Hey y'all! I'm making a working model based off the Warwick castle trebuchet at 1:24 scale. I made a CAD model then put the info into trebuchet simulator V2 (idk if y'all find that reliable) but it's pathetic. What am I doing wrong? I tried tinkering with the variables but I can't figure it out. If anyone has any wisdom I'd be super grateful!
For extra information the arm will be made from European ash and the structure is euro oak. The basket and the wheels are 3D printed. the projectile is a ping pong ball.
Launch angle is low. Should be over 40 degrees with this machine. Ping pong ball "Projectile Ratios" are terrible. low density to surface area. Beam ratio I think is 6.25:1. That's good. Mass ratio is 777:1. Which is super high for a HCW. A good well tuned HCW can throw 60 "Arms" at 150:1 "Mass Ratio". 23+m with the length of your arm. Low mass/high surface area projectiles will not go very far. Throw a grape...
Thank you so much!! Sorry if this is a silly question but what exactly does a mass ratio refer to? The mass of the arm, weight or the projectile? This is my new result from some of suggestions, which is more energy efficient but less range efficient: https://virtualtrebuchet.com/?lengthArmShort=0.054&lengthArmLong=0.388&lengthSling=0.37&lengthWeight=0.093&heightOfPivot=0.319&massArm=0.052&inertiaArm=0.1052&pivotToArmCG=0.122&massWeight=1.7&inertiaWeight=0.1286&massProjectile=0.07&projectileDiameter=0.043&windSpeed=0&releaseAngle=45&units=metric&projectile=custom&uniformArm=false&distance=0.8124111895884073
Mass Ratio is the weight of counterweight divided by the weight of the projectile.
Okay so if I use something like a golf ball with a mass of 0.046kg with the same diameter as the ping pong ball with a 2.1kg CW I’d get a mass ratio of 45.7 which means I should be able to throw around 7m. The only thing I could think to change is to lengthen the short arm but you said that ratio is okay and id have to change all the other qualities right since the mass of the arm, inertia and it’s CG would change. What should I be doing to tune it? https://virtualtrebuchet.com/?lengthArmShort=0.052&lengthArmLong=0.387&lengthSling=0.38&lengthWeight=0.1&heightOfPivot=0.319&massArm=0.052&inertiaArm=0.1052&pivotToArmCG=0.122&massWeight=2.1&inertiaWeight=0.1286&massProjectile=0.046&projectileDiameter=0.043&windSpeed=0&releaseAngle=40&units=metric&projectile=golfBall&uniformArm=false&distance=2.054220150898488
Traditional beam ratio for a HCW is more like 5:1. 45.7:1 mass ratio is too low. Double it. I changed the beam ratio, sling length, mass ratio, and weight length to this. https://virtualtrebuchet.com/?lengthArmShort=0.0774&lengthArmLong=0.387&lengthSling=0.45&lengthWeight=0.17&heightOfPivot=0.319&massArm=0.052&inertiaArm=0.1052&pivotToArmCG=0.122&massWeight=6.8895&inertiaWeight=0.1286&massProjectile=0.046&projectileDiameter=0.043&windSpeed=0&releaseAngle=43&units=metric&projectile=golfBall&uniformArm=false&distance=13.155860845424913
sorry, that link is the same treb i sent
Sorry try it now.
These 150:1 mass ratio performance numbers are in line with a primitive build.
Thank you so so much! I adapted it a bit since otherwise the CW would collide into the wheel axle. Initially I was reluctant to change the weight since I couldn't add more and have it fit in the basket (since I can't use lead bc it's for children) but I think I'll to get my weight CNCed out of steel to get it up to 6.8.