Efficiencies

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lllazar
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Re: Efficiencies

Post by lllazar »

Ok heres how you do it, from past bridge experiences it is the best.

Slowly bring it up to full speed, then just keep it at full speed. That's it.
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Re: Efficiencies

Post by iYOA »

JimY wrote:As for C division scores from the 2006 national tourney, this is what happened after having this event for 2 previous seasons:
1st place 4.18 g - loaded to 13.625 kg --> old score was 3260 and new score would be 44.4
2nd place 5.42 g - loaded to 15 kg --> old score was 2767 and new score would be 41.5
3rd place 4.53 g - loaded to 12.22 kg --> old score was 2698 and new score would be 33.0
4th place 5.44 g - loaded to 13.745 kg --> old score was 2527 and new score would be 34.7
5th place 6.19 g - loaded to 15 kg --> old score was 2423 and new score would be 36.3
6th place 6.05 g - loaded to 14.58 kg --> old score was 2410 and new score would be 35.1
7th place 6.56 g - loaded to 15 kg --> old score was 2287 and new score would be 34.3
8th place 6.29 g - loaded to 13.935 kg --> old score was 2215 and new score would be 30.9
9th place 5.14 g - loaded to 10.895 kg --> old score was 2120 and new score would be 23.1
10th place 6.47 g - loaded to 13.495 kg --> old score was 2086 and new score would be 28.1

I also computed new scores for places 11-30. The interesting thing is that after looking at 1-30 with the new system, the top 10 stayed the same, and only their order was changed. The third place tower from 2006 ended up in 7th with the new system and is the one that changed the most places in the top 10. In places 11-30 from 2006, the 19th and 21st place finishers would have ended much further down under the new scoring system, probably 2/3 to 3/4 of the way down the list. They were light towers that failed at low loads (4.92 grams and 6.815 kg for one and 3.83g and 5.065 kg for the other).

So, there you have it from 5 seasons ago. A grand total of 2 C division towers would have scores above 40 with the new formula. So, based on this, I'm changing my previous position and am agreeing with rjm in that anything above 50 will be breakout new technology. So, scores above 40 will likely earn medals in Wisconsin next May for both B and C.

Do you know what the ratios from 11th -18th place were? and where would a 1644 fit in with those?
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Re: Efficiencies

Post by bmbw123 »

Ok thanks, illazar. That makes sense :)
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Re: Efficiencies

Post by iYOA »

paronomasia wrote:So our tower doesn't hold more than 1 kg... efficiency less than 1 :lol: fail
that happened to a group for our team tryouts lol
it was because they did not let the glue dry
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Re: Efficiencies

Post by lllazar »

I've been getting efficiencies in the range of 19-22 mil, and there has been an increasing trend. Now, they've all held the full load (im just building lighter as i go, i want to make sure it holds the max load), so by last years formulas my effiencies are 1400ish...i was just thinking, would tower efficiencies be naturally higher than bridge efficiencies? It'd seem so, since the forces are more vertical in towers than bridges, and towers generally tend to be lighter (or at they can generally be built lighter more easily).

Also, my towers have been in the weight range of about 11-10 grams, what have you guys been getting?
2011 Season Events~

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Towers (Regionals ~1st) (State ~3rd)
Helicopter (Regionals -3rd gahhh) (State ~5th)
Wind Power (Regionals ~1st) (State ~3rd TIERED!)

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Re: Efficiencies

Post by iYOA »

well, we have been getting ratios in the 19.5 range. We have never had a tower hold all the weight. I think they can hold all the weight but they usually break for some stupid reason. recently we tested one that was 7g and held 12kg. it broke because the top part was too flimsy and usually, our top part NEVER breaks. now we are building even lighter towers( 6g-5.5g) because we feel that each tower we build CAN hold all the weight but it just doesnt.
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Re: Efficiencies

Post by lllazar »

Yes i see where your coming from - it's not really your design that's flawed i think, rather just the uncontrollable strength variance in balsa. You'd really need to go through over a 100 sticks of balsa to get 4 that are light, strong, and all of the about the same stiffness, so that 1 isn't unnecessarily stronger than the others.

I have a suggestion, take it how you will, but build the tower stronger than it needs to be next time - even if it adds a bit of weight. Weighing 1 more gram but holding 1 or even more kg of mass would result in an improvement of your ratio.

Good luck!
2011 Season Events~

Fossils (Regionals ~1st) (State ~6th)
Towers (Regionals ~1st) (State ~3rd)
Helicopter (Regionals -3rd gahhh) (State ~5th)
Wind Power (Regionals ~1st) (State ~3rd TIERED!)

Hooray for getting everything i wanted?
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Re: Efficiencies

Post by iYOA »

well, actually what happens is that we usually built 9-10.5g towers and they were fairly strong. but the reason they broke was because of connection issues with the top and the bottom. We ordered a new batch of wood and the wood was amazingly light. However we usually have issues with our base so we used lamination on the legs to make it stronger. Even though the base was about 1.5g lighter than usual, it still seemed extremely overbuilt and it was not the part that failed. We did not strengthen the top part in any way so that is why it broke. For the next tower with this kind of wood, we again laminated on the base and also laminated on the top. so if all goes well, this one will hold nearly all the weight. We are also crunched for time because an invitationals is coming up on the 8th and we want to have a 6g tower that holds all the weight by then(maybe even lighter, if possible).
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Re: Efficiencies

Post by lllazar »

Ahh, well i wish you good luck at your invitational - btw where do you buy your wood?

I ask because no matter how simple i make my design, i don't think it could get below 7 grams.
2011 Season Events~

Fossils (Regionals ~1st) (State ~6th)
Towers (Regionals ~1st) (State ~3rd)
Helicopter (Regionals -3rd gahhh) (State ~5th)
Wind Power (Regionals ~1st) (State ~3rd TIERED!)

Hooray for getting everything i wanted?
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Re: Efficiencies

Post by soccerkid812 »

lllazar wrote:Ahh, well i wish you good luck at your invitational - btw where do you buy your wood?

I ask because no matter how simple i make my design, i don't think it could get below 7 grams.

yea, i have the same problem
i made a forum topic about it but only got a few replies
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