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Air Bushings Designed into a Large Pendulum Wave

Wed, 11/20/2013

Ivