Mousetrap Vehicle C

User avatar
Things2do
Member
Member
Posts: 111
Joined: February 12th, 2018, 2:30 pm
Division: C
State: TN
Location: Unfortunately, not Utah somewhere near the Colorado border

Re: Mousetrap Vehicle C

Postby Things2do » January 14th, 2019, 8:32 am

sciencecat42 wrote:
dragonfruit35 wrote:
sciencecat42 wrote:What has everyone been using to attach the arm to the mousetraps? I've been using wire and tape but these are either super tedious to attach or not very modular.


I’ve used mini zip ties both last year and this year and they seem to work fine if you put a few of them.


Can't believe that I didn't think of that earlier. :lol: What's the best way to attach the mousetraps to the chassis? I tried screws but I ended up splitting the mousetrap wood so I've been using superglue but then I can't swap them out.

I've got two plastic nuts and bolts for each trap, and I have drilled holes for them in my traps and car. It works fine for me, and I can change both traps in 3 minutes. I use 2 tiny zip ties to attach my arm, and I have spares in case something happens or I need to change traps at a competition. I've got one trap that self-destructed on a practice run, so... It pulled one of the staples out of the base while it was set...
John 5:46-47
When your signature exceeds the allotted 300 characters, you put it here...
Is this where I put the Builder Cult?
"I think that we're all mentally ill. Those of us outside the asylums only hide it a little better - and maybe not all that much better after all." - Stephen King

User avatar
PM2017
Member
Member
Posts: 483
Joined: January 20th, 2017, 5:02 pm
Division: Grad
State: CA

Re: Mousetrap Vehicle C

Postby PM2017 » January 14th, 2019, 6:06 pm

sciencecat42 wrote:
dragonfruit35 wrote:
sciencecat42 wrote:What has everyone been using to attach the arm to the mousetraps? I've been using wire and tape but these are either super tedious to attach or not very modular.


I’ve used mini zip ties both last year and this year and they seem to work fine if you put a few of them.


Can't believe that I didn't think of that earlier. :lol: What's the best way to attach the mousetraps to the chassis? I tried screws but I ended up splitting the mousetrap wood so I've been using superglue but then I can't swap them out.

Nuts and Bolts are pretty solid choices. Nails should be good as well. (I've used both in the past)
2018 Events
Astronomy, Mousetrap Vehicle, Mission Possible, Fermi Questions

2019 Events
Astronomy, Mousetrap Vehicle, Mission Possible, Fermi Questions :cry: , Circuit Lab

--
West High '19
UC Berkeley '23

FermiGod
Member
Member
Posts: 24
Joined: May 22nd, 2018, 8:20 pm
State: -

Re: Mousetrap Vehicle C

Postby FermiGod » January 15th, 2019, 4:22 am

How can I make my car go further with smaller wheels? I want to use 3inch diamater wheels for the drive axle

User avatar
MadCow2357
Member
Member
Posts: 583
Joined: November 19th, 2017, 9:09 am
Division: C
State: RI
Location: Stark Industries Internship
Contact:

Re: Mousetrap Vehicle C

Postby MadCow2357 » January 15th, 2019, 3:33 pm

FermiGod wrote:How can I make my car go further with smaller wheels? I want to use 3inch diamater wheels for the drive axle

Umm not sure what you are looking for, but you can use a pulley system or extend your lever arm. If you are going for something else, well I can't help you, gotta wait for a person who does mousetrap to answer you lol
MadCow2357's Userpage
Projected 2020 Events: Boomilever, Gravity Vehicle
Considering: Fossils, Machines, Sounds of Music, Wright Stuff
Builder Cult - builders rise up! :)
Dank Memes Area Homeschool
234.36
#BalsaManForever

mnoga
Member
Member
Posts: 80
Joined: March 19th, 2015, 6:12 pm
Division: C
State: CA

Re: Mousetrap Vehicle C

Postby mnoga » January 15th, 2019, 4:49 pm

MadCow2357 wrote:
FermiGod wrote:How can I make my car go further with smaller wheels? I want to use 3inch diamater wheels for the drive axle

Umm not sure what you are looking for, but you can use a pulley system or extend your lever arm. If you are going for something else, well I can't help you, gotta wait for a person who does mousetrap to answer you lol


Our combination for the drive wheels is 3mm shaft (approximately 1/8 inch) and 60mm (approximately 2.35 inch) diameter wheels. We just wrap the string around the shaft.

FermiGod
Member
Member
Posts: 24
Joined: May 22nd, 2018, 8:20 pm
State: -

Re: Mousetrap Vehicle C

Postby FermiGod » January 16th, 2019, 7:05 am

alright so our car design has its main frame and like a "front" piece that is adjustable but we have to loosen the screw or nut in order to adjust the angle and when we get the angle we tighten the screw or nut back. But when we do this it always gets loose. whats a better long term solution that will work?

mnoga
Member
Member
Posts: 80
Joined: March 19th, 2015, 6:12 pm
Division: C
State: CA

Re: Mousetrap Vehicle C

Postby mnoga » January 16th, 2019, 2:23 pm

FermiGod wrote:alright so our car design has its main frame and like a "front" piece that is adjustable but we have to loosen the screw or nut in order to adjust the angle and when we get the angle we tighten the screw or nut back. But when we do this it always gets loose. whats a better long term solution that will work?


