2024 Science Olympiad Tower: Div C Initial Build

[@김지윤-f5b3e]

Hi, balsa engineering! I finished the north carolina state competition with 5th place(2500 actual efficiency). I worked on myself, and practiced without sleeping. I wished I had someone who can teach me, but my teachers didn’t know very much about towers, so I had to watch your videos over and over again. I really appreciate for your information, but I couldn’t get the design log points, because I turned in incomplete design log. So I would suggest you to make a short design log video, it would help a lot of people, because the referee said only 40% turned in design log when I asked for the them. I am the only one who got a medal in my school, but you were the reason that made me to do this. I really appreciate you again. Thank you.

[@balsaengineering6686]

Hi! Congratulations on your results! That is a fantastic job, especially considering you didn't have any real support from your teachers or coaches. Regarding the log, there is a template in the actual rules that shows what at least the minimum log should contain. If you want to see everything that I record, you can check out my Taking Notes video: kzbin.info/www/bejne/bJu2nZuOj7SFg9U In general, I would record what the rules ask for specifically, and then record even more detailed information like what I show in my notebook which really help to know from build to build. Good luck if you compete again next year!

[@김지윤-f5b3e]

Thank you so much again. I will do better next year so that I can beat NCSSM! Cause I live in NC.. I will see you next year thanks!

[@omramchandrajieducational]

I swear, the second the rules come out for bridge, boomi, or tower, instantly you make the best one, and then EVERYONE copies. In scioly it isnte even a question of who can design the best bridge/tower/boomilever anymore, it's just "who can copy Balsa Engineering the most consistently"

[@balsaengineering6686]

One of my goals is to allow any team to be able to compete at the highest level if they want to put in the effort. First, you need a good design to start, then the real work begins with refining the design, material optimization, and build skills. In the past, only teams who had historic knowledge were starting from good designs. (BTW, these tower rules are essentially identical to 2017, so any school that knew anyone working on it then would have a huge head start). So, yes, I'm definitely trying to help the bottom 75% of teams bring up their builds instead of starting from something like the really bad template designs SciOly puts out there. The top 25% doesn't really need my help, but now any team that wants to put in the effort, at least has the chance to complete. Good luck this season!

[@EmmettFerguson-rs9dw]

Thanks so much for the videos again this year! my partner and I just ordered our materials and they should be arriving soon, but I noticed that you might be able to lower the weight on your build with less crosses and possibly lower density crosses.

[@balsaengineering6686]

Thanks for the positive feedback! Be sure to check out my other Div C video for my current best build. I also hope to have an even better one coming soon, so stay tuned! Good luck this season!

[@aidan8600]

thank you so much for your extremely helpful videos! incredibly fast as well

[@vinyaaleti4430]

Hi Balsa Engineering, I was wondering, what is the angle tilt of the tower? And also what is the size of the opening at the top of the tower?

[@balsaengineering6686]

The angle is 5.28 degrees, but that just came out of the other dimensions. The top of my jig is 40mm x 40mm square

[@timchristensen5548]

Thanks!

[@김지윤-f5b3e]

Hi, at 3:08, do you mean to glue the crossing point of cross members? Like crossing point of the “X”? And does it help the tower to hold more weight a lot?

[@balsaengineering6686]

Yes, you 100% want to make sure you glue those center points of the cross-members. That effectively makes them 1/2 the length and 4 times stronger wrt buckling! If you haven't been doing that, this will really help your future builds. Good luck!

[@김지윤-f5b3e]

Hi, balsa engineering! So i tested two towers, which is very similar but different to your tower. I used the jig, so the first one was 6grams, and second was 5grams. Both tower couldnt go over 10kg, and I recorded the video of it breaking! I saw that the 1/8*1/8 was the problem. The bottom part was too weak, so it broke, which leads to the whole tower break. I used 0.8grams for each 1/8 sticks. Can you please give me some advice? Thank you.

[@balsaengineering6686]

Hi! Without seeing slow motion footage of your actual tower being tested, it's hard to know for sure, but in general, 0.8g 1/8 x 1/8 legs should be plenty strong enough to hold over 15kg. That makes me think there was an issue with your cross bracing. Did you use 10 layers? Did you glue the middle of the Xes? Even a single bad cross-member piece can ruin the entire tower, so it's very important you weigh and examine every piece to make sure one isn't too light or has a flaw. If the tower is slightly off-level, that can also cause early failure. So, double check the level of your tower and focus on the cross-bracing for your next build. Good luck!

[@ElonaYoder]

Can you glue multiple sticks to the legs for sturdiness? Can you use a 3D printer to print each side? Can you use a hot glue gun?

[@balsaengineering6686]

If you mean, could you add sticks vertically to the legs for added strength, you definitely could, but that would be way less efficient than just increasing the density or size of just the legs. You can't 3d print the sides as it has to all be made out of wood. You could use hot glue, but I would highly recommend that you don't do that as it's way too heavy and not nearly as strong as something like CA (superglue)

[@김지윤-f5b3e]

Hi, balsa engineering, I apparently got 3rd place in the regional. I had a arguing with the referees that the width of the tower has to be 20cm or not. I said it has to span an opening of 20 cm, not a width. And they agreed eventually. And while the referee tried to weigh my tower, one of my crossmembers break.. And I had to fix it. And the problem of my tower was the 1/8,1/8 wood. I think it’s too weak. Can I know the density of this wood also? I’m not preparing state, so wish me a luck! Thanks!

[@balsaengineering6686]

The tower needs to span the 20x20cm hole, but to do that, it only needs to be a little over 15x15cm wide. If they said it needed to be 20cm wide, they were wrong. Also, the event supervisor should have never touched your device. The students are the ones who put it on the scale. That is explicitly stated in the rules. Next time, don't let them touch your tower! 1/8 x 1/8 legs are a good choice, probably the best choice. If you check my notes in my Benchmark build video, you can see exactly what I used. You want to be around 0.7-0.8g each. Good luck at your state competition!

[@jiyagupta5467]

Hello! Thank you so much for this video! I was wondering what the numbers marked in green meant at 0:28 seconds. And consequently, what the total at the bottom means

[@balsaengineering6686]

Thanks! The green numbers there are the lengths and number of cross-members and the bottom is the total length of all the cross members. I made an entire video on how I take notes to explain this all in much more detail if you want to watch: kzbin.info/www/bejne/bJu2nZuOj7SFg9U

[@hkp1015]

What advice would you give in terms of design if my only wood lengths are 1/16, 1/8, and 1/4? Is it advised to go for bonus? And should wood be thickest at the bottom in that case?

[@balsaengineering6686]

I would not go for the bonus. Try to find 1/8 x 1/8 sticks for the legs that are between .7 and 0.8g (or as close as you can get), and use your lightest 1/16 sticks for the cross members. If you have 1/16" sheet, try cutting it smaller than square to save some mass. Forgot about using the 1/4" wood. Good luck!!

[@hkp1015]

@@balsaengineering6686 Thanks! I have a quiet a few questions. Sorry if it's a lot. So why exactly is the 1/4 wood not as advisable? Should I cut them up into fourths? Also, if I go for the bonus, is there a way I can efficiently do it, or is that really something I have to scrap? Is using lines instead of X's for half of the tower with 1/4 legs advisable or is this worse? My current plan is 10 crosses using your lengths in the video, with 1/8 size on the legs + bottom and 1/16 for the rest of the X's. Will this work well?

[@balsaengineering6686]

@@hkp1015 Basically, using 1/4" is too heavy for this build and won't make a competitive tower. If you can cut them into 4 pieces of 1/8 x 1/8, then definitely give that a try. I made an entire video where I talk about this bonus build for Div C you might want to check out: kzbin.info/www/bejne/qYXLn5dqh5JsldEsi=zjn0_qUrSSvlzvY2 The short version is that it might be possible to get a good tower, but it's too risky having to hold 15kg and it's most likely not competitive with the best non-bonus builds which have no risk because they don't need to hold 15kg. If you build a 10 layer tower with 1/8 legs and 1/16 Xs, that should get you a good build. It all depends on the mass of the material you are using if it'll be super competitive or not. Good luck!!

[@hkp1015]

I'm using solely balsa. So would maybe making the first 2 layers 1/4, next 3 layers as 1/8, and the next 5 as 1/16 be a good option, so I can have a strong base?

[@balsaengineering6686]

@@hkp1015 It all depends on the mass/density. Most likely, what you are describing is overkill. Remember, the best towers this year will be around 5g and hold all 15kg, or nearly all 15kg.

[@김지윤-f5b3e]

Hi balsa wood, i was confused what the density of balsa stick is. Can you tell which stick I should buy? (Ex 0.2g per 1/16*1/16*36 stick) I want to know which balsa you used for this tower. Regional is coming up! I need to order specialized balsa as soon as possible!

[@balsaengineering6686]

I buy all my balsa in sheets and cut my own sticks. If you watch my Taking notes video: kzbin.info/www/bejne/bJu2nZuOj7SFg9U and then check out the note pages in my build videos, you can calculate exactly the wood I used to try and duplicate the results. Remember though, there is no single correct answer, so use my notes and builds only as a starting point.

[@김지윤-f5b3e]

Thanks!

[@lorip9027]

when I press the 1/8 sticks I feel like a little harder sponge .How to determine the sticks good or not

[@balsaengineering6686]

You'll definitely want to get a decent scale and start weighing your sticks. You can then compare them to what I have shown in this build. In general, if they are between 0.7g and 0.8g each, that is a good place to be.

[@lorip9027]

Thank you@@balsaengineering6686

[@김지윤-f5b3e]

Hi! Can I bake the tower in the oven? with the lowest temperature to dry more and faster

[@balsaengineering6686]

You can, but unless you have an excellent dry-box to put it in, it's definitely not worth the effort as it will gain all the weight back in a few minutes. I have used 200 deg F for 20 minutes for my baking tests. You might want to watch this video I made that covers this topic in more detail: kzbin.info/www/bejne/bKuyp3uDj7GUhKc

[@FikrieHodzhova-cx5ud]

Hello! I’ve been building towers that are about 9.5 grams each. I’ve been using 1/8 by 1/8 pieces balsa pieces for the 4 side pieces like you, and then for the crosses I’ve been using 1/16 x 3/32 pieces. In lower parts of the tower I used more dense pieces. Do you have any recommendations for how I should make my tower lighter?

[@balsaengineering6686]

Hi! Without seeing all the details of your tower builds I can only guess, but my first reaction is your cross-members are way too big and heavy. 1/16 x 3/32 is overkill for the cross-members. Even 1/16 x 1/16 is typically too heavy unless you get really light material. I would try and use something like 1/20 x 1/20 or even 1/32 x 1/20. The real key is the mass though, not the dimension. It's also possible/likely that your 1/8 x 1/8 legs are much heavier than what I'm using. Try to get those legs in the 0.7-0.8g range to start. I would recommend checking out my Div C benchmark video and take a close look at my notebook page (You can watch my Taking Notes video if you don't understand what's there). That will show you the exact pieces and material I used to get a ~5.1g tower which you can try and replicate. Good luck!!

[@FikrieHodzhova-cx5ud]

It’s hard for me to find pieces that are 1/20 in length and/or in width. One more question. Do you think it is more important that more surface area touches the 4 leg pieces or that they are the right density even if only a little bit of the x pieces touches the legs? For instance, on my most recent build I used bass pieces for the bottom that are 1/32 in length so very little surface area touches the leg pieces. Is that important?

[@balsaengineering6686]

@@FikrieHodzhova-cx5ud Mass is the most important thing. 1/32 basswood pieces can be glued well enough in place, but even at that size, it's way too heavy for this application (IMHO). 1/32" sheet balsa is easier to find than 1/20, so if you can find that, you can cut pieces that are around 1/32 x 1/20 (ish) at a good mass for this application and should do well and be about half the weight of your bass pieces.

[@FikrieHodzhova-cx5ud]

Okay, thank you! Is it normal for my tower to be twistable or for its sides to shift when I press a little on them? Is that normal due to the light weight, or is it a sign of weakness and that the tower won’t hold much?

[@balsaengineering6686]

@@FikrieHodzhova-cx5ud No problem! Yeah, for this X-only cross member design, the tower will be a little flexible. You'll be able to grab the opposite bottom legs and it will flex. As long as you take care to set it up completely flat so all 4 legs are touching the ground in the same way, it'll be fine.

[@skgamedev]

Hello, quick question, can you please provide a link to the specific wood you used. I know that it is balsa wood, but I'm having trouble looking for the correct dimensions online. Also, the 1/8x1/8x65cm dimensions for the legs, are the first two dimensions 1/8cm or 1/8 inch. Thanks for the video.

[@balsaengineering6686]

Hi! I like to buy sheets of balsa from Specialized Balsa and cut my own strips for everything: specializedbalsa.com/products/balsa_sheets.php I would recommend buying 4"x36" sheets of "light" balsa. The legs I'm using are 1/8" x 1/8" The cross-members can be a lot of thicknesses and sizes, but in general, anything from 1/16 x 1/16 to around 1/20 x 1/32 depending on density. Good luck!

[@skgamedev]

Hello. thanks for the swift response. One more thing, when printing out the jig on 3d printing websites like Xometry or ProtoLabs, the quote ends up being very high (in the thousands) for some reason. Do you know why this could be. What infill did you use, was it completely hollow?@@balsaengineering6686

[@SnikithaPeriketi]

Thank you so much for the video. Where can I find the 3D printed jig you were using in the video?

[@balsaengineering6686]

Thanks! You can find links to all the STL files in the description of the Intro video here: kzbin.info/www/bejne/e3TGq2aKa8uthsk

[@MaryamA-i1p]

Hi! Thanks so much for the video! Do you have the dimensions of the 3d printed jig anywhere?

[@balsaengineering6686]

Hi! Thanks! I have links to all the jig STL files in the description of the Intro video: kzbin.info/www/bejne/e3TGq2aKa8uthsk You should be able to get the key dimensions directly from the files if you want to design your own.

[@therealswan]

Hello, what material should I print jigs for this event with? Thanks for the video

[@balsaengineering6686]

Hi! I used very inexpensive PLA for all of these jigs, nothing special should be needed. Good luck!

[@suziel5523]

Hi! Quick question: after gluing the cross members to one side using the jig, would it squish the wood/affect tower performance if I flip the tower to glue the opposite side (3:18), such the assembled side faces down? Or should I glue the cross members while having the tower stand up vertically? My jig is weighted around 1kg.

[@balsaengineering6686]

Hi! I haven't found that to be an issue at all and I've found that there is a huge benefit to gluing it flat on the table to help minimize the glue usage and to keep the glue from dripping into the edge grooves and having the tower stick to the jig. Good luck!

[@suziel5523]

@@balsaengineering6686thank you for the quick reply!

[@lisavargas4862]

Hey I was just wondering if I could have the complete dimensions for the bridge (like the top and bottom width and length)

[@balsaengineering6686]

Hi! The best way to get all the dimensions would be to just download the STL jig files and take a look at them in a viewer or slicer program. You can find links to them all in the description of the Intro video here: kzbin.info/www/bejne/e3TGq2aKa8uthsk Good luck this season!

