Ongoing Contest(Scores)

[benklee127]

Does anyone know the specs from 2008?
apparently the best efficiency was around 2500 o.o
I just cant imagine that happening
its too awesome xD

[juicemanman]

Hey, just a suggestion: Build a heavy boomilever that can hold 15kg, then whittle down the parts you don't need instead of building a light boomilever that can't hold anything and then making it better. Makes you feel better about yourself

[juicemanman]

test test test test test test test test test test
reply

Edit: oh wait your div. B and your rules are diffrent ah well
~Benjamin Lee

Erm, what's different? The 15 v. 20 cm height? I built mine with 12 cm, anyways.

[Balsa Man]

Does anyone know the specs from 2008?
apparently the best efficiency was around 2500 o.o
I just cant imagine that happening
its too awesome xD

Specs for 2008 are discussed in the boom thread- for C-Div they are the the same as this year. The B-Div specs are different only by the height (20cm- 5 cm higher than C-Div).

test test test test test test test test test test
reply

Edit: oh wait your div. B and your rules are diffrent ah well
~Benjamin Lee

Erm, what's different? The 15 v. 20 cm height? I built mine with 12 cm, anyways.

There is a reason B-Div height is more than C-Div; the smaller the height, the smaller the angle at the tip end; the smaller the angle, the greater the forces on the tension and compression members. Posted the basic forces numbers earlier; in B-Div, forces are about 3/4 what you have in C. At the full 15 kg load, 44kg tension & 40kg compression in a C, vs 34T & 30C in a B. By building to a 12cm height, you are badly shooting yourself in the foot; without running the numbers, at a 15kg load, tension will be well over 50kg; pushing 55, w/ compression well over 45kg, probably approaching 50. So, if your "build" (tensile strength of the tension member(s) & compression/column strength of the boom arm) could carry the forces generated by a 15kg load (if it were configured with a 20cm height), with a 12cm height, it would only be able to carry...8 or 9kg. Oops, not good.....
Before settling in on a design, you really need to understand the basic science at work- the physics/forces that are going on. You want every little bit of height you can get. The forces generated in a boom are a LOT higher than in towers from last year......

[juicemanman]

I guess... if after I test it and it doesn't do well, I could make it higher. But wouldn't it add a lot more mass?

[Balsa Man]

I guess... if after I test it and it doesn't do well, I could make it higher. But wouldn't it add a lot more mass?

It will add a bit- how much depending on your design. Tension member length will go up a couple centimeters. If you're running vertical bracing btw tension member(s) and compression member(s) - which is nit really a good/optimal idea, that'll go up. You can weigh the "extra" lumber needed, and know how much that will bring mass up. But it will get you at least 2/3 more strength/load bearing capacity, so even if your weight goes up 50%, if your load carrying goes up by 67%, you are well ahead of the game.... do the math

[deezee]

1. mass: 6.49 g
held: 2 kg

It would have held a lot more, but i didnt glue the base at an angle to the wood, so when i mounted it the bottom didn't touch the wall and the wood bent until it broke

[benklee127]

Tested 2 more
Boomi #5:
Mass: 10.92
Held: 9011
eff: 825


Boomi #6:
Mass: 8.25
Held: 5006
eff: 607
(didn't see enough improvement between 4 and 5 so I tried a completely different design which failed xD)

dissapointed :/

[benklee127]

My school is pretty competitive so I'm hoping to break 900-1000 by tryouts (which is in two weeks)
This year there are 120+ people trying out for the team -.-

[Rath4o1]

When we score the boomilever if the boomilever fails should i put that as a tier two boomilever? or if it fails it does not matter?