Trebuchet - Why won't the darn thing shoot further?

[@daviddavidson2357]

I like the way you said "This is my first trebuchet" like everyone owns one.

[@antonisauren8998]

When this one brakes, He's gonna build whole battery of improved designs. :D

[@IamOutOfNames]

First... but not his last.

[@anaemic]

Its a starter trebuchet, before he moves on to buy a larger family trebuchet at a later date.

[@CristiNeagu]

No, more like people are expected to own several.

[@molybdaen11]

Sadly no. But everyone should own one. As the great Koyfish once said: "They say you can not buy happyness. But you can buy a trebucket which can throw a 90kg bolder over 300m. And if this don't give you happyness, then nothing will."

[@dawndarklight44]

Real life footage of a siege engineer explaining to his lord why the shots are not hitting the enemy castle.

[@tods_workshop]

I think I would have been executed by now

[@nonna_sof5889]

"The next shot better hit or you'll be the one after that!"

[@-Zevin-]

@@EpsilonNought I think he's mostly being sarcastic, although you never know, under feudalism the whims of a lord were law, if he was just or completely mad. Although I think any rational lord would have understood the value and rarity of a trained siege engineer, not someone who can easily be replaced.

[@kenrobba5831]

Now, does he get beheaded ? Can we watch ? LOL ! Great Fun !!!

[@Greenfeld13]

"M'lord, you know what it is....it's the wind and the iron on this trebuchet is warping due to the wind and basically it's not arcing right for reasons beyond my control."

[@curtishoffmann6956]

Way to increase distance when pacing out the shot - shorter paces.

[@piotrmroczkowski2324]

Nice and simple solution - I will allow it!

[@mawe9878]

Work smarter, not harder.

[@tods_workshop]

Curtis - a nice plan, but sadly one that's not for me. Made me laugh though

[@MonkeyJedi99]

Ah yes, the "Fisherman's Ruler" method!

[@whirving]

Pacing can be very accurate with practice. I used to pace out my distances for stake out (I'm a surveyor), and the instrument man would read the distance and say "lucky, go 2.4 feet." Until it happened another 10 or so times, always under 10' from the target distance. I'm not special, I just did it A LOT because we were staking out power pole locations for long transmission lines, so hundreds of repeats.

[@senorjp21]

The pin angle isn't the only factor that determines release. The arm is decelerating as the weight approaches the bottom of the swing. The easier factor for you to adjust is the length of the sling. You want to adjust the length of the sling unti the weight stops at the bottom. Tom Stanton has a good video on optimizing the trebuchet.

[@dooleyfussle8634]

Yes, Tom has a good series on his trebuchet. If I remember right, he built in a "kick" on purpose to optimise the thing. It was much smaller and threw tennis balls (a long way).

[@dawnmaster68]

i saw what you mean ... wouldn't it be easier to control, if you somehow fixed the counterweight. i mean it even starts to stall before the 180 degree angle because the weight and the arm lose connectivity while the counterweight alters it's path. that way the arm actually holds it's momentum until it can give the energy into a path forward much rather then up.

[@tihomirrasperic]

they change the wrong thing all the time, there no problem in pin length the catapult has 3x factors that affect the distance 1. weight (the heavier, the stronger the swing) 2. catapult arm, the longer, higher speed 3. length of the slingshot I personally think that is his problem, under point 3.

[@matthewwright4975]

@@dawnmaster68 As a kid I saw a 'make a trebuchet' tv show & iirc their design was a counterweight fixed to the arm on a simple frame & it wanted to tear itself apart on each throw. They added wheels to frame so that it could roll back & forth after the throw to damp down the energy. Their researcher then got historical images & it looked like the original ones were simple frames with weight in hanging baskets & they said that that swinging about would provide the dampening effect, plus you wouldn't have to cart special weights all over with you but could just use some handy rocks when you reached your destination.

[@dawnmaster68]

@@matthewwright4975 oke so maybe restrictions to the counterweight. A basket sounds like it's fixed to an axel much rather then straps

[@MrBlasz]

Thank you for adding the flight path. It makes it way more enjoyable

[@tods_workshop]

Thanks and I like those too and for those that remember - "missile command"

[@angrypotato_fz]

I like to imagine that there's a a castle on the other end of this field, you're the aggressor slowly working on understanding this trebuchet and making it work reliably, and the defenders on the battlements stand there wondering how many safe months they have before you manage to hit their wall with a bowling ball :) Thanks for superimposing the trajectories in the last shot - that's exactly what I wanted to see all this time :)

[@gustavchambert7072]

I think the problem is with the counterweight. The arm stops at almost perfect vertical every time, so it does not transfer a lot of the force. From what I can see the problem is that the weight falls straight down, while the arm rotates. This leads to a situation where the arm rotates PAST the weight, which then arrests the movement before being pulled into the rotation again. This seems to lead to a premature release, that is both weak and difficult to control, since the sling is pulled off the hook by force, rather than just slipping off at the right angle.

[@R0swell5104]

Sorry just mentioned a similar observation in my post. Apologies for stealing your thunder.

[@Trebuchet48]

We hurlers call that "counterweight stall". It's entirely usual.

[@dougler500]

@@Trebuchet48 Can you go into more detail for the sake of our and Tod's enlightenment?

[@Khar_Toba]

I don't know anything but now you mention it, it seems to me that maybe the counterweight would rob less of its own energy if it was on a shorter arm?

[@guillaumehenin6192]

Not sure to agree with the above. It seems to me that by extending the arm length without increasing the main axle height above ground, you have reduced the distance over which the projectile is being accelerated (arm is longer, the "ideal" point of release remains more or less the same, so the arc length (edit: not the arc length, the angle of rotation) between initial and release point is actually smaller), thus the initial speed of the ball at release point is lower. If I have got the dimensions right, your 1.2m extension might have cost you about 15 degrees of rotation of the main arm during which to accelerate the ball. Edit: you've also reduced the drop height of the counterweight, which reduces the energy imparted to the projectile, hence the dampening of the counterweight motions.

[@oldseer7610]

Consult a physicist. Lengthening the arm also requires adding more to the weight box. Lengthening the arm will require more energy as the leverage has changed but the power applied is the same. It's called "gearing". You geared up but didn't power up. The same process takes place in an auto transmission. Different sized gears require different power applications. Basically what you did was change gears.

[@ianrosie4431]

Not a failure. You're achieving a similar distance without the machine trying to tear itself apart. A serious attempt at distance would require a clean sheet I think.

[@alanrickett2537]

No just wheels but he has his heart set on not doing that

[@braddbradd5671]

Im sorry if he dont listen to use fans its a failure .Dont kiss his ars .hes making money out of you ..........................................Like i said before you need a flexible tip ,Why cant you make one out of strips of bamboo tied together ..But you seem to know it all mate thats why it aint going that far..I cant watch this any more your gona fail every time .Do you ever watch cricket and Fast Bowlers ? The flexibly at the elbow increases the speed and thus distance Watch this you dont need no experts watch this .....Its called Hyperextension .What better model to base it on but the Human body .......kzbin.info/www/bejne/a56lY3mOmsl8f7c ............................I mean do you actually listen to us plebs were the ones paying for this fuking shit ??????..........I dont see you ever answering any ones questions .i think your a fuking big head....If your not caught up with your talking to you collaborations KZbin mates ..Can you answer me why a flexible tip wont work ?..I mean do you think it will break ????......Well isn't that your job to find out ????...Or maybe your dragging it out cos you get more hits when you fail >?

[@ianrosie4431]

@@alanrickett2537 Thank you, alan.

[@thatkn1ghtguy942]

Thanks dad I needed to hear that

[@Auxius.]

shouldn't that extra energy go into the ball though? or is it still lost due to the longer shaft requiring more energy to swing?

[@xXScissorHandsXx]

the pure joy on Tod's face and in his voice when he gets to loose this mayhem is just priceless. Thanks for what you do!

[@Deipnosophist_the_Gastronomer]

Loose!

[@vivianevans8323]

A brilliant start to the week: Tod experimenting with his beloved trebuchet! Your enthusiasm is infectious, Tod!

[@tods_workshop]

Thanks, but I am thinking of retiring it for a bit

[@haydenduvall162]

I wish we'd had this kind of stuff to watch when I was a kid in the 70's and 80's.

[@tods_workshop]

I hope it does help Hayden, I enjoy it and science and history should be fun

[@troelsandersen9654]

Would have probably built one in the back yard and wrecked havoc on the neighbours' roof........

[@mrmicro22]

Never too late.

[@_aullik]

With the extended arm the release speed is less even tho there is a greater lever effect. From what i can see the weight reaches its lowest point far to early during the arms rotation. This means for the rest of the swing, the weight is slowing you down and you have no further acceleration on the ball.

[@FluffyTrainz]

I was thinking that. With a longer arm, maybe the pivot needs to be raised higher...

[@GuitarsRockForever]

That was my observations too.

[@thomasneal9291]

@@FluffyTrainz *ding* correct. just like when a dancer extends their arms to slow a spin, the longer the arm is from the pivot, the slower it is going to accelerate. you need to increase the arc travel to compensate. which means a higher pivot. basic, basic physics. this guy SHOULD already know this. hell it's even quite a simple equation, and we used to have exactly these kinds of questions on high school physics exams.

[@joeyoung6987]

"Every day's a learning day" sums up the series nicely. Watching the instructor learn while he's teaching really pulls you into the project. Your excitement at the unexpected becomes our own - love it!

[@euansmith3699]

This is yet another great episode of Tod's Workshop. It never fails to inform and entertain. I find it interesting how relatively short the weapon's range it. The siege works would need to be set pretty close to the city walls. No wonder, Sallying Forth was a viable option for disrupting the engineers' activities.

[@joosttijsen3559]

the great castle destroying trebuchets could fire like 300 meters for iirc, which is a long time to to go if ur running between arrows and pikes i guess :P

[@axistec]

Just the fact that you built a trebuchet and improved it to the point where it shoots safely and solid, it's a huge achievement in my books. Also, I can see you figuring out a way of getting more distances with the throw soon. Love this stuff.

[@ludecom-cz1wz]

Drinking game alert, drink every time Tod says I Don't Know. Thanks for another wonderful video.

[@tods_workshop]

Great idea, but you would drunk within 4 minutes

[@Ben-ry1py]

In a world that goes from catastrophe to catastrophe your videos are pure joy Tod! Thank you, really.

[@tods_workshop]

Thanks and glad to be of help

[@gordonlawrence1448]

I think the most ridiculous use of a trebuchet I have ever heard of was at the siege of Bedford Castle (1224). Supposedly a very arrogant knight was sent into the castle to negotiate a surrender. He was insisting it was unconditional and was more than a little rude. The reply was to tie him to his horse and use a trebuchet to launch him and the horse over the wall and into the enemy forward camp which was apparently only 30 meters away. Not sure if it's true but it's still funny.

[@molybdaen11]

That would have to be a really big trebuchet to do that.

[@Deipnosophist_the_Gastronomer]

Run away! Run away!

[@Arkantos117]

My favourite trebuchet story is Warwolf. The English built the biggest trebuchet ever and even though the Scottish offered to surrender they were like, "Na we want to use this badboy," and proceeded to take down an entire wall with it.

