Boomilever B/C

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Re: Boomilever B/C

Post by wzhang5460 » March 31st, 2019, 4:58 pm

sciencecat42 wrote:
wzhang5460 wrote:I found that using two 1/4 by 1/8 balsa for compression and 1/16 by 1/16 balsa for tension will yield very good results.
Isn't 1/16 balsa super weak?
As long as you don't taper it the tensile force alone I found to be sufficient
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Re: Boomilever B/C

Post by sciencecat42 » March 31st, 2019, 5:44 pm

wzhang5460 wrote:
sciencecat42 wrote:
wzhang5460 wrote:I found that using two 1/4 by 1/8 balsa for compression and 1/16 by 1/16 balsa for tension will yield very good results.
Isn't 1/16 balsa super weak?
As long as you don't taper it the tensile force alone I found to be sufficient
How do you glue the distal end? Isn't the gluing surface area very small?

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Re: Boomilever B/C

Post by RobertYL » April 2nd, 2019, 5:49 pm

sciencecat42 wrote:
wzhang5460 wrote:
sciencecat42 wrote:
Isn't 1/16 balsa super weak?
As long as you don't taper it the tensile force alone I found to be sufficient
How do you glue the distal end? Isn't the gluing surface area very small?
I would assume they laminated the connection.

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Re: Boomilever B/C

Post by MadCow2357 » April 5th, 2019, 1:47 pm

Just gonna leave this here:
viewtopic.php?f=4&t=6237&p=386162#p386162

Feel free to express outrage and disbelief, but everything I said is completely true...
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Re: Boomilever B/C

Post by TheSquaad » April 5th, 2019, 7:44 pm

MadCow2357 wrote:Just gonna leave this here:
viewtopic.php?f=4&t=6237&p=386162#p386162

Feel free to express outrage and disbelief, but everything I said is completely true...
That’s almost bad as when my state’s es’s let people use phones as calculators in expedes.

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Re: Boomilever B/C

Post by TheChiScientist » April 5th, 2019, 7:49 pm

TheSquaad wrote:
MadCow2357 wrote:Just gonna leave this here:
viewtopic.php?f=4&t=6237&p=386162#p386162

Feel free to express outrage and disbelief, but everything I said is completely true...
That’s almost bad as when my state’s es’s let people use phones as calculators in expedes.
Well... :| Yea this is why I wanna become an ES so I can at least know what I'm doing...
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Re: Boomilever B/C

Post by Anomaly » April 25th, 2019, 3:42 pm

Kind of irrelevant, but my one teammate who was on boomi kept calling her boomi a "bridge" smh (she did bridge building back in 2016 but are you kidding me)
she also got kicked off of boomi so i wonder if there's a correlation hm
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Re: Boomilever B/C

Post by scioly2345 » May 1st, 2019, 5:56 am

Let’s say I use a super low viscocity glue to connect my tension members and the round dowel by the hook. If the super glue soaks down far onto the tension sticks, will the tension members strength be damaged resulting in a break right below the connection of the dowel and the tension members?
Using balsa as tension imo is worse with this situation, bass is less worse ish.
And also, does it matter if I laminate with balsa or bass? Trying to stay away from bass cs it’s heavy..,,
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Re: Boomilever B/C

Post by dholdgreve » May 16th, 2019, 6:24 am

scioly2345 wrote:Let’s say I use a super low viscocity glue to connect my tension members and the round dowel by the hook. If the super glue soaks down far onto the tension sticks, will the tension members strength be damaged resulting in a break right below the connection of the dowel and the tension members?
Using balsa as tension imo is worse with this situation, bass is less worse ish.
And also, does it matter if I laminate with balsa or bass? Trying to stay away from bass cs it’s heavy..,,
Multiple questions!
1) Yes, your tension rods will likely break right below the dowel, not because the glue weakens the fibers, in fact, the opposite. The glue will strengthen it as far as it will soak in... once the capillary action stops, and the glue no longer penetrates, the tension rod will abruptly return to its non-superhuman strength. This abrupt change in strength will be your weak point.
2) I would agree that bass is far better than balsa FOR TENSION RODS ONLY. They are more consistent in grain and strength, contain more lignen, and will tolerate misalignment (shear) far better than balsa. The down side is that is because the bass is more dense, it will not allow the thin viscosity glue you spoke of to soak in the way balsa would.
3) I'm a little unsure on where you are planning on laminating, and the location makes a huge difference, but I would add that if you are "laminating" by adding gussets, the only way to go is with very light 1/32 or even 1/64 balsa. That is all that is needed.
4) Just as an afterthought, it sounds like you are using a dowel as your mounting block. I assume you are possibly drilling you tension rods into it. We have had very little success using thin viscosity super glue... any viscosity super glue for that matter. Consider changing to a urethane based glue like gorilla glue, and even wet the tension rod before inserting, so that the glue will foam up and make the joint as tight as possible.
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Re: Boomilever B/C

Post by scioly2345 » May 17th, 2019, 8:13 am

dholdgreve wrote:
scioly2345 wrote:Let’s say I use a super low viscocity glue to connect my tension members and the round dowel by the hook. If the super glue soaks down far onto the tension sticks, will the tension members strength be damaged resulting in a break right below the connection of the dowel and the tension members?
Using balsa as tension imo is worse with this situation, bass is less worse ish.
And also, does it matter if I laminate with balsa or bass? Trying to stay away from bass cs it’s heavy..,,
Multiple questions!
1) Yes, your tension rods will likely break right below the dowel, not because the glue weakens the fibers, in fact, the opposite. The glue will strengthen it as far as it will soak in... once the capillary action stops, and the glue no longer penetrates, the tension rod will abruptly return to its non-superhuman strength. This abrupt change in strength will be your weak point.
2) I would agree that bass is far better than balsa FOR TENSION RODS ONLY. They are more consistent in grain and strength, contain more lignen, and will tolerate misalignment (shear) far better than balsa. The down side is that is because the bass is more dense, it will not allow the thin viscosity glue you spoke of to soak in the way balsa would.
3) I'm a little unsure on where you are planning on laminating, and the location makes a huge difference, but I would add that if you are "laminating" by adding gussets, the only way to go is with very light 1/32 or even 1/64 balsa. That is all that is needed.
4) Just as an afterthought, it sounds like you are using a dowel as your mounting block. I assume you are possibly drilling you tension rods into it. We have had very little success using thin viscosity super glue... any viscosity super glue for that matter. Consider changing to a urethane based glue like gorilla glue, and even wet the tension rod before inserting, so that the glue will foam up and make the joint as tight as possible.
Thanks so much Dan!
Yes I do use dowels and I did start the season with drilling the tension rods in, but after having a very consistent lineup of boomis breaking exactly where the dowel is, I decided that extra lamination is better for the dowel rather than drilling in the tension rods.
Also, the amount of things user error wise that could’ve and probably did go wrong with my boomis that were drilled in were a lot. The drill spilt the tension rods, the drill accidentally went in the wrong direction, the drill went all the way through the dowel, etc etc. I opted for a sense of “don’t use a heavy drill on literally the softest and most fragile wood ever” because absolute precision is needed for something to not go wrong, so I just stuck to extra lamination :). If you are able to drill the tension with precision AND success, major props because I had a very hard time doing that.
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