[@srilakshmivishnubhotla7576]

Hello how can we get the loading set-up? Thank you for this very informative video

[@balsaengineering6686]

You can buy one of the fancy auto-loaders here: www.balsawoodhoppers.com/services but they are pretty expensive. Most teams just build something that gets the job done with manual loading. The rules outline the specifics of the testing setup, that is the best place to figure out exactly what is needed. Good luck!

[@Spencerisgoated]

thank you so much for the advice but can you please give me the measurement's of the bracing pieces or just give me a link to amazon

[@balsaengineering6686]

Thanks! Unfortunately, it's not quite that simple. There is no one best cross-member material and dimension. You will wanto eventually buy sheets of balsa and cut your own strips. If you watch my Notes video: kzbin.info/www/bejne/bJu2nZuOj7SFg9U you will learn in detail how I record my notebook notes and then you can freeze the video where I show that and you'll gave all that information. In this video it's at around 1:17.

[@Spencerisgoated]

@@balsaengineering6686 ok thank you for this information I have been trying to get my hands on this bracing and I kept looking on Amazon but could not find this so I will use the balsa stripper I used last year so thank you

[@Spencerisgoated]

@@balsaengineering6686 and what do you use to cut the strips of wood

[@user-sp3hm2zu5z]

Hi, I noticed that you said you separated your cross bracing into three different types. What size of 1/32" sheets do you use, and what are the masses of them? (When I tried cutting pieces of balsa for cross bracing, the pieces I got were very bendy and easily broken just by pulling lightly on it, so I was wondering what density of balsa wood you are using.) Thanks in advance!

[@balsaengineering6686]

Hi! I like to buy all my sheets at 36" x 4". For the 1/32" cross bracing, I'd say the mass of the sheets I've been using are around 10g or so. I have also found that light 1/20" works very well too, sheets around 12g. There is no one right answer though, as that is part of the optimization problem. Good luck!!

[@bhargavamortha8077]

hiya! your videos are great! One quick question-do you sand the bottom of the legs as well to make sure they are flush with the floor? thanks I’m advance

[@bhargavamortha8077]

good question!

[@balsaengineering6686]

Hi! I used to sand the bottom of the legs flat, but now I don't bother. It doesn't seem to make any difference at all and it's just one more variable where things could make your tower less level. If you feel more comfortable doing that, take the extra time to make sure the tower remains as level as possible before testing. Good luck this season!

[@Demon-ky2mx]

Hey Balsa Engineering! My first iteration got stuck to the jig. Is there any way to prevent this? Is the jig still usable even with the glue that is stuck to it? Thank you for your time!

[@balsaengineering6686]

Hi! Yeah, that happens to the best of us! I found the best way to prevent it in the first place was to make sure you are gluing the cross-members in place with the jig on its side like I show in a lot of my more recent videos. Obviously, try to use as little glue as possible. If the tower does get stuck, don't try and pull it up off the jig. First, find something small - I 3d printed a 30x30x5mm square piece, and temporarily tape this to the top of your jig. Then carefully turn the entire jig upside-down and put it on a solid table. Then firmly press at least 2 legs at once from the bottom and hopefully the tower will pop off. That is what has worked well for me. The jig should be fine for future use even with that tiny bit of glue on there, don't worry about that. Good luck!!

[@FikrieHodzhova-cx5ud]

Hi, I am having trouble getting the tower off of the jig. Can you give me advice on how to get it off?? I have tried very hard.

[@balsaengineering6686]

Yes, that can be tricky. What I've found that works best is to find a small block, or 3d print one 30x30x5mm and temporarily tape it to the top of your jig. Then carefully turn the entire thing upside down and put it on a hard surface. Then firmly press at least 2 of the legs at once from the bottom and with any luck, your tower will pop off. The key is to push from the bottom rather than try and pull it off upward. Good luck! (PS. make sure you build the tower on the side once the legs are taped in place. That really helps to limit the glue and the chance it drips on to the jig fixing the problem before it even happens)

[@FikrieHodzhova-cx5ud]

What is the point of putting a block on top of the jig though? I am a little confused as to how to do this.

