Mousetrap Vehicle C

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Re: Mousetrap Vehicle C

Post by winneratlife » January 17th, 2011, 6:43 am

Vizard007 wrote:Hey guys, so, I'm running the mousetrap vehicle I made at school, and on it's way forward pushing the cup it's fine, but on it's way backwards it randomly curves. Also, is anyone we're using the wingnut design and for some reason the break isn't stopping the vehicle on time. The vehicle always passes the -4 meter line by quite a bit. Is anyone else experiencing issues like this? And does anyone have any ideas? Thanks for the help guys!
Data > theory, always.

Quite simply, move your wingnut closer to the end, so the car would travel less distance. Basically, compensate for the overshooting by giving the wingnut less room.

And how bad is the curve?

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Re: Mousetrap Vehicle C

Post by packer-backer91 » January 17th, 2011, 12:06 pm

Vizard007 wrote:Hey guys, so, I'm running the mousetrap vehicle I made at school, and on it's way forward pushing the cup it's fine, but on it's way backwards it randomly curves. Also, is anyone we're using the wingnut design and for some reason the break isn't stopping the vehicle on time. The vehicle always passes the -4 meter line by quite a bit. Is anyone else experiencing issues like this? And does anyone have any ideas? Thanks for the help guys!

Well from the way that the wing nut brake would work for this year’s rules the brake would be lose at the start of the run. Now there are in my eyes two things that could be happening to cause the overshoot (A) the wheel slips a little at takeoff causing the revs to be off. Or placing the vehicle on the floor you accidently roll the vehicle backward some amount, thus if you move the wheel any amount it's completely logical for you to overshoot or undershoot the -4m line. Is it always the same amount?

To help explain the possible reason for a curve on the way back it depends on how you wrap the string on the axel, depending on where the wraps are you will have a different angle at which the arm and string is being pulled from the axel thus resulting in some curve. To overcome this last year I had a small piece of plastic in the center of the frame that served to help keep the angle at which the sting is pulled much more constant without it [helped tracking a lot] the downside to this is your vehicle can be slowed down some too because of added friction.


Out of curiosity of the people that use a wing nut design, did everyone just use the traditional wing-nut brake or did people 'add' something to the brake to make it more effective. [I’m sorry if that seems way to general, but if most teams didn't make what I knew to be very important adjustment to the brake I’m not going to give it away. I own that to my High School to keep secret]
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Re: Mousetrap Vehicle C

Post by Vizard007 » January 17th, 2011, 7:27 pm

Uhm, for one thing, the distance is consistent MOST OF THE TIME, but not all of the time. Thanks for the advice, I'll try what you guys said. What do you mean by move the wingnut out though? And, yes, the wingnut design on the mousetrap I built is the traditional one.

Edit:

Oh wow, haha, sorry, I didn't think about what you meant by moving the wingnut. Yea I'll just do that until I get the correct distance I guess xD. Also, will the angle the string it's pulled really make that much of a difference?
It's so easy, even a Badger could do it.

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Re: Mousetrap Vehicle C

Post by zcshiner » January 18th, 2011, 2:35 pm

Vizard007 wrote:Hey guys, so, I'm running the mousetrap vehicle I made at school, and on it's way forward pushing the cup it's fine, but on it's way backwards it randomly curves. Also, is anyone we're using the wingnut design and for some reason the break isn't stopping the vehicle on time. The vehicle always passes the -4 meter line by quite a bit. Is anyone else experiencing issues like this? And does anyone have any ideas? Thanks for the help guys!
Another thing to consider is the play in the wingnut. In my case, the wingnut rides on one surface moving outward, and another moving inward (as it rotates to hit the two wing parts). The wingnut can rotate almost 3/4 of a turn when moving between these two surfaces. Depending on the size of your wheels, this could add some significant over or undershoot to your vehicle.

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Re: Mousetrap Vehicle C

Post by robotman » January 19th, 2011, 3:24 pm

In my case, the wingnut rides on one surface moving outward, and another moving inward (as it rotates to hit the two wing parts). The wingnut can rotate almost 3/4 of a turn when moving between these two surfaces.
One way I found to fix the movement was to add a U shaped piece of metal in for the wingnut to move along in

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Re: Mousetrap Vehicle C

Post by lllazar » January 20th, 2011, 11:17 pm

Hello MTV people, so today in physics we got a project - build a vehicle powered by elastic potential energy of any sort. Being the loyal science olympian that i am, i thought "hmm...Mousetrap Vehicle, i got this in the bag :)"

Anyway, unlike scioly MTV, this vehicle has to move a distance of either 9 feet or 15 feet and stop as close to as possible at those distances. So it only has to go forward, doesn't need to come backwards.

The idea i have right now: Use a mousetrap to pull on a string tied around the axle to rotate the axle. For the wheels, i'm looking for vinyl records (i'll explain why not just CD's later).

My question is, what could i do for the break system (wingnut on axle?) and will said wingnut cause the vehicle to stop without continuing to skid (maybe put rubber band on the wheels for more friction?).

And the reason i want to use vinyl records is because there is a competition for max distance, and obviously larger wheels = more distance.

Thanks a lot, i'm really looking forward to this!
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Re: Mousetrap Vehicle C

Post by lllazar » January 22nd, 2011, 1:01 pm

Alright my design actually seems to be doing well, so scratch all the questions above except for:

1. What should i use to hold the axles in place and in line, parallel to the ground?
2. What can i do to add more traction for vinyl records - much larger than cds, so i can't use balloons or rubber bands.
3. The wingnut needs to be still to move down the axle, how should i do this?

Thanks again and hopefully i get some answers for these narrowed down questions :)
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Re: Mousetrap Vehicle C

Post by robotman » January 22nd, 2011, 4:29 pm

lllazar wrote:Alright my design actually seems to be doing well, so scratch all the questions above except for:

1. What should i use to hold the axles in place and in line, parallel to the ground?
2. What can i do to add more traction for vinyl records - much larger than cds, so i can't use balloons or rubber bands.
3. The wingnut needs to be still to move down the axle, how should i do this?

Thanks again and hopefully i get some answers for these narrowed down questions :)
Well first off what are you asking for number 1?
like how to have the axles?
i would suggest metal with bearings or wood with bearings

2. There are large rubber bands that would work

3.As long as the wingnut it touching something it will move while the axle turns

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Re: Mousetrap Vehicle C

Post by lllazar » January 22nd, 2011, 6:12 pm

Thanks. I have one last question that i realized would make or break my design. How can i reduce mass on the vinyl discs or increase the power of my mousetrap(s) so that i can actually rotate the axle?
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Re: Mousetrap Vehicle C

Post by robotman » January 22nd, 2011, 6:52 pm

you can increase the power by adding a bar to your moustraps take a look at the [url=http://gallery.scioly.org/categories.php?cat_id=40]MTV gallery[/url[ for more ideas
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