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Re: Mousetrap Vehicle C

Posted: January 19th, 2019, 9:40 am
by DarthBuilder
During competition are we allowed to put down a protractor on the starting point then before we start our vehicle can we remove it? The last two competitions were pretty confused too but they did let us as long as we removed it before our first and second runs.

Re: Mousetrap Vehicle C

Posted: January 19th, 2019, 10:23 am
by sciencecat42
bernard wrote:Handheld rotary tools and lathe by themselves are not safe methods for cutting carbon fiber; both would disperse fine abrasive glass-like fibers that can easily accumulate in your lungs and irritate your respiratory tract. These fibers are also electrically conductive and can damage electronics.

If you decide you must use carbon fiber in your device, consider designing your vehicle around the dimensions of stock carbon fiber so you can avoid cutting. If you want threads, consider attaching a component that has threads rather than modifying the carbon fiber. And if you decide you must cut carbon fiber, process it wet, e.g. in a liquid bath, and dispose of your waste properly. Please read about carbon fiber safety before using it.

https://www.rhinocarbonfiber.com/carbon-safety/

http://www.fullforcerc.com/carbon-care/

https://www.tapplastics.com/uploads/pdf ... 0Sheet.pdf


So it sounds like people aren't actually using CF for their axles? Or maybe they use an unthreaded rod for the back and a non-CF threaded rod in front.

Re: Mousetrap Vehicle C

Posted: January 23rd, 2019, 5:46 pm
by sciencecat42
Anyone finding an issue with their wing nut not winding that far on the brake axle? Is this even an issue?

Re: Mousetrap Vehicle C

Posted: January 23rd, 2019, 6:22 pm
by dragonfruit35
sciencecat42 wrote:Anyone finding an issue with their wing nut not winding that far on the brake axle? Is this even an issue?


What do you mean by that? Is it just not traveling very far? If so, you might want to find one with a lower thread count per inch so that the wingnut travels further over the same vehicle travel distance.

Re: Mousetrap Vehicle C

Posted: January 23rd, 2019, 8:38 pm
by sciencecat42
dragonfruit35 wrote:
sciencecat42 wrote:Anyone finding an issue with their wing nut not winding that far on the brake axle? Is this even an issue?


What do you mean by that? Is it just not traveling very far? If so, you might want to find one with a lower thread count per inch so that the wingnut travels further over the same vehicle travel distance.


Yeah it only travels about a fifth of the length of the rod. I'm not sure if this is even an issue though. Wouldn't it be more precise?

Re: Mousetrap Vehicle C

Posted: January 23rd, 2019, 10:38 pm
by dragonfruit35
sciencecat42 wrote:
dragonfruit35 wrote:
sciencecat42 wrote:Anyone finding an issue with their wing nut not winding that far on the brake axle? Is this even an issue?


What do you mean by that? Is it just not traveling very far? If so, you might want to find one with a lower thread count per inch so that the wingnut travels further over the same vehicle travel distance.


Yeah it only travels about a fifth of the length of the rod. I'm not sure if this is even an issue though. Wouldn't it be more precise?


It’s not necessarily an issue. It depends on whether you’re determining your brake setting just by looking at it, in which case it would be advantageous to use a lower thread count because the marks will be more spaced out. Otherwise, there shouldn’t be any effect on the braking precision.

Re: Mousetrap Vehicle C

Posted: January 27th, 2019, 11:27 am
by TheGhghp
What size braided fishing line have you guys been using? I'm thinking of buying a 0.1mm diameter line with strength up to 8lb, but I'm not sure if I should go for something thicker.

Re: Mousetrap Vehicle C

Posted: January 27th, 2019, 12:27 pm
by 4Head
TheGhghp wrote:What size braided fishing line have you guys been using? I'm thinking of buying a 0.1mm diameter line with strength up to 8lb, but I'm not sure if I should go for something thicker.

that'll be strong enough, just very hard to work with

Re: Mousetrap Vehicle C

Posted: January 27th, 2019, 1:08 pm
by Things2do
4Head wrote:
TheGhghp wrote:What size braided fishing line have you guys been using? I'm thinking of buying a 0.1mm diameter line with strength up to 8lb, but I'm not sure if I should go for something thicker.

that'll be strong enough, just very hard to work with

I'm using Kevlar fishing line. It's 50 lb test, I think... It's a little hard to tie a small loop in it without leaving a long running end, but it lasts quite a while.

Re: Mousetrap Vehicle C

Posted: January 27th, 2019, 3:32 pm
by 4build
What material are people using for the drive arms of their vehicle? We're currently using balsa wood but it's flexing a lot.

Re: Mousetrap Vehicle C

Posted: January 27th, 2019, 4:40 pm
by PM2017
4build wrote:What material are people using for the drive arms of their vehicle? We're currently using balsa wood but it's flexing a lot.

I'm using a 6 mm cf square tube. I can honestly probably get away with an even smaller cf rod tbh, because the 6mm is a bit heavier than I like.

1/4 inch basswood would probably also do just fine, come to think of it.

Re: Mousetrap Vehicle C

Posted: January 27th, 2019, 5:01 pm
by 4Head
4build wrote:What material are people using for the drive arms of their vehicle? We're currently using balsa wood but it's flexing a lot.

Try to be me some more...

Re: Mousetrap Vehicle C

Posted: January 27th, 2019, 6:36 pm
by PM2017
4Head wrote:
4build wrote:What material are people using for the drive arms of their vehicle? We're currently using balsa wood but it's flexing a lot.

Try to be me some more...

wooah I didn't even realize that it wasn't you. I was just curious where the KY went... :/

Re: Mousetrap Vehicle C

Posted: January 27th, 2019, 8:03 pm
by Things2do
4build wrote:What material are people using for the drive arms of their vehicle? We're currently using balsa wood but it's flexing a lot.

I'm using a tiny diameter brass tube, and it's got a permanent flex... I don't really mind since I can just turn it over and get some negligible extra pulling distance.

Re: Mousetrap Vehicle C

Posted: January 27th, 2019, 8:38 pm
by 4Head
PM2017 wrote:
4Head wrote:
4build wrote:What material are people using for the drive arms of their vehicle? We're currently using balsa wood but it's flexing a lot.

Try to be me some more...

wooah I didn't even realize that it wasn't you. I was just curious where the KY went... :/

You think little enough of me to not assume I’d make my entire vehicle out of carbon fiber?