, so the force is transmitted to the string. Here’s a little picture.
By the way - the CVT is an awesome idea. I did that for a mouse trap car in high school and it worked great! (We had to carry a can of pop on board.)
i finished my car which ended up very similar to this and won the competition by going across our entire gym long ways and crossing the 5 meter mark in 2 seconds
We had to make a mouse trap ball launching mechanism that could shoot a ball of our choice onto a drum and bounce into a box. We could take the spring off the mousetrap, I was the only one to do that and ours could shoot the ball quite well.
I had to make one in gr9. I used cd’s as wheels, lathed hubs for them, framing was aluminum angle with thin aluminum sheeting. it went 70 feet on the school floor
