Medieval trebuchets threw 100 kg stones about 300 m. Modern materials, servomotors, and the sheer permission to build big let us ask a serious question: could a skyscraper-scale counterweight trebuchet replace a cargo helicopter for isolated mountain communities? No fuel, no rotor, no forest fires from a crash.

The machine. Picture a steel A-frame 380 m tall — Empire State height — anchored on a Himalayan ridge. The throwing arm is a 300 m carbon-fiber-wrapped steel tube pivoting near the top. The short end carries a 10,000-tonne counterweight (a hollow concrete cube 16 m per side, filled with local rock). The long end holds a sling cradling a 100-tonne freight pod — a 100:1 mass ratio, the sweet spot medieval engineers converged on empirically.

Range calculation. The counterweight falls roughly 300 m:

E_stored = m·g·h = 10⁷ kg × 9.8 m/s² × 300 m = 2.94×10¹⁰ J

Trebuchet efficiency (energy delivered to projectile vs. potential energy of counterweight) tops out around 50% for a well-tuned sling. So the pod receives ~1.47×10¹⁰ J:

v = √(2E/m) = √(2 × 1.47×10¹⁰ / 10⁵) ≈ 542 m/s

That's Mach 1.6 — genuinely supersonic. Vacuum range at 45° would be v²/g ≈ 30 km. Air drag mugs us: a 3 m radius pod (Cd ≈ 0.3, ρ ≈ 1.2 kg/m³) sees ~1.5 MN of drag at release, decelerating at ~15 m/s². Numerical integration gives a realistic range of ~18–22 km. Enough to sling supplies from a valley depot to three or four ridge villages.

The arm is the killer. At release, the tip moves at 542 m/s along a 250 m radius. Angular velocity ω = v/r = 2.17 rad/s. Centripetal acceleration on the pod: a = ω²r = 4.7 × 250 ≈ 1,180 m/s² = 120 g. Cargo must be potted like an artillery shell — no eggs, no pianos, no people. Fine for concrete, rebar, sealed water tanks, batteries.

Stress on the arm. A 300 m arm carrying 100 tonnes at its tip under 120 g experiences a moment near the pivot of roughly M = 10⁵ × 1180 × 250 ≈ 3×10¹⁰ N·m. Even a 3 m diameter carbon-composite tube with 5 cm walls has a section modulus around 1 m³, giving stresses ~30 GPa — ten times what any real composite survives. So the arm must taper aggressively, shed mass, and probably use a hinged secondary sling to store part of the energy elastically (this is what makes real trebuchets efficient anyway). A tapered arm with an active pre-tensioned sling drops peak stress into the ~500 MPa range — still brutal, but achievable in maraging steel.

Throughput. Reset is the bottleneck. Winching 10,000 tonnes up 300 m takes E/P = 2.94×10¹⁰ J ÷ 1 MW winch = 8.2 hours per throw. Two throws per day, 200 tonnes/day — comparable to a Chinook flying eight sorties. But your fuel is gravity plus overnight solar charging.

What actually kills it. Aim. A 1° release error at 20 km puts your medicine crate 350 m from the pad. You'd need active fin control on the pod plus a laser-guided landing net. At which point you've built a small suborbital rocket and used gravity as the propellant.