Towers B/C

[Balsa Man]

I've heard a bunch of varied scores- top schools in the NE breaking 2800+, some Cali schools breaking the 3000 mark and getting near amazing 3300 (good lord the time needed for that and I guess money) but all in all, just strive to beat your own score. That should be motivational enough- also asking nearby invitationals or just invitationals in-state or that contain schools from your state could be beneficial as well.

Since I cannot find the edit function... these are division C scores

NoCal high schools getting that high?
May I ask which ones... As far as I know, I haven't heard much div C's above 3k, and barely in competitions....

Just a point of comparison; working with B and C teams-
comparable designs (meet 29cm circle bonus), estimated weight, scores at 14950 carried; 2775 C; 3037 B. C is about 9% heavier. Longer legs and higher density/more bracing.

[random-username]

How should the X's be attached to the legs? I've been using butt joints but I want to use lighter wood (1/16x1/16) for my X's. I'm not sure how I could attach it using a butt joint, as my legs are larger, (1/8x1/8). Would it be better to use a lap joint?

[Unome]

How should the X's be attached to the legs? I've been using butt joints but I want to use lighter wood (1/16x1/16) for my X's. I'm not sure how I could attach it using a butt joint, as my legs are larger, (1/8x1/8). Would it be better to use a lap joint?

Since X's are in tension, I would think a lap joint would be more appropriate.

[Balsa Man]

How should the X's be attached to the legs? I've been using butt joints but I want to use lighter wood (1/16x1/16) for my X's. I'm not sure how I could attach it using a butt joint, as my legs are larger, (1/8x1/8). Would it be better to use a lap joint?

Since X's are in tension, I would think a lap joint would be more appropriate.

Well, it depends on the bracing...system/configuration you're using. In an Xs and ladders system; yes, Xs work only in tension; lap jointed. In an Xs only, the Xs have to carry both tension and compression forces. OK under tension, if the density is high enough. Under compression (from a leg starting to buckle to an adjacent leg), because they're not between the legs, the compression force is not along the centerline of the piece (non-axial loading). It will bow/buckle/break under significantly less force than it would if mounted between the legs. But as you note, with brace smaller than the leg, very difficult to get a joint that can handle the tension force the piece will also see.

All these issues/pros/cons are discussed in some detail if you care to look through previous pages.

[fdf4]

Is it ok to have about a centimeter of leg freestanding past the last set of bracing?

[Tesel]

Is it ok to have about a centimeter of leg freestanding past the last set of bracing?

I haven't tested it with a centimeter, but it should be good with about 0.5cm on either side and in fact that would be recommended. It allows you to put a tension piece at the bottom and a compression piece at the top to increase performance, while still meeting the bonus. Also, it allows you to evenly sand the tower to get all 4 points flush with the loading block or base.

[fdf4]

Is there a downside to going over the recommended?

[Unome]

Is there a downside to going over the recommended?

The downside to having significant space between your lowest brace end and the bottom of the leg is that you know have a section of the tower that is essentially unbraced. For smaller values this shouldn't matter much; I would expect it only really becomes a problem when the length below the brace approaches the length between braces (not sure though).

[fdf4]

Is there a downside to going over the recommended?

The downside to having significant space between your lowest brace end and the bottom of the leg is that you know have a section of the tower that is essentially unbraced. For smaller values this shouldn't matter much; I would expect it only really becomes a problem when the length below the brace approaches the length between braces (not sure though).

Thank you, knowing this makes me less nervous going forth with my current tower!

[Stear]

I don't know about the rest of you guys and girls, but this season of science olympiad is over for me. My state tournament ending a couple weeks ago and I managed to place 2nd in Towers with the help of this forum thread. For that, I would like to say thank you to everyone. Towers has been my most favorite event for this year and after coming home I looked at all of the balsa wood events for the last ten years. From my observations I have concluded that Towers will stay for the next year. My question is for all of you people who have participated in the balsa wood events; do the rules for the balsa wood events change during the second year of their cycle? Something that you guys could think about is if the rules for Bridges in 2014-2015 were different from the rules in 2015-2016.