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Daniel Bertrand




Location: Logan, Utah
Joined: 13 Apr 2015

Posts: 6

PostPosted: Thu 12 Mar, 2020 3:44 pm    Post subject: Show me your Trebuchets!         Reply with quote

I have a working 1/2 scale machine that we took Punkin Chunkin last fall. Need to fix it up this summer and I'm looking forward to getting some more throwing in. It's 33 feet tall and when it's in prime it throws 16lb bowling balls 250 yards with about 2,000lbs of weight. On wooden axles.

I am always interested in finding other people with trebuchets and similar interests in siege engines. Especially anyone studying this stuff. I want to make a full scale eventually but not sure how that is going to happen.

Lots of videos on my YouTube channel: https://www.youtube.com/channel/UCXIB2SLLkMPzr6BjajJe_DA?

The picture is us winding it down last October.

I'm new to this forum, I apologize if there is already a thread about this.



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Dan Howard




Location: Maitland, NSW, Australia
Joined: 08 Dec 2004

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PostPosted: Thu 12 Mar, 2020 11:19 pm    Post subject:         Reply with quote

Very cool. I made one for the kids using meat skewers and popsicle sticks. I'd love to make a bigger one.






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Author: Bronze Age Military Equipment, Pen and Sword Books
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Dan Howard




Location: Maitland, NSW, Australia
Joined: 08 Dec 2004

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PostPosted: Fri 13 Mar, 2020 1:45 am    Post subject:         Reply with quote

I've read some studies suggesting that more energy can be delivered to the projectile if the trebuchet is on wheels. As the arm swings over, the frame rolls forward, which lets the counterweight fall vertically for a little longer while also shifting the stall point of the arm to a more vertical position.

Edit: Here is a video explaining it.
https://www.youtube.com/watch?v=KpFTyE-wiNo

Author: Bronze Age Military Equipment, Pen and Sword Books
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Matthew Amt




Location: Laurel, MD, USA
Joined: 17 Sep 2003

Posts: 1,373

PostPosted: Fri 13 Mar, 2020 4:26 am    Post subject:         Reply with quote

Dan Howard wrote:
I've read some studies suggesting that more energy can be delivered to the projectile if the trebuchet is on wheels. As the arm swings over, the frame rolls forward, which lets the counterweight fall vertically for a little longer while also shifting the stall point of the arm to a more vertical position.

Edit: Here is a video explaining it.
https://www.youtube.com/watch?v=KpFTyE-wiNo


Your design with the hinged/articulated weight does the same thing, according to the old Nova "Medieval Siege" documentary.

https://www.youtube.com/watch?v=QVO8VznqMeQ

The analysis of the advantage of wheels starts about 14 minutes in. It's really a wonderful show.

The video you posted certainly is revealing, but his basic machine design is not what was used in the middle ages. So he's not going to find *historical* answers. Heck of a throw, though!

Matthew
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Matthew Amt




Location: Laurel, MD, USA
Joined: 17 Sep 2003

Posts: 1,373

PostPosted: Fri 13 Mar, 2020 4:28 am    Post subject:         Reply with quote

I should add that when I first saw that Nova show, I was so amazed that I ran for my Legos and built a trebuchet, so I could test it myself! The difference between wheeled and unwheeled (with a fixed counterweight) was impressive. But the swinging weight design achieves the same effect without the wheels.

Matthew
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Dan Howard




Location: Maitland, NSW, Australia
Joined: 08 Dec 2004

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PostPosted: Fri 13 Mar, 2020 7:02 am    Post subject:         Reply with quote

Matthew Amt wrote:
I should add that when I first saw that Nova show, I was so amazed that I ran for my Legos and built a trebuchet, so I could test it myself! The difference between wheeled and unwheeled (with a fixed counterweight) was impressive. But the swinging weight design achieves the same effect without the wheels.

It allows the counterweight to fall vertically but I don't think it fixes the stall point of the arm.

Author: Bronze Age Military Equipment, Pen and Sword Books
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Daniel Bertrand




Location: Logan, Utah
Joined: 13 Apr 2015

Posts: 6

PostPosted: Fri 13 Mar, 2020 10:10 am    Post subject:         Reply with quote

Hey, that popsicle stick one you made is cool! I actually inherited some craft sticks and glue from a class project a year ago and kept thinking I would make something like that. Finally realized I would never get around to it so I gave the sticks and glue away to someone else who would use them.

