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Re: Boomilever B/C
Posted: September 8th, 2018, 10:29 am
by Raleway
dholdgreve wrote:Raleway wrote:"c. Participants may NOT bring any equipment such as levels or squares"
Why is that a thing...?
A couple thoughts...
Having a level to check the plumb of the wall could create a reason for appeal, if the wall were out of plumb.
If the wall were out of plumb, the E/C would be faced with 2 choices: 1) adjust it accordingly, thus changing the parameters for all that follows, meaning those that went before the adjustment may be at a disadvantage, or 2) Leave it as is and continue testing, knowing that it is out of plumb, thus calling into question the entire legitimacy of the event. Neither are good answers. Sometime it is just better to not know.
Even if competitors checked to see if their boom was level, since you are not able to modify after check-in, the point is moot, and since a boom must be in 1 piece, shimming would / should not be allowed either.
Even if that's true, that's very disadvantageous to those who pursue high score designs. At that point, any deviation from the assumed "level" testing device is a much quicker failure. With my experience at States, the tables were NEVER level. However, we made sure to check this during impound as so we would not have an unfair advantage. In this way, it discourages those to try for ambitious designs which goes against the spirit of developing higher and higher scores. At one invitational where we did this, the ES checked the levelness after every few structures or at a request to ensure fairness- it was a simple adjustment of placing paper under the pegs. Just my two cents.
Re: Boomilever B/C
Posted: September 10th, 2018, 8:35 am
by dholdgreve
Raleway wrote:dholdgreve wrote:Raleway wrote:"c. Participants may NOT bring any equipment such as levels or squares"
Why is that a thing...?
A couple thoughts...
Having a level to check the plumb of the wall could create a reason for appeal, if the wall were out of plumb.
If the wall were out of plumb, the E/C would be faced with 2 choices: 1) adjust it accordingly, thus changing the parameters for all that follows, meaning those that went before the adjustment may be at a disadvantage, or 2) Leave it as is and continue testing, knowing that it is out of plumb, thus calling into question the entire legitimacy of the event. Neither are good answers. Sometime it is just better to not know.
Even if competitors checked to see if their boom was level, since you are not able to modify after check-in, the point is moot, and since a boom must be in 1 piece, shimming would / should not be allowed either.
Even if that's true, that's very disadvantageous to those who pursue high score designs. At that point, any deviation from the assumed "level" testing device is a much quicker failure. With my experience at States, the tables were NEVER level. However, we made sure to check this during impound as so we would not have an unfair advantage. In this way, it discourages those to try for ambitious designs which goes against the spirit of developing higher and higher scores. At one invitational where we did this, the ES checked the levelness after every few structures or at a request to ensure fairness- it was a simple adjustment of placing paper under the pegs. Just my two cents.
Rale,
I don't disagree with anything you said... I'm just trying to apply any type of logic that may fit... As an E/C I agree that checking initially as well as frequently throughout the competition is an unwritten responsibility of those running it!
Re: Boomilever B/C
Posted: September 20th, 2018, 2:31 pm
by Jacobi
dholdgreve wrote:Raleway wrote:dholdgreve wrote:
A couple thoughts...
Having a level to check the plumb of the wall could create a reason for appeal, if the wall were out of plumb.
If the wall were out of plumb, the E/C would be faced with 2 choices: 1) adjust it accordingly, thus changing the parameters for all that follows, meaning those that went before the adjustment may be at a disadvantage, or 2) Leave it as is and continue testing, knowing that it is out of plumb, thus calling into question the entire legitimacy of the event. Neither are good answers. Sometime it is just better to not know.
Even if competitors checked to see if their boom was level, since you are not able to modify after check-in, the point is moot, and since a boom must be in 1 piece, shimming would / should not be allowed either.
