Boomilever B/C

[scioly2345]

Hey everyone,
Does anybody know how viable 1/16 square tension members are for Division C this year? I'm using 3/32 square tension members this year, but I'd like to reduce as much as I can. Thanks!

I’d go a rectangle size (I use 1/8 by 1/16 to give the compression and tension a bigger area to connect. I personally have not tried square tension members, but if 3/32 is working for you and it consistently doesn’t break, I don’t see why you shouldn’t try 1/16 square for tension (assuming this is all bass).
I don’t think people’s main problems with tension is the size of the actual pieces, but it is the way they laminate the area where the connect it to both compression and the hook area. If not laminated properly, these major pressure points will break.

[kjlokesh]

I'm sure this has been asked before but I can't readily find it. What's the best use of a tested boom that held the whole load? My kids are a little unsure of some of the dimensions so we are thinking about just taking it apart and weighing/reweighing sfpding/re-sfpding each piece and using that info to figure out how to get lighter. Anything else? Use it as a backup? Keep adding sand til it breaks? Put it in the trophy case? Burn it?

Before going to the competition i will ask the kids to review the device. Identify potential point of failure and review after the competition. This will help them build a better device next time. If we win the competition then we will place it in the trophy case/shelf.

[jinhusong]

Hey everyone,
Does anybody know how viable 1/16 square tension members are for Division C this year? I'm using 3/32 square tension members this year, but I'd like to reduce as much as I can. Thanks!

I’d go a rectangle size (I use 1/8 by 1/16 to give the compression and tension a bigger area to connect. I personally have not tried square tension members, but if 3/32 is working for you and it consistently doesn’t break, I don’t see why you shouldn’t try 1/16 square for tension (assuming this is all bass).
I don’t think people’s main problems with tension is the size of the actual pieces, but it is the way they laminate the area where the connect it to both compression and the hook area. If not laminated properly, these major pressure points will break.

square 1/16 can only hold 11-13 kg. We will try 1/16X1/18 and 2 of 1/32X1/8.

[BigBootyBason]

The rules state the boomilever must support the loading assembly consisting of the block, bolt, chain, and wingnut. Are we allowed to unscrew the loading block and put the bolt holding the block. The boomilever wouldn't be holding the whole assembly as the weight is still being held by the bolt. Would this be allowed? I hope this makes sense. If not I will draw a diagram later today.

[Lorant]

From what I understand, you have to hold all the pieces of the loading assembly, fully assembled. That means not only do all the pieces have to be held, the loading assembly also has to be put together, meaning you can't just go rouge and mount the s-hook to the boomi while the loading block is just placed on the boomi in some random spot.

[saracupp]

At a recent invitational some boomilevers were judged to be illegal on the basis of rule 3.a.iii (relevant excerpt below):

Adhesive is a substance used to join two or more materials together and may be used only for this purpose.

The illegal boomilevers had used a large amount of glue near the connection point between the tension members and the j-hook. The glue formed a curved saddle shape that nestled against the hook such that it was the glue in contact with the j-hook and not the wooden portions of the boomilever.

Could you please clarify as to whether that use of glue constitutes a violation of the construction parameters (which places the boomilever into Tier 2)?

Additionally, the judges felt that it was a slippery slope to allow any excessive glue to contact the j-hook, even if it didn't serve as the predominant contact point between the boomilever and j-hook. This received a lot of discussion and ultimately it was decided that unless the device appeared to be designed so that glue purposefully served some role other than adhesion that it would be allowed.

Could you also please clarify as to whether it was appropriate to rule devices of this kind (excess glue in contact with the j-hook, but no evidence that the glue was used for anything other than adhesion) as a Tier 1 device?

Thank you for the help!

[saracupp]

At a recent invitational the event supervisor allowed participants to adjust the boomilever up to the point of connecting the loading assembly to the boomilever and the boomilever to the testing wall. When they completed these steps they were instructed to declare "ready to load". At that point a volunteer would check the competition parameters for chain center line between 40 and 45cm and no contact between the boomilever and the testing wall within the contact width lines or below the contact depth line. If a violation was found, the boomilever was ruled to be Tier 2 and the participants were not allowed to make further adjustments.

Restricting further adjustment of the loading assembly or the boomilever's position on the testing wall after speaking the words "ready to load" seems to contradict 4.2.d (below):

The participants will be allowed to adjust the boomilever until they start loading sand. Once loading of sand has begun , the boomilever must not be further adjusted.

Can you confirm whether the participants should have been allowed to make further adjustments since no sand had been loaded?

Thank you for the help!

[bernard]

Could you please clarify as to whether that use of glue constitutes a violation of the construction parameters (which places the boomilever into Tier 2)?

Could you also please clarify as to whether it was appropriate to rule devices of this kind (excess glue in contact with the j-hook, but no evidence that the glue was used for anything other than adhesion) as a Tier 1 device?

As you've noted, the rules explicitly define adhesive and identify where it may be used. Can you demonstrate that the excess glue was used only for adhesion? Here is the link for submitting questions for official responses (FAQs).

Opinions expressed on this site are not official; the only place for official rules changes and FAQs is soinc.org.

[knightmoves]

The rules state the boomilever must support the loading assembly consisting of the block, bolt, chain, and wingnut. Are we allowed to unscrew the loading block and put the bolt holding the block. The boomilever wouldn't be holding the whole assembly as the weight is still being held by the bolt. Would this be allowed? I hope this makes sense. If not I will draw a diagram later today.

You are allowed to disassemble the loading assembly to fit it to your device, but you must reassemble it. You cannot just miss out the loading block.

Are you asking if you can put the loading block below your boom (so looking from the top, you see wingnut, your boomilever, loading block, eye and chain?) I don't see the advantage of doing that, but I also don't see it being illegal.

[knightmoves]

Additionally, the judges felt that it was a slippery slope to allow any excessive glue to contact the j-hook, even if it didn't serve as the predominant contact point between the boomilever and j-hook. This received a lot of discussion and ultimately it was decided that unless the device appeared to be designed so that glue purposefully served some role other than adhesion that it would be allowed.

Could you also please clarify as to whether it was appropriate to rule devices of this kind (excess glue in contact with the j-hook, but no evidence that the glue was used for anything other than adhesion) as a Tier 1 device?

You correctly point out the rule (glue is only to be used to bond together bits of wood. You may not make structural members out of glue, glue/sawdust composite, and so on).

This is a competition which will display a significant range of student skill. Some kids are building very carefully-built devices, with glue weight kept to a minimum. Others are building big heavy things with massive glue-blobs at each joint. I don't think we want to tier kids who aren't very careful builders.

I think that's where the judges are going in the example you give. There is a rule about not using glue for things other than joining wood. There is not a rule about "no glue is allowed to contact the j-hook". Careless building is legal. Deliberately constructing structural pieces out of glue is not.