Launching a Trebuchet Straight UP

when an object is raised it has gravitational potential energy and using a simple lever setter like this its energy can be transferred to a smaller object now when I drop this weight it will accelerate towards the ground converting its gravitational potential energy into kinetic energy as it impacts the plank of wood its momentum will be transferred to the smaller object launching it higher into the air but the problem is with this setup is that it's really inefficient and the tennis ball doesn't go that high this is where this trebuchet comes in I built this about a year ago and it's designed and optimized to transfer the gravitational potential energy of this counterweight into kinetic energy of this projectile a tennis ball as efficiently as possible when released this tennis ball goes from 0 to 130 miles an hour in under a second and launches about 80 meters downrange so how about we make a few adjustments to see how high we can launch a projectile straight up into the air to measure how high the projectile is launched from the trebuchet I'm going to be using an altimeter however I don't just want to stick without a meter inside of the tennis ball for a number of different reasons the first reason being that this tennis ball will most likely go quite high into the air and that also means that it will come down quite quickly and hit the ground quite hard which could risk breaking the altimeter also tennis balls aren't that aerodynamic with their very covered surface so what I want to do is 3d print a rocket shaped projectile which will be more aerodynamic than the tennis ball and also have a parachute deployment system so the altimeter can float down nice and safely so here is the first prototype as you can see it's not very aerodynamic at the top and that's because I haven't actually built the parachute deployment mechanism into this yet this is sort of like a dummy model and I've put the foam nose cone on it so that when it comes back down hopefully it won't destroy itself or anything else around it on the ground the reason why I've built this model is to test the launch portion of the flight so I've got the 3d printed projectile mounted inside of the trebuchet and I've got the string wrapped up around the release pin so yeah fingers crossed this goes successfully and I think we should probably step back a little bit and give it a quick test launch okay in three two one that was a successful release think that as high as I'd hoped right let's try this again in three two one oh that's not good right so that previous launch had the exact same setup in terms of pin release and the sling mounting however instead of going forwards it went backwards and ended up in Mike's or neighbors garden I think we need to do some serious rethinking about the design of this over the next few days I decided to try it a few more times with a few different attachment methods but still struggled to get it to launch reliably even when the trebuchet threw it in the correct direction keeping the projectile pointing directly into the oncoming air was very difficult this causes a lot of drag and therefore defeats the whole point of its purpose in fact the release velocity was barely above 30 meters per second whereas the tennis ball releases at around 50 meters per second and it's rotation doesn't have much of an effect so it's time for Plan B so plan B is to scrap this rocket shaped projectile and move back to a sphere shaped projectile like the tennis ball however what's more aerodynamic than a tennis ball golf ball golf balls are famous for their dimpled shaped aerodynamic properties however it's going to be very difficult to fit this altimeter and also its battery inside of a golf ball as well as a parachute deployment system so what I've done is I've 3d printed an enlarged golf ball this is roughly one hundred and eighty seven percent scale so it's almost doubled the diameter of regular golf ball and I should easily be able to fit all of the electronics and a parachute system inside now this current ball doesn't have anything special to it it's just like a dummy model so I can give it a few test launches to get an idea of release velocity and also flight trajectory and also I've made a larger sling for it because the old sling wouldn't fit this boy it was designed for tennis ball-sized so let's load this onto the trebuchet and see how high this thing will go right first test of the oversized 3d printed golf ball in three two one Wow that one sir right let's try that again in three two one wow that's never gonna get home so this new ball works incredibly well and it goes so high into the air I'm really pleased with the way it performs and more importantly it releases reliably from the sling now in terms of release velocity this is slightly slower than the tennis ball but that's expected because it does weigh a bit more I believe the tennis ball is about two-thirds the weight or mass of this ball but the real question is how high does this ball actually go now this is the ball that will give us the answer or release the various parts of the ball now in terms of electronics there's obviously the altimeter there's also the battery which powers everything and then there is the electronics to control the parachute deployment with many of my projects I make them radio-controlled so that I can flick a switch on a radio control transmitter and it will deploy the parachute but I wanted to make this fully automated so inside of here there is an accelerometer which will basically detect when the ball is launched from the trebuchet when it detects over 2 G's of acceleration