Having a big treb is awesome, but it's also a pain. I need four people to operate it at full weight. There is a balance of size somewhere for the average joe. Maybe something that throws baseballs or tennis balls. If I wind up with a desk job though I will definitely need to get some kind of gumball throwing trebuchet.

And yes, I think the hinged box does the same thing as the wheels. There aren't many medieval illustrations of these things on wheels, but there are definitely a few -- I think wheeled trebs were a minority. I'm not sure anyone has done some legit practical testing on this matter though. Would love to see some good experiments with a decent-sized model between wheels+fixed weight, wheels+hinged weight, and no wheels+fixed weight, no wheels+hinged weight. All other variables the same.
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Daniel Bertrand




Location: Logan, Utah
Joined: 13 Apr 2015

Posts: 6

PostPosted: Fri 13 Mar, 2020 10:21 am    Post subject:         Reply with quote

Whoa, I forgot about that Tom Stanton video. That was a great experiment. There you have it. I guess wheels do make it throw farther because they synchronize the stalls later and make the throw more efficient.

Probably not going to add wheels to my treb anytime soon though. Not sure how that would be feasible on my frame design. It's a lot safer for me to have the frame just staked to the ground.

I suppose most medieval trebuchets weren't on wheels simply because it's so much easier to just put them on the ground. Not sure. The difference in performance maybe wasn't worth the extra effort in design and construction?
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Roger Hooper




Location: Northern California
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PostPosted: Fri 13 Mar, 2020 2:45 pm    Post subject:         Reply with quote

Does this one count? Made by Elastolin in Germany, back around 1960.


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J.D. Crawford




Location: Toronto
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PostPosted: Fri 13 Mar, 2020 4:01 pm    Post subject: Re: Show me your Trebuchets!         Reply with quote

Daniel Bertrand wrote:
It's 33 feet tall and when it's in prime it throws 16lb bowling balls 250 yards with about 2,000lbs of weight.


So that's where these dang bowling balls in my back yard are coming from.
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Dan Howard




Location: Maitland, NSW, Australia
Joined: 08 Dec 2004

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PostPosted: Fri 13 Mar, 2020 4:28 pm    Post subject:         Reply with quote

Daniel Bertrand wrote:
I suppose most medieval trebuchets weren't on wheels simply because it's so much easier to just put them on the ground. Not sure. The difference in performance maybe wasn't worth the extra effort in design and construction?

It is counter-intuitive. If the treb is on wheels, you'd expect some of the energy to go into moving the frame, which leaves less for the projectile, but it is a lot more complicated than that.

Author: Bronze Age Military Equipment, Pen and Sword Books
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Daniel Bertrand




Location: Logan, Utah
Joined: 13 Apr 2015

Posts: 6

PostPosted: Fri 13 Mar, 2020 9:03 pm    Post subject:         Reply with quote

Roger Hooper wrote:
Does this one count? Made by Elastolin in Germany, back around 1960.



That model is awesome! It certainly counts. It's got style. Bummer it's not functional, then it would take the cake.
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Daniel Bertrand




Location: Logan, Utah
Joined: 13 Apr 2015

Posts: 6

PostPosted: Fri 13 Mar, 2020 9:05 pm    Post subject: Re: Show me your Trebuchets!         Reply with quote

J.D. Crawford wrote:
Daniel Bertrand wrote:
It's 33 feet tall and when it's in prime it throws 16lb bowling balls 250 yards with about 2,000lbs of weight.


So that's where these dang bowling balls in my back yard are coming from.



Hey, I would love to have those back, especially the 16lbers. Could you mail them to me? lol
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Roger Hooper




Location: Northern California
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PostPosted: Fri 13 Mar, 2020 11:25 pm    Post subject:         Reply with quote

Daniel Bertrand wrote:
Roger Hooper wrote:
Does this one count? Made by Elastolin in Germany, back around 1960.



That model is awesome! It certainly counts. It's got style. Bummer it's not functional, then it would take the cake.


It is functional though not very accurate



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J.D. Crawford




Location: Toronto
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PostPosted: Sat 14 Mar, 2020 10:46 am    Post subject: Re: Show me your Trebuchets!         Reply with quote

Daniel Bertrand wrote:
J.D. Crawford wrote:
Daniel Bertrand wrote:
It's 33 feet tall and when it's in prime it throws 16lb bowling balls 250 yards with about 2,000lbs of weight.


So that's where these dang bowling balls in my back yard are coming from.



Hey, I would love to have those back, especially the 16lbers. Could you mail them to me? lol


Couldn't fit them in our local mailbox, so I used a courier. Reverse charges of course. Wink
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