Scores B/C

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Re: Scores B/C

Postby bernard » January 20th, 2015, 4:56 am

The wood's density affects its strength quite a lot believe.
So if I use the same design but say I had a 4g and it held all the weight, would the 3g beam be too weak to hold all the weight? I don't have very many light pieces so I don't want to use them up quite yet
Probably. Lighter members buckle significantly more so you might need to make additional changes to your design to prevent the buckling.
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Re: Scores B/C

Postby hi im andrew » January 20th, 2015, 7:28 am

For anyone that is getting over 2200~ are you using basswood for the tensions? PM me if you want to talk about dimensions of the tension pieces. I'm the only one in my school to do the building events well, so I need to brainstorm with others :D
Last edited by hi im andrew on January 26th, 2015, 7:11 am, edited 1 time in total.

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Re: Scores B/C

Postby retired1 » January 20th, 2015, 8:09 am

Generally speaking, the higher the density of the wood, the stronger it is, BUT there are exceptions! When A2Z started out in business (now closed) Tim used to weigh each stick. He also ran bend strength on each. He had several different stiffness ratings from poor to crazy stiff. Since there was very little of the top stiffness in the light weight, he charged dearly for it.

So, restated, strength of a given size balsa normally is directly related to the density but some is better than others. If you have unusually good A/C grain, it is much stiffer in the C direction.

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Re: Scores B/C

Postby S4BB » January 20th, 2015, 2:36 pm

For anyone that is getting over 2200~ are you using basswood for the tensions? PM me if you want to talk about dimensions of the tension pieces. I'm the only on in my school to do the building events well, so I need to brainstorm with others :D
We have hit 3000 (Div. B) and are using only Balsa wood in our designs of the tension members. Have held significantly more than the 15kg with Balsa only, on a heavier design.

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Re: Scores B/C

Postby Scioly99 » January 20th, 2015, 2:54 pm

Ive been getting scores in the 2600 to 2800 range. Any idea of how that might do at nationals assuming I cant successfully drop any more weight?

also how much does the woods density actually effect its strength?
I'd estimate a 2800 would get anywhere from 8th-4th place at nats, but I can't say for sure. I would almost guarantee that 1st place will be over 4000.

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Re: Scores B/C

Postby Unome » January 20th, 2015, 3:52 pm

Ive been getting scores in the 2600 to 2800 range. Any idea of how that might do at nationals assuming I cant successfully drop any more weight?

also how much does the woods density actually effect its strength?
I'd estimate a 2800 would get anywhere from 8th-4th place at nats, but I can't say for sure. I would almost guarantee that 1st place will be over 4000.
Would the differences from 8th to 1st really be that large?
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Re: Scores B/C

Postby DoctaDave » January 20th, 2015, 4:26 pm

Scioly99, he's in C division, so a 2800 would definitely medal at nats, but for B division that's a different story.

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Re: Scores B/C

Postby Scioly99 » January 20th, 2015, 4:37 pm

Ive been getting scores in the 2600 to 2800 range. Any idea of how that might do at nationals assuming I cant successfully drop any more weight?

also how much does the woods density actually effect its strength?
I'd estimate a 2800 would get anywhere from 8th-4th place at nats, but I can't say for sure. I would almost guarantee that 1st place will be over 4000.
Would the differences from 8th to 1st really be that large?
Well, Its just an estimate. But if you look at boomilever in 2013, 8th place was about 1300 and 1st place was over 2100 which is a difference of about 60%, and if the 1st place score this year is 4000, following this rule, 8th place would be about 2500.

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Re: Scores B/C

Postby Scioly99 » January 20th, 2015, 4:50 pm

Scioly99, he's in C division, so a 2800 would definitely medal at nats, but for B division that's a different story.
I am a freshman but I am still in B division (Sorry, I can see why you would think I'm in C :lol: ) and the score estimates I posted are also for B division just to clarify. For C division it;s very unlikely that scores would be as high as 4000 (at least for this year). Sorry for the confusion, I should have looked to see what division you were in before posting :o

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Re: Scores B/C

Postby Unome » January 20th, 2015, 5:05 pm

I'd estimate a 2800 would get anywhere from 8th-4th place at nats, but I can't say for sure. I would almost guarantee that 1st place will be over 4000.
Would the differences from 8th to 1st really be that large?
Well, Its just an estimate. But if you look at boomilever in 2013, 8th place was about 1300 and 1st place was over 2100 which is a difference of about 60%, and if the 1st place score this year is 4000, following this rule, 8th place would be about 2500.
I forgot the rules for a second; since it's mass held over mass of bridge, scores would rise higher for the same mass removed at lower total masses.
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