Thursday, June 2, 2011

The MURLIN Trebuchet

Don't forget there are only 121 days until the 3rd Annual Vermont Pumpkin Chuckin' Festival on October, 2nd, 2011.
There were some folks from Tucson,
Who wanted to get their geek on,
They built a MURLIN trebuchet,
That on YouTube they did display,
Three cheers for brain over brawn.
Development of a Dynamically Tuned MURLIN Trebuchet [video channel] -- Development of a MURLIN (rhymes with hurlin') trebuchet which is tuned to work with a bending structure.

The Golf Ball MURLIN:

Full power tests for the 5-armed MURLIN (Multi-Radius Linear Nodes) Trebuchet.

Dropping the full 37.5 counterweight in a still wind results in consistent distances (5 shots) over 600 feet. Longest shot found was 620 ft. The frame is reinforced for these tests because previous movies had shown substantial flexure under the 1000lb load just before release.

I believe my radar gun is unreliable (reading low due to slow sampling rates), but one reading of 127 mph was taken.

If you look carefully, you can see the golf balls actually curve upwards in flight due to the (Magnus effect) spin given by the pouch upon release...

Update: 22 May 2011 - Distances recorded up to 708 ft. this morning in a calm wind. 5mm Spectra cord and larger pulleys responsible for improved performance.
More videos: