Efficiencies

[jander14indoor]

Even when you order specific weights, expect to sort AGAIN and still through out a lot of wood. Its just part of the normal variability of a natural product like balsa.

But, if you want to do really well, this is just a necessary part of the process. You can design the best structure, but unless you select the right materials its just junk.

Jeff Anderson
Livonia, MI

If you do order light wood, how would you sort through them again?

The company is only going to sort wood to a general range, light, medium, heavy. You need a specific weight for your tower, you'll need to weigh each piece to ensure its density is correct for the intended use. In addition, weight is NOT the only parameter. Stiffness (see threads on construction and design) is as or more important. After selecting for correct weight/density, you need to compare how easy the pieces are to bend. Select matching stiff ones.

Jeff Anderson
Livonia, MI

[iYOA]

IYoa, that site looks very nice for pricing, but how much shipping did u end up paying? Specialized balsa charged us like 17 bucks - our order itself cost 17 bucks.

Also, where do you specify that you want hand selected wood? I don't see anything for that anywhere.

Thanks!

Im not sure where to specify but they say here, under balsawood http://www.balsawoodinc.com/balsawoodproducts that they will hand select it. We have not asked for a hand selected order yet so we dont know how that would work.

Shipping costs about $12 and our order totaled to about $40 with the shipping.

[soccerkid812]

What size wood and wood densities are you guys using for the compression and tension members?

[Arthur]

does anyone know the winning efficiency from the conestoga invite?

[sj]

does anyone know the winning efficiency from the conestoga invite?

Yeah, I had a 9.7 gram tower that held all 15 kilos so a 23.1 efficiency.

[sciolyswizzle16]

wow, that's really good!
my school was suppose to go to that invitational, but unfortunately we couldn't due to the "snowstorm".

[sj]

Thanks!

[SLM]

Yeah, I had a 9.7 gram tower that held all 15 kilos so a 23.1 efficiency.

Congratulations on your success at Towers and your other events.

Out of curiosity, how much time have you been spending on your events since the beginning of this SO season?

[lllazar]

Just got new wood a few days ago, after revising our base design and testing today our 8.2 g tower held all the weight, 27.4~

I speak from experience, plan out your design and building method first before you even build a tower, i don't think we'd be getting anywhere close to this high without an accurate jig and consistent building technique. The design honestly isn't that important as far as placing at state goes (now at nats, definitely...design is paramount, how else would they get lower than 5 grams )

[hpfananu]

Congrats! We just had an invite and I'm not sure what happened but our tower that was 16.5 g (not specialized wood yet) wasn't able to hold the weight. I'm thinking it was because while bracing, we tried to straighten the tower and that may have put a lot of stress on it. We had a tower of the exact same design not nearly as straight holding approximately 18 kg and this one holding 6.5 kg. Do you guys think this could have been it or some other factor like wood? We've been using a foam board but no actual jig yet, but this time we're planning on using that paper jig that NC SO has a video of. Any other jig recommendations? Thanks in advance!