Use two holes with one being the pivot point ... there should be no play in the pivot point. The other hole would allow a small amount of play so you can adjust your car’s curvature.

sciencecat42
Member
Member
Posts: 74
Joined: March 14th, 2016, 7:07 pm
State: -

Re: Mousetrap Vehicle C

Postby sciencecat42 » January 16th, 2019, 7:51 pm

mnoga wrote:
MadCow2357 wrote:
FermiGod wrote:How can I make my car go further with smaller wheels? I want to use 3inch diamater wheels for the drive axle

Umm not sure what you are looking for, but you can use a pulley system or extend your lever arm. If you are going for something else, well I can't help you, gotta wait for a person who does mousetrap to answer you lol


Our combination for the drive wheels is 3mm shaft (approximately 1/8 inch) and 60mm (approximately 2.35 inch) diameter wheels. We just wrap the string around the shaft.


Is there any benefit to having a smaller shaft and smaller wheels? We have a slightly larger shaft and wheels because I heard that 1/8" rods could bend. However, our theoretical max distance is also less than yours but I don't want to spend more money to get a new set of everything.

User avatar
MadCow2357
Member
Member
Posts: 583
Joined: November 19th, 2017, 9:09 am
Division: C
State: RI
Location: Stark Industries Internship
Contact:

Re: Mousetrap Vehicle C

Postby MadCow2357 » January 16th, 2019, 8:35 pm

sciencecat42 wrote:Is there any benefit to having a smaller shaft and smaller wheels? We have a slightly larger shaft and wheels because I heard that 1/8" rods could bend. However, our theoretical max distance is also less than yours but I don't want to spend more money to get a new set of everything.

If I'm not mistaken, a smaller shaft means "more rotations" of the driving axle. Smaller wheels are not really beneficial, other than the fact that they have a less rotational inertia (I believe that's the term for it). I think it's widely accepted that the increase in rotational inertia is negligible when compared the distance increase a larger wheel gives you. 1/8" will bend, but depending on how heavy your vehicle is, it may be good enough. You could always try using a different material for the axle, like aluminum or CF, I suppose, and get away with an extremely thin axle.
MadCow2357's Userpage
Projected 2020 Events: Boomilever, Gravity Vehicle
Considering: Fossils, Machines, Sounds of Music, Wright Stuff
Builder Cult - builders rise up! :)
Dank Memes Area Homeschool
234.36
#BalsaManForever

sciencecat42
Member
Member
Posts: 74
Joined: March 14th, 2016, 7:07 pm
State: -

Re: Mousetrap Vehicle C

Postby sciencecat42 » January 16th, 2019, 8:53 pm

MadCow2357 wrote:
sciencecat42 wrote:Is there any benefit to having a smaller shaft and smaller wheels? We have a slightly larger shaft and wheels because I heard that 1/8" rods could bend. However, our theoretical max distance is also less than yours but I don't want to spend more money to get a new set of everything.

If I'm not mistaken, a smaller shaft means "more rotations" of the driving axle. Smaller wheels are not really beneficial, other than the fact that they have a less rotational inertia (I believe that's the term for it). I think it's widely accepted that the increase in rotational inertia is negligible when compared the distance increase a larger wheel gives you. 1/8" will bend, but depending on how heavy your vehicle is, it may be good enough. You could always try using a different material for the axle, like aluminum or CF, I suppose, and get away with an extremely thin axle.


Wouldn't aluminum bend easier than stainless steel? Plus, aluminum/CF rods are pretty hard to find. I know that larger axles provide more torque, but I'm worried that they will get too heavy or decrease the distance of my car too much.

I read earlier in this thread that last year someone's 1/8" axles bent, but perhaps those were aluminum? Since mnoga claims to be using 3mm axles which are thinner than 1/8".

Also, how do you tell if traction is an issue with your car?

DarthBuilder
Member
Member
Posts: 283
Joined: August 1st, 2017, 8:02 am
Division: Grad
State: IL

Re: Mousetrap Vehicle C

Postby DarthBuilder » January 17th, 2019, 4:18 am

sciencecat42 wrote:
MadCow2357 wrote:
sciencecat42 wrote:Is there any benefit to having a smaller shaft and smaller wheels? We have a slightly larger shaft and wheels because I heard that 1/8" rods could bend. However, our theoretical max distance is also less than yours but I don't want to spend more money to get a new set of everything.

If I'm not mistaken, a smaller shaft means "more rotations" of the driving axle. Smaller wheels are not really beneficial, other than the fact that they have a less rotational inertia (I believe that's the term for it). I think it's widely accepted that the increase in rotational inertia is negligible when compared the distance increase a larger wheel gives you. 1/8" will bend, but depending on how heavy your vehicle is, it may be good enough. You could always try using a different material for the axle, like aluminum or CF, I suppose, and get away with an extremely thin axle.


Wouldn't aluminum bend easier than stainless steel? Plus, aluminum/CF rods are pretty hard to find. I know that larger axles provide more torque, but I'm worried that they will get too heavy or decrease the distance of my car too much.

