Page 27 of 31
Re: Designs
Posted: April 10th, 2012, 11:05 am
by flyingwatermelon
SLM wrote:hpfananu wrote:So a few weeks ago I was watching that old Towers video that's in the SOINC store. There's one section where someone analyzes some of the first towers at the ?1994 competition. What was kind of interesting was that this person said that you should have bracings all meet at one point, similar to this.
(Mind the awful image but I think you can understand the idea)
Wouldn't this leave a lot of the section of the other legs unbraced? If this was done all around.
Instead, would
be beneficial instead? It doesn't leave more of the leg unbraced but they don't all meet at one point. Thoughts?
In terms of material usage, both patterns seem to use the same amount. In terms of strength, however, there are differences. Here is a simple analysis showing which pattern works better for the chimney and why.
A Comparison Between two Bracing Patterns
So SLM, what you're saying is that the first pattern is more efficient?
Re: Designs
Posted: April 10th, 2012, 1:31 pm
by SLM
flyingwatermelon wrote:SLM wrote:hpfananu wrote:So a few weeks ago I was watching that old Towers video that's in the SOINC store. There's one section where someone analyzes some of the first towers at the ?1994 competition. What was kind of interesting was that this person said that you should have bracings all meet at one point, similar to this.
(Mind the awful image but I think you can understand the idea)
Wouldn't this leave a lot of the section of the other legs unbraced? If this was done all around.
Instead, would
be beneficial instead? It doesn't leave more of the leg unbraced but they don't all meet at one point. Thoughts?
In terms of material usage, both patterns seem to use the same amount. In terms of strength, however, there are differences. Here is a simple analysis showing which pattern works better for the chimney and why.
A Comparison Between two Bracing Patterns
So SLM, what you're saying is that the first pattern is more efficient?
I cannot tell from the drawings. It seems to me that the first drawing shows bracings on two adjacent sides of the tower whereas the second drawing is of two opposite sides. You need to know the orientation of the bracings on all four sides of the tower to decide which scenario offers more stability.
Re: Designs
Posted: April 15th, 2012, 1:46 pm
by thsom
Hey, What is the average mass of a 24" 1/8*1/8 basswood stick. I know that it's about 1.5 for balsa for 36"
Re: Designs
Posted: April 15th, 2012, 6:20 pm
by mrsteven
thsom wrote:Hey, What is the average mass of a 24" 1/8*1/8 basswood stick. I know that it's about 1.5 for balsa for 36"
Really? From my sources I get a pretty consistent baseline of 1.3-1.4
^ Which is good, b/c there isn't really much use for anything above 1.3
Re: Designs
Posted: April 15th, 2012, 6:44 pm
by thsom
mrsteven wrote:thsom wrote:Hey, What is the average mass of a 24" 1/8*1/8 basswood stick. I know that it's about 1.5 for balsa for 36"
Really? From my sources I get a pretty consistent baseline of 1.3-1.4
^ Which is good, b/c there isn't really much use for anything above 1.3
right around that ballpark, but what about basswood?
Re: Designs
Posted: April 15th, 2012, 6:54 pm
by mrsteven
I never find the need for it. I get fairly constantly at and under 9 grams holding full load with balsa
Re: Designs
Posted: April 15th, 2012, 7:14 pm
by thsom
mrsteven wrote:I never find the need for it. I get fairly constantly at and under 9 grams holding full load with balsa
True, true, yet i think I have found a 6 or so gram design that could hold all at 70 cm, if only i had this AHA moment 1 week ago....
Re: Designs
Posted: April 16th, 2012, 6:45 am
by LKN
About where have any Division C builders here had your base legs massed at? I'm always under 2.5 grams, usually hovering right at about 2 grams. But, I seem to be getting to heavy from bracing, since most of my bases come out at 3.4-4g with the different modifications I have had. Where is everyone else at? Our team is hitting around 8-9g at 70cm, holding 15kg.
Re: Designs
Posted: April 16th, 2012, 7:04 am
by mrsteven
LKN wrote:About where have any Division C builders here had your base legs massed at? I'm always under 2.5 grams, usually hovering right at about 2 grams. But, I seem to be getting to heavy from bracing, since most of my bases come out at 3.4-4g with the different modifications I have had. Where is everyone else at? Our team is hitting around 8-9g at 70cm, holding 15kg.
I'm at the same place although my season is over so im not really improving anymore...
Re: Designs
Posted: April 16th, 2012, 6:09 pm
by thsom
so... nobody knows the mass????