It would be worse if he found only one and then got pelted by 5 supersonic tennis balls though. Then he would run to yell at tom, and have a heart attack thinking he was a time traveler. Imagine that video.
@@wheelslifts851 The balls were no where near supersonic speeds though. The speed of sound is 343 m/s and the balls were launched at roughly 55 m/s but I bet that farmer would be yelling of pain anyway and come after Tom anyway lol
IKEA names is not random. Beds are named after places in Norway, outdoor furniture after Scandinavian islands etc. Though some things that doesn't fit nicely in one of the categories are named after some Swedish word that is somehow related to it's function. So unless trebuchets is considered garden furniture, it could be called "kasta" (throw) or "skjuta" (shoot). I don't think "flingå" is a word in Swedish, but "å" is a word for river in Scandinavian so it could hypothetically be a river.
A friend of mine made a trebucket (it is when he's made it). I think he got about everything wrong then he saw your vid with the whip trebuchet. How could something so wrong go even "wronger". The trebucket is now precisely balanced and set up to launch a cricket ball nearly a foot straight down into the ground.
You should enter the "Pumpkin Chunkin'" contest. I'm not sure if they have international contests though. They have trebuchets and pneumatic cannons and spinning arm pumpkin tossing competitions. All these seem right squarely in your field of study!
Your video should be required viewing for Physics 101 classes. The presentation is great and your enthusiasm is infectious. It also makes dry concepts much more exciting.
A lot of maker videos are no longer explaining things, but instead show montages, etc. I love that you’re videos actually still dive into a subject. Loving this. BTW, Winston Moy has nice videos on CNC; in one of the previous videos you struggled with frizzy edges-you might want to look at his upcut, downcut, compression end mill video. Love the sound of the trebuchet. 👍
If the frame has more weight, it would take more energy to move it the same distance forward, which is the distance required so the counterweight falls directly down the whole time
A old NOVA special covers this in great detail. The wheels are originally intended for a fixed weight arm. The basket arm does most of what the wheeled fixed arm accomplished. On a fixed arm, the weight falls in an arc like a pendulum. The wheels allow the frame to move forward, allowing the fixed arm weight to fall in a vertical line, taking out the arc of the pendulum. The vertical drop gathers more force than the arc.. it’s not the trebuchet moving forward... it’s the weight falling “faster.”
Good idea, even though in practice it'll end up a little complicated. This will require a lot of stabilisation if we want to see a smooth image rather than a shaking hell
I really like your work on this. Thank you. I wanted to add something. I heard that wheels were added to medieval trebuchets to reduce the strain on the support frame, aka 'the crushing lurch.' Fewer repairs, greater lifespan, etcetera. Of course, they were working on a much larger scale, under very different circumstances, but it's still worth mentioning. Thanks again for all your great videos and careful, skillful work!!
Amazing video dude! I have been trying to find videos on youtube about the physics of trebuchets and couldn't find a good insightful infomation about the specifics of how to build an efficent trebuchet until you started the trebuchet project. KEEP UP THE GOOD WORK!😄
Gotta make one with my daughter for a yr 7 project/competition in Australia. Very glad to have come across your work!. Very impressive!. I agree with a comment you received about showing the full journey of the payload for a bit of action. Love it!. Thanks mate!.
Hi Tom, I watch all your videos the day they come out...and today I joined your patreon. No idea why I haven't joined earlier. Keep the fantastic work up. I absolutely love your calm and analytical way of beeing fascinated. Greetings from Switzerland
For the wheels, the suggestion probably comes from people who saw the PBS special on trebuchets and they got a great improvement from adding wheels - in that case it was more critical due to the massive size and risk of damage if wheels don't help dampen the rocking of the machine.
it looked so clean! no bouncing or anything. you can really see that its really important to sync up the stall points of the arm and the counterweight and the release of the ball.
Tom, awesome videos. But since its summer and cricket season is on, can you do a launch of a cricket ball and see if you can thow it a 90mph, or thow it back in from the boundry line?
That was all jolly interested and clearly explained. It's good to see the proper detail in the way you went about designing and improving this trebuchet. I was actually sceptical that the wheels would help but I was wrong. It's always interesting to be wrong. You have earned yourself a subscription.
The really good trebuchet vids that I’ve seen (MIT) use a stationary frame, but only the axle of the arm is on wheels. This allows the weight to drop nearly vertical. If the weight had no horizontal speed, then the potential is transferred more efficiently. You don’t have the mass of the frame being accelerated.
Great video, as always. I catch myself looking forward to the weekly video on Friday, by far my favorite channel. I should probably sign up with Patreon so you don't run out of tennis balls. Thank you for another high quality and proper engineering video.
Build a set of rails for the wheels to roll on. That'll greatly reduce your rolling resistance and should allow the frame to accelerate faster. Also, maybe bearings on the wheels?
That was really interesting! I'd watch more of these analysis videos. Still interested in watching more air pressure machines, but I'd also be interested in watching you throw some heavier items, like fruit or pumpkins.
THIS IS AMAZING! GREAT WORK!!! Adam Savage and Jamie Hyneman would be proud! Great experimenting and controlling the variables to make your trebuchet more efficient!! I really enjoyed watching this!
The wheels are also moving the fulcrum (the hinge that the throwing arm spins around) forward which simulates a longer throwing arm. You could add the distance between where the hinge starts and where the hinge is when the projectile releases and I would guess that would be close to the distance between the end of the arm when stationary release and when its rolling release. Still awesome work Tom!
Holy crap, dude! This is a brilliant series! And I am new to your channel! And I did subscribe/all! I am... like since yesterday you popped from “never heard of him” to “Top 3 UA-cam channels”. Seriously. This has been WICKED cool... thank you for making my weekend better.
Great set of videos! Trebuchets rocks. You may try a launch with the counterweight fixed to the arm, as the wheels will make the counterweight do a vertical fall instead of a circular movement.
U can also try adding a second frame which contains the rails for the first, triangular frame. This would probably lower the energy losses due to terrain being not entirely flat and the fact that you didn't use bearings for the wheels.
So, your main source of inefficiency here seems to be that your frame has horizontal kinetic energy at the release point. Your wheels make the weight move more or less straight down. So now you could gain efficiency by making your weight and your "tennis ball" more massive. If you increased the weights to the max amount the frame can handle, you'd have something pretty impressive on your hands. ;-) Very cool videos, Tom!
I've always thought it was because it let the counter weight fall straight down instead of in an arch which to me makes sense since the shortest distance between two points is a straight line your counter weight is using the same amount of energy over a shorter amount of time thus it would go faster.
Great work and research Tom. The amazing fact to me is that the original designer of this machine achieved all this without the aid of modern day computers to analyse the performace. They would have had wheels to transport and manouver the machine into the attacking position. You certainly wouldn't want to be standing behind one when it was loosed....
Dang, that's pretty sick. It feels like a scratch I can't itch when you don't show how far the ball goes but this series was pretty great non the less.
I have always been a fan of the trebuchet and I have really enjoyed your science. Well done, Tom! Can we have another video with more emphasis on the ball and the target? Thanks again!
The frame moving forward is not loosing energy, compared to not moving you are just not moving the planet as much. With regards efficiency of the device with wheels, the counterweight does move backwards as part of the rotational path, if instead of the weight moving backwards the fulcrum moved forward the lighter end of the arm gains more forward momentum. ie by adding wheels you are effectively changing the rotation point of the whole arm, moving the effective fulcrum closer to the counterweight and increasing the throw arm length just as it approaches the release. (see moving fulcrum trebuchets) If you put markers on the arm you will see that the arm no longer rotates precisely around the axle but slightly closer to the counterweight as the frame moves forward. To get even more energy out, try getting just the axle to move rather than the whole frame by putting it on a track on top of the frame.
Follow my channel. I developed the curved hanger, and the double linked hanger systems. I also work with advanced timed arms. "Gap" is another timing instrument.
Another way of looking at the wheel advantage is that when weighed down you are effectively transmitting the waste energy into the ground which rotates planet earth an unmeasureably tiny amount (no really!). By adding the wheels that energy moved the frame enabling you to work out the necessary adjustments. I wonder if further improvements can be made with a few more tweaks? Great video!
Tom, your analysis of the stall points was very clever, and I do believe that their synchronization is what allows your trebuchet to throw faster. However, I do think that your idea that allowing the trebuchet to move causes a loss of energy is flawed. If there is one thing I have learned about physics, it is that every action has an equal and opposite reaction. Regardless of the presence of wheels, the same amount of energy should be lost. With the wheels that energy is utilized to move the frame of the trebuchet forward, and when it is anchored that same energy goes into changing the earth's rotation which, due to it huge mass, is altered an imperceptible amount.