[@balsaengineering6686]

@@FikrieHodzhova-cx5ud The tiny block on top allows you to have a small gap between the top of the legs and the table when you turn the entire jig upside down and set it on table. The goal is to be able to push on the very bottom of the legs to pop the tower off

[@frankdai3167]

Thanks for the great video! How can we contact you? Can we order the jig from you?

[@balsaengineering6686]

Thanks!! You can contact me at mklinger at comcast dot net. I have all the STL files for the jigs linked in the Intro video: kzbin.info/www/bejne/e3TGq2aKa8uthsk but I don't sell them. I don't have any specific recommendations for this, but you can definitely find online services to print STL files if you can't print them yourself. Good luck!!

[@frankdai3167]

@@balsaengineering6686

[@frankdai3167]

Thanks a lot!

[@evaqiao6388]

Hi, I was wondering how you cut your balsa sheets, since I'm worried that using a power saw would create issues (like the wood potentially breaking/cracking). Thank you!

[@balsaengineering6686]

Hi, you want to use a balsa stripper tool for that, definitely not a power saw. Something like this: www.amazon.com/Master-Airscrew-Windsor-Propeller-Stripper/dp/B0000WS5OQ/ref=sr_1_5?crid=37PEGMYEWR1RW&keywords=balsa+stripper+tool&qid=1694694767&sprefix=balsa+stri%2Caps%2C187&sr=8-5 Also, you can see how I used that tool in my Balsa Library video you might want to check out: kzbin.info/www/bejne/mH3WhYKmotStfas

[@Guthhhiii]

at 3:05 what is the difference between glued and unglued cross sections?

[@balsaengineering6686]

I don't quite understand your question. At 3:05, I'm showing one side completed. After that, I'll turn the jig over and assemble the opposite side. Then I stand it up and sand the edges and repeat the process for the other 2 sides.

[@Guthhhiii]

@@balsaengineering6686 sorry if I was being unclear so at 3:05 you said make sure to glue the center point of the cross sections I was wondering what was be the difference between a glued and unglued center of the cross section

[@balsaengineering6686]

@@Guthhhiii Ahh! Yes, you need to glue that center point to effectively make that cross-member half the length which makes it 4 times stronger with respect to buckling. If you get a chance, watch my 5-part series on tower basics where I go over a bunch of the theory behind this, specifically, check out the part on buckling theory: kzbin.info/www/bejne/rnq1haF_iNqYmJY

[@brianturnbull3875]

Thanks very much for the very informative videos! I see that the notes for this tower indicate 4.96g dry and 5.11g complete. Does this mean that the glue added only 0.15g? Or, is does the dry weight include some oversize to parts that is cut off after gluing? Also, what glue is used on this tower?

[@balsaengineering6686]

Hi! That's just my naming convention. Complete means the weight of the device right after I finished building it, which is in ambient conditions. The "dry" weight is after it has spent a day or two in my dry-box at around 18-20% RH. In this case, which is fairly typical, it drops the weight by about 3%. If you want to learn more about what the dry-box (and baking) can do, check out my Competition Prep video: kzbin.info/www/bejne/bKuyp3uDj7GUhKc I like to use 50cps CA glue for all my builds. PS, The glue mass for this device can be calculated by taking the "complete" mass and subtracting the sum of the leg and layer masses in red; or (5.11 - (3.109+1.502)) or 0.499g

[@krishivray]

What is the finished height of the tower and the length of the legs because my 3d print isn’t matching with the drawing I made so I’m just asking

[@krishivray]

Because the drawing I made was 61.24 cm tall, the legs were 61.5cm total, the width of the top was 40mm, the bottom width was, 152mm, and what I printed so far was half of the top which has a width of around 81mm and it doesn’t match my drawing

[@balsaengineering6686]

@@krishivray If you used the 120% scale for my Div C jig, the height would be 60.6cm tall. The length of the legs are about 61.3cm

[@krishivray]

@@balsaengineering6686but the 61.3cm legs would contradict with the 61.5cm legs listed in the video where there are 10layers every 6.1cm

[@karthikkurapati9410]

Hi, how did you make your testing apparatus? How thick is the chain?

