Official Automotive Rigs - DIY Thread

[Spikeydevilbandit]

OK. My Turn.

Riddle me this.

If square was stronger than round, why are trees round and not square?
Nature knows you know ...

[Johandyman]

Originally Posted by Spikeydevilbandit

OK. My Turn.

Riddle me this.

If square was stronger than round, why are trees round and not square?
Nature knows you know ...

to make sure all of the water is absorbed equally fast?

however i must say that im on the round is better boat, the reason a piston in an engine is round is because of the "perfect shape" a circle is, there are prob. reasons why the carbon monster from move'n'shoot is boxed, i think price, stackability and easiness when working with it.
also, from a quick google search ive come across the idea that bigger needs boxed and smaller needs round?
http://image.shutterstock.com/displa...m-71262412.jpg
this is a big MF crane, and its all boxed.
this smaller - very very awesome - crane is with round.
http://farm5.static.flickr.com/4104/...af169362_o.jpg


Stolen from http://forum.ih8mud.com/hardcore-cor...ound-tube.html

The size square tube you are using will hold up, but on a geometric consideration, no other shape dissapates forces and is stronger than a circle. That is why almost everything is made out of circular tube instead of square. The bending rigidity of a tube is radius to the 4th power so even a thinner gauge metal can be stoopid strong

Again, i know jacksh*t about this stuff, im just a FF from denmark lol but this could be why the bigger stuff is made from boxed stuff and the smaller is made from round.
get it?

[VisualEchos]

Had a chat with a guy last night that has used the MNS system several times, and was told by MNS that the reason it's square is because it's easier to manufacture CF that way for strength.

[spb]

For structural beams, what matters in their resistance to deflection is their second moment of area (often referred to as moment of inertia) or "I".
If you have two beams that are made of the same material same length, all you have to do to compare their stiffness is compare their I's.

For a square hollow beam with cross section dimensions
a=outer side,
b=inner side:
I=(a^4-b^4)/12

For a round hollow tube with cross section dimensions
a=outer diameter,
b=inner diameter:
I=(a^4-b^4)*(π/64)


Now if you want to take in account the length and material, you need to introduce:
L=length,
E=modulus of elasticity (property of material, may be found on matweb.com)
q= lb/ft weight of the beam per foot (approx. cross sectional area * density)
P=load due to camera mounted.
δ1=max deflection (at the end of the beam) due to the weight of the beam.
δ2=max deflection (at the end of the beam) due to weight of the camera.
δt=max total deflection

δ1 = (q*L^4)/(8EI)
δ2 = (P*L^3)/(3EI)
δt = δ1+δ2

Assumptions:
-Camera is mounted at the end of the beam.
-Weight of the beam is uniformly distributed.
-Cantilever beam.

[p27rpy]

Haven't posted in here in a while! Recent rig shot:

[VisualEchos]

Originally Posted by spb

For structural beams, what matters in their resistance to deflection is their second moment of area (often referred to as moment of inertia) or "I".
If you have two beams that are made of the same material same length, all you have to do to compare their stiffness is compare their I's.

For a square hollow beam with cross section dimensions
a=outer side,
b=inner side:
I=(a^4-b^4)/12

For a round hollow tube with cross section dimensions
a=outer diameter,
b=inner diameter:
I=(a^4-b^4)*(π/64)


Now if you want to take in account the length and material, you need to introduce:
L=length,
E=modulus of elasticity (property of material, may be found on matweb.com)
q= lb/ft weight of the beam per foot (approx. cross sectional area * density)
P=load due to camera mounted.
δ1=max deflection (at the end of the beam) due to the weight of the beam.
δ2=max deflection (at the end of the beam) due to weight of the camera.
δt=max total deflection

δ1 = (q*L^4)/(8EI)
δ2 = (P*L^3)/(3EI)
δt = δ1+δ2

Assumptions:
-Camera is mounted at the end of the beam.
-Weight of the beam is uniformly distributed.
-Cantilever beam.

Dude, just tell us which is stiffer up-to-down lol.

[StE823]

What the hell, I'm not an engineer and I never calculate the stiffness when I built my rig four years ago.

[Spikeydevilbandit]

QUOTE=Johandyman; to make sure all of the water is absorbed equally fast?



LOL .... OMG, I don't know what you were doing in your biology class at school ... looking out the window maybe?

[spb]

just wanted to get it out of my system.

[Johandyman]

Originally Posted by Spikeydevilbandit

QUOTE=Johandyman; to make sure all of the water is absorbed equally fast?



LOL .... OMG, I don't know what you were doing in your biology class at school ... looking out the window maybe?

take a joke dude

[Indecent Exposure]

Are there any good off-the-shelf bags to carry and store the 5' poles in? What are people using? Inquiring minds want to know...

[Johandyman]

Originally Posted by Indecent Exposure

Are there any good off-the-shelf bags to carry and store the 5' poles in? What are people using? Inquiring minds want to know...

i believe many use fishingrodbags for the poles themselves, i reckon a hificase for the small stuff would be good?

[Indecent Exposure]

Interesting. I'll have to check those out. Thanks.

[apixelintime]

Check out shotgun cases at Walmart...

[Boobo-oobo]