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General >> Other Primitive Weapons >> Balearic-Inspired Sling for a Trebuchet!
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Message started by Dawesome21 on Dec 31st, 2021 at 9:37pm

Title: Balearic-Inspired Sling for a Trebuchet!
Post by Dawesome21 on Dec 31st, 2021 at 9:37pm
A crazy idea I had last month.  More details are in the YouTube description.

What do you think, did it work, did you hear a bullwhip-crack?

https://youtu.be/pZYWOlZMZzs

Title: Re: Balearic-Inspired Sling for a Trebuchet!
Post by joe_meadmaker on Jan 1st, 2022 at 12:34am
That is fantastic!  I'm not too surprised by the stretch that was experienced.  That's got to be a heck of a lot of tension the sling is experiencing.

I did not hear the crack.  It could just be my computer speakers.  Great idea though!  :thumb:

Title: Re: Balearic-Inspired Sling for a Trebuchet!
Post by Dawesome21 on Jan 2nd, 2022 at 1:06pm
When we go at this again in the spring I will have to station some microphones in front of the machine, or maybe set up a small wall that could catch the sound.  I'm wondering if the crack happened but just wasn't echoed back at any cameras because of the open environment.

Title: Re: Balearic-Inspired Sling for a Trebuchet!
Post by IronGoober on Jan 3rd, 2022 at 9:39pm
I liked the idea. I think you need to borrow a drone and put it above the trebuchet when firing. I bet you'll hear it then!!

Title: Re: Balearic-Inspired Sling for a Trebuchet!
Post by joe_meadmaker on Jan 4th, 2022 at 11:29am

IronGoober wrote on Jan 3rd, 2022 at 9:39pm:
I think you need to borrow a drone

YES!  Try to get the crack from above.  Not to mention some awesome video that could be recorded from the air.

Title: Re: Balearic-Inspired Sling for a Trebuchet!
Post by IronGoober on Jan 5th, 2022 at 3:59pm
@Dawesome21 I see you had a mention in one of Todd Cutler's recent videos! Maybe you can borrow one of his drones :)
https://www.youtube.com/watch?v=Vd2UU-x-Hfg

Or, if you don't mind low quality video/audio, I have one I could send you. It uses a microUSB chip to record video, so you have to kind of guess what it is seeing, but it's better than nothing.

Title: Re: Balearic-Inspired Sling for a Trebuchet!
Post by Dawesome21 on Jan 5th, 2022 at 10:02pm
Drones are a great idea!

I know a guy with one, we will try to schedule this in a few months once the snow melts.

Yes I was very happy to have some conversations with Tod about his new trebuchet!

Title: Re: Balearic-Inspired Sling for a Trebuchet!
Post by Curious Aardvark on Jan 6th, 2022 at 7:47am
Love the sound the guy ropes make.
You could probably tune those and get an actual tune :-)

From what I see there are several reasons you won't get a whip crack.

1) trebuchets use a vertical release, the release cord stays straight and due to wind resistance and the sheer length of it, the tip is just never going to go supersonic.

2) compared to a human throwing with a hand sling, trebuchets just don't move very fast. You'd need to use a short sling, very light ammo and the maximum weight to even get near the overall speed of a hand sling. But it could well cause the trebuchet to tear itself apart.
The release velocity of a treb is high. But the actual speed of the whole sling is fairly slow.
It's the arm length and sling length that create the release velocity at the pouch.
But because of how it's released and the sheer length of the sling. The tip of the release cord is just never going to hit those supersonic speeds.

With a sidearm throw, you actually create a wave through wrist movement, that ripples down the release cord and causes the tip to snap straight at supersonic speeds.

You just don't get the same wrist snap and cord wave/ripple with a vertical release.

Try it, if you can get a whip crack from a vertical release throw, I'll be seriously impressed.
I've never seen it done or been able to do it.
Sidearm, cracking is an absolute doddle.
Because of the wrist snap that sends a small fast ripple down the cord.

But I reckon experimenting with different length and material guy ropes, you could get a simple tune :-)
Or at least a recognisable chord.

Not sure how you'd make a sidearm throwing treb with a surrogate 'wrist', but until you do, I doubt you'll ever get a whip crack.

I suppose you could make snapping joint instead of a fixed release point. That might work.
But without some similar gimmick, you just won't get a crack.

I suspect if it were possible the Romans would have done it, for added psychological effect.
A huge band followed by the missile would have had an enhanced effect on the enemy.

I don't think there's a single report of a trebuchet ever making a whip crack.

But they didn't have the materials and tools we do.
Make that 'wrist' create that wave/ripple and there's a chance you might get a cracking treb.

Title: Re: Balearic-Inspired Sling for a Trebuchet!
Post by Dawesome21 on Jan 6th, 2022 at 9:57pm
Great points, CA, I think you are on track with what I have seen so far with the experiment.  I was surprised how slow the treb sling is moving compared to a hand sling, and there is a lot of air resistance to the roll-out of the sling, and there is no wrist action or wave/ripple.

I want to try to eliminate environmental acoustics as a variable, if we can station a drone above and slightly in front of the sling opening I wonder what kind of sound we can capture.  Or maybe I need to try the experiment with a smaller treb in a more urban area that provides echoes.

The psychological effect was just what I was thinking, it's kind of like how the Romans sometimes made whistling sling ammo.  But I haven't seen any historical accounts of whip-cracking siege engines either.

Trying to introduce a kind of surrogate wrist action on the treb is an interesting idea, I'm not sure how I would do that, I wonder if I can think of something that would have been in the bounds of historical possibility.

I do like the guy ropes!

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