Brussell chucker

[Don P]

I'd been trying to think of the perfect ordinance when someone brought up the perfect thing, good mass but won't hurt anything. What is a trebuchet projectile called?

A couple of weeks ago I was asked to come up with a program for the upcoming school break. We decided a shop project would be good this time of year but we like to tie back to nature in as many ways as we can. So, I've been machining parts for tabletop trebuchets out of a bunch of different woods. In the shop I'll have the harder planks predrilled for nails to drop through, also hard to ding with a missed blow. Self polishing beech in the sling track, hickory, oak and walnut for fun. The frame the nails attach to will be poplar and pine which will easily accept the nails. This should help set them up to succeed. I've been digging for some tupelo, black gum, mainly to get one of the guys to break out in song, but with its interlocked grain it is almost impossible to split, say around a pivot point in the weight basket, in this model they are poplar as I continue to dig in the barn. It was often used for pulleys, rollers, I've used it for timberframe splines. We'll have pieces of each species set up where they can try sawing and nailing to get a feel side by side how they initially work. I'm trying to make it with several hole options at each pivot so they can experiment for more gravity powered fun. Then we'll take a walk in the state forest and visit the trees, see who and what are associated with it, where it grows, etc. Should be fun.


I was brainstorming with the guys in hardware at Lowes this morning, hope they didn't get in trouble. I had no idea it could throw a nut that far   ;D

[low_48]

Nice job!   I made one in walnut for our son when he was in grade school. It resides on his fireplace mantel now, 22 years latter. I'd have to go to Chicago to get a picture.

[Ljohnsaw]

Made a monster model with my daughter 12 years ago.  Cut 6" wheels out of wood and used dowel pins to put it all together.  I had a 12 pound downrigger cannon ball we used for the weight.  It tossed a golf ball about 150' down our road.  Didn't think about how it would bounce.  It went WAY down the road :D

[Don P]

Nice job!   I made one in walnut for our son when he was in grade school. It resides on his fireplace mantel now, 22 years latter. I'd have to go to Chicago to get a picture.

That's what I'm hoping for. I'm planning on having them write the common and latin names on the backside of the different woods so that later on they might take it off the shelf and go look up more on the wood and trees.

There is a larger one down at the shop that was chunking rocks about 100' before I broke the weight basket with logging chains and scrap steel. I'll fix it and have it outside. Then, there is a large one that a local contractor will let us have. The end of the forest walk might end up at a big field there and... well how about that, a big treb locked and loaded  ;D

[Don P]

I've been working on the big treb. It just had 3 dumbells slung under it and was waaay too slow bringing the arm around. I had some nice foundation stones my friend Mule had dropped off when he found out Michelle has a rock problem. So anyway, welded them up into a "basket" and hung that from the arm. Gravity is powerful now  :D.

I spent the day making a safety chain to throw over the arm when cocked and loading the sling... then proceeded to fling the trigger and sling off the thing, but they had excellent hang time, unfortunately in the friendly direction. It's ready to (mis)fire in this shot, the safety chain has just been thrown off and it is resting on the "trigger". We're wearing out St Barbara but it's getting close.

[Don P]

We had good luck with the big trebuchet today. It got a new cocking mechanism, trigger and sling.

The first shot went about 200' and tangled in a walnut. We played with and then replaced the release pin and changed its angle a little and got it to release later and finally cleared over the trees and sent a 3 or 4 lb rock about 300'.

We started playing with larger rocks but need to modify the track to do larger stuff. This is the only shot I got in action. One of those larger rocks has slipped out of the sling but it shows pretty well the sling coming around and the rock in motion.

About then I noticed one of the blocks that holds the weight pivot had sheared so a run to Lowes for some steel strap and ledgerlocks, a little job for in the morning.

This is what I came up with for the brussell chuckers. I was trying to make them adjustable so the kids can play with different combinations of setup... arm length, basket swing, weight, sling length. There's a ton of possible setups if they get into it. I'm hoping they will set them up differently and have contests to find the optimum combination.

[Darrel]

You really need to be careful, one can get himself in a whole whack of trouble having that much fun.  8) 8) 8) 8) 8)

[thecfarm]

I have a bunch of rocks that need chucking.   ;D
I like it.

[Don P]

There's a way to get the kids to clear the field  :D. It is a big hoot to watch... I guess we should bill it as the Highlands Fling. I need to fact check but one story I read somewhere was that when King Edward besieged Sterling castle in Scotland he took his time building the large trebuchet Warwolf, giving the inhabitant's of the castle plenty of time to think about their impending doom. On the day he completed it the castle surrendered. He supposedly refused their surrender until he fired a shot... I can sure understand the desire to see it hurl  .

[Kbeitz]

Try chucking a wood chuck... Ha ha...

[WV Sawmiller]

   I read an article last week where DEA had found a large trebuchet along the border in Mexico that had been used to project drugs over the border.

[Don P]

 I heard that a day or two ago, we were welding up parts and had a good laugh.  So there I am driving this thing over to the forest this afternoon and passed a trooper and a deputy with a large mobile trebuchet in tow and thinking "they are not gonna believe this  :D" 

We made a steel boot for that entire bottom end. It was a textbook block shear in the wood. we got it out there and had enough time to make several throws. It looks like its good for about 300' with this setup. I got some good pics I think, it was throwing tight enough I could go downrange and snap a couple. If the camera is still on it when I get back.

[thecfarm]

In some of our drivings yesterday,I saw one of them. Could only see the top,the bottom was buried in about 3 feet of snow.

[Don P]

I'd love to see pics of other ones, I'm starting to have a clue what to look at to modify.
My camera was happily sitting right there;
Right at release. I've blown it up and cropped so its a little fuzzy, I was way downrange.


and from the side, the angles that counterweight go through surprised me. Hopefully we can get some video and slow it down.

[Don P]

I've never you tubed before, let's see if this works;
https://youtu.be/yHohp_8z94k

Cool, I think it worked.
We walked with the forester through the woods and visited the trees that gave up the wood we used in the tabletop models. He planned the walk well and I carried samples of wood for them to try to recall and put with the tree they were looking at. One of the kids did quite well with that. As we got to the last tree they spotted the big treb down in the field and they left us in the dust. The chunking was on. The watermelon made the best splash. I think that was an acorn squash or one of the rutabegas in the video. We all had big fun. I don't know what the counterweight weighs but realized tonite that I have 2 @ 50 lb dumbells and the arm is basically a balance, we can do a little math lesson tomorrow and figure that out. I think we'll build a cardboard box castle wall and try a little demolition as well  ;D

[Darrel]

Wow that is so cool!

[Don P]

We had to do some edumacation with the fun so for today when they arrived at the pavilion I had a red maple branch in bloom, between when Zach had taken us on a walk yesterday and this morning they had begun to pop. we had told them to keep their eyes open cause we were really close, so that was cool. I also brought a piece of red maple... and because of the conversation going on here I grabbed a really sweet piece of ambrosia maple and we did a few minutes of nature study.

I also had one of the models set up. The weight basket on them contained two 14 oz cans. I took another 14 oz can, slung it with string and slid it out on the throwing arm until it balanced. We then measured the distances left and right of the pivot and came up with a ratio. Multiplying the weight of our single can x the ratio we determined the weight basket was 35 oz. We then deducted the 28 oz of cans in the basket from the total basket weight and determined that the basket itself weighed 7 oz.

I haven't posted a pic of their finished models yet. umm yeah, maintenance in the school shop is gonna find some play dough in the overhead heater next time they go in




We then carried two 50 lb dumbells out to the big treb, winched it down to level and then slung our 100 lb weight over the arm and slid it out until it balanced. It was touch and go but it finally slacked the winch line right at the end of the throwing arm. We did our math again and determined that we had a 440lb counterweight, cool beans. We fired some more, obviously a football wouldn't go as far but it threw 3 beautiful spirals. The baseball came all the way around and released practically into the ground. If anyone got a slo-mo I expect to see that it couldn't open the big sling properly, a different pouch maybe.

We then strapped the dumbells to the counterweight and threw the big rutabaga pretty much the same 300', our record was 302'. I think we had hit the parabolic limit of that geometry but probably could have thrown a heavier projectile the same distance. From reading we should max out in the 100:1 weight ratio area.  We sent the kids off with their models, they had a great time.

Looking for ideas for next time...