Even if that's true, that's very disadvantageous to those who pursue high score designs. At that point, any deviation from the assumed "level" testing device is a much quicker failure. With my experience at States, the tables were NEVER level. However, we made sure to check this during impound as so we would not have an unfair advantage. In this way, it discourages those to try for ambitious designs which goes against the spirit of developing higher and higher scores. At one invitational where we did this, the ES checked the levelness after every few structures or at a request to ensure fairness- it was a simple adjustment of placing paper under the pegs. Just my two cents.
Rale,
I don't disagree with anything you said... I'm just trying to apply any type of logic that may fit... As an E/C I agree that checking initially as well as frequently throughout the competition is an unwritten responsibility of those running it!
Here's the physics of the situation:
A wall tilting forward will put more stress on the tension member.
A wall tilting back will put more stress on the compression member.
Wood decreases strength the longer the compression chord is, while tension does not alter strength. Thus, it is reasonable to conclude that a wall tilting back could fatally shatter some designs.
A wall tilting forward would favor a compression boom, which is the less common type. A wall tilting back would favor the tension boom, which is the more common type.
A tower chimney design is favored by back-leaning. A box beam is favored by front-leaning. A compression tube is favored by front-leaning.
I hope this helps.
Re: Boomilever B/C
Posted: September 21st, 2018, 4:18 am
by kinghong1970
While optimal situation is to have a perfectly perpendicular wall, the rule may be implemented so that all contestants are tested with the same level playing ground affecting, if any, benefits or disadvantages evenly throughout the numerous contestants...?
Re: Boomilever B/C
Posted: September 21st, 2018, 5:27 am
by Carrot
Is a wall likely to have the plumb change throughout the day, like starting perfectly vertical but end up tilting? If so, would it be more beneficial to test within the first few blocks of an invitational in hopes that the wall started out closest to vertical at the beginning of the day?
Re: Boomilever B/C
Posted: September 21st, 2018, 6:23 am
by kinghong1970
Carrot wrote:Is a wall likely to have the plumb change throughout the day, like starting perfectly vertical but end up tilting? If so, would it be more beneficial to test within the first few blocks of an invitational in hopes that the wall started out closest to vertical at the beginning of the day?
i think that will depend on the EC and how meticulously the rig is built...
i've seen some vertical walls on youtube vids that are made of 3/4 ply and with some form of brackets at the end... i'm sure with all the testing and loading, there is some form of movement...
but it's really hard to determine this.
great events but as you can see, each year, there are threads about horribly run events...
but hoping for the best... excited to do boomilever, although it scares the poopy out of me just thinking about coaching this to the kids.
Al
Re: Boomilever B/C
Posted: September 21st, 2018, 6:56 am
by Jacobi
Carrot wrote:Is a wall likely to have the plumb change throughout the day, like starting perfectly vertical but end up tilting? If so, would it be more beneficial to test within the first few blocks of an invitational in hopes that the wall started out closest to vertical at the beginning of the day?
In the long haul, differences are fairly insubstantial. A good boom should be strong in both tension and compression.
Re: Boomilever B/C
Posted: September 24th, 2018, 2:46 pm
by TheChiScientist
Where do you guys acquire your wood? I have considered purchasing balsa online yet I doubt it's quality...
Re: Boomilever B/C
Posted: September 24th, 2018, 2:57 pm
by DarthBuilder
TheChiScientist wrote:Where do you guys acquire your wood? I have considered purchasing balsa online yet I doubt it's quality...
Online wood is good too since you can choose its sizes and such
Sometimes if I’m in a rush I go to Ace, Lowes, Home Depot
Hobby Lobby, Tom Thumb
Blicks
Michaels
Re: Boomilever B/C
Posted: September 24th, 2018, 3:33 pm
by Carrot
TheChiScientist wrote:Where do you guys acquire your wood? I have considered purchasing balsa online yet I doubt it's quality...
Most of the wood I use is ordered online from specialized balsa. It allows you to specify many things such as wood density and grain which tends to give me sticks that I want.