[@888johnmac]

@@Deipnosophist_the_Gastronomer .. beware of French knight firing cows .. lol

[@Lionbug]

FAR too heavy for a trebuchet

[@rafaelbischof8524]

You went into the statistics of how you cannot evaluate the effects of your changes after only one shot. Yet you make changes after every shot and try to evaluate them on that basis. In German we have a word for what you are doing: "verschlimmbessern" which is a combination of the words for worsen and improve, meaning the act of trying to improve something and in doing so ending up worsening it.

[@JuergenGmeiner]

The video was uploaded 14 seconds ago and didn't have any comments! Can't have that, can we?

[@axerxes3981]

Absolutely Delightful!! I've always been fascinated with trebuchets and always wondered HOW were they built and aimed and adjusted, etc. Not so easy I see. Thank you so much for sharing your joy and your frustration. What wonderful fun!!

[@karlh.9743]

Love this channel. Thanks for keeping it up Tod! PS: Not everyone 'owns' a trebuchet, even if it doesn't shoot further, atleast ya get one haha! Cheers buddy

[@Trebuchet48]

I don't own "a trebuchet". I own three of them! And two onagers!

[@tods_workshop]

I would like an onager.....

[@karlh.9743]

@@tods_workshop Now that'd be a sight to behold

[@lightningandodinify]

@@Trebuchet48 living in a condo so no artillery for me! 😣

[@whirving]

@@tods_workshop maybe you'll meet up at a siege conference or something?

[@andrewr2955]

I've always enjoyed your videos, but this one was absolutely hilarious. Your enthusiasm and almost child-like excitement is infectious, and the self-deprecating comments made me laugh. Keep up the great work, and I hope you figure out the mechanics and physics of that beautiful machine!

[@tyediedhair]

When I was building Trebuchets I would think of the pin as a delayed release that has two variables, length and pin angle. A given Pin length will have a optimal pin angle and a pin angle will have an optimal length. There is a range of working pin length and angles from my experience and just takes trial and error. Also from my experience you want the sling length to match the length of the arm to the axle. From the videos it looks a little short. The grouping looks good considering all the variables involved. My most accurate Treb (6ft arm) Could hit a standard piece of plywood consistently.

[@tommylitchfield3450]

Don't despair, Todd! You have achieved the same distance as before, but with a MUCH more controlled counterweight. I would bet that the distance is actually greater, but you had to shoot into the wind today. From reading the comments of experienced people here, it seems that your arm is a little too long to get pulled back to "full draw" before it hits the ground. It was pretty surprising how much your changes to the release pin made! You are on the right track, I think. Your first attempts were powerful but hard on the gear. You have proven that you can tame the wildness and still reach the same distance. I'd say on a calm day or especially with a trailing wind, you'd have surpassed your longest toss to date.

[@gpetheri]

I thought these things were supposed to be on wheels, so as the weight drops, the base can move so the weight drops perfectly vertically down and not rotate around a pivot point. This will also stop your arm stopping and jerking at the 12 O'clock position and not flinging properly. Put it on wheels so it can move itself during the weight drop.

[@poppymason-smith1051]

ik this was a comment you made ages ago. but some had wheels and some didnt. theyre were some mobile ones but also massive big siege ones when an army had the time an resources. look up the one at warwick castle in the uk for a hamster wheel type drawn one. there was a tv program in the 2000s in the uk i think that tested one against the other? I cant remember the results or even find it anywhere tho. but they did go into the wheels letting it move about. I think the standing one damaged itself more but I did last see this program when I was about 6. I dont know if they varied on the time periods they were in use?

[@gpetheri]

@@poppymason-smith1051 Yeah I saw either the same or a similar show, which is where I got it from. Basically the system needs to be on wheels so when the weight drops, the chassis moves backwards and thus the weight drops straight down instead of taking a curved path. I think for the fixed ones they have a slightly different method to account for this. But.... for this fellow in this video, I think he needs wheels.

[@percyhart5070]

@@gpetheri @Poppy Mason-Smith Yup I'm 69 & saw that show both of you have mentioned at least 30 years ago. As well as allowing the weight to drop straight down getting the full effect of the weight in a shorter drop distance making for a faster arm swing it also alleviates the tendency of the trebuchet to break the uprights off the base thus allowing for a lighter build.

[@johncochran8497]

First thing that comes to mind is put wheels on the darn thing. For more efficiency, you want the counterweight to fall straight down. Not in a curve. Putting wheels on it, allows the entire trebuchet to roll forwards and backwards to allow the counterweight to fall straight down.

[@bambigotclaws1504]

Hello Tod, when i look at the release pin, it looks quite rusty. My gut feeling says if you polish the pin and maybe even grease the loop on the sling, you might get more consistency in the release, thus might be able to see effects of your change in the direction you intended because it’s not clouded by inconsistent release…

[@loupiscanis9449]

Thank you , Tod . 🐺

[@demacherius1]

Tod: "Playing games with kids and a trebuchet" My mind: "Ill throw you catch" 🤣

[@spudgn]

Yep. Happy fellows are big kids. Thanks my friend. It is always a great watch.

[@senatuspopulusqueromanus3011]

Another trebuchet video!

[@stefanmuller2913]

If you can get your trebuchet on wheels it can shoot further. There was a very good documentary about trebuchets and they explained the physics there. My brother did an experiment in school, where he built a trebuchet (about 2 metres high) and tested it with and without wheels

[@hiltonian_1260]

Totally agree. Also make two rails with side walls for the wheels to run in. Better than on turf. If the frame can roll then the weight can fall in a nearly vertical line instead of a sideways arc. Better vector, longer range.

[@farmandmao]

hi Todd. I think it is the counter weight. It dangles. Might it hang on a hinge rather than a rope, to avoid that dangling effect? If you watch in slow motion, the weight seems to make the arm stall before the motion is complete.

[@gustavchambert7072]

I noticed that too. The arm stops at almost perfect vertical every time, so it does not transfer a lot of the force. I think it is already on a metal hinge though, not a rope. From what I can see the problem is that the weight falls straight down, while the arm rotates. This leads to a situation where the arm rotates PAST the weight, which then arrests the movement before being pulled into the rotation again. This seems to lead to a premature release, that is both weak and difficult to control, since the sling is pulled off the hook by force, rather than just slipping off at the right angle.

[@agurdel]

I was about to comment something similar. The arm stops when its upright which means that it slows down before that. When you step through the video frames at 1:32 (side view), you can see that the weight drops not only down but to the right (as the pivot for the arm goes to the left). When the arm reaches about parallel with the front support the weight is in line, but the arm is much faster at that point than the weight. After that the weight is dragged by the arm until it reaches about upright where it performs a dead stop and the sling is released. If I had to guess, I would say that that upright stop also bucks up your release. And all those jerks from the weight cant be good for the whole mechanism.

[@kevingeanes2655]

Probably 15 years ago, maybe more, I saw a TV show about these guys who wanted to build a trebuchet. They were engineers or something. Anyway, when they were researching, they kept finding medieval illustrations of trebuchets mounted on wheels. At first they thought it so they could move the things around the battlefield. But one of them thought maybe it was something else. When they built the thing and fired it, the entire machine lurched forward about 6 feet. And that lurching did 2 things. It imparted more forward momentum to the stone increasing range. And it prevented the counterweight basket from swinging around so wildly. I wish I could remember the show. It may have been on BBC. I just don't remember. Anyway, I love watching your channel. It gives combat nerds something to look forward to. Cheers!

[@bunyanforgings7849]

I remember seeing that program too. I seem to remember it made for a smoother throw adding something like 50 % further? It was significant.

[@2xwrt281]

Loved it. Loved the work, the experimental history and engineering...I imagine this is the process for which any trebuchet went until calibrated properly. Only one complaint...next time I want to see that thing HIT SOMETHING

[@michaelhoran955]

I always enjoy watching you get excited and enthused. Great stuff. Mike

[@Or_else_it_gets_the_hose_again]

Great content as usual! There's a great 2006 NOVA: Secrets of Lost Empires episode about trebuchets. They get two teams of craftsmen from the US and UK to build two full size trebs (one swinging one fixed counterweight) to see which type Longshanks used in his conquest of Scotland. They built a section of period correct castle wall and ramparts to launch period correct projectiles at as well. Loads of fun! They also have some archery and armor bits interspersed throughout the episode. The full episode is free on KZbin- kzbin.info/www/bejne/h4eyaYmwo9aAm7M

[@BobT36]

LOL, I imagine Todd is now looking up stonemasons...

[@Waschbööör]

Just watched it, really awesome video you linked for us!

[@Or_else_it_gets_the_hose_again]

@@Waschbööör glad you enjoyed it! I’ve watched it a number of times over the years and it always entertains

[@mattpastell3728]

Things always get interesting when you start saying I don’t know! I do enjoy watch the arcs displayed

[@onbedoeldekut1515]

I think what you need more than anything else is/are more bowling balls. (and rig a cheap salvaged/2nd hand motability scooter for offroad purposes, with a hitched trailer). That'd afford you the ability to make the required amount of shots without spending most of your day trudging back and forth to get just a few balls.

[@TheLordGhee]

he shooting in a field so damage to it might be an issue (kind to the farmer)

[@senatorjosephmccarthy2720]

A target will enable shorter measurements (from it). I've humorously suggested a whitetail decoy.

[@Tubepoacher]

I love your energy and passion

[@nowthenzen]

Tod, one way to get the Treb to throw farther is to reduce the mass of the earth, thus reducing the force of gravity. This is indisputable physics and is guaranteed to work.

[@tods_workshop]

That is a great idea! How do I swing that?

[@nowthenzen]

@@tods_workshop Well, I just think of the great ideas, it's up to somebody else to make them work.

[@colobossable]

@@tods_workshop try shaving a tad more off the pin

[@nowthenzen]

@@colobossable that won't reduce the mass of the earth very much if at all, unless you launch the shavings into space.

[@2bingtim]

@@tods_workshop Lol. NASA or Elon Musk?

[@onogrirwin]

I made trebuchets and other catapults as a young teen, and I have to say this one looks awesome. Putting the whole thing on wheels can help a lot.

[@QuentinStephens]

You've mentioned wheels on other trebuchets before, mainly in the context of a cleaner drop of the weight, so how about adding them?

[@pikablu81]

absolutely fantastic, gives a new found respect for the guys that first created them. they must have gone through the same process at some point

[@backonlazer791]

The first trebuchet ever built was the best of its time, though ;)

[@D-B-Cooper]

The arm goes faster than the weight and the weight slows down the forward momentum as the weight pivots forward. The length of the arch of the weight needs to be in sink with arm and needs to come down smoothly. The weight should also come to rest on a brake so as not to try to destroy the machine. If you had a brake you might get away with adding more weight.

[@pavementsailor]

That's what I was seeing. It looks like the counter weight is braking/slowing momentum at the release. There is a sudden sharp back pivot on the weight that looks to have a dampening motion. By design? Maybe this could be adjusted. Tod did lengthen the arm, but perhaps that threw it out of rotational frequency - if that's a thing. Potting the radius movements over time might reveal the instance of interference. These would all need to be in sync for maximum distance. But maybe the sudden abrupt movement is what is supposed to happen?

[@TheValinov]

@@pavementsailor isnt there an specific ratio how long the distance between ball and weight must be? when you only lenghten the throwing arm the ratio is broken. but im not sure. maybe i missremember.

[@matthewsulzbach9084]

Could the rope be too long as well? Dig a channel in the ground so you can rotate the longer arm further back at the load side

[@senatorjosephmccarthy2720]

Better to let the weight and arm continue until naturally stopping, or with slight braking over "long" distance.

[@D-B-Cooper]

@@senatorjosephmccarthy2720 there was a wooden ramp at the base that the weight touched at the bottom, almost like a springboard.

[@KillmanPit]

Hey! Robotics engineer here. Just as you I'm completelly suprised by how intuitive this machine worked. However, I have came up with few hypothesis that might explain parts of what happenned: 1. After first pin adjustment, you have lowered the trajectory closer to optimal, but your ball had lower initial velocity. This tells me that either there was some energy loss or external factor. The effect seemed a bit too big for external factor. 2. After second pin adjustment, trajectory was lower than optimal, but initial velocity was bigger. 3. After the pin cut everything begun happening as expected again Based on that here is my hypothesis: Energy loss was due to friction with a pin (probably insignificant), and in weight. You see, when the ball got released earlier, the weight was still moving basically vertically, but when it was released later it was already moving horizontally. Internal friction required to change direction of this huge mass, must have ate a bunch of energy. Another consideration which is way harder to see or predict is the arm itself working as a spring! When the weight begins to fall, and ball starts accelerating, the arm gets stretched a bit, however at some point acceleration from weight decreases, and energy stored in this stretch gets released. If this coincides with release of the ball, you get perfect shot. However, after initial energy release the arm bends the opposite way, and then releases that energy backwards to direction of the shot. If ball is released at this moment you get way lower than optimal result. This is all way cleaner if you model your trebuchet as made of springs instead of solids. The effects may seem small , but judging by how the wood curves in those shots there may be a lot energy lost there.

[@gustavchambert7072]

In the third shot the pin is bent too far. That shot is launched at significantly less than 45°. And you get the same range for the same deviation in launch angle, with 50° giving the same range as 40°, it's just the trajectory that changes.

[@MichaelOnines]

You are using the physics 101 launch angle for 0 air resistance. When you add air resistance the optimum angle is shallower.

[@chigglywiggly]

It would be useful to measure the actual angle from the video

[@sweepsp8468]

Kids of today have Iphones and computers to waste time, real adults have trebuchet's. Long live Tod.

[@tods_workshop]

Quite right.

[@carlredbird3054]

Try greasing the axle, or run it on bearings. More speed will give further distance Historically they could have used animal fat mixed with beeswax as a lubricant in place of modern grease lube

[@thomasneal9291]

no. it is much simpler than that. if you increase the length of the arm from the pivot, you need to increase the arc of travel to get the same acceleration at the point of release. which means you need to raise the pivot to give the arm more travel time. it's very simple physics. Hell, you can probably find a very similar example used in any freshman or high school physics text.

[@WeaponKingNZ]

If you want the max distance you have to find the 45° release point. If you want any further you need to up the weight.

[@CMZneu]

Theoretically the most distance you are going to get is when you release it at a 45 degree angle. And besides that idk, a smaller ball with the same mass, and shouldn't you make it taller if you make the arm longer? i think the arm should almost be able to swing under it.

[@_ExTitus]

45 degree angle is best theoretically but there are more forces at work than just gravity. iirc somewhere between 30 and 40 degrees is generally the best mix of horizontal and vertical vectors when accounting for gravitational force and air friction. But that can change with wind speed and the density/mass of the projectile ie: wind speed is different at different altitudes so sometimes going more vertical could carry a lighter projectile further

[@mini_bunney]

One of the assignments we had in a course of mathematical computing was to figure out the optimal launch angle for horizontal range when accounting for air resistance, the result that I got was roughly 37.5 degrees for a small spherical projectile. This was just with air resistance, so there was no wind, meaning that the angle would be different in different conditions, but still, somewhere between 35 and 40 should be good.

[@kuroinokitsune]

... I've been on English KZbin for so long that hearing metric system gives me tears of nostalgia and joy. No damn feets and pounds, priceless.

[@R0swell5104]

I am far from an expert but this is just my observation. It seemed to me looking at the footage that when the arm came to about the roughly vertical position it seemed to really hesitate perhaps even go back slightly. It was almost as if the counter weight effectively just fell vertically instead of doing an arc. I was just contrasting this with a simple sling where the movement up to the point of release is smooth as is the follow through. Could it be something to do with the counterweight being articulated rather than mounted rigidly or semi rigidly at the end of the throwing arm????

[@senatorjosephmccarthy2720]

ROswell5104, The lever stops at vertical because of the weight being able to swivel. So some of the length to accelerate the projectile is lost. The weight movement has to be timed to have the weight reach its highest velocity at the same time the projectile is released. The weight's highest speed is before its farthest point of travel. And the best point of release must be determined or estimated first. The weight must be attached solidly to the arm. Seems the weight might have to be moved a bit toward the front of the trebuchet so it reaches the end of its work at the same time the projectile is released, which will be at some point slightly past the arm being vertical. So the arm swings up; the arm swings smoothly thru whatever arc it makes because the weight is attached solidly to it. The projectile releases at the right point. The weight reaches the end of its travel at the right point, the same point the weight is making the most work, because it's attached solidly to the arm. Seems.

[@keithfowler2013]

You work so hard to keep us entertained, . Thank you .

[@tods_workshop]

A pleasure - kept me entertained too!

[@picklep3076]

Suggestion: Why not build a table top version that you can load rapidly and science the heck out of? Like a sales sample. I'm not an engineer so i don't know if it would be scalable. I know a few people that would love to have a table top one. Just for those occasional food fight Etc...

[@allstarwoo4]

It will to a point. Scale models are good for rapid testing but it scale model and full can still differ due to may things.

[@tods_workshop]

a scale model would be fun and educational, but as Nathan says; only useful to a point

[@reav3rtm]

I think the only differences between scaled down and original would be in material integrity, not performance, so I still think it is useful. In other comment I suggested software simulation with algorithm to tweak parameters to maximise performance, which is even taller order than table-top real model for experimentation.

[@ChrisKing25]

Really enjoying this trebuchet series, Todd! Keep on keeping on!

[@johnhenkel1828]

I think your issue is the amount of time the counterweight has for acceleration, and I am not sure there is much if anything that you can do to increase the amount of time the counterweight has for dropping, which creates the acceleration rate. Because of this, I am afraid that you have probably reached about as far as this trebuchet will hit, unless there is some way to increase the height at which the counterweight falls. Watching the counterweight closely on this video, you have about 0.9 seconds of acceleration on the counterweight.

[@roberthamblett9619]

Raising the frame / pivot would allow the throwing arm to come back to its former position underneath. Lengthening the arm but not raising the pivot has reduced the travel.

[@kevinchristensen534]

Love watching the learning!

[@steveschainost7590]

Knowing little about the physics of the trebuchet . . . . . but I do note that the swing arm comes to a jerky stop at the vertical then swings further. Maybe some tweek to smooth out and lengthen the swing moment. I also wonder if you might already be at the limit of what this particular machine will do. For what it's worth (nothing?) I found this video that might have some useful info for you trebuchet builders out there: kzbin.info/www/bejne/mJ62nWx3ptKJr8U

[@leebaldwin8072]

Love it Todd! Who knows??? But it’s fun to watch and I’m sure more fun to do!!!!!

[@sarchlalaith8836]

When you shoot a bullet often high velocity, low weigh shots fall short. Increase the weight of the shot.

[@lukeorlando6088]

I had to scroll further than I thought to find this suggestion. I feel that a slightly increased projectile may take the energy out of the counterweight. As others have noted, the bucket seems to be wiggling quite a bit and stalling out as the arm reaches vertical. This tells me that the energy has not all been transferred to the projectile. But my experience comes from archery, which has a fundamentally different method of energy transfer.

[@bronco5334]

That has nothing to do with the throwing dynamics, though. That's just a matter of projectile ballistic coefficient: namely, the ratio between drag and momentum. Heavier projectiles have a better ratio. And drag increases logarithmically velocity: doubling velocity much more than doubles drag. Fast projectiles encounter a lot of drag, and differences in drag make a big difference at high velocities. At low velocities, it's less important. These are already pretty massive, slow moving projectiles. I very much doubt ballistic coefficient is playing all that much of a role here.

[@glennchartrand5411]

Back in the 70's our Boy Scouts summer camp had a 3 day contest with 1/8 scale models and we discovered that: 1. The longer the sling , the easier it is to get a consistent release angle. 2. Getting the arm pointing down about 70⁰ before launch was crucial. Going past that didn't do much since the weight had very little leverage ( Like when your bike pedal is nearly straight up) 3. The faster the arm = the longer the sling. Because you lengthened the arm you can not get it down far enough, which slowed the arm down, forcing you to a shorter sling , which threw off your release point. I'd shorten the arm so it touches the ground at 75⁰ down, go to the longest sling possible ( it barely touches the ground when the arm is level) and go from there.

[@BugCatcher1]

I have seen a few comments saying that all else being equal, the optimal release angle would be 45 degrees. This is true for an object in a vacuum being launched at ground level, but it is not true for an object being launched at any height above the ground (assuming the shots land at ground level). In general, the higher up the object is launched from, the closer to 0 degrees it should be. I am not sure how big of a difference it would make at this scale and with this trebuchet but is just something to know about. This is also with all other factors being equal, which is not necessarily the case here. For example, different release angles might correspond with different amounts of energy being put into the projectile, resulting in different end distances. It complicated!

[@tomtruesdale6901]

Tod, keep slugging along and you will figure it out and then have one heck of an AH HA moment. Looking forward to seeing that moment

[@zweispurmopped]

Remember the law of energy conservation: Your trebuchet converts potential energy into kinetic energy of the projectile. The transmission ratio of the longer arm just has it requiring less angular velocity to achieve the same speed of the projectile, which makes the entire thing not tear itself apart on launch. To get more range add weight to the accelerating mass now. Try placing some stones on top of the box, for example. You will see a difference then. A different mounting of the accelerating mass might help, too. I have a suspicion that the pendulum-style mounting is slowing the arm just when you want it to move fast. For maximum range you want to have the release at around 42° upwards. That also roughly happens to be the angle when the mounting of the weight is getting drawn towards the base of the trebuchet. Seen from the arm's pivot, this is when the centrifugal force stretches the mass to its point the furthest away from the pivot. Here angular momentum comes into play, the thing with the spinning skater that slows down as it spreads its arms and spins faster when it pulls in its arms: the shape with the mass far away from the pivot has a greater moment of inertia, thus requires less angular velocity to acquire the same angular momentum. The arm and sling and projectile thus will be slowest in this part of the swing. That's about when your trebuchet releases, so you want maximum angular velocity there! Oddly enough at the end of the swing, the mass will get raised closer to the pivot when braking. This configuration will do the opposite of the fully stretched out one, the mass will add an extra push to the arm in the last few degrees of the swing. That makes me think this design with the trebuchet's accelerating mass in a pendulum could have been specially designed for having the projectiles go fast at shallow trajectories, not so much for throwing nice, high arches _over_ walls but smashing heavy things _into_ them half way up.

[@ShuRugal]

for ranging it in, you need to get a dozen or so identical projectiles, file them in sequence, and then evaluate the grouping. just like sighting in a rifle, or any other ranged weapon. do it with a bunch of projectiles to save you the hassle of walking out and retrieving each shot. it'll go much faster.

[@chriswest1996]

Put it on wheels. If the weight falls closer to straight down and the pivot is moving forward, it will throw further.

