WIP: City Bridge 1

[alienwar9]

LXF (1,700 pieces. Its hard to rotate, and you need to remove some pieces first that are not connected; and possibly the "motor" gears)

I got excited so I wanted to share this with you all before it was finished

It's 1 of 3 bridges in the city, and the easiest one to make, so I started with it. The 2nd one is in the city section pictures, and is a diagonal street bridge (will be an extreme pain ) and the 3rd one is a double-decker two sided draw bridge (bascule bridge).

Here you can see the bridge in place in my city section 2.

And open. (It was such a pain to rotate, its now 2 days later that I post this)

And a street view

Here you can see how it is held together and how it rotates. Its not that sturdy, but it was the only way I could get it to work and not hit other pieces.

This is the best view of the mechanism I could get. You can see the structure under the road, the mechanism down the center used to push the lock in place once closed, the arched support, and the gears "motor". You can notice I took the gear system from the UCS lambda shuttle wing design, and added a third gear set. It was supposed to be a temporary solution to make the bridge move slow.

Since the gear design is fragile at best, I really want to redesign some of it. I want to place the gear housing "motor" below the main large gears, instead of next to it. Then I have room under the road to make a counter-weight (another problem).

[XimenaPaulina]

Amazing job as always with this promising WIP bridge ultra-build alienwar! What's even more amazing is the functional mechanism of this bridge. But wait, do Technic parts work on LDD, I mean you could actually see them functioning (rotating gears, etc) in LDD? (Sorry, it's the ignorant non-Technic guy in me speaking )

[alienwar9]

Thanks! No, technic rotating parts don't "work" in LDD. You have to fake it by manually rotating a piece that has the whole group together, in this case rotating the center of one of the really large gray gears. The rest of the bridge moves with the gear because they are connected.

I tried it in SR3D builder (since it actually has working animations for gears), but it didn't work and parts were flying everywhere when I tried to rotate. (Still helpful to test the lock mechanism).

[XimenaPaulina]

Thanks! No, technic rotating parts don't "work" in LDD. You have to fake it by manually rotating a piece that has the whole group together, in this case rotating the center of one of the really large gray gears. The rest of the bridge moves with the gear because they are connected.

I tried it in SR3D builder (since it actually has working animations for gears), but it didn't work and parts were flying everywhere when I tried to rotate. (Still helpful to test the lock mechanism).

Yeah that's what I thought so. I just got curious since I always experience having a difficult time rotating a whole assembly together (probably due to wrong choice of pivot point). Anyway, I'm looking foward how this one progresses.

[Brickdoctor]

A new alienwar model! And it's only 1,700 pieces! It's my lucky day!

Great job, as always, alienwar, and it looks fantastic with the rest of the section. This is one model I really can't wait to see in physical bricks.

[alienwar9]

Update:

I've rebuilt the central mechanism, so that the "motor" is beneath the large gears, and there is room for a counter-weight. My only problem now is figuring out what the counter-weight will be.

LXF

The yellow is where the counter-weight will go, and the green is what the weight has to counter...the entire bridge. I also highlighted the central column that everything sits on in purple. ALL the weight goes there, so if anyone has an idea on how to re-enforce it or if it needs any at all, let me know

(ignore the direction of the giant red arrow, its the other way )

I am deciding between just putting a bag of sand or mini weights there, or actually building something from lego. I need help though in figuring out roughly what would be good to do to counter the bridge weight.

Any ideas?....

[DLuders]

@ alienwar9: The 73090a "Train Weight 2 x 6 x 2 - bottom openings, center seam on end" are VERY HEAVY for their size.

More common are the 73090b "Boat Weight 2 x 6 x 2 - bottom sealed, dimple on ends". They keep pirate ships from tipping over!

If you modeled a 2x6x2 brick shape in LDD, it will work well for your bridge counterweight.

[alienwar9]

Thanks! I was thinking that piece too (I had a couple from some old sets I barely remember) but I checked the price on bricklink and they aren't cheap. And since I need 6 sets of counter-weights for 6 bridges, the price for just counter-weights might go into the hundreds

I probably should build it in real life first, huh

[DLuders]

There is another possibility for a counterweight. One could use one or more of the Technic Bricks below (stacked one on top of another), with the open pin holes PLUGGED with 4073 1x1 Round Plates placed on the INSIDE.

Appropriately-sized Plates can be placed on the top and bottom of the Technic Brick stack. Then, one can fill the interior of the stack with sand, gravel, or other heavy material. The Technic Bricks offer many points to attach things.

32324 "Technic, Brick 4 x 4 Open Center":

40344 "Technic, Brick 4 x 6 Open Center":

40345 "Technic, Brick 6 x 8 Open Center":

Edited April 23, 2011 by DLuders