There was a recent post about Botswana sending Germany elephants so I was wondering what size trebuchet would be needed to launch them that distance

Is there anyone here who can help with the maths?

  • Elephants are heavier than 90kg, so...

    You'd need a very large trebuchet, that's all got.

    parent

  • According to chatGPT:

    We want horizontal range R = ~7,500 km ≈ 7.5 × 10⁶ m.

    For a projectile with no air resistance and optimum launch angle (45°):

    The required launch speed to reach that distance would be 8.6 km/s, about 25× the speed of sound, and a third of low-Earth orbital velocity.

    So the trebuchet arm must be ~75 km long.

    If you allow 1,000 g [for the limit of the launch arm's velocity], then:

    L≈7.5 kmL ≈ 7.5\text{ km}L≈7.5 km

    If you allow 10,000 g, then:

    L≈750 mL ≈ 750\text{ m}L≈750 m

    Kinetic energy of the elephant: 1.85×10¹¹ joules, roughly:

    • the energy of 45 tons of TNT
    • or the daily electrical use of a small town
    • or roughly 10% of the energy of the Hiroshima bomb

    To achieve this energy assuming 100m of drop height, the counterweight required would be2,000 tons of counterweight.

    In all cases, you end up with:

    • A physically impossible machine
    • An elephant that reaches a third of orbital velocity
    • A landing in Germany that would qualify as a high-energy astrophysical event.
    parent

    I asked too. I won't post the whole response, but here's the

    Bottom line

    • Launch speed needed: ~9 km/s
    • Example arm: ~200 m throwing arm, 50 m counterweight arm
    • Counterweight mass (50 m drop): ~340,000 tonnes
    • Make the drop only 10 m and you’re up to ~1.7 million tonnes.
    • Elephant acceleration: tens of thousands of g (~42,000g)

    Thinking time: 4m 33s

    parent root

  • It would need to be at least 145x bigger for the weight and possibly bigger than that to get the distance.

    parent