[@beezo2560]

Mmmmm, trebuchet science. Keep at it Todd, we're cheering you on.

[@promiscuous5761]

Thank you.

[@andrewsock1608]

Maybe you need to move the axle further away from the counter weight. Shorten the counter weights straps and lengthen the counter weights leverage. ? Love this channel ❤️👍👍

[@kasuha]

If you stop the video exactly at 5:40, you can see that at the point where the counterweight is at its maximum extension (i.e. it is hanging at the same angle at which the arm is), the projectile has not been released yet. Since that point, the counterweight is actually slowing down the arm and that reduces energy of the shot. The very least you can do about it is to make the counterweight hang on longer hinge. It may require making the trebuchet higher to prevent it hitting the ground. You can also put a "scythe" at the end of the arm to make sure the counterweight goes straight down and is not being pulled towards the back at the end of the arm swing. Or you can put the trebuchet on wheels, that way the pull of the counterweight will move it slightly forwards during the shot and that way some of the energy lost on pulling the counterweight back will be put into speed of the arm end.

[@Smallathe]

Fascinating! I'd love to see more details!

[@troelsandersen9654]

Once again, we are reminded that "Patience is a Virtue"! Festina Lente Tod.

[@grahamh4960]

I left a note on one of your throwing dart video about adding a short length of slingshot elastic to the string to increase power. I really think the same would help with this if you could find anything strong enough. It depends on if you was comfortable using modern materials on ancient machinery. One thought, a leaf spring from a car (could also make a good crossbow)

[@Deavertex]

A trebuchet's range depends on the speed of the arm at the time of release. The sling just multiplies that speed. While increasing the length of the arm will extend the range somewhat, it does so at the expense of energy imparted to the projectile -- need to use a lighter projectile to get the same range. Remember, the arm is just a lever. The speed of the weighted end of the trebuchet arm is absolutely controlled by gravity acting over a distance. The farther the weight falls, the faster the arm rotates, and the greater the range. That's why medieval trebuchets were huge. The bigger they are, the better they work, as long as the wood and the fittings aren't stressed to failure.

[@MartinGreywolf]

I really hope I'll be able to get my thoughts across like this in text. This is a problem of optimizing two systems that are almost independent. You have two levers making two independent circles. Okay, not really, but let's imagine you do. Circle A is done by the treb arm, and you want to release this one when the arm is vertical, just before the weight starts to go other way and decelarate the entire thing. Cirlce B is done by the sling, and you want that one to release when the projectile travels at 45 degrees (or your chosen angle) to the ground (or, more mathematically, at 45 degrees to the gravity vector). The pin, by its angle and length, only determines the release moment by angle of sling to arm - not the ground. So your pin that releases at 45 degrees to gravity has a pin that releases when the sling is 135 (90+45) degrees from bottom of the arm, IF the release happens with the arm in vertical position. If you change things so that that 135 degree angle is reached by your system before the arm is in vertical position (0 degrees to gravity), you will get a release at an improper angle. Furthermore, if you then alter your pin angle to release at 45 degrees to gravity, it will no longer be in the optimal position and you will get a weaker release (too early and the weight didn't transfer all of its potential energy, too late and the weight is working against itself) as a result - and this last part is what is happening to you, I think.You had the treb in a fairly optimized config, then changed circle A and altered the pin to release at 45 degrees to gravity, without harmonizing it again. So, you need to alter something. You could change the weight, or the arm extension, but those are kinda hard to alter, and definitely too hard to fine tune, so the answer is obvious (well, it is for me who has messed around with staff slings): set the pin to release the sling at 135 degrees from bottom of arm and then change the length of sling so that it releases with arm in vertical position. And if it doesn't work, we will know we missed something.

[@johnladuke6475]

I really like how this series involves everything except either inviting an expert to physically visit the trebuchet or putting wheels on the thing. It keeps the suspense building for the inevitable conclusion.

[@2bingtim]

Wheels allowed to move when shooting is supposed to allow the mechanics to work better than when fixed stationary. I think I read or saw that somewhere. Allows the counterwieght box to fall more vertically? The whole engine moves back, then forward(or vise versa) as the arm swings.

[@johnladuke6475]

@@2bingtim I'm not the only one who's been saying exactly that since Tod first got the trebuchet. However he refuses to listen to any of the chorus of people telling him that this is part of the problem, and he continues to insist that he doesn't need wheels on his trebuchet.

[@thoriated]

@@2bingtim Yes, the weight box travels vertically. The whole machine moves back as the drop starts, tightening the sling. As the weight nears the bottom, the machine moves forward, adding momentum to the throw. Wheels don't matter as much when the weight is on a long swinging link, but are a significant advantage if the weight is fixed to the arm.

[@MrZnarffy]

Ways to increase range.... Put it on wheels... that way you get higher efficiency..Also looks like a very short length for weight to pivot point..

[@mikurusagawa6897]

Trebuchet - a series where Tod slowly loses his sanity and lets us watch the process. Love it!

[@pavementsailor]

Take the videos and frame by frame plot the radius for each component over time as you did with the trajectory plotting. (BTW, very nice) This should reveal the points of rotational misalignment. The timing is off some where. Like a car engine, everything must be timed properly for the exact moment the fuel must be ignited. Love this communal discovery process. Keep going!

[@Soren015]

Last summer I tried to make a longbow in my backyard, and it exploded into three pieces only after +30 hours of amateur woodworking. Don't feel bad, Tod. You're grand.

[@seanfaherty]

Lifted from make magazine regarding wheels on trebuchets Wheels: Trebuchets large and small tend to have wheels, which initially appear to be for transport. And while this would be true for minor adjustments, the largest trebuchets were so massive and heavy that they would have to be assembled on location. The real purpose of the wheels is to allow the entire mechanism to move back and forth as the counterweight is released, keeping the weight’s movement as vertically linear as possible. A weight that rotates downwards loses some of the power of gravity as the force on it has to be transferred into a forward and then backward motion. But if the counterweight drops directly downwards, it can maximize the effect of gravity.