Excellent investigation. The stall point of the counterweight is lower with wheels. The difference in height of the counterweight stall point between the fixed and wheels version gives rise to the additional transfer of potential to kinetic, partially offset by the loss from the weight of the trebuchet moving forward. Maybe....
I've seen designs where instead of having the main arm attached with a fixed axle, you add wheels to that as well, and let it roll on a track on top of the frame. That way more energy is transferred.
The way Ive seen it explained somewhere else is that the moving frame allows the weight to fall more freely, in a straight line down, thus giving a more explosive release of energy. In a way this allows you to beat the otherwise fixed relationship between mass and rotational inertia. Perhaps it also makes it easier to synchronise the stall points perfectly, but it seems to me that you could have them line up with a fixed trebuchet by playing with other variables as well? Sometimes these are just different way of looking at the same thing though... either way great experimental spirit and awesome results!
Thinking in terms of a closed system, it should be that the counterweight has less remaining energy after the launch with wheels. Did you measure the counterweight velocity after the launch? Guess that's where the extra energy on the projectile comes from. Hence the wheels raise the efficiency. BTW, great job!
By moving the frame forward you actually move the point of rotation of the arm as well. Look at the footage, the point of the rotation now closer to the weight which means you have a longer leaver to throw the projectile. +1 ms at the frame multiplies to +5 ms at the tip of the arm
Try building a fixed frame with the central Axle/arm assembly on a wheel - If the wheel is scaled well, then as the counter weight falls the whole thing will roll forward as the arm raises, and you waste less energy shifting the counterweight backwards before the arm reaches release point. You can bulk up the supporting frame to keep things stable without having to put any energy into moving said frame forward when firing.
Great explanation despite its complexity... Kind of Trump during a press conference with the French president Macron:When Macron finished giving a statement in French, Trump quickly responded to tell the French leader he enjoyed listening despite not actually having any idea what was being said.“It sounded beautiful,” Trump joked. “I have no idea what he said, but it sounded great.”I have no idea what you said but it sounded great.... Of course it's a joke... Your videos are as entertaining as instructive. Thanks Tom! Happy that the UK still has dynamic young engineers like you.
I’ve been following your channel for a while, I’ve never felt compelled to comment before this video. It is both informational and entertaining… I was thinking he better do a slow-motion shot... Then there it was :-)! Cheers!
Execellent video! I want to see a more massive projectile! Only one critique. Depth of field is about optical focus. I don't know the correct terminology though.
in physics (optics) it's called "spherical aberration" en.wikipedia.org/wiki/Spherical_aberration, old school aerial photography is riddled with it. If your plane is directly over a tall building you only see the top of the building. But as the plane moves past a building, despite the camera being pointed straight down, the curved lens captures light from the side of the building now. If you increase the altitiude of the plane and increase the "zoom" this effect decreases. Now we have satellite photography which has improved this effect in programs like Google Earth, but it still exists. Additionally satellite imagery to save money (in orbits) often they shoot off-axis so that is a completely separate reason why you might see the side of a building in google earth.
Paused at 5:21 - I believe the wheels help the velocity because the frame moving has the effect of lengthening the radius of the arm, so yes, you lose 3m/s in the 1 m roll forwards, but you gain 1 m of radius on the arm, which magnifies the release velocity by much more than you lose in the roll. I think. Based on college physics 20+ years ago and very little practical knowledge, so I'm likely wrong, but wanted to lock in my guess before I watch further.
Sweet! Glad to learn that, and very happy that you could get more efficiency with your trebuchet. :) When the zombie apocalypse comes, I'll be naming my trebuchet defenses after you.
I think you can make the projectile even faster by building a very lightweight frame and swing arm. The weight starts at a point with high potential energy. In order to transfer all the energy to the projectile, it needs to exit the system when the energy of the weight equals 0. That is only the case when the weight has no velocity and it is on the lowest point. The trebuchet benefits from having wheels, because the weight can drop vertically and has no horizontal velocity. When the energy of the weight is zero the initial energy is stored in the projectile, the frame and the swing arms. Now it is important that the frame and the swing arms contain minimal energy. Since these parts have to move at certain speeds to accelerate the projectile properly, you can still try to reduce the energy by using lighter materials. I suggest to start with the upper swing arm, because it stores the most kinetic energy (E~v^2). Or try to build a swing arm, that gets lighter towards the top. By using lighter materials, less energy is stored in the frame and swing arm, thus more energy can be transferred to the projectile. This is especially important for fast moving objects, e.g. the tip of the upper swingarm.
Exactly. The entire potential energy of the weights makesup for the tennis ball, moment of inertia of the arm, and the accelerating the frame. If you calculate the energy in the arm (E = 0.5 *moment_of_inertia * angular_velocity^2), and the energy in the frame (E = 0.5 * m * v^2) you will find a big chunk of the missing efficiency percentages. When you know these numbers, you'll also know which part takes up the biggest chunk and is ripe for improvement (reduce weight). Great video's btw!
Man - my head is spinning with all these math calculations. When are you going to complete the air engine series? Am really interested seeing this working in a model plane.
With the wheels on there you should try a fixed counterweight. A public tv (PBS here in the states, if you're familiar with that) special I watched they found that with wheels, the fixed counterweight followed a nice straight path downward, which has the added benefit of sending the trebuchet forward, like yours.
A couple of years ago me and some friends got to the same conclusion after a weekend of fun tests, but we had no idea why. Basically we noted the counterweight swung less affter firing on a wheeled trebuchet. This did explain it so much better though. :D
I think you may have slightly missed one point. The remaining energy in the system after ball release is lower with the wheels because you have less angular velocity of the counterweight, the wheels on the frame allow it to fall straighter.
![[Weapons 101] Trebuchet - How they work - Traction & Counterweight Trebuchets Medieval Equipment](/img/n.gif)
Some poor farmer's going to be incredibly confused when they find a bunch of tennis balls in their field.
12:41
Snaily and craters from wherever they landed
@David It makes more sense to compare efficiency. He could jack up the weight and it would go a lot farther.
It would be worse if he found only one and then got pelted by 5 supersonic tennis balls though. Then he would run to yell at tom, and have a heart attack thinking he was a time traveler. Imagine that video.
@@wheelslifts851 The balls were no where near supersonic speeds though. The speed of sound is 343 m/s and the balls were launched at roughly 55 m/s but I bet that farmer would be yelling of pain anyway and come after Tom anyway lol
Any truth to the rumor that this will be available from IKEA sold in a flat-pack? Will they call it Flingå?
IKEA names is not random. Beds are named after places in Norway, outdoor furniture after Scandinavian islands etc. Though some things that doesn't fit nicely in one of the categories are named after some Swedish word that is somehow related to it's function. So unless trebuchets is considered garden furniture, it could be called "kasta" (throw) or "skjuta" (shoot).
I don't think "flingå" is a word in Swedish, but "å" is a word for river in Scandinavian so it could hypothetically be a river.
@@SteinGauslaaStrindhaug r/ whoosh
@@burkhardtniec3653 No, I know it's a joke. I'm just being needlessly pedantic
@halnywiatr made me laugh
@Stein Gauslaa Strindhaug floored me with knowledge. Well done.
Stein Gauslaa Strindhaug. Doesn’t pedantic inherently mean “needlessly pedantic?”
A friend of mine made a trebucket (it is when he's made it). I think he got about everything wrong then he saw your vid with the whip trebuchet. How could something so wrong go even "wronger". The trebucket is now precisely balanced and set up to launch a cricket ball nearly a foot straight down into the ground.
XDXD This made me laugh my ass off! I need to see this!
@@ericolens3 Hes calling it a trebucket probably because he used a bucket for the counterweight.
😂
😂
You should enter the "Pumpkin Chunkin'" contest. I'm not sure if they have international contests though. They have trebuchets and pneumatic cannons and spinning arm pumpkin tossing competitions. All these seem right squarely in your field of study!
Oh hell yes!
I always thought those were really cool
Last I checked, that event had been cancelled. I'm not sure they'll be coming back. There was a personal injury lawsuit after someone was hurt.
Evan M. Jones rip
The worst part is the guy who sued was hurt riding a quad bike and it had nothing to do with chunkin punkins. What an asshat.
I've been teaching people about synchronizing the stall points for years. Nice to see it quantified.
Me Too!
Can you please optimise it a little more so it's 69% efficient... that is all.
Matthew Evans 69% efficient is not shoddy.
68% is shoddy, 69% is perfect, 70% is too much :)
Add just enough weight to the frame to increase it to 69%. Reduce the little bunny hop it does, thatll get it to 69% haha
Spencer Coleman cast iron wheels
This is where 6 9 started
I was waiting for your best English pronunciation... and it didn't even happened!
Well done Tom, you truly know how to explain things.
Oh yes pronouncing words is hard 🍄
Your video should be required viewing for Physics 101 classes. The presentation is great and your enthusiasm is infectious. It also makes dry concepts much more exciting.
might as well, modern "scientists" don't seem to be learning anything anyway..
A lot of maker videos are no longer explaining things, but instead show montages, etc. I love that you’re videos actually still dive into a subject. Loving this. BTW, Winston Moy has nice videos on CNC; in one of the previous videos you struggled with frizzy edges-you might want to look at his upcut, downcut, compression end mill video. Love the sound of the trebuchet. 👍
you still need the frame weights with the wheels, supposed to roll, not jump in the air
Jusb1066 noticed that too
This is a test I'd be interested to see. Will a weighted, wheeled frame break 70% efficiency? Can we get the tennis ball to 140?
If the frame has more weight, it would take more energy to move it the same distance forward, which is the distance required so the counterweight falls directly down the whole time
But there's already wasted energy in the jumping around of the frame. The weights may damp that. Or not.
Yeah but if the frame is weighted to resist jumping, it might end up being less wasted energy. I think it's worth a test.
A old NOVA special covers this in great detail.
The wheels are originally intended for a fixed weight arm. The basket arm does most of what the wheeled fixed arm accomplished.
On a fixed arm, the weight falls in an arc like a pendulum. The wheels allow the frame to move forward, allowing the fixed arm weight to fall in a vertical line, taking out the arc of the pendulum. The vertical drop gathers more force than the arc.. it’s not the trebuchet moving forward... it’s the weight falling “faster.”
Amazing work, dude! Really nice! 😀
Thanks man!
Launch a gopro!
Bill Codey Yes!
Good idea, even though in practice it'll end up a little complicated. This will require a lot of stabilisation if we want to see a smooth image rather than a shaking hell
It d be epic. Just add a spherical frame and fins to make it stable.. Otherwise a gyroscope inside the spherical frame
And add a parachute.
And fins to stabilize it.
Time for a castle siege, I think we're ready.
I really like your work on this. Thank you. I wanted to add something. I heard that wheels were added to medieval trebuchets to reduce the strain on the support frame, aka 'the crushing lurch.' Fewer repairs, greater lifespan, etcetera. Of course, they were working on a much larger scale, under very different circumstances, but it's still worth mentioning. Thanks again for all your great videos and careful, skillful work!!
the wheels also increase the hight, so unless the cross bars get in the way, that means you should be able to increase the length of the arm as well.
This is the video that introduced me to the Tracker software, and I've gone and introduced it to my team when developing the Mars helicopters. Thanks!
Amazing video dude! I have been trying to find videos on youtube about the physics of trebuchets and couldn't find a good insightful infomation about the specifics of how to build an efficent trebuchet until you started the trebuchet project. KEEP UP THE GOOD WORK!😄
Gotta make one with my daughter for a yr 7 project/competition in Australia.
Very glad to have come across your work!.
Very impressive!.
I agree with a comment you received about showing the full journey of the payload for a bit of action.
Love it!.
Thanks mate!.
I hope that's a cup of tea you are drinking at 5:46. Tea has powered British ingenuity for centuries.
We need more Trebuchet stuff! Your videos are great!
Hi Tom, I watch all your videos the day they come out...and today I joined your patreon. No idea why I haven't joined earlier. Keep the fantastic work up. I absolutely love your calm and analytical way of beeing fascinated.
Greetings from Switzerland
For the wheels, the suggestion probably comes from people who saw the PBS special on trebuchets and they got a great improvement from adding wheels - in that case it was more critical due to the massive size and risk of damage if wheels don't help dampen the rocking of the machine.
it looked so clean! no bouncing or anything. you can really see that its really important to sync up the stall points of the arm and the counterweight and the release of the ball.
This is one of my favorite channels. He actually thinks about how he does his projects and learns things.
You introduced that tracker software to me, and it's changed the way I analyze my PhD research! Thank You
Did you succeed in getting that PhD? 🍄
@@davidbergmann8948 I quit with a masters because my boss was an insufferable narcissist!
This is bloody good work mate, keep it up!
Tom, awesome videos. But since its summer and cricket season is on, can you do a launch of a cricket ball and see if you can thow it a 90mph, or thow it back in from the boundry line?
Plausible
Wow, this is actually amazing. I don’t think research of this kind has been done on UA-cam, and it’s a mind blower. Keep up the fantastic work!!
5:45 tea. He needs his cup of Tea.
This is my favourite UA-cam vid for a long time. Bloody well done!
