Towers B/C

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MadCow2357
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Re: Towers B/C

Post by MadCow2357 »

Unome wrote:
MadCow2357 wrote:I am estimating that I will use about 2 grams of glue (Many joints, and I use a ton of glue :? ).
You can easily shave off 75% of this without losing any structural integrity. Most joints only require in the range of 5-10 micrograms of glue or less.
How much is that? I have yet to figure out how to use exactly the right amount of glue. I usually just add a little more, in case I have not added enough. "Better safe than sorry".
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Re: Towers B/C

Post by Unome »

MadCow2357 wrote:
Unome wrote:
MadCow2357 wrote:I am estimating that I will use about 2 grams of glue (Many joints, and I use a ton of glue :? ).
You can easily shave off 75% of this without losing any structural integrity. Most joints only require in the range of 5-10 micrograms of glue or less.
How much is that? I have yet to figure out how to use exactly the right amount of glue. I usually just add a little more, in case I have not added enough. "Better safe than sorry".
For most joints, a microapplicator, to pick up glue with capillary action and deposit it in amounts less than a drop, should work well (I believe there are instructions on how to make a microapplicator on soinc.org under one of the flight events). If the two pieces fit flat at the joint, you should need no more than a few micrograms to join them effectively.
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Re: Towers B/C

Post by MadCow2357 »

MadCow2357 wrote:
Crtomir wrote:
MadCow2357 wrote:Well, kind of wish that I asked this question earlier. Anyways, yesterday night I decided to order 1.8 gram for 1/8, and 0.4 for 1/16. I calculated that the 1/8 will account for about 4.25 grams, and the 1/16 bracing will weigh about 0.5 grams in total. I am estimating that I will use about 2 grams of glue (Many joints, and I use a ton of glue :? ). that would bring me to a 6.75 gram tower that I am hoping will hold full load, or near it. I would score 2963, which would be an all time high for me! But, as many people have said before, math only works if everything is perfect. I will probably score somewhere in the low 2000s for this one, which would still be VERY GOOD FOR ME! My top is 1184 right now, 13 grams and 10.8 kg held. Not so good...
But this is my first time doing a balsa structures event, and 1500 can win gold at RI, so I'm pretty hyped! If I can score 2000, I will beat last year's tower (1133) by almost 900 points. And last year's 1133 won gold.

To address your about the rectangular base, I did start with a square tower. But, I did not understand the importance of a one piece jig at that time, so I built the tower entirely without a jig. I built the top half and the bottom half separately, and that tower scored 680 :cry: . So, I decided to build a rectangular base tower like my local high school's team did. They also gave me their jig, because they made a new one, so I was all set to build a rectangular tower. I find rectangular towers easier to build, as I just create 2 sides and lace them together.

However, if I had more time before competition, I would definitely use the time to design a good square tower, as well as build a good one piece jig out of clear acrylic. After doing more and more research to understand the concepts, I am becoming increasingly dissatisfied with what I have accomplished, and my decision to build rectangular base towers.
I don't see how using 1.8g for the 1/8" x 1/8" x 36" sticks to use as the main columns (legs) of your tower is going to get you a 6.75g tower. Measure the length of your legs (base and top "chimney") and multiply by 4 to get the total length of all legs. The height of the tower is at least 50cm, right? So because the base is diagonal, you will use more than 50cm per leg, but lets just say you had 50cm on each leg, that would be 200cm total for all 4 legs, right? So your total weight for just the legs would be

1.8g * 200cm / 36in = 1.8g * 200cm / 91.4cm = 4.2g

But your tower design has essentially 8 legs on the base and 4 on the chimney, so the total length of all your legs together is probably more like 4* 80cm = 320cm. That would give you

1.8g * 320cm / 36in = 1.8g * 320cm / 91.4cm = 6.3g

So, I'm guessing that just the columns (legs) of your tower alone will add up to at least 6g. Then you have all the bracing and glue to factor in. Bracing starts to add up. Really. Also, don't use so much glue. It should be only about 0.2g-0.3g total if you are careful.

Of course if you use 1.8g columns, you don't need nearly as many bracing intervals to support the columns, but it won't cut your weight down that much. I'm guessing you will have a 9-10g tower.

The real question is how much weight can your tower support? How much weight has your tower been holding so far?
I want to cry right now... Because you are definitely right on the fact that I messed up the calculations. But you may have underestimated how much I messed up on this...