[@balsaengineering6686]

I don't have any plans or diagrams regarding my testing apparatus. I basically just made a wood table/box that has a top with a hole in it. The chain was bought at a local Lowes, anything should work well there. Make sure you have something to cut it with in case it's too long as you don't want too much extra chain

[@rainyparadisegaming6344]

Hello I was wondering if there is any file that would have the 3d print for the jig?

[@Idontcaretomakearealusername]

Go to the division B video and I believe the file is there, just scale it vertically by 120%

[@balsaengineering6686]

@@Idontcaretomakearealusername Yes, they are all available in the description of the Intro video. I also have since made a zip with the files already scaled by 120% in the Z if you don't want to do it yourself: kzbin.info/www/bejne/e3TGq2aKa8uthsk Good luck this season!

[@gabrieldeng3990]

Great video. Have you built the one for bonus tower?

[@balsaengineering6686]

I have, but I'm not quite ready to share the results in a video yet. The spoiler is that it's not obviously better than the non-bonus version, similar to the Div B results. I would definitely focus on the non-bonus version to start with.

[@atristand5603]

Hi there, i was just curious on what kinr of glue you were using

[@balsaengineering6686]

Hi! I like to use 50cps CA glue for all my builds

[@therealswan]

Hello, in the rules it states that the tower must span a 20cm by 20cm opening. However, after 3d printing your jig (found in the descripotion of your introduction video), it seems like the tower only spans a 15cm by 15cm opening. The bottom piece is 15x15cm. Is this a mistake on ur part? Why is this?

[@balsaengineering6686]

Imagine rotating the tower 45 degrees and it will properly span a 20x20cm opening! I show this in more detail in my Intro video if you want to check it out: kzbin.info/www/bejne/e3TGq2aKa8uthsksi=Msr5g8XCVENm0Gun&t=118

[@FikrieHodzhova-cx5ud]

Hi, Can you please send me the jig STL so I can print my own jigs? Thank you!!

[@balsaengineering6686]

Hi! All the jig STL files are linked in the description of the Intro video here: kzbin.info/www/bejne/e3TGq2aKa8uthsk

[@FikrieHodzhova-cx5ud]

Okay, I see. And what is the difference between the bonus build jigs and the initial build jigs? Which ones are better?

[@balsaengineering6686]

@@FikrieHodzhova-cx5ud The bonus build jig follows the rules to achieve the design bonus where-as the non-bonus/initial build one doesn't. From my experience so far, I would focus on the non-bonus design. Here is my current best Div C build: kzbin.info/www/bejne/h5LXh51qbbqieK8

[@FikrieHodzhova-cx5ud]

Are the non-bonus jigs the ones that say "minimum wrk6" once you go into the link titled "All 6 division B jigs scaled to 120% in the Z direction?" @@balsaengineering6686

[@treeman2849]

Where do you get the balsa wood that you use for your builds?

[@balsaengineering6686]

I like to get my balsa sheets from Specialized Balsa: specializedbalsa.com/products/balsa_sheets.php

[@connor-db7ch]

what size balsa should i get

[@balsaengineering6686]

I would recommend getting a variety of sheets at 36" x 4". Get 1/8" thick for the legs and then a mixture of 1/16, 1/20, and 1/32 to have options for the cross-bracing material.

[@dmoneyfr]

where do u buy wood?

[@balsaengineering6686]

I like to buy my balsa sheets from Specialized Balsa: specializedbalsa.com/products/balsa_sheets.php