Optimize Trebuchet: Advice on Equations for Rope

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SUMMARY

To optimize a trebuchet, focus on maximizing the height from which the weight is dropped, increasing the weight itself, and ensuring the catapult arm is long enough to provide adequate exit speed without being excessively long. Key considerations include the stiffness and lightweight nature of the catapult arm and rope, as well as minimizing gear and belt losses through high coefficients of static friction. Modeling the rope as a perfectly rigid beam is suggested, although this may not be entirely accurate. Effective optimization involves ensuring the trebuchet arm stops dead at the end of its cycle to enhance efficiency and reduce wear on the main beam.

PREREQUISITES
  • Understanding of mechanical energy transfer principles
  • Familiarity with static friction coefficients in mechanical systems
  • Knowledge of catapult arm dynamics and projectile motion
  • Basic concepts of structural stiffness in materials
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  • Research equations for mechanical energy transfer in trebuchets
  • Explore software tools for trebuchet design and optimization
  • Learn about the effects of static friction in gear systems
  • Investigate materials that provide high stiffness-to-weight ratios for catapult arms
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Mechanical engineers, physics students, hobbyists building trebuchets, and anyone interested in optimizing projectile launch systems.

nbnate
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Can anyone give me advise on how i would optimize a trebuchet? I think i can figure out most of it except what equations should i use for the rope attached to the projectile.
 
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Hmm, well this would probably due better over on the 'Mechanical Engineering' thread, but I could think of a few qualitative possibilities:

- (Obvious) Height from which you drop weight should be as high as you can make it - this is your only source of power so it sets the maximum amount of energy you can deliver to the projectile.
- Similiarly, you want as much weight as possible!
- Length of catapult arm: should be long, but not so long that you projectile has small exit speed

The rest of considerations all have to do with effiecient energy transfer from the energy of the falling weight to the projectile:

- Catapult arm should be stiff, yet lightweight
- So should the rope
- Minimal gear/belt losses - not too familiar with this area, but if you use a belt their should be a large coefficient of static friction between the belt and the wheel
 
nbnate said:
Can anyone give me advise on how i would optimize a trebuchet? I think i can figure out most of it except what equations should i use for the rope attached to the projectile.

I would attempt to model the rope as a perfectly rigid beam, myself. This is probably not quite right of course.

There are some shareware programs out there to design trebuchets, but I've never looked at them closely, I don't think they provide much theory.

There are different forms of "optimization", but probably what you're talking about is to get the arm of the trebuchet to essentially stop dead at the end of the cycle due to the load, so that it doesn't slam into the stops. This both makes the machine more efficient, and saves wear & tear on the main beam.
 
pervect said:
There are different forms of "optimization", but probably what you're talking about is to get the arm of the trebuchet to essentially stop dead at the end of the cycle due to the load, so that it doesn't slam into the stops. This both makes the machine more efficient, and saves wear & tear on the main beam.

Sounds tricky?
 

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