Search found 89 matches

by sciencecat42
February 18th, 2020, 11:42 am
Forum: Gravity Vehicle C
Topic: Wheels
Replies: 30
Views: 3484

Re: Wheels

Would it be better to get green or orange T81 wheels? I know green has better traction and could reduce skidding, but they also deteriorate faster. I don't want to have to replace the wheels before the state competition in early March. Why T81 as opposed to T40? Won't they just take more energy due...
by sciencecat42
February 13th, 2020, 12:14 pm
Forum: Gravity Vehicle C
Topic: 3D printing
Replies: 8
Views: 694

Re: 3D printing

I have never had any issues with layer adhesion. My guess is either your printer is not calibrated well or that the design/print orientation is bad.
by sciencecat42
February 8th, 2020, 11:05 am
Forum: Gravity Vehicle C
Topic: Scores
Replies: 87
Views: 8010

Re: Scores

I don't know if National Committee has ever changed the rules mid-season, but because everyone is so accurate, maybe multiple the time component by something like ten (10). So let's say car 1 runs in 3.5 seconds and ends up 2cm away, and car 2 runs in 2.5 seconds and ends up 4cm away then scores wo...
by sciencecat42
February 1st, 2020, 9:20 pm
Forum: Boomilever B/C
Topic: Wood Sources
Replies: 3
Views: 601

Wood Sources

Where is everyone sourcing their wood? Is specializedbalsa still considered the best?
by sciencecat42
February 1st, 2020, 9:18 pm
Forum: Gravity Vehicle C
Topic: Wheels
Replies: 30
Views: 3484

Re: Wheels

I'm using the BaneBots T81 2-7/8" wheels (blue, 50A) and still getting a lott of skid (up to ~30 cm, but pretty variable). Granted, the vehicle is relatively fast and heavy (~1.4 kg). What can I do to reduce skidding? I know about rubber washers, but are there any other solutions? Thanks! Clean whe...
by sciencecat42
January 30th, 2020, 12:38 pm
Forum: Boomilever B/C
Topic: help
Replies: 3
Views: 532

Re: help

Yes! The joint on the tension beams to the box is usually just crushing or snapping off. I believe that we should try adding more braces in that area but the problem with that is that our boomilever is very heavy at about 15 grams and extra weight might cut into our score. For reference, we get an ...
by sciencecat42
January 29th, 2020, 4:02 pm
Forum: Boomilever B/C
Topic: Re: PICTURES, SCORES, VIDEOS!!
Replies: 77
Views: 7166

Re: PICTURES, SCORES, VIDEOS!!

sciencenerd123 wrote:
January 27th, 2020, 5:28 pm
At my invitationals the 1st place got score of 1k but every one else was under 1k the top 5 places ranged from 600-1k. I think top 3 in my regionals will def. hit 1k
What state?
by sciencecat42
January 29th, 2020, 4:01 pm
Forum: Boomilever B/C
Topic: help
Replies: 3
Views: 532

Re: help

ganesh wrote:
January 28th, 2020, 6:13 pm
Any ideas on how to make the joint where the two extending beams are connected to the box stronger or more secure? ( In a box beam lever )


Thanks <3
What do you mean by extending beams? The tension chords?
by sciencecat42
November 27th, 2019, 10:18 am
Forum: Mousetrap Vehicle B
Topic: Wheels
Replies: 7
Views: 1045

Re: Wheels

Last year when this was a C event I found that 3D printing and balloons worked well enough. Never had any issues with skidding as the acceleration is never large enough.
by sciencecat42
November 21st, 2019, 6:34 pm
Forum: Gravity Vehicle C
Topic: Gravity Vehicle C
Replies: 241
Views: 22977

Re: Gravity Vehicle C

a.) Many teams will make an insert to fit between the rod and bearing to get a "interference fit". I always 3D printed a thin insert, but you could certainly do it other ways. How do you print the thin insert? My threaded rod is about 4.9mm in diameter and the bearing has a 5mm inner diameter. But ...

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