
The Walking Arm Trebuchet - rfreytag
https://www.instructables.com/id/Worlds-Simplest-and-Newest-Trebuchet-Walking-Arm-T/
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pontifier
To me, the most interesting thing about this design is that the counterweight
comes to an almost complete stop as the projectile launches, putting a high
portion of the initial energy into it. A normal trebuchet seems to be less
efficient, because you often see the counterweight swinging after the launch.

Getting the large one balanced stably seems difficult, and repeatability might
suffer as well.

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elliottkember
This video was an interesting experiment in optimizing trebuchets:
[https://www.youtube.com/watch?v=-gn2RGPqe_A](https://www.youtube.com/watch?v=-gn2RGPqe_A)

Edit: and the followup with wheels: [https://www.youtube.com/watch?v=KpFTyE-
wiNo](https://www.youtube.com/watch?v=KpFTyE-wiNo)

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Twirrim
That's a really interesting design. Not sure if "World's simplest" applies or
not, but surely has to be contender. Wonder how practical that is from a siege
weapon perspective.

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klyrs
It looks fairly unreliable to me -- it appears that a successful shot requires
it to fall just right, and even then it might miss a barn.

OTOH it looks like a single person can carry it around, which could make for
quite the ambush

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r00fus
Might make sense where range is important but accuracy is not needed.

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pnutjam
This could be very accurate if it was, for example, set in a sort of guide
bed. You could dig one with some wooden supports, or use concrete for a larger
version.

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kstenerud
Very cool! It would be a lot easier to use if the "arm" part had an inverted
"T" base to make it more stable on the ground. Although he may have needed to
forego that modification to keep maximum efficiency within the competition's
rules...

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drallison
Of course, everyone has wanted to build a Trebuchet. A classic book about the
experience is Jim Paul's CATAPULT: Harry and I Build a Siege Weapon
([https://www.amazon.com/Catapult-Harry-Build-Siege-
Weapon/dp/...](https://www.amazon.com/Catapult-Harry-Build-Siege-
Weapon/dp/0394585070)).

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roel_v
I built a trebuchet once when I was 10 or 12. It was about as high as I was
tall at the time, and it was on a platform with 6 wheels. I shot some of the
neighbors' prunes into a meadow next to our house, and then when I went for a
massive load of IIRC pebbles, shot myself straight in the face. I wobbled
home, had a headache for 3 days, then tore the thing down.

Not sure what my point is - maybe 'careful what you wish for'?

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drallison
Jim and Harry's Trebuchet was built in part at the Exploratorium and was
tested in the Marin Headlands. They were not allowed to chuck rocks into the
ocean so they marked all of the rocks used for their tests with the tag "This
is not a rock", a paean to surrealist Rene Magritte.

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JoeAltmaier
I've often thought, much of the trebuchet energy goes into pushing at the
pivot point in a non-tangential way. Creating waste heat instead of velocity.

Another design, is to wrap the rope once around a round pulley at the hub, run
it to a tower and drop the weight straight down. Now all the force is applied
tangentially, going into rotational energy.

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scarejunba
Wait, so this is a novel design of an age-old siege weapon? That sounds crazy
inventive!

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ourmandave
These two mentions...

 _TEACHER NOTES Teachers! Did you use this instructable in your classroom?_

...

 _The racquetball that my son was launching in the videos above was partially
filled with water to bring it up to a regulation weight of 3 ounces. Water-
filled racquetballs make fun projectiles._

I had wood shop in middle school. Imagine a shops teacher assigning this as a
final project to his 8th grade students.

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cellular
The pumpkin market is really rising.

