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iorbiteuropa4776 wrote:Hey guys!

This is the first time I've ever done Boomilever. I've built a few simple ones, all weighing 7-15 grams. I built a compression tube after reading about it here, but it ended up weighing about 17 grams. I went to the local hobby store and selected the lightest wood I could find, but it still ended up being way too heavy to beat any of my previous scores (usually around 800-1000 with a 9 gram boomilever).

I was wondering how good scores compression tubes actually get, and what some of the top scores would be. I've heard about some teams getting the mass of the compression tube down to under 7.5 grams, but I'm struggling to understand how this is even possible. Mine weighs a lot more, and using it wouldn't increase my best score, even if it held all 15 kg.

We take a small, battery powered scale to the local hobby store and weigh the balsa. A 1/16"x3"x36" sheet shouldn't weigh more than 12g. You'll use half of it on the tube.

iorbiteuropa4776 wrote:Hey guys!

This is the first time I've ever done Boomilever. I've built a few simple ones, all weighing 7-15 grams. I built a compression tube after reading about it here, but it ended up weighing about 17 grams. I went to the local hobby store and selected the lightest wood I could find, but it still ended up being way too heavy to beat any of my previous scores (usually around 800-1000 with a 9 gram boomilever).

I was wondering how good scores compression tubes actually get, and what some of the top scores would be. I've heard about some teams getting the mass of the compression tube down to under 7.5 grams, but I'm struggling to understand how this is even possible. Mine weighs a lot more, and using it wouldn't increase my best score, even if it held all 15 kg.

9 grams and got 800-1000 means that you did not hold nearly close to 15 kg. A better way and probably easier and more traditional way would be to carefully examine your current design and how it broke during test and iteratively improve it. If your compression piece broke, look into using more dense compression member or larger cross-section piece or closer distance between bracing (which means you need to record the density of your previous pieces).

If the problem is the piece that attach to the hook or the distal end, then you try to come up with a better way to handle the load (usually it means you need more surface area for glue joint).

Does anyone know what Charter School of Wilmington's score was for boomilever from their state competitions? I'm guessing it's pretty high because they got 1st at nationals last year and also 1st at their states this year.

chinesesushi wrote:Does anyone know what Charter School of Wilmington's score was for boomilever from their state competitions? I'm guessing it's pretty high because they got 1st at nationals last year and also 1st at their states this year.

I know Wilmington came very close last year, but has anyone heard of any teams getting 2000 with this year's rules?

We just had our state competition last Saturday, and I heard the first place team got an 1800. However, the person who told me said that their nats score last year was like a 2500. I think the change with the j-hook may be the reason why they got a significantly lower score. The highest score I have gotten is a 1200, nowhere close to 2500, but for both div B and C I would assume the nationals winning score this year will be well over 2000.

nxtscholar wrote:

iorbiteuropa4776 wrote:Hey guys!

This is the first time I've ever done Boomilever. I've built a few simple ones, all weighing 7-15 grams. I built a compression tube after reading about it here, but it ended up weighing about 17 grams. I went to the local hobby store and selected the lightest wood I could find, but it still ended up being way too heavy to beat any of my previous scores (usually around 800-1000 with a 9 gram boomilever).

I was wondering how good scores compression tubes actually get, and what some of the top scores would be. I've heard about some teams getting the mass of the compression tube down to under 7.5 grams, but I'm struggling to understand how this is even possible. Mine weighs a lot more, and using it wouldn't increase my best score, even if it held all 15 kg.

Have you tried using thinner sheets when making your tube? It's quite possible you're using sheets thicker than necessary. Also, I actually dehydrated my booms with a simple method: hairdryer. I found that, especially with tubes (since there's a lot of surface area), you can knock off quite a bit of weight.

Do you just leave the hair dryer alone? I found it kind of tiring holding up the hairdryer for 15min. Also, my boomilever keeps blowing away. Also, how long do you let the boomilever dry out.

wwmsscioly wrote:We just had our state competition last Saturday, and I heard the first place team got an 1800. However, the person who told me said that their nats score last year was like a 2500. I think the change with the j-hook may be the reason why they got a significantly lower score. The highest score I have gotten is a 1200, nowhere close to 2500, but for both div B and C I would assume the nationals winning score this year will be well over 2000.

FIrst, I think Azn is asking about Division C. Also, the highest score in Div. B last year was Daniel Wright with a score of 2001. Second place was 1967. http://scioly.org/phpBB3/viewtopic.php? ... &start=345 . In div. b the highest score was 1983. In div b it should be easier to get a higher score due to the higher height. Also, scores should see a general trend down this year because of the longer length of the boomilever, i think.

bearasmith wrote:

nxtscholar wrote:

iorbiteuropa4776 wrote:Hey guys!

This is the first time I've ever done Boomilever. I've built a few simple ones, all weighing 7-15 grams. I built a compression tube after reading about it here, but it ended up weighing about 17 grams. I went to the local hobby store and selected the lightest wood I could find, but it still ended up being way too heavy to beat any of my previous scores (usually around 800-1000 with a 9 gram boomilever).

I was wondering how good scores compression tubes actually get, and what some of the top scores would be. I've heard about some teams getting the mass of the compression tube down to under 7.5 grams, but I'm struggling to understand how this is even possible. Mine weighs a lot more, and using it wouldn't increase my best score, even if it held all 15 kg.

Have you tried using thinner sheets when making your tube? It's quite possible you're using sheets thicker than necessary. Also, I actually dehydrated my booms with a simple method: hairdryer. I found that, especially with tubes (since there's a lot of surface area), you can knock off quite a bit of weight.

Do you just leave the hair dryer alone? I found it kind of tiring holding up the hairdryer for 15min. Also, my boomilever keeps blowing away. Also, how long do you let the boomilever dry out.

15 minutes? I just usually dry it for 5 minutes and already lose about .6-1.5 grams, depending on the design I used.

So to answer your question, no, I don't leave it alone; I hold the boom in one hand, and the dryer in the other and make sure to dry the boom as evenly as possible. The important thing to know though is that the boom will reabsorb moisture as quickly (if not quicker) as it lost it. So generally, I try to dry the boom as close to possible as to the moment I hand in the boom to be weighed.

15 minutes? I just usually dry it for 5 minutes and already lose about .6-1.5 grams, depending on the design I used.

So to answer your question, no, I don't leave it alone; I hold the boom in one hand, and the dryer in the other and make sure to dry the boom as evenly as possible. The important thing to know though is that the boom will reabsorb moisture as quickly (if not quicker) as it lost it. So generally, I try to dry the boom as close to possible as to the moment I hand in the boom to be weighed.

How is this even possible during competition. I'm imagining a whole row of kids, sitting on the side blow drying their boomi

Well, first of all, the thing about drying booms is that you have to be careful not to overdo it. You could very well leave some pieces (particularly the smaller ones) brittle.

It's possible, but it depends on your tournament set up and how it's run. Like, at NJ states, you could have just dried your boom for a few minutes somewhere off to the side, then go up to the E/C and ask to weigh your boom. They would weigh it. But then, you might have to wait for like, 10 minutes because there's already schools testing. Of course, you can't physically change your boom after you weigh it. But in the meantime, you could actually allow your boom to reabsorb moisture (experience suggests this actually makes your boom stronger) until a school finishes testing, and you can finally start setting up.