[@davidwhite6878]

Not sure if anyone else has suggested it, but if you put the trebuchet on wheels that run on a short wooden track that should increase the range. Reason being that the counterweight, at the moment,describes a downward arc which is less efficient than a straight drop. Allowing the whole machine to move forward slightly when the throwing arm is released allows the counterweight to drop vertically, increasing efficiency.

[@charcolew]

When you learn that you're not as smart / good as you thought you were, you have learned something extremely useful and valuable

[@markvanpopering4598]

I'm pretty sure you could fix the problem many people mentioning, that the weight is stalling the swing, by not using a straight arm.Past the pin the counterweight sould be attached to a bar at about a fifteen degree angle. That would cause it too throw while the weight is dropping, instead of after it begins to swing back against the throwing motion.

[@redhammer92]

"Ive learned im not as smart as i thought i was" Thats a pretty smart thing to say!

[@cujomojo]

I built a scaled down trebuchet many years ago, with a three foot arm and an open bucket so weight could be added or subtracted. I won’t say it was accurate, I couldn’t pick a spot in the distance and hit it, but it was surprisingly consistent with most shots landing pretty close to each other. I found that once I had got that sweet spot with the weight I could get more range by raising the front of the entire machine a bit, a lot easier to do on a small scale, not so easy with a machine the size of yours. Similar to modern artillery you would want it on level ground but if you had an earthen slope formed in front of the machine you could push it forward a little at a time to adjust the angle of the base.

[@Daremo6969]

Long time ago, (so long ago I saw it on TV, not youtube or the internet in general) saw a study about adding wheels to the trebuchet to let it pivot during the throw (I think it also helped reduce the structural stress to the moving parts). something in the movement added to the release point (better balance) and by adjusting the length of the sling, you could dial in the release point and get a lot more umph out of it. :) It's funny because I think of that story every time i see a trebuchet (movie or youtube, never saw one in person, no room to build one :) )

[@thechumpsbeendumped.7797]

Woohoo! I’ve been waiting for this.

[@LuxisAlukard]

I really enjoy these videos! And you can tell Tod is having a time of his life =)

[@wrobelmike]

Oh, man! I was right there with you, every time, ready for the thing to fling a bowling ball to the moon! Keep at it!!!!!

[@jackmclane1826]

You learned the reason why the smartest people in a medieval army were the siege machine engineers! Man I love trebuchets... I only have a tiny one on my desk that I sometimes use to fire plastic pellets at my coworkers. 😅

[@huddunlap3999]

Miniature catapults are used occasionally to teach Statiscal Process Control.

[@Son-of-the-Furies]

@Tod's Workshop According to Donald B. Siano, in his analysis of trebuchet physics (Trebuchet Mechanics, March 28, 2001), the optimal release position and design, based on his definition of "range efficiency" is such that: • The initial release position is such that the beam on the counterweight side makes an angle of 45° with the vertical. [n.b. adjust pin angle, as you have been doing - don't adjust it's length]. • The length of the long arm of the beam (on the payload side) is 3.75 times the length of the short arm of the beam (on the counterweight side) [n.b. the long arm on your machine looks around 5.6 times the length of the short arm - i.e. the long arm is too long - reduce the length of the long arm to ~ where the metal reinforcement is (i.e. to probably where you had it before adding the extension)]. • The length of the sling is equal to the length of the long arm of the beam (on the payload side). [n.b. the sling length looks about right on your machine, but would need to be shortened as per dot point above]. • Furthermore, he recommends using a counterweight that has a mass 100 times greater than the mass of the payload. [n.b. with your upped 550 kg counterweight, the payload should be 5.5 kg (12 lb bowling ball sounds good) but a bowling ball isn't very dense (the larger surface area means more drag on the missile as it travels through the air). Try using a stone or metal ball e.g. cannon ball to maximise range] • However, it is certainly possible to achieve a good design with a much lighter counterweight than this. [n.b. to reduce the amount of "jazz" in the counterweight basket after the throw, there are a few options, each requiring different amounts of work and expense. The easiest would be to shorten the overall length between the counterweight axel and the bottom of the counterweight basket. Another approach would be to thicken the short arm (put as much weight as possible on the short arm itself). The best would be to have the centre of gravity of the counterweight on the actual short arm with a U-shaped basket with the axel running through the basket itself. If you can manage any of these modifications, it may also allow for a longer short arm, and consequently, a longer long arm, meaning more mechanical advantage (without having to rebuild the machine's main structure), resulting in less mass in the basket, a smaller basket, and resulting in less "jazz" in the basket after the throw] • Grease all points of friction. This combination should yield the maximum range of a trebuchet with an axel at the height of your machine. For greater range, the axel must be elevated and all associated measures increased accordingly.

[@OutOfNamesToChoose]

I don't know where to write my suggestion, so I'll write it here: It would be a childhood dream come true if you could consider making a series on Greek fire. Possible formulations, the devices used by Byzantine ships to spray it, clay Greek fire 'grenades'. There's a lot of mystery and interest around it, but very few videos.

[@_aullik]

You could increase the power output a bit by adding a raiser on the short part of the arm. This way the hinge point is a bit off axis which will increase performance.

[@Fittgris]

How about adding more momentum to the system? It seems like you have reached topspeed that trebuche can produce, but what if you lobb heavier objects that has more momentum to push against the air? Add more weight both in the shot and in the basket and see if that makes a difference

[@friedfish69]

" What did I learn today? I'm not as smart as I thought I was." That's how you know you learned something.