Scioly.org

nxtscholar wrote: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.

However, someone posted a couple pages back that drying a boom makes it the wood cells more rigid and therefore stronger if no unanticipated forces are applied.

ckssv07 wrote:

UQOnyx wrote:Wouldn't making them more brittle make them more prone to snap?

If I understand correctly, dehydrating the wood compacts the cells while the water evaporates out making it rigid and stronger in the naturally stiffer,stronger areas, but it also makes it very brittle in the parts that are naturally weak. Therefore, if the boomilever has a sound structure it should have a greater efficiency, but when it does break, it usually shatters instead of torsioning some and then snapping.

Yeah, I believe this was the quote. But do note the tone of caution expressed in parts of the quote.

If you have a good design that shouldn't be a problem. If you have a bad design that would be a problem. A good design has minimal weaknesses. He also posted that in general his scores increased after he dried the base, but idk where that post is. I think it was like 50-200 points each time? I don't remember, but I think it was a substantial amount.

chinesesushi wrote:

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.

From what I've heard, a Div. B team that was highly competitive last year is getting scores about 200 lower this year than last (I don't want to give a name just for sake of fairness to that team). At the same time though, I've heard of Div. C teams still easily surpassing 2000 this year.

Tupperware and LOTS of silica gel for transport and storage. No hairdryer needed before weigh in. Works for us.

JonB wrote:Tupperware and LOTS of silica gel for transport and storage. No hairdryer needed before weigh in. Works for us.

Well, every person to his or her own method Where'd you get that much silica gel?

nxtscholar wrote:

JonB wrote:Tupperware and LOTS of silica gel for transport and storage. No hairdryer needed before weigh in. Works for us.

Well, every person to his or her own method Where'd you get that much silica gel?

Lots of shoe boxes. jk

http://silicagelpackets.com/ for all of your silica gel needs, or really any website that sells it. It's pretty cheap. I do not recommend using it for gliders. I have become fairly convinced that drying the balsa with silica after construction warps the wings (I am not positive about this though).

We can have insane humidity here in Florida even during SO season. For those going to Nationals, plan accordingly.

JonB wrote:

nxtscholar wrote:

JonB wrote:Tupperware and LOTS of silica gel for transport and storage. No hairdryer needed before weigh in. Works for us.

Well, every person to his or her own method Where'd you get that much silica gel?

Lots of shoe boxes. jk

http://silicagelpackets.com/ for all of your silica gel needs, or really any website that sells it. It's pretty cheap. I do not recommend using it for gliders. I have become fairly convinced that drying the balsa with silica after construction warps the wings (I am not positive about this though).

We can have insane humidity here in Florida even during SO season. For those going to Nationals, plan accordingly.

I have no support documentation on what I'm about to say, other than 17 years of coaching structural events, but i believe that drying down structures with a hair dryer may not negatively affect the strength of the wood (it may even improve it), but it may well increase the brittleness of the cyanoacrylate type glues. I've long been a proponent of not building more than 30 days in advance, or the glue will dry out become brittle, and cause joint failure... I've seen it happen many times... A structure gets tested and holds the entire load... next month they use the same structure again, it fails at half load... immediately, everyone jumps to the conclusion that it was somehow damaged by the first loading, when in reality it was brittle glue. Had the structure been reloaded in the week following the first load, it would probably have done fine.

This is not to say that there are not merits in driving off excess moisture in the structure... just don't overdo it or you will weaken the glue.

xAkali wrote:

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

Exactly. My feelings are that drying the structure right before competition is a little bit dubious, or at least I have awkward feeling that it is not exactly fair game. If it is perfectly legal and on the up and up, why don't everyone at impound has their structure in a sealed turkey bag blasting away with the hair dryer right up to the moment where the event supervisor is ready to put their structure on the scale?

Because people don't know it helps? There's a ton of things that are legal in SO, but they just aren't common. I don't see how this is wrong, it's just another technique that allows you to do better. I used to bring a level with me before the rules stated that they're to be provided, I was one of probably two people each contest that brought a level. This doesn't mean we're cheating, it's not illegal, it just means we're doing something that helps out that not a lot of people know or want to try.