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Re: Boomilever B/C

Posted: March 14th, 2019, 9:36 am
by Chameleon02
I have been having some trouble gluing my tension pieces between the base and compression pieces. My base attachment is about 1 cm (light weight, easily holds 15kg), and my compression pieces are spaced 5cm apart measuring from the outside edges. I have been having difficulty attaching the tension pieces (1/16x square bass) to the base and compression pieces on the outside edges. What are the solutions to this issue?
Some suggested that I could glue the tension pieces to the insides of the compression pieces (reduces gap by about .75cm) but are tension pieces equally effective when glued on the inside? Thanks. I hope I have explained the issue (basically I'm trying to glue pieces on 2 planes), but I can clarify if necessary.

Re: Boomilever B/C

Posted: March 18th, 2019, 4:11 pm
by colorblind16
I was looking over the different boomilever design options and reading through the forums and noticed some talk about the box beam boomilever design. However, it was hard to find any pictures showing this model. I also saw the chimney design, which I did see some pictures of. I was wondering if these were the same design or different designs. Is the box beam design the large prism, or is that the chimney design. If it isn't the box beam, what would a standard box beam boomilever look like? This is our first year doing this so we are new. Thanks for all of your help!

Re: Boomilever B/C

Posted: March 18th, 2019, 6:21 pm
by AlexDeKuang
colorblind16 wrote:I was looking over the different boomilever design options and reading through the forums and noticed some talk about the box beam boomilever design. However, it was hard to find any pictures showing this model. I also saw the chimney design, which I did see some pictures of. I was wondering if these were the same design or different designs. Is the box beam design the large prism, or is that the chimney design. If it isn't the box beam, what would a standard box beam boomilever look like? This is our first year doing this so we are new. Thanks for all of your help!
https://scioly.org/wiki/index.php/Boomilever describes the box beam boomilever pretty well, but there isn't a picture.

Re: Boomilever B/C

Posted: March 19th, 2019, 9:29 am
by OpticsNerd
Chameleon02 wrote:I have been having some trouble gluing my tension pieces between the base and compression pieces. My base attachment is about 1 cm (light weight, easily holds 15kg), and my compression pieces are spaced 5cm apart measuring from the outside edges. I have been having difficulty attaching the tension pieces (1/16x square bass) to the base and compression pieces on the outside edges. What are the solutions to this issue?
Some suggested that I could glue the tension pieces to the insides of the compression pieces (reduces gap by about .75cm) but are tension pieces equally effective when glued on the inside? Thanks. I hope I have explained the issue (basically I'm trying to glue pieces on 2 planes), but I can clarify if necessary.
Soak the tension cords in hot water before gluing them?

Re: Boomilever B/C

Posted: March 19th, 2019, 10:08 am
by stringman
How many horizontal trusses do you guys think are optimal for the compression beam?

Re: Boomilever B/C

Posted: March 19th, 2019, 11:34 am
by jinhusong
stringman wrote:How many horizontal trusses do you guys think are optimal for the compression beam?
Normally 8 to 10. Depend on the strength of the beam. First, use the single finger push to see how much weight the beam can hold while starting to bend, then calculate how many internal you need.

For example, you found beam can hold 300 grams before it bend. It needs to hold more than 30,000/2 grams for division B.
num of interval = sqrt( 15000/300)= 7. Give some safe margin, 8 internal should be OK. (I learned this from Balsaman, you can search last year's tower forum for more details.).

For each interval, you can do X only or X and ladder.


Jinhu

Re: Boomilever B/C

Posted: March 27th, 2019, 9:58 am
by Cow481
It is necessary to use gorilla glue for the distal endsif I want to get full hold? I currently use gorilla glue but can the purple cap CA glue get full hold? I use basswood for tension and laminate it to my compression pieces which are balsa.

Re: Boomilever B/C

Posted: March 28th, 2019, 8:46 am
by TheSquaad
Cow481 wrote:It is necessary to use gorilla glue for the distal endsif I want to get full hold? I currently use gorilla glue but can the purple cap CA glue get full hold? I use basswood for tension and laminate it to my compression pieces which are balsa.
It probably depends how you laminate it. I exclusively use purple Bob Smith, and I have never had issues with tension members tearing off. I stick extra balsa stick on either side of the tension member, and then I glue a small balsa strip over all 3 sticks.

Re: Boomilever B/C

Posted: March 30th, 2019, 8:43 am
by wzhang5460
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.

Re: Boomilever B/C

Posted: March 30th, 2019, 9:08 am
by sciencecat42
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?