2025 Science Olympiad Tower Div B: Bases
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- Опубліковано 8 лют 2025
- This video shows the build and optimization process for base portion of the Division B Science Olympiad 2024-2025 Tower event.
Here is a link to a zip file of all the jigs and support objects I used throughout the series:
klingerphotogr...
Feel free to contact me with any specific questions or comments at mklinger(at)comcast(dot)net
Hi, Thanks for your informative videos. Wanted to understand why you need the horizontal members all the way at the bottom. Thanks
They may not be necessary depending on the strength of those bottom cross members, but because the base is so wide for the bonus build, those pieces are in pure tension and a single horizontal cross member is a good way to hold the legs in place at the bottom.
Thanks for the informational videos. These are really helpful. I have a question, should the base or the column must contain crossovers?
Please help.
Thanks.
Thanks! If you are asking if the base and column need to have cross-bracing between the legs, the answer is definitely. The X design is only one option, although probably the best option. If you want to learn the theory behind this and see some other examples, I recommend you watch my 5-part Tower Basics series where I explain all of that. Here is part 1: ua-cam.com/video/XLtn8frygYo/v-deo.html Good luck this season!
I understand but if we don’t do cross bracing will it be disqualified?@@balsaengineering6686
Hello, thank you for the great video. Can you please attach the link to the wood that you used for the base,= that made the entire base’s mass 4.296 grams? Thank you.
There are no direct links to the pieces like that. You will have to buy "light" density balsa sheets and cut your own sticks to get exactly what you want. That is exactly how I do it. I like to buy my balsa sheets from Specialized Balsa: specializedbalsa.com/products/balsa_sheets.php
Hello balsa enginnering, thank you for the videos. I was wondering the physics behind the bonus bases and why it's more likely to break than a normal base. Also, should you dedicate more weight to the legs or crossmembers? Which cross members endure most weight in the design, is it the last ones or second to last and why? Sorry for all the questions 😅, but last, what are some tips to reduce the weight as much as possible? thanks so much
Hi! The two main reasons the bonus base is more likely to break and needs to be heaver than the non-bonus is that the angle of the legs is more shallow which introducing bending forces in the legs and the cross-member pieces need to be longer which means they are weaker wrt to buckling. You can watch my buckling video as part of the 5-part series to see more details of that theory. The perfect mass budget to balance between the legs, the cross bracing, and the number of the layers is really the main challenge of this entire event. Again, check out the 5-part series on the theory to really see in this detail. There is no magic to reduce the weight, you really just need to use lighter balsa which usually means buying it from a specialty store and cutting up a bunch of sheets to get exactly what you want. Good luck!!
Hi! What weight did you use for the pillars and cross section wood to make it around 4 grams?
Hi! If you check out the video at the 4:51 mark, you can see my notebook page for the benchmark build. There you can see the masses of all the parts including the legs and each cross bracing layer in written in red. The measurements on the right for the cross bracing are for all 8 pieces of a layer together, so for example, the bottom layer used (8) pieces that were 20.3cm long each and together they all weighed 0.492g.
Can we use 1/4 inch balsa sticks for building the tower?
You can definitely use 1/4" balsa when building the tower. You will probably find that it is overkill, meaning your tower will be pretty heavy, but it's fine to use especially if you are just starting out. Good luck!
Hi Balsa Engineering , I was wondering if you made the tower as a whole or you made the column and the base separate and glued them together?
Hi! I definitely make the base and columns separately. I also test them separately before gluing them together. I have some other videos in this series where I show the that as well.
Hello, I was wondering if it was possible to make the column more than 26 cm and the base less than 24, which we were thinking could possibly increase the structural integrity of the tower (because our column can handle a good amount of weight)/reduce the weight of the tower. (The column would be pretty long but still fit the ring requirement, but the base would be short).
Hi! I encourage you to experiment with that a bit. The rules definitely allow what you are describing. You could have a really long column with a very short base. I think you'll find that any weight you might save with a longer column will be more than used up by needing to make the base stronger due to the increasing leg angles. The base would become much more like a bridge. That is the beauty of testing the bases and columns separately though. See if you can build your short base that holds what you want and within the mass budget that makes it worthwhile. You won't even need to make a complete tower to know if your design change is worthwhile or not. Good luck!!
Wait the base of my tower is near 30 cms tall should I shorten it to make sure the ring can fit.
You need to make sure your tower follows the rules. The ring needs to fit around the finished tower at a height of 25cm above of the testing surface.
For your tower builds, do you use sticks or sheets or a combination of both (for the legs sticks and the cross bracing sheets)? Also, what dimensions do you recommend buying?