That was all jolly interested and clearly explained. It's good to see the proper detail in the way you went about designing and improving this trebuchet. I was actually sceptical that the wheels would help but I was wrong. It's always interesting to be wrong.
You have earned yourself a subscription.
The really good trebuchet vids that I’ve seen (MIT) use a stationary frame, but only the axle of the arm is on wheels. This allows the weight to drop nearly vertical. If the weight had no horizontal speed, then the potential is transferred more efficiently. You don’t have the mass of the frame being accelerated.
This hurts my brain, but I can't stop watching your videos! Good stuff!
Great video, as always. I catch myself looking forward to the weekly video on Friday, by far my favorite channel. I should probably sign up with Patreon so you don't run out of tennis balls. Thank you for another high quality and proper engineering video.
Gotta love that golden spiral the projectile makes.
Build a set of rails for the wheels to roll on. That'll greatly reduce your rolling resistance and should allow the frame to accelerate faster. Also, maybe bearings on the wheels?
Very well done, I enjoyed the journey through these videos. Your reveal of the result with the wheels was great. Thanks.
Great work, Tom 🍄🍄🍄
This was the best and most inspiring mechanics lesson I ever watched.
That was really interesting! I'd watch more of these analysis videos. Still interested in watching more air pressure machines, but I'd also be interested in watching you throw some heavier items, like fruit or pumpkins.
THIS IS AMAZING! GREAT WORK!!! Adam Savage and Jamie Hyneman would be proud! Great experimenting and controlling the variables to make your trebuchet more efficient!! I really enjoyed watching this!
The wheels are also moving the fulcrum (the hinge that the throwing arm spins around) forward which simulates a longer throwing arm. You could add the distance between where the hinge starts and where the hinge is when the projectile releases and I would guess that would be close to the distance between the end of the arm when stationary release and when its rolling release. Still awesome work Tom!
Holy crap, dude! This is a brilliant series! And I am new to your channel! And I did subscribe/all! I am... like since yesterday you popped from “never heard of him” to “Top 3 UA-cam channels”. Seriously.
This has been WICKED cool... thank you for making my weekend better.
thank you for the technical bits, facinating
Truly excellent video and project. A hearty thumbs up for doing replications and showing some data!!
6 shots within 4 meters? That is some tight grouping, amazing accuracy!
tenacity patience and thoroughness
I endorsed - wheels and weights- or wheels restrained in channels to prevent frame lift
I really enjoyed watching this video, great work!
Great set of videos! Trebuchets rocks. You may try a launch with the counterweight fixed to the arm, as the wheels will make the counterweight do a vertical fall instead of a circular movement.
I love your dedication to the scientific method, really great video!
Really been enjoying the trebuchet vids, cheers!
This was awesome! Perfect blend of engineering and fun.
U can also try adding a second frame which contains the rails for the first, triangular frame. This would probably lower the energy losses due to terrain being not entirely flat and the fact that you didn't use bearings for the wheels.
This is awesome! Real science and craftsmanship in practice. I gotta build me one eventually.
What a cool series on mechanical optimization!
I loved this series. My first building project was a trebuchet so it strikes a soft spot
So, your main source of inefficiency here seems to be that your frame has horizontal kinetic energy at the release point. Your wheels make the weight move more or less straight down. So now you could gain efficiency by making your weight and your "tennis ball" more massive. If you increased the weights to the max amount the frame can handle, you'd have something pretty impressive on your hands. ;-)
Very cool videos, Tom!
I've always thought it was because it let the counter weight fall straight down instead of in an arch which to me makes sense since the shortest distance between two points is a straight line your counter weight is using the same amount of energy over a shorter amount of time thus it would go faster.
this is legendary research. I'm using it in my middle school tech class.
Great video! I appreciate all the effort you put in this project.
Great work and research Tom.
The amazing fact to me is that the original designer of this machine achieved all this without the aid of modern day computers to analyse the performace. They would have had wheels to transport and manouver the machine into the attacking position. You certainly wouldn't want to be standing behind one when it was loosed....
Awesome! Addressed questions I had myself after watching the first video
I see a future for you as a great physics teacher. Well explained
Love these engineering related videos, keep it up!
Dang, that's pretty sick. It feels like a scratch I can't itch when you don't show how far the ball goes but this series was pretty great non the less.
Physics is awesome! Very well done Tom, and i hope to see more like this :)
Great additional research and presentation!
I have always been a fan of the trebuchet and I have really enjoyed your science. Well done, Tom! Can we have another video with more emphasis on the ball and the target? Thanks again!
The frame moving forward is not loosing energy, compared to not moving you are just not moving the planet as much. With regards efficiency of the device with wheels, the counterweight does move backwards as part of the rotational path, if instead of the weight moving backwards the fulcrum moved forward the lighter end of the arm gains more forward momentum. ie by adding wheels you are effectively changing the rotation point of the whole arm, moving the effective fulcrum closer to the counterweight and increasing the throw arm length just as it approaches the release. (see moving fulcrum trebuchets)
If you put markers on the arm you will see that the arm no longer rotates precisely around the axle but slightly closer to the counterweight as the frame moves forward.
To get even more energy out, try getting just the axle to move rather than the whole frame by putting it on a track on top of the frame.
Excellent, fascinating - very happy to be a Patreon supporter :-)
Are there other ways to achieve that synchronization? changing the length/shape of the weight arm, or a bent launch arm, etc?
Even the radius of the wheels could matter, a lot of variables here to mess with calculations.
That grass surface too. Couldn't help thinking some sort of track would improve efficiency, but no idea whether the effect would be negligible or not.
Aron Green why not just put drawer sliders on the bottom and weigh down the frame?
Actually i completely misread this. If you let it move on its own, its not gonna syncronize, ever. That would be like a gun recoiling forwards.
Follow my channel. I developed the curved hanger, and the double linked hanger systems. I also work with advanced timed arms. "Gap" is another timing instrument.
Another way of looking at the wheel advantage is that when weighed down you are effectively transmitting the waste energy into the ground which rotates planet earth an unmeasureably tiny amount (no really!). By adding the wheels that energy moved the frame enabling you to work out the necessary adjustments. I wonder if further improvements can be made with a few more tweaks? Great video!
This video was worth watching to behold the extreme tidiness of that workshop, alone.
Tom, your analysis of the stall points was very clever, and I do believe that their synchronization is what allows your trebuchet to throw faster. However, I do think that your idea that allowing the trebuchet to move causes a loss of energy is flawed. If there is one thing I have learned about physics, it is that every action has an equal and opposite reaction. Regardless of the presence of wheels, the same amount of energy should be lost. With the wheels that energy is utilized to move the frame of the trebuchet forward, and when it is anchored that same energy goes into changing the earth's rotation which, due to it huge mass, is altered an imperceptible amount.
Great video Tom! Keep up the maths and that software!
Excellent investigation. The stall point of the counterweight is lower with wheels. The difference in height of the counterweight stall point between the fixed and wheels version gives rise to the additional transfer of potential to kinetic, partially offset by the loss from the weight of the trebuchet moving forward. Maybe....
Nicely shaken down, Tom!
Educating and entertaining, well done. I enjoy your videos very much!!
I've seen designs where instead of having the main arm attached with a fixed axle, you add wheels to that as well, and let it roll on a track on top of the frame. That way more energy is transferred.
The way Ive seen it explained somewhere else is that the moving frame allows the weight to fall more freely, in a straight line down, thus giving a more explosive release of energy. In a way this allows you to beat the otherwise fixed relationship between mass and rotational inertia. Perhaps it also makes it easier to synchronise the stall points perfectly, but it seems to me that you could have them line up with a fixed trebuchet by playing with other variables as well? Sometimes these are just different way of looking at the same thing though... either way great experimental spirit and awesome results!
Thinking in terms of a closed system, it should be that the counterweight has less remaining energy after the launch with wheels. Did you measure the counterweight velocity after the launch? Guess that's where the extra energy on the projectile comes from. Hence the wheels raise the efficiency.
BTW, great job!
By moving the frame forward you actually move the point of rotation of the arm as well. Look at the footage, the point of the rotation now closer to the weight which means you have a longer leaver to throw the projectile. +1 ms at the frame multiplies to +5 ms at the tip of the arm
Brilliant Video! Fantastic work!
Try building a fixed frame with the central Axle/arm assembly on a wheel - If the wheel is scaled well, then as the counter weight falls the whole thing will roll forward as the arm raises, and you waste less energy shifting the counterweight backwards before the arm reaches release point. You can bulk up the supporting frame to keep things stable without having to put any energy into moving said frame forward when firing.
Great explanation despite its complexity... Kind of Trump during a press conference with the French president Macron:When Macron finished giving a statement in French, Trump quickly
responded to tell the French leader he enjoyed listening despite not
actually having any idea what was being said.“It sounded beautiful,” Trump joked. “I have no idea what he said, but it sounded great.”I have no idea what you said but it sounded great.... Of course it's a joke... Your videos are as entertaining as instructive. Thanks Tom! Happy that the UK still has dynamic young engineers like you.
I’ve been following your channel for a while, I’ve never felt compelled to comment before this video. It is both informational and entertaining… I was thinking he better do a slow-motion shot... Then there it was :-)! Cheers!
Wow. That's awesome. Thanks for your work
This series has been excellent. So well presented and explained. Looks like it was fun, but quite a lot of work...
Execellent video! I want to see a more massive projectile! Only one critique. Depth of field is about optical focus. I don't know the correct terminology though.
In photography we call this perspective distorsion, I don't know of a more specific term in optics.
I think he means parallax error.
in physics (optics) it's called "spherical aberration" en.wikipedia.org/wiki/Spherical_aberration, old school aerial photography is riddled with it. If your plane is directly over a tall building you only see the top of the building. But as the plane moves past a building, despite the camera being pointed straight down, the curved lens captures light from the side of the building now. If you increase the altitiude of the plane and increase the "zoom" this effect decreases. Now we have satellite photography which has improved this effect in programs like Google Earth, but it still exists. Additionally satellite imagery to save money (in orbits) often they shoot off-axis so that is a completely separate reason why you might see the side of a building in google earth.
Wagacca if I remember correctly you could actually model with Google sketch-up and have it published to Google maps.
this channel is a yt-gem
Paused at 5:21 - I believe the wheels help the velocity because the frame moving has the effect of lengthening the radius of the arm, so yes, you lose 3m/s in the 1 m roll forwards, but you gain 1 m of radius on the arm, which magnifies the release velocity by much more than you lose in the roll.
I think.
Based on college physics 20+ years ago and very little practical knowledge, so I'm likely wrong, but wanted to lock in my guess before I watch further.
Sweet! Glad to learn that, and very happy that you could get more efficiency with your trebuchet.
:)
When the zombie apocalypse comes, I'll be naming my trebuchet defenses after you.
Very, very informative. Really love math based videos like this. You should tranfer some of this knowledge, software and physics basis to RC!!!
I think you can make the projectile even faster by building a very lightweight frame and swing arm.
The weight starts at a point with high potential energy. In order to transfer all the energy to the projectile, it needs to exit the system when the energy of the weight equals 0. That is only the case when the weight has no velocity and it is on the lowest point. The trebuchet benefits from having wheels, because the weight can drop vertically and has no horizontal velocity.
When the energy of the weight is zero the initial energy is stored in the projectile, the frame and the swing arms. Now it is important that the frame and the swing arms contain minimal energy. Since these parts have to move at certain speeds to accelerate the projectile properly, you can still try to reduce the energy by using lighter materials. I suggest to start with the upper swing arm, because it stores the most kinetic energy (E~v^2). Or try to build a swing arm, that gets lighter towards the top.
By using lighter materials, less energy is stored in the frame and swing arm, thus more energy can be transferred to the projectile. This is especially important for fast moving objects, e.g. the tip of the upper swingarm.
Exactly. The entire potential energy of the weights makesup for the tennis ball, moment of inertia of the arm, and the accelerating the frame.
If you calculate the energy in the arm (E = 0.5 *moment_of_inertia * angular_velocity^2), and the energy in the frame (E = 0.5 * m * v^2) you will find a big chunk of the missing efficiency percentages. When you know these numbers, you'll also know which part takes up the biggest chunk and is ripe for improvement (reduce weight).
Great video's btw!
Man - my head is spinning with all these math calculations. When are you going to complete the air engine series? Am really interested seeing this working in a model plane.
I do hope physics and math teachers around the world will use you material to make their bone dry lessons a lot better.
With the wheels on there you should try a fixed counterweight. A public tv (PBS here in the states, if you're familiar with that) special I watched they found that with wheels, the fixed counterweight followed a nice straight path downward, which has the added benefit of sending the trebuchet forward, like yours.
Jeezus Tom, this could have been an educational video, like on e by Tom Scott or Veritasium. Well done dude. Incredible analysis.
A couple of years ago me and some friends got to the same conclusion after a weekend of fun tests, but we had no idea why. Basically we noted the counterweight swung less affter firing on a wheeled trebuchet. This did explain it so much better though. :D
I think you may have slightly missed one point. The remaining energy in the system after ball release is lower with the wheels because you have less angular velocity of the counterweight, the wheels on the frame allow it to fall straighter.