Mousetrap Vehicle C

[JasperKota]

Testing the strength of a mousetrap - tie a string to the metal catcher, securely hold down the mousetrap, and pull the string sideways with a weighing scale (one of those hanging types) until the catcher points straight up (for consistency, and also to get the perpendicular force, since that may be useful).

Thanks for the informative reply Unome!

[Chameleon02]

Without doubt, the number one thing I have been struggling with is straightness. I have tried multiple times to fix the problem, even completely scrapped my car and rebuilt it.It always curves off to one side by atleast 20cm each run. If you guys could answer some of my questions, I would be greatly helped
Does having 3 wheels have an effect on straightness?
Does a crooked lever arm have anything to do with it?
My vehicle sometimes slightly jumps when I set off the mousetraps and I think this might make it go off to a side. (My car is very light, under 150g)
My vehicle has also been recoiling and coming forward about 20cm after it finishes reversing. This is because the string wraps again from the other side. How can I combat this problem? My partner suggested just taking this recoil into stride and manipulating car so it stops at the line after recoiling, but I am reluctant with the idea. As my vehicle axle is made of lego pieces, I am unable to have a proper braking system. Are there any temporary solutions?
I think after my invitational in December I will redesign my mousetrap with threaded rods.
Thanks, although I have been doing Scioly for years, I am relatively inexperienced with wheeled events.

[rafaelnadal]

Is the Ward Kit any good?

Thinking of buying one.

[antoine_ego]

Is the Ward Kit any good?

Thinking of buying one.

I'd advise against it. Ward Science kits are almost always uncompetitive and you'd be far better off building one yourself.

[windu34]

Without doubt, the number one thing I have been struggling with is straightness. I have tried multiple times to fix the problem, even completely scrapped my car and rebuilt it.It always curves off to one side by atleast 20cm each run. If you guys could answer some of my questions, I would be greatly helped
Does having 3 wheels have an effect on straightness?
Does a crooked lever arm have anything to do with it?
My vehicle sometimes slightly jumps when I set off the mousetraps and I think this might make it go off to a side. (My car is very light, under 150g)
My vehicle has also been recoiling and coming forward about 20cm after it finishes reversing. This is because the string wraps again from the other side. How can I combat this problem? My partner suggested just taking this recoil into stride and manipulating car so it stops at the line after recoiling, but I am reluctant with the idea. As my vehicle axle is made of lego pieces, I am unable to have a proper braking system. Are there any temporary solutions?
I think after my invitational in December I will redesign my mousetrap with threaded rods.
Thanks, although I have been doing Scioly for years, I am relatively inexperienced with wheeled events.

3 wheels is easier to achieve going straight. I think there are alot of variable involved with this that I have not experienced because I never pursued a 3 wheel design for any of my national vehicles so I only briefly explored it with one of my vehicles before MIT last year. From what I remember, it was very easy to calibrate to go straight and adjusting it was simplified compared to 4 wheels. I dont know the effect on stability though.
Make sure there is no slack in the line when you are starting - that is likely the jumping issue
Add wingnut break for the recoil
I cant think of any temp solutions

[rafaelnadal]

So can someone guide me a little?

I'm planning on ordering all the parts for my mousetrap and I was wondering if these were good parts for an MV:

Wheels:

BaneBot 2 7/8" 50A

http://www.banebots.com/product/T40P-295BA-HS4.html

(Are the hubs on their website any good? Is there any particular one I should order?)

Frame:

Carbon Fiber Square Tube:

http://www.cstsales.com/carbon_sh.html

(39 inches long lol? Any particular sizes that work? I don't quite understand the dimensions they list, but I'm probably dumb...)

Mousetrap:

Tomcat Mousetraps

https://www.amazon.com/dp/B00N6XKVNY/re ... 4497935460

Axles:

Can't find any good axles, can anyone recommend some???

Wingnuts I have already, anything else I should get for a mousetrap?

If anyone knows where I can find better materials, that'd be helpful too

[JasperKota]

I think you'll just have to cut the carbon fiber tube to a more appropriate size. I don't see any shorter lengths listed on that site. I've heard Victor mousetraps are also good, perhaps buy some of those just to experiment.

As for axles: I'm currently using a hollow aluminum tube, but I read somewhere that it bends too much (haven't actually tested it yet), so maybe something like brass would work better although heavier. For the braking system, I'm using a steel 1/4 threaded rod and wingnut.

Most of my materials (including tomcat mousetraps) I found at my local Lowes.

[PM2017]

I got my cf from hobby king.

[windu34]

So can someone guide me a little?

I'm planning on ordering all the parts for my mousetrap and I was wondering if these were good parts for an MV:

Wheels:

BaneBot 2 7/8" 50A

http://www.banebots.com/product/T40P-295BA-HS4.html

(Are the hubs on their website any good? Is there any particular one I should order?)

Frame:

Carbon Fiber Square Tube:

http://www.cstsales.com/carbon_sh.html

(39 inches long lol? Any particular sizes that work? I don't quite understand the dimensions they list, but I'm probably dumb...)

Mousetrap:

Tomcat Mousetraps

https://www.amazon.com/dp/B00N6XKVNY/re ... 4497935460

Axles:

Can't find any good axles, can anyone recommend some???

Wingnuts I have already, anything else I should get for a mousetrap?

If anyone knows where I can find better materials, that'd be helpful too

Get the 0.236" carbon. Look online for either stainless steel, aluminum, or titanium (if youre ambitious) threaded rods.

[rafaelnadal]

Thank you !!

Thanks @Jasper too!