the Arduino will start a four second timer after four seconds is up this server will move pulling this pin and also deploying the parachute so let's assemble this ball quickly and see whether the parachute can be deployed so this rubberband holds the two halves of the ball together and hooks around the servo pin and if I give this a quick shake in four seconds time it should split open like an oddly colored poker ball so give it a shake and then there we go that deploys the parachute so I think this is all ready for an actual test launch so I've got the parachute ball mounted inside of the trebuchet now I haven't got the altimeter inside of it just yet because I want to test if it actually deploys the parachute successfully I've also moved the trebuchet so that hopefully it will fire somewhat into the field and the parachute won't land in any of these trees either side so let's see if this thing will actually work parachute projectile first test in three two one come on welcome first try nice so cool test number two in three two those so satisfying floats down very slightly maybe I need a smaller parachute don't have to drift too far in the wind I think carried out a few more test launches to make sure the parachute deployment was reliable as well as capturing some more high-speed shots until one of the launches resulted in a catastrophic failure of the trebuchet arm as well as the parachute getting stuck in a tree so whilst I saw some new arm and figure out how to retrieve the parachute let's take a more detailed look at what's going on where the trebuchet is loaded the counterweight of 15 kilograms is raised 1.2 2 meters from its end position we can calculate its gravitational potential energy by multiplying the mass by the acceleration due to gravity and the height it's raised giving a total stored energy of one hundred and seventy nine point five joules but let's round it to 180 joules because the bar that holds the weights to the arm probably adds a bit more mass from this we can calculate the maximum altitude the ball could theoretically reach by equaling it to the end gravitational potential energy of the ball if we rearrange this equation for the height of the ball we get to max theoretical altitude of 160 six point eight meters or 550 feet now this altitude assumes the whole system is 100% efficient and there is no drag acting on the ball which obviously isn't realistic but we can use this max value to work out the efficiency of the system once we know the final altitude oh and here's my genius method of retrieving the parachute or maybe not let's get to the actual launch price I've now got the altimeter mounted inside of the ball and I've also got a smaller parachute on it so I hopefully won't drift too far in the wind it's quite windy right now slight headwind but hopefully it doesn't drift too far with a smaller parachute so let's see how how this thing really goes okay ultimate a bull test in three two one oh that was a late deploy couldn't get much closer to the trebuchet though let's check the altitude probably can't see that on camera but it says 61 meters which is almost exactly 200 feet let's do a few more launches and gets an average max altitude so after gathering all the altitude data the ball reached an average altitude of 59 meters or 193 point 6 feet which is about 35% of the estimated max altitude this means that 65% of the total starting potential energy was lost now we can measure the release velocity of the ball using the high speed footage which gives us the speed of 41 meters per second from this we can calculate the kinetic energy of the ball just after release and this shows that 49 percent of the energy is lost just in the launch itself and the remaining 16% is lost due to drag so this shows that the enlarged golf ball is either very aerodynamic or my trebuchet is very inefficient either way it's very satisfying to see this thing launch altimeter bull test in 3 2 1 oh yes oh yeah one nice looks like the lids come off what perfect speaking of the trebuchet design I never got around to uploading the files to the Internet as fusion 360 kept crashing every time I tried to export the model so I've rebuilt the CAD model completely from scratch and uploaded it so that you guys can build your own if you want to the link to the files will be down in the description below so there we have it I've made the world's most safest trebuchet projectile if you enjoyed this video or found it interesting it'd be great if you can leave a thumbs up if you're new to my channel I want to see projects similar to this then click subscribe down below and a huge huge huge thanks to all of my supporters over on patreon you guys make these videos possible and I honestly couldn't do various projects on this without your support so thank you very much thanks again for watching and I'll see you in the next video goodbye that's gone backwards no think that was good don't know how well you can see that but the ball looks like it's in multiple pieces not good

Channel: Tom Stanton

Views: 675,208

Rating: 4.9648337 out of 5

Keywords: gravitational potential energy, kinetic energy, energy, transfer, trebuchet, catapult, launch, parachute, golf, physics, engineering, 3D printed, 3D print, altitude, altimeter, arduino, electronics, maths, science, potential energy, gravity, gravitational, tennis ball, geforce, acceleration, velocity, weight, high altitude, DIY, homemade, CAD, fusion, fusion360, aerodynamic, middle ages

Id: mjEpN5_31go

Length: 15min 11sec (911 seconds)

Published: Fri May 17 2019

Reddit Comments

[u/pick_on_the_moon]

What is this ‘fusion’ program he talks of?