Deep Blue

[SavaTheAggie]

Here is my entry to the TEXLug Fall 2003 Meeting siege engine contest, the trebuchet 'Deep Blue.'

It's ugly. I know. Get over it. Function over form baby!

And man does it function! (well I think it does).

The contest requires that the seige engine be built out of nothing but official LEGO parts, with the exception of string. I did not use any LEGO or Non-LEGO weights. The counterweight is pure brick, almost pure 1x1 bricks.

The standardized shot is a cube of 2x4 bricks, 4x4 studs and three bricks high.

Right now I'm very consitantly getting an initial impact distance of 12 feet, and my record for total distance right now is 26 feet rolling distance.
Here are the pics:





So there ya go.

--Anthony

[Bricksidge]

This looks great. Functional LEGO gets a big thumbs up from me.

Is there a problem with the weight and force applied? Are beams threatening to detach or even snap?

Good luck in the contest!

[architect]

Indoor firing range! My family would hate that! hehe

I like your trebuchet very much. Colors do not matter much for seige weapons. Have you considered putting wheels under the trebuchet to increase the projectile distance?

[SavaTheAggie]

This looks great. Functional LEGO gets a big thumbs up from me.

Is there a problem with the weight and force applied? Are beams threatening to detach or even snap?

Good luck in the contest!

Thanks much! I haven't seen much problem with detachment or snapping. I surrounded the axle the beam sits on with bushings so that hopefully any deformation to the axle is handled by the bushings and not the axle itself. I also sandwiched the beams of the throwing arm with plates so that it'll stay together without catastrophic failure.

Indoor firing range! My family would hate that! hehe

I like your trebuchet very much. Colors do not matter much for seige weapons. Have you considered putting wheels under the trebuchet to increase the projectile distance?

Hehe.. well, my father gave me a neat idea to redo the counterweight in white and blue to make it more patriotic, but I think I'll leave it be the way it is and deal with that idea some other time.

As for wheels, wheels add a lot of distance to Trebuchets with a fixed weight counterweight, that is, with the counterweight attached physically to the throwing arm. But wheels won't help in my case. Wheels do very little to add any distance to Trebuchets with a swinging weight counterweight, that is, with the counterweight hanging from the end of the throwing arm.

The physics behind this is complex, but is described as simply as possibly as this: With a fixed weight, the falling weight moves forward as well as down, so wheels would absorb this forward motion and push the trebuchet forward adding speed to the shot. Hanging weights transmit almost all of the forward motion into downward motion, so the machine would move very little with wheels attached. However, with the transformation of this forward motion into downward motion, the swinging arm ends up moving faster than a fixed weight, so the shot will fly faster and farther than without the hanging weight.

And now I'm done.

--Anthony

[fcarcanague]

Morn'n...
Nice Trebuchet, and rather large. Seige weapons are fun to test at home,
my trebuchet averages about 20 feet using a regulation minifig soccer ball for the progectile.

Is the the the whole thing. The only non-Lego parts were the actual weights.
Since I have vast access to these weights they worked well.
There's only 1/4 of a pound, but that's enuff.

The swinging weight was the easiest to make when I thought about making seige weapons.

Please check out the rest of the pictures of it on my website
http://www.carcanague.com/52003treb/ (direct link to the trebuchet)
or
http://www.carcanague.com/ (for the whole site)

Fred

[SavaTheAggie]

By adding more weight to the counterweight, extending the loading ramp farther out, and adjusting the hook, i've now been able to reach an initial impact distance of about 22-23 feet, with an imeasurable rolling distance cause I keep hitting the wall with the window in it in the picture shown. I'll report official scores when I come back from the TEXLug meeting.

--Anthony

[jeff_o_rama]

How do you guys design the sling so that it releases the proectile at the right time?

-Jeff

[SavaTheAggie]

How do you guys design the sling so that it releases the proectile at the right time?

-Jeff

The sling I used was a simple piece of cloth from one of the adventurer series. I believe it was the blanket for the back of an elephant.

The string or rope attached to the sling should be the length of the long side of the throwing arm. That is to say, if loaded with the throwing arm pointed straight up, the shot should be hanging at the axis of the throwing arm. (So the total length of both pieces of string should be double the length of the long side of the throwing arm). This is crucial.

One side of the sling should be attached to the end of the throwing arm, and the other side of the sling should end in a loop.

When loaded and ready to fire, a traditional trebuchet's shot should be laying directly under or farther forward than the counterweight. This will give you the most power out of your siege engine.

Now according to the experts, the perfect angle for the hook is between 30 and 33 degrees. So a good hook would be either a technic angle connector #3 or #4. It will depend on the weight of your shot and the weight of your counterweight. However, typically, a sharper angle (like 45 or greater) will make the sling release later, and the shot will fly lower and straighter. This would be good for shorter distances and direct assaults like target practice. But for longest distances, something closer to 33 degrees is best. You'll get an almost perfect 45 degree arc of fire.

Hope that helps.

--Anthony

[jeff_o_rama]

Wow, thanks a lot. I want to try to build one of these things after seeing yours and Fred's.

Thanks again,
Jeff

[wlister]

Thanks for the info about the sling. I am hoping to put a few smaller trebuchets together for my next display. I am hoping to make them in brown so they'll match the rest of my catapults etc... I'll post my desings once I get them working. The sharing of ideas is one of the great things about this community.

WL