How Did a 4v Icosahedron Transform My Breakfast Nook?

[rcgldr]

First starting making these back in 1973, but those are long gone. Decided to make a 4v icosahedron recently and this is what I ended up with. Web page shows the progress, and the final sphere:

4f.htm

 

[Rach3]

Link is broken. It should be:

http://jeffareid.net/4f.htm

 

[rcgldr]

Already fixed. Wow, you were quick.

 

[Rach3]

Looks neat... I did something smaller like that, but with resistor networks - 1/4 watt resistors soldered together into polyhedra. Actually deriving what the resistances should be was a fun exercise in combinatorics (well, for a freshman...).

 

[Danger]

It looks great, Jeff, but how do you change the bulb?
Hey, wait a second! You forgot to put the fixture in!

 

[siddharth]

Looks neat... I did something smaller like that, but with resistor networks - 1/4 watt resistors soldered together into polyhedra. Actually deriving what the resistances should be was a fun exercise in combinatorics (well, for a freshman...).

You calculated the effective resistance across two vertices? That sounds like some tedious work with star/delta transforms.

Looks great Jeff.

 

[Rach3]

You calculated the effective resistance across two vertices? That sounds like some tedious work with star/delta transforms.

Looks great Jeff.

Never needed those, I just simplified things with symmetry arguments.

 

[rcgldr]

From wiki, the resistance is cut in 1/2 by a icosahedron (search for the word ohm):

http://en.wikipedia.org/wiki/Icosahedron

Icosahedron made from 6 platic tubes and one very long string:

geo1.jpg

 

[Moonbear]

Wow, you either drink a lot of coffee, or some cafe is wondering where all their stirrers went! How long were you allowed to leave it hanging from the ceiling on display in the living room before told to move it someplace better, like the basement or garage?

 

[rcgldr]

display in the living room

It wouldn't be allowed in the living room. It's in the computer room. Kids are grown up and moved out, so my status is married with pet.

Pics of the computer room:

cr.htm

 

[heartless]

I like it. Very nice design and idea Jeff. School will be over soon, and I think I'll try to create a sphere by myself.

 

[Moonbear]

It wouldn't be allowed in the living room. It's in the computer room. Kids are grown up and moved out, so my status is married with pet.

Oh, okay. From the pics, I saw the couch and the stuffed toy sitting in the corner, which seemed to suggest there was a feminine hand involved in the decorating of the room, and figured it was a living room. I didn't think the same person who carefully placed a little stuffed toy and frilly thing in the corner of the couch would be too thrilled with a geodesic dome made of coffee stirrers decorating the living room. I guess the living room is just where the construction took place.

 

[rcgldr]

From the pics, I saw the couch and the stuffed toy sitting in the corner

Oh, where the "construction" took place; we call it the breakfast nook, a small room on the far side of the kitchen. It's a low usage room, so taking it over for a few days was OK. As noted, there are no stuffed animals or toys in the computer room, unless our dog brings one of her toys downstairs.

In case anyone is wondering about the v-tails in the first computer room picture, those are the fuselages of my larger radio control gliders.

Video of the white with red trim glider, 122" wingspan. The power source for launching is 60 feet of 7/16" diameter latex tubing, 210 feet of monofilament fishing line (27lb pull, 4 .25 lb model, about 50mph during launch). For storage, it's wound up on the right most orange spool you see in the 3rd computer room picture.

jrartms.wmv

Video of the white glider from the 3rd photo, 71" winspan, at a canyon ridge where there is an updraft:

jr126.wmv