Did someone say Trebuchet? - Tilted Forum Project Discussion Community

Devilinmypants · 10-21-2005, 07:12 PM

I'm going to try and construct a trebuchet, but I have no plans. Does anyone have a PDF file that I could gank? I'm going to build one big enough to lob a ball of frozen urine over my house and through a neighbor's window. (Not that I would do that sort of thing just to confuse someone.)

Fire · 10-21-2005, 10:51 PM

Check google for S.C.A. - they got the plans, and use em on the field of battle- it is amazing to watch a volleyball wrapped in duct tape knock a guy over at 50 yards.....

ziadel · 10-23-2005, 02:04 AM

if you find the plans, post em up.

I've wanted to weld one together for a while now.

moot1337 · 10-26-2005, 02:59 PM

Are you a tinkerer, or do you need actual plans to follow? Trebuchets are a bit more finicky than catapults because of the sling, but if you're up for some trial and error, and lots of tinkering/testing, they're not hard to make.

Pretty much, you design a base that will be tall enough for the weight not to hit the bottom when it swings underneath the pivot, and wide enough to give room for the sling... probably a good 4x the width of the object you intend to load into it.

Then, you make an arm with a pivot hole in it, the pivot being about 3/4 to 2/3 down the arm from the sling-end. Attach to the short end a weight (it can be a bucket filled with something, or a solid object like lifting-weights) and put an adjustable hook on the sling-end. By adjustable, I mean something that you can bend or adjust the angle of, that will let the loop of the sling fly off at some point in the air.

Remember that torque=force * lever arm: if you want to launch something heavy, you're going to need something a good deal heavier if you want to give it some good velocity. The length of the sling will also influence the way it shoots. A short sling is going to whip around and release very quickly, wasting some of the energy remaining in the weight. Too long of a sling is not going to be past that critical point around the arc when the weight doesn't add to the energy of the projectile. Fortunately, all that is easily adjustable.

On the base, in the middle, make a running board for your sling's pouch and the projectile. It needs to be snag free, and ideally it will gently center the projectile/pouch in the middle of the board, so it doesn't come out until it needs to. This should run from as far back as the sling goes in the armed postion and then some, back to about as far as the arm extends out of the back of the trebuchet when it's horizontal.

If you get this thing built, the length of the sling, and the angle of that adjustable release hook are what control the release point of the sling. Too late, and your projectile will slam into the ground... too early, and it'll go backwards or straight up in the air

Devilinmypants · 11-03-2005, 09:19 PM

I can only tinker when it comes to certain things. I'm going to try and use a floating arm trebuchet. I hear that they get better range for the size.

moot1337 · 11-15-2005, 04:23 PM

Another tip on the best range: it comes when the weight falls straight down, converting it's PE to KE as efficiently as possible, with less friction from the grinding rotation/etc. Two ways to make this happen: make the weight hanging, and put the whole thing on wheels. If the base can move while the weight stays pretty much in the same place, falling vertically, you'll see that the trebuchet moves forward some and the sling gets an extra kick of power. Tinker and have some fun! Just make sure that the angled hook that holds the loose end of the sling is finely adjustable via screw or something, and you should be good to go

10-21-2005, 07:12 PM	#1 (permalink)
Devilinmypants Hippie relocationist. Location: Greensboro NC	Did someone say Trebuchet? I'm going to try and construct a trebuchet, but I have no plans. Does anyone have a PDF file that I could gank? I'm going to build one big enough to lob a ball of frozen urine over my house and through a neighbor's window. (Not that I would do that sort of thing just to confuse someone.)

10-21-2005, 10:51 PM	#2 (permalink)
Fire Warrior Smith Location: missouri	Check google for S.C.A. - they got the plans, and use em on the field of battle- it is amazing to watch a volleyball wrapped in duct tape knock a guy over at 50 yards..... __________________ Thought the harder, Heart the bolder, Mood the more as our might lessens

10-23-2005, 02:04 AM	#3 (permalink)
ziadel Myrmidon Location: In the twilight and mist.	if you find the plans, post em up. I've wanted to weld one together for a while now. __________________ Ron Paul '08 Vote for Freedom Go ahead and google Dr. Ron Paul. You'll like what you read.

10-26-2005, 02:59 PM	#4 (permalink)
moot1337 Insane Location: Learning to Fly...	Are you a tinkerer, or do you need actual plans to follow? Trebuchets are a bit more finicky than catapults because of the sling, but if you're up for some trial and error, and lots of tinkering/testing, they're not hard to make. Pretty much, you design a base that will be tall enough for the weight not to hit the bottom when it swings underneath the pivot, and wide enough to give room for the sling... probably a good 4x the width of the object you intend to load into it. Then, you make an arm with a pivot hole in it, the pivot being about 3/4 to 2/3 down the arm from the sling-end. Attach to the short end a weight (it can be a bucket filled with something, or a solid object like lifting-weights) and put an adjustable hook on the sling-end. By adjustable, I mean something that you can bend or adjust the angle of, that will let the loop of the sling fly off at some point in the air. Remember that torque=force * lever arm: if you want to launch something heavy, you're going to need something a good deal heavier if you want to give it some good velocity. The length of the sling will also influence the way it shoots. A short sling is going to whip around and release very quickly, wasting some of the energy remaining in the weight. Too long of a sling is not going to be past that critical point around the arc when the weight doesn't add to the energy of the projectile. Fortunately, all that is easily adjustable. On the base, in the middle, make a running board for your sling's pouch and the projectile. It needs to be snag free, and ideally it will gently center the projectile/pouch in the middle of the board, so it doesn't come out until it needs to. This should run from as far back as the sling goes in the armed postion and then some, back to about as far as the arm extends out of the back of the trebuchet when it's horizontal. If you get this thing built, the length of the sling, and the angle of that adjustable release hook are what control the release point of the sling. Too late, and your projectile will slam into the ground... too early, and it'll go backwards or straight up in the air __________________ And that, my liege, is how we know the Earth to be banana-shaped. This new learning amazes me, Sir Bedevere. Explain again how sheeps' bladders may be employed to prevent earthquakes. Oh, certainly, sir.

11-15-2005, 04:23 PM	#6 (permalink)
moot1337 Insane Location: Learning to Fly...	Another tip on the best range: it comes when the weight falls straight down, converting it's PE to KE as efficiently as possible, with less friction from the grinding rotation/etc. Two ways to make this happen: make the weight hanging, and put the whole thing on wheels. If the base can move while the weight stays pretty much in the same place, falling vertically, you'll see that the trebuchet moves forward some and the sling gets an extra kick of power. Tinker and have some fun! Just make sure that the angled hook that holds the loose end of the sling is finely adjustable via screw or something, and you should be good to go __________________ And that, my liege, is how we know the Earth to be banana-shaped. This new learning amazes me, Sir Bedevere. Explain again how sheeps' bladders may be employed to prevent earthquakes. Oh, certainly, sir.

11-03-2005, 09:19 PM	#5 (permalink)
Devilinmypants Hippie relocationist. Location: Greensboro NC	I can only tinker when it comes to certain things. I'm going to try and use a floating arm trebuchet. I hear that they get better range for the size.