Compound Lego Crossbow

[Siercon and Coral]

This is a fully functional Lego Compound Crossbow. It is around 100 studs long - and combines several techniques that place the Legos under stress to undergo the significant tension of a compound cam with an idler wheel. We used Lego electronics to create the cables, and various wheel elements to distribute the compound pull function with various pulleys.

And of course we wouldn't want to leave ya without letting you see it in action!

So check out the video in the link!

Thanks for reading!

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This was created for our Iron Builder against the Erickson Brothers, and uses the green flexible spike piece as 1:1 scale crossbow bolt tips, viper fangs, a sight window, crosshairs, and trigger.

[Blakbird]

Very cool build! Welcome to our forum and the world of functional Lego building. I have seen various Lego weapons before, sometimes functional and sometimes full scale, but I think this is the first time I have seen a full scale working compound crossbow. The "compound" part is what I find most interesting and seems to have been deftly handled. How well does it hold up to the forces structurally? Any problems with weakness due to the large longitudinal slot?

[Svad]

Okay, I've seen a lot of crossbows as I tried to build myself one a few months ago and this one is badass.

None of the crossbows I've seen had a nice design, they were just functionnal, this is one is beautiful.

Great job!

Edited September 11, 2013 by Svad

[Siercon and Coral]

Very cool build! Welcome to our forum and the world of functional Lego building. I have seen various Lego weapons before, sometimes functional and sometimes full scale, but I think this is the first time I have seen a full scale working compound crossbow. The "compound" part is what I find most interesting and seems to have been deftly handled. How well does it hold up to the forces structurally? Any problems with weakness due to the large longitudinal slot?

Thanks, glad to be here! We'd love to explore more Legos in motion. :)

Actually that's the strongest part. Whereas most our builds are super fragile, if you were to hold it just above the triangular shoulder piece, you can grip this like a baseball bat and whip it around rather violently even whacking it against stuff and twisting and it would be fine. I would expect the first piece on this moc to break would be the cables from fraying over time.

[Blakbird]

Actually that's the strongest part. Whereas most our builds are super fragile, if you were to hold it just above the triangular shoulder piece, you can grip this like a baseball bat and whip it around rather violently even whacking it against stuff and twisting and it would be fine. I would expect the first piece on this moc to break would be the cables from fraying over time.

Only one way to be sure. You'll have to go fire several thousand bolts from it and see how it holds up.

As a Technic guy, I'm just as interested in exactly how it works and how it is strengthened as in the overall design itself. Is this model still assembled and there any chance of some detail photos of the mechanisms and assembly methods?

[rm8]

You waited for 42009'and its long axles, didn't you?

Gpvery intersting video, and it really shoots:)

You waited for 42009'and its long axles, didn't you?

Very intersting video, and it really shoots:)

Edited September 11, 2013 by rm8

[timslegos]

Other crossbows that I have seen are not nearly as nice looking, great work!

tim

[Dreadredbeard]

This makes me want to pick up the lego weapons books again :S

[pluto7443]

Somewhat ironically, I made my own crossbow a couple weeks ago before I knew of this one. Much simpler, not compound, and it uses non-Lego string. It works though, and will pierce paper at similar ranges as in the video for this much prettier one.

It fires the beige pieces in the center of the crossbow, made mostly of three 15L beams.