I read earlier in this thread that last year someone's 1/8" axles bent, but perhaps those were aluminum? Since mnoga claims to be using 3mm axles which are thinner than 1/8".

Also, how do you tell if traction is an issue with your car?


I’m now using 3 mm carbon fiber axles and I can almost certainly say they don’t bend unless you try to. Once attached there shouldn’t really be any problems with it.
You can tell if traction is an issue when the car skids usually (someone else might have a better answer to this).
Last edited by DarthBuilder on January 17th, 2019, 11:29 am, edited 1 time in total.
Deleted

User avatar
PM2017
Member
Member
Posts: 483
Joined: January 20th, 2017, 5:02 pm
Division: Grad
State: CA

Re: Mousetrap Vehicle C

Postby PM2017 » January 17th, 2019, 11:23 am

As for finding CF, I've been ordering via HobbyKing.
2018 Events
Astronomy, Mousetrap Vehicle, Mission Possible, Fermi Questions

2019 Events
Astronomy, Mousetrap Vehicle, Mission Possible, Fermi Questions :cry: , Circuit Lab

--
West High '19
UC Berkeley '23

sciencecat42
Member
Member
Posts: 74
Joined: March 14th, 2016, 7:07 pm
State: -

Re: Mousetrap Vehicle C

Postby sciencecat42 » January 17th, 2019, 7:19 pm

PM2017 wrote:As for finding CF, I've been ordering via HobbyKing.


I am a bit of a noob with CF so please excuse me if this is a stupid question. You can cut it with a regular hack saw and use regular steel nuts and bearings and stuff with it right?

edit: so I did some research and apparently it is dangerous to cut carbon fiber if you don't have the proper ventilation and everything.

edit 2: I don't think actual carbon fiber threaded rods exist. You can find smooth rods, but I'm pretty sure the ones on hobby king are actually carbon steel or some other metal.

DarthBuilder wrote:I’m now using 3 mm carbon fiber axles and I can almost certainly say they don’t bend unless you try to. Once attached there shouldn’t really be any problems with it.
You can tell if traction is an issue when the car skids usually (someone else might have a better answer to this).


Also, I am considering using a carbon fiber rod for the arm as well. Will 3mm bend if it is twice as long and under the force of the mouse trap?

User avatar
MadCow2357
Member
Member
Posts: 583
Joined: November 19th, 2017, 9:09 am
Division: C
State: RI
Location: Stark Industries Internship
Contact:

Re: Mousetrap Vehicle C

Postby MadCow2357 » January 19th, 2019, 8:28 am

sciencecat42 wrote:I am a bit of a noob with CF so please excuse me if this is a stupid question. You can cut it with a regular hack saw and use regular steel nuts and bearings and stuff with it right?

edit: so I did some research and apparently it is dangerous to cut carbon fiber if you don't have the proper ventilation and everything.

edit 2: I don't think actual carbon fiber threaded rods exist. You can find smooth rods, but I'm pretty sure the ones on hobby king are actually carbon steel or some other metal.

Yeah don't cut CF with a normal hacksaw. That would get messy... Use a Dremel, or another cutting tool with a strictly abrasive blade. Best to do it outside. However, I do recall my partner saying that he was able to cut it very accurately with a miter saw. ¯\_(ツ)_/¯

For threaded carbon fiber rods, it could be possible to thread them with a lathe? I don't know, I'm not an expert so best listen to other people.
MadCow2357's Userpage
Projected 2020 Events: Boomilever, Gravity Vehicle
Considering: Fossils, Machines, Sounds of Music, Wright Stuff
Builder Cult - builders rise up! :)
Dank Memes Area Homeschool
234.36
#BalsaManForever

User avatar
bernard
Administrator
Administrator
Posts: 1964
Joined: January 5th, 2014, 3:12 pm
Division: Grad
State: WA
Location: Seattle, WA
Contact:

Re: Mousetrap Vehicle C

Postby bernard » January 19th, 2019, 9:33 am

MadCow2357 wrote:
sciencecat42 wrote:I am a bit of a noob with CF so please excuse me if this is a stupid question. You can cut it with a regular hack saw and use regular steel nuts and bearings and stuff with it right?

edit: so I did some research and apparently it is dangerous to cut carbon fiber if you don't have the proper ventilation and everything.

edit 2: I don't think actual carbon fiber threaded rods exist. You can find smooth rods, but I'm pretty sure the ones on hobby king are actually carbon steel or some other metal.

Yeah don't cut CF with a normal hacksaw. That would get messy... Use a Dremel, or another cutting tool with a strictly abrasive blade. Best to do it outside. However, I do recall my partner saying that he was able to cut it very accurately with a miter saw. ¯\_(ツ)_/¯

For threaded carbon fiber rods, it could be possible to thread them with a lathe? I don't know, I'm not an expert so best listen to other people.

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
"One of the ways that I believe people express their appreciation to the rest of humanity is to make something wonderful and put it out there."


Return to “Mousetrap Vehicle C”

Who is online

Users browsing this forum: No registered users and 1 guest