Boomilever B/C

[Sciencer101]

I saw this design called a "compression beam" on the scioly wiki where it is basically 2 tension sticks attached to a hollow cylinder of balsa wood instead of your standard compression member. The wiki also said that it can be very competitive. I was wondering how you would go about constructing this, and whether or not it would be effective. Working with a drill on a boomilever seems a little... overpowered. Also, what are the estimated competitive weights this ear? For towers the competitive ones were ~ 6-7 g, but it seems like you could make a very light boomilever.

The cylinder would be made by taking a sheet and rolling it (there's a process involving soaking it in warm water/steam, although I don't know the details). It's quite difficult, both because the construction takes a long time and is very delicate, and it's quite a challenge to find a uniform sheet that's strong enough.

Boomilever scores tend to be lower. As a general rule of thumb, I would take Towers scores from last year and divide them by 2 to get roughly equivalent boomilever scores.

So if 2500 is a standard competitive tower score, that would mean the standard boomilever (@ 5 g) would only hold ~ 6.25 kg? That seems much lower than it should be.

[Unome]

I saw this design called a "compression beam" on the scioly wiki where it is basically 2 tension sticks attached to a hollow cylinder of balsa wood instead of your standard compression member. The wiki also said that it can be very competitive. I was wondering how you would go about constructing this, and whether or not it would be effective. Working with a drill on a boomilever seems a little... overpowered. Also, what are the estimated competitive weights this ear? For towers the competitive ones were ~ 6-7 g, but it seems like you could make a very light boomilever.

The cylinder would be made by taking a sheet and rolling it (there's a process involving soaking it in warm water/steam, although I don't know the details). It's quite difficult, both because the construction takes a long time and is very delicate, and it's quite a challenge to find a uniform sheet that's strong enough.

Boomilever scores tend to be lower. As a general rule of thumb, I would take Towers scores from last year and divide them by 2 to get roughly equivalent boomilever scores.

So if 2500 is a standard competitive tower score, that would mean the standard boomilever (@ 5 g) would only hold ~ 6.25 kg? That seems much lower than it should be.

Ruels this year are comparable to 2014, except for a slightly smaller length. A 10g boomilever holding full weight is quite impressive. The compression part of the boomilever needs to withstand a lot more force than Towers.

[Cow481]

The cylinder would be made by taking a sheet and rolling it (there's a process involving soaking it in warm water/steam, although I don't know the details). It's quite difficult, both because the construction takes a long time and is very delicate, and it's quite a challenge to find a uniform sheet that's strong enough.

Boomilever scores tend to be lower. As a general rule of thumb, I would take Towers scores from last year and divide them by 2 to get roughly equivalent boomilever scores.

So if 2500 is a standard competitive tower score, that would mean the standard boomilever (@ 5 g) would only hold ~ 6.25 kg? That seems much lower than it should be.

Ruels this year are comparable to 2014, except for a slightly smaller length. A 10g boomilever holding full weight is quite impressive. The compression part of the boomilever needs to withstand a lot more force than Towers.

It seems from looking at the 2014 forums that nats placeing will be 1700-2200

[Unome]

So if 2500 is a standard competitive tower score, that would mean the standard boomilever (@ 5 g) would only hold ~ 6.25 kg? That seems much lower than it should be.

Ruels this year are comparable to 2014, except for a slightly smaller length. A 10g boomilever holding full weight is quite impressive. The compression part of the boomilever needs to withstand a lot more force than Towers.

It seems from looking at the 2014 forums that nats placeing will be 1700-2200

That seems plausible. Scores might be slightly higher than that. Although, at the highest levels I suspect individual variation is a more important determiner.

[dholdgreve]

With the projection only being 40-45 cm, I think the scores will be considerable higher than they were in 2014.

[Unome]

With the projection only being 40-45 cm, I think the scores will be considerable higher than they were in 2014.

That much of an increase with only a 5 cm reduction? (granted I haven't done the relevant calculations)

[dholdgreve]

With the projection only being 40-45 cm, I think the scores will be considerable higher than they were in 2014.

That much of an increase with only a 5 cm reduction? (granted I haven't done the relevant calculations)

If I remember correctly, 2014 had a projection of 50 cm, which could mean a reduction of as much as 20% horizontal, with no change in height, so the angle is increased. I think we will see scores 20 to 25% higher than in 2014! JMHO... These types of events have gotten substantially more competitive over the years with the advent of digital stress modeling and 3-D printing of templates, etc... The increases may even be higher than that!

[Raleway]

"c. Participants may NOT bring any equipment such as levels or squares"

Why is that a thing...?

[TheChiScientist]

Could be to prevent on sight modification? Not sure how though...

[dholdgreve]

"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.