Towers B/C

[hearthstone224]

1. Ah so the tower wlil have 4x the buckling strength of one leg, which will total to 15,000 g?

2. Just for confirmation- I did the chart you told me I should set up in Google Sheets, and I was wondering whether I should add a column for the weight of the sticks that i am using, because how would I then compare one stick to another? I'm just looking for the lightest stick that is holding the certain amount (4608 while applying the safety factor)? Should I test all the sticks that are given to me or just roll with the first one that goes above 4608? Also I want to brace as little as possible, because then weight will be less?

[Balsa Man]

Ah so the tower wlil have 4x the buckling strength of one leg, which will total to 15,000 g?

Yes, I think; not sure the way you're saying it. Just to be sure-

If built symmetrically, the 4 legs of the tower will each equally carry 1/4th of the load put on top (15,000gr). 1/4th of 15,000 is 3,750gr. Because the legs are angled, the (axial) force on them is a bit higher; 3,810 for a C-div tower, 3,840 for a B-div tower (with bottom 3mm outside a 29cm circle, and height 3mm over minimum height). If all legs have a buckling strength > 3,810/3,840gr, the tower will carry the full 15,000gr load

[hearthstone224]

Ok I see what you mean, that was what I think I was trying to say. Just for safety, we are wanting at least 4608 when taking the safety factor in account?

I'm just curious- How did you figure out the angle and what force would be added to our base of 3,750 grams on each leg? And will this value change for a more angled tower?

[hearthstone224]

Oh one more thing- The jig is because of the shape, right? The jig helps us align the tower so that it is perfectly symmetrical?

This is my first time building a jig, its gonna be pretty rocky

Still trying to read through all your instructions, but I think I get the general jist of it.

Can someone post an image of one, that would be very helpful. I've seen SPP SCiO's picture of it, but a real life one would solidify my understanding.

Also I'm still a bit confused on how the jig is used. Do we build the whole tower on it or only parts? Again, a picture would be awesome.

[hearthstone224]

Oh yeah Balsa Man, the thing you posted on bracing, I couldn't see or view the images. Is anyone else having the same problem?

It would be great if you could fix it.

[Balsa Man]

Ok I see what you mean, that was what I think I was trying to say. Just for safety, we are wanting at least 4608 when taking the safety factor in account?

I'm just curious- How did you figure out the angle and what force would be added to our base of 3,750 grams on each leg? And will this value change for a more angled tower?

See discussion on basic math relationships a few pages back; the increase in force is a function of 1 over the cosine of the angle from vertical; 12.6 degrees for B, 10.6 for C; that means 3,840gr for a B, 3,810gr for a C. With 20% SF, that's 4,608 for a B, 4,572 for a C.
Yes it changes (increases with increased angle, but there is no need or purpose for greater angles

Oh one more thing- The jig is because of the shape, right? The jig helps us align the tower so that it is perfectly symmetrical?

This is my first time building a jig, its gonna be pretty rocky

Still trying to read through all your instructions, but I think I get the general jist of it.

Can someone post an image of one, that would be very helpful. I've seen SPP SCiO's picture of it, but a real life one would solidify my understanding.

Also I'm still a bit confused on how the jig is used. Do we build the whole tower on it or only parts? Again, a picture would be awesome.

As described in some detail, the legs get taped on the plate edges of the jig, the bracing gets put between the legs. The tower doesn't come off the jug until the tower is done.

Oh yeah Balsa Man, the thing you posted on bracing, I couldn't see or view the images. Is anyone else having the same problem?

It would be great if you could fix it.

Are you opening it in Microsoft Word? Checked it on 2 different computers- It works fine if you do

[hearthstone224]

Sorry for something that I might've not read before, but should I worry about the weights of the sticks right now? Should I test BS of all the sticks I have before choosing four of them to use, or should I use the ones that i have right away that hit at least 60 g?

[Balsa Man]

Sorry for something that I might've not read before, but should I worry about the weights of the sticks right now? Should I test BS of all the sticks I have before choosing four of them to use, or should I use the ones that i have right away that hit at least 60 g?

Yes, you should weigh and BS test all the sticks you have (and any new ones you get. As to which to use, there's building 1) just for the practice of building (which as a new builder, you'll want...a couple rounds at least of), 2) building for confirming things, and, 3) building for competition. For 1) really doesn't matter, as long as you don't use up what would be good competition sticks. For 2) weight doesn't matter- BS does, to confirm that measured BS at 36" translates to enough strength when braced in the tower. Also, you'll need to figure out weight/BS for ladders for bracing that'll be enough; the ones toward the top can be really light- like 0.8-0.9gr/36"- you'll need to dial the weight/BS up as you get down to the long bottom ladder. Testing will tell you- as in whole tower load tests; to get close, you know enough now you can work out the math from 36" BS testing; you'll need around 1,000gr (maybe 750, but 1,000 should be safe) at the length they are in the tower For 3), you'll be looking for the four lightest sticks that have a 36" BS at strength you've confirmed is enough.

Have fun

[hearthstone224]

AH I see, you want me to build three towers to test the BS and the building skills of the towers? Final one is the real deal.

Cool. I still need to read your post on bracing so I'll be a bit quiet for the next few days.

[Unome]

AH I see, you want me to build three towers to test the BS and the building skills of the towers? Final one is the real deal.

It's more like three categories of towers, depending on what you're using them for. You'll probably end up making two or three of category 2, and probably not more than 1 or 2 of category 3 (Balsa Man?)