I always buy sheets and cut my own sticks. It's less expensive that way and you get more control over the entire process. A good place to start is 1/8" sheets for the legs. For the cross-members, there is no one correct answer. I have used 1/16, 1/20, and 1/32 thick balsa successfully. You can check out my notebook pages for these builds to see exactly what I used, size and mass if you want a good starting point. Good luck!
I am trying to build the tower without a jig. Could you please share a basic template (showing the length and angles of legs)of one side of the base and column?
I don't really have a template like that to share. Probably the best thing would be to watch my approach video that shows I designed the jigs. You can use that to try and create some kind of template. ua-cam.com/video/JdWY8FcbSGI/v-deo.html I warn you though, it will be extremely difficult to make good tower without some kind of assembly jig. It doesn't have to be 3d printed, but you'll want to build something to help make it as symmetric and level as possible.
@@balsaengineering6686 Thank you! That video is really helpful.
you used 1/8x1/8 for the vertical legs, what size did you use for the crossmembers? Thanks
You can see that when I show my notebook pages, for example at 3:45. Most of the cross members for this build was 1/16 x 1/16. Many options can work for cross bracing though depending on the material you have on hand.
Hello! For our students we are going to focus on the bonus build. For the jig, do we print every part except the non-bonus tower base? Thank you.
Yes, you'll want to print the base, the top and bottom column parts. You can print the custom loading block if you want to test the base separately and the ring is for final competition verification of the rules. Good luck!!
Thank you!
@balsaengineering6686, thanks a lot for sharing! With your Div B non-bonus stl file, I can make a base jig with the size 21.5cm * 21.5 cm. This must be due to the 2025 rule that the base must span a 20 cm x 20 cm square opening. I wonder if a base jig with the size 14.2 cm * 14.2 cm will work? (Here 14.2 cm = 10cm *sqrt(2))
The non bonus jig base I have provided is big enough to span the 20x20 square hole if you rotate it 45 degrees on the testing surface
Can I test the base without the top horizontal cross pieces using a flat block and glue the horizontal cross pieces afterwards? Will the base without the top horizontal cross pieces too weak for testing? Thanks!
I would not recommend that. Unless you make the base strong enough so it doesn't ever need those horizontal cross pieces. That is something worth experimenting with as you build devices this year. Good luck!
@@balsaengineering6686 Thanks! What about lower the cross pieces a bit so that they don't take weight during testing? I printed a loading block from a library but the library did not do a good job.
@@MsShuangshuang I'm not sure I quite understand what you are asking. The custom loading block should be a fairly easy thing for most printers to print. Try having them increase the infill to something like 40 or 50% and make sure it's being printed with the flat side down. That might help getting the block legs to print well.
@@balsaengineering6686I will print it again. I was thinking instead of having the horizonal cross pieces right at the top, what about gluing them 0.5 cm down from the top. Will the base be as stable? I am working on nonbonus base and the cross sections will be slightly different anyways.
@@MsShuangshuang Having those top horizontal cross pieces 5mm down will probably be fine. It all depends on the rest of your build. Only one way to know for sure and that's to try it :)
How far apart did you attach each member from the other
By this I meant the horizontal member above ot
@@King_Kay_66 You can see that information (and more) in this video when I show my notebook pages. For example at 5:17 On the drawing on the right side, the first layer is at 0.5cm and then each layer has a spacing of 5.2cm
Hi There
the links for the stl files are not working. Can you send me the stl files to me or direct me where to get them.
Thank You for your work!
Hi! Some browsers block the download if you just click on them. Try copying and pasting the link into a new tab in your browser and then overriding the warning to download the file. If that doesn't work, send me an email and I can get them to you that way.
Hi balsa engineering! Could you please tell me what ur dimensions of the cross members you used.
If you check out my notebook page for each build, I show the cross member sizes. The benchmark tower used a combination of 3/32 x 3/32 for the top, 1/16 x 1/16 for the bottom and 1/20 x ~1.5mm for the cross members (carry over from base #2). Really, the size is not as important as the mass of the layers which you can also see from my notebook page written in red 5:04
hey Balsa Engineering
What is the width you used to make the both columns and the base
Hi! I'm not exactly sure I understand your question. If you mean the material width, I used 1/8 x 1/8 for the legs for both the base and column. If you mean the dimensions of the base and column, I have an entire video where I talk about the overall design approach. Definitely give this a watch if you haven't already: ua-cam.com/video/JdWY8FcbSGI/v-deo.htmlsi=ZmJscB9zWSoGnM2v
Where are the 3d print files?
There is a link to a zip file that contains all the jigs and support stl files in the description of this video
Hi, Is it possible to ship me a non bonus Jig, I will pay?
Hi! I don't sell the printed jigs, but you can download the stl files in the description of this video. You can either print them yourself or potentially use a 3rd party online service to print them, but I would recommend you find a local option if possible.
Thanks a lot.