Mousetrap Vehicle C

[bernard]

The rules to me did not make this quite clear, but are u allowed to roll the vehicle on the track before the run to calibrate it?

This is quite clear in the rules, see 5.f.

[Unome]

Is there a diagram of the track?

If you just need an idea of what's going on, I've attached a makeshift diagram that's hopefully helpful.

Mousetrap 2018 track.png

[retired1]

how are they doing the time score? I'm kind of confused by the rules

The time is from the moment you push the button to when the vehicle comes to a complete stop from what I have read of the rules. There are no timing lines, so there is no way to use photo gates or even lasers to assist manual timers. It is going to be hard to get accurate times with this setup.

Timing is not a problem of any significance as the vehicle is slow compared to electric powered or rubber powered.

Also, the distances are fairly short - from the start point to the finish point. 3 timers can virtually stand over the top of it, so there is no visual problem and nearly zero parallax error.

[retired1]

Ceramic bearings are a bit of overkill for this event. Open bearings that you can flush out the "oil" or "grease" with kerosene will provide a very low friction bearing and provide a bit of lubrication. I do not like WD-40 as it leaves a sticky residue if you are not careful.

You might want to make 1 unit with low friction bushings to save even more weight (Igus is a good source).

I like flange units.

For axles, 4 mm stainless all thread is more than strong enough and is light weight. Using nylon nuts and thin stainless steel washers make wheel attachment no problem and light weight.

Teacher geek wheels with wide rubber band tires are light and have good traction. Plastic tubing will be needed to reduce the axle hole a it is nearly 1/4 ".

[windu34]

Ceramic bearings are a bit of overkill for this event. Open bearings that you can flush out the "oil" or "grease" with kerosene will provide a very low friction bearing and provide a bit of lubrication. I do not like WD-40 as it leaves a sticky residue if you are not careful.

You might want to make 1 unit with low friction bushings to save even more weight (Igus is a good source).

I like flange units.

For axles, 4 mm stainless all thread is more than strong enough and is light weight. Using nylon nuts and thin stainless steel washers make wheel attachment no problem and light weight.

Teacher geek wheels with wide rubber band tires are light and have good traction. Plastic tubing will be needed to reduce the axle hole a it is nearly 1/4 ".

Agree that ceramic bearings are overkill for MOST competitors. That said, if you are looking at top 6 at nationals, you dont know how close it will be so if I were doing this event, Id email/call ceramic bearing companies and try for sponsorships. That said, it will have a very small impact on your performance and good stainless steel bearings are perfectly fine.
You can buy small bearings if you are looking to save weight. Definitely use bearings though - the increase in weight is worth it.
Not a fan of those wheels and using rubber bands introduces a huge possible point of failure as the rubber wears out and could result in snapping. Also if the rubber band slips off during competition, you are screwed. Balloons are a good low-price option, but I still recommend the 0.4" thick banebot wheels with parts of the wheel cut out to reduce weight/rotational intertia

[depo1213]

Is there a diagram of the track?

If you just need an idea of what's going on, I've attached a makeshift diagram that's hopefully helpful.
Mousetrap 2018 track.png

Thanks

[Aristotle]

Hey everyone,

I was watching a few videos and saw the usage of geared axles. I was wondering what the advantages/disadvantages were of using geared axles instead of a simply thicker axle.

Thanks

[depo1213]

Is it better to have a lower time score or to be more accurate with the cup and end position?

[antoine_ego]

Is it better to have a lower time score or to be more accurate with the cup and end position?

Accuracy is preferable since the accuracy is worth twice as much as time. That being said, being quick does give you a little bit more wiggle room when it comes to accuracy.

[windu34]

Hey everyone,

I was watching a few videos and saw the usage of geared axles. I was wondering what the advantages/disadvantages were of using geared axles instead of a simply thicker axle.

Thanks

Gearing is typically used to increase torque allowing faster acceleration in this application (unlikely its being used for the reverse). Not sure why you would think a thicker axle is equivalent to gearing