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Tom Stanton's gravity-powered trebuchet breaks sound barrier at 776 mph

Engineer achieves supersonic projectile velocity using only a falling weight and mechanical leverage, surpassing physics constraints.

3 items259 engagement91 comments Hacker NewsPressMastodon

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Aug 10

Summary, timeline and people extracted by Claude from 3 items across 3 sources · 21h ago. Quotes are verbatim.

Tom Stanton successfully launched a 4-gram projectile at 776 miles per hour—9 mph past the speed of sound—using a purely gravity-powered trebuchet. The achievement required engineering innovations including a 3:1 pulley ratio, a 116-gram carbon-fiber arm, and a precisely-timed release mechanism. The feat overcomes fundamental physics limitations that had previously constrained gravity-driven projectile systems.

  • Stanton overcame fundamental physics constraints by using a 3:1 pulley ratio that increases rotational speed as the counterweight descends.
  • A 116-gram carbon-fiber arm proved essential—light enough to avoid dragging down the system while rigid enough to handle the forces.
  • Testing progressed from 10 kg to 40 kg counterweight, with the final configuration achieving 2,342 rpm and launching the projectile at 776 mph.
  • The achievement represents the first time a purely gravity-powered trebuchet has achieved supersonic velocity without additional energy sources.

How it unfolded

  1. Report Achievement reported on Hacker News

    Techeblog article detailing Stanton's design and testing process reaches Hacker News frontpage with 41 points and 11 comments.

  2. Event Supersonic trebuchet test succeeds

    Tom Stanton's gravity-powered trebuchet launches a 4-gram projectile at 776 mph with a 40-kilogram counterweight, achieving 2,342 rpm arm rotation and 274 mph tip speed.

What people are saying verbatim

“For the first time, a purely gravity-powered trebuchet crossed the barrier.”

Techeblog article · Techeblog

“No matter how heavy you make the weight, the speed remains constant, and a typical arm is like a car with a bike chain stuck in first gear, with lots of torque at first but just enough to get it moving by the end.”

Techeblog article · Techeblog · Aug 8

“Carbon fiber was really the only option because it isn't heavy enough to weigh down the entire system while yet being able to withstand punishment.”

Techeblog article · Techeblog