Let me explain what I did wrong. First, I only calculated the weight of one side. Second, I miscounted the bracings for a single side. Third, I only accounted for the bracings that would lace the two sides together. Lastly, I did not order enough wood. This all said, I believed that I could get a 6.75 gram tower when I would actually get a 11.39 gram tower. Not so good, eh? :cry:

Here is a link to the revised data and calculations:
https://docs.google.com/document/d/169h ... sp=sharing
https://drive.google.com/file/d/1sRQwF3 ... sp=sharing

I guess I will just reorder wood, since I have decided to switch from 1.8g 1/8 sticks and 0.4g 1/16 sticks to 1.2g 1/8 sticks and 0.3g 1/16 sticks. Should I order enough for 2 towers?
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Re: Towers B/C

Post by Crtomir »

MadCow2357 wrote:I want to cry right now... Because you are definitely right on the fact that I messed up the calculations. But you may have underestimated how much I messed up on this...

Let me explain what I did wrong. First, I only calculated the weight of one side. Second, I miscounted the bracings for a single side. Third, I only accounted for the bracings that would lace the two sides together. Lastly, I did not order enough wood. This all said, I believed that I could get a 6.75 gram tower when I would actually get a 11.39 gram tower. Not so good, eh? :cry:

Here is a link to the revised data and calculations:
https://docs.google.com/document/d/169h ... sp=sharing
https://drive.google.com/file/d/1sRQwF3 ... sp=sharing

I guess I will just reorder wood, since I have decided to switch from 1.8g 1/8 sticks and 0.4g 1/16 sticks to 1.2g 1/8 sticks and 0.3g 1/16 sticks. Should I order enough for 2 towers?
Wish you were close by us in Ohio. We would just give you some wood. We'd set you up with a decent jig too. You should definitely get wood for more than just one tower. You should get wood for lots of towers. There is always a balsa structure event every year, so having extra is useful. How much you order depends on your budget.

I think if you could do a square base design, it would be better. Then if you did X-braces all the way up, that would be good. Five X's per side on the base and 4-5 X's per side for the top. Try 1.2g for the bottom 4 legs and 1.0g for the top four columns. I mean 1.2g and 1.0g for the whole 1/8" x 1/8" x 36" sticks. Then, instead of using 1/16" x 1/16" sticks for braces, use take some 1/16" thick sheets of balsa that are 3-4" x 36" and use a balsa stripper to cut strips just a tad bigger than 1/32" thick, so they will be 1/16" by slightly larger than 1/32". Use these as your braces. The 1/16" thick sheet should have a density of about 8# which is 8 lbs/ft^3. Just adjust the thickness of your braces that you strip so that the 36" pieces weigh between 0.20g and 0.25g.

Make sure to put a compression piece between the legs of your base at the top on each side. These must be 1/8" x 1/8" piece cut at a precise angle to fit between the top of the legs of the base pyramid (not between the bottom columns of the top chimney part of the tower). This can be from lighter 1/8" x 1/8" x 36" sticks that weigh maybe 0.8g. The compression piece keeps the top of your base from caving inward.

Then, add a tension strap at the bottom of all four sides of the base that is 1/16" x 3/32". Again, cut this from that same 1/16" thick sheet of balsa you use for stripping the braces from. This tension strap keeps the legs of your tower from spreading outward.

I'm not sure how helpful this is, but one of our towers is here: https://www.dropbox.com/s/eux948o9uovpd ... n.JPG?dl=0 Maybe that will help with seeing how it should look at the end. That tower our girls build weighed 6.9 g held all the weight (15 kg), and scored 2882 (Division-B) with the bonus.

Here is a picture of our Tower girls building one on the jig: https://photos.app.goo.gl/gmLSh7ila23zzrq63
And a picture of just the jig itself: https://photos.app.goo.gl/GnjINS3WzJrUriD82
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Re: Towers B/C

Post by MadCow2357 »

Crtomir wrote:
MadCow2357 wrote:I want to cry right now... Because you are definitely right on the fact that I messed up the calculations. But you may have underestimated how much I messed up on this...

Let me explain what I did wrong. First, I only calculated the weight of one side. Second, I miscounted the bracings for a single side. Third, I only accounted for the bracings that would lace the two sides together. Lastly, I did not order enough wood. This all said, I believed that I could get a 6.75 gram tower when I would actually get a 11.39 gram tower. Not so good, eh? :cry:

Here is a link to the revised data and calculations:
https://docs.google.com/document/d/169h ... sp=sharing
https://drive.google.com/file/d/1sRQwF3 ... sp=sharing

I guess I will just reorder wood, since I have decided to switch from 1.8g 1/8 sticks and 0.4g 1/16 sticks to 1.2g 1/8 sticks and 0.3g 1/16 sticks. Should I order enough for 2 towers?
Wish you were close by us in Ohio. We would just give you some wood. We'd set you up with a decent jig too. You should definitely get wood for more than just one tower. You should get wood for lots of towers. There is always a balsa structure event every year, so having extra is useful. How much you order depends on your budget.

I think if you could do a square base design, it would be better. Then if you did X-braces all the way up, that would be good. Five X's per side on the base and 4-5 X's per side for the top. Try 1.2g for the bottom 4 legs and 1.0g for the top four columns. I mean 1.2g and 1.0g for the whole 1/8" x 1/8" x 36" sticks. Then, instead of using 1/16" x 1/16" sticks for braces, use take some 1/16" thick sheets of balsa that are 3-4" x 36" and use a balsa stripper to cut strips just a tad bigger than 1/32" thick, so they will be 1/16" by slightly larger than 1/32". Use these as your braces. The 1/16" thick sheet should have a density of about 8# which is 8 lbs/ft^3. Just adjust the thickness of your braces that you strip so that the 36" pieces weigh between 0.20g and 0.25g.

Make sure to put a compression piece between the legs of your base at the top on each side. These must be 1/8" x 1/8" piece cut at a precise angle to fit between the top of the legs of the base pyramid (not between the bottom columns of the top chimney part of the tower). This can be from lighter 1/8" x 1/8" x 36" sticks that weigh maybe 0.8g. The compression piece keeps the top of your base from caving inward.

Then, add a tension strap at the bottom of all four sides of the base that is 1/16" x 3/32". Again, cut this from that same 1/16" thick sheet of balsa you use for stripping the braces from. This tension strap keeps the legs of your tower from spreading outward.

I'm not sure how helpful this is, but one of our towers is here: https://www.dropbox.com/s/eux948o9uovpd ... n.JPG?dl=0 Maybe that will help with seeing how it should look at the end. That tower our girls build weighed 6.9 g held all the weight (15 kg), and scored 2882 (Division-B) with the bonus.

Here is a picture of our Tower girls building one on the jig: https://photos.app.goo.gl/gmLSh7ila23zzrq63
And a picture of just the jig itself: https://photos.app.goo.gl/GnjINS3WzJrUriD82
Thanks for the offer of a decent jig and some wood, but as you pointed out, I am nowhere near you guys (current location: "a hole in the ground", or more specifically, a hobbit hole located in RI. :D )

However, you are right. It would be better if I was doing a square base design. And it would also be nice to have a jig like that. But I would have to come up with a completely new design, draw it out to scale, and build a new jig. Then I would have to build at least 2 more towers before April 21st (competition day). Which would be a problem... because I build almost all of my towers myself without any help from my partner.

Right now, I will have to be satisfied with my rectangular base design, because there is no time to make any major changes. While it certainly would not hold a candle to any decent tower at nationals, I firmly believe that I can win gold at RI. But if my team somehow managed to pull off another states win, then maybe... maybe I could change things up a bit.

With much gratefulness and respect, MadCow2357
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Re: Towers B/C

Post by jocoboxo »

Would either 1/16x1/16 or 1/32x1/32 be viable for competition?
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Re: Towers B/C

Post by MadCow2357 »

jocoboxo wrote:Would either 1/16x1/16 or 1/32x1/32 be viable for competition?
Your question has been addressed in many previous posts. But to save you some time reading through 27 pages of previous posts, I will simply say that most teams will use 1/16"*1/16" or 1/32"*1/16" for braces. I am personally using 1/8"*1/8" legs and 1/16"*1/16" braces.

Take some time to read through the entire Towers forums. I did a few weeks ago, and I have benefited to a degree to which I cannot describe.
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Re: Towers B/C

Post by DarthBuilder »

jocoboxo wrote:Would either 1/16x1/16 or 1/32x1/32 be viable for competition?
Both would be viable but most people as stated by MadCow is the 1/16 x 1/16 and 1/32 x 1/16
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Re: Towers B/C

Post by jbjbjbjb888 »

So my State competition was this past Saturday (full scores came out yesterday), and we found out that the supervisors did not count our 5,000 g bonus, which dropped us from 1st to 12th. Our tower was 21.5 cm square and did not touch the test base inside the 29 cm circle, so we thought we got the bonus. Is there anything I'm missing with these rules in terms of getting the bonus?
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Re: Towers B/C

Post by cool hand luke »

at regionals one of our two towers had the bottom cross brace touching the inside the circle so it didn't get the points despite having legs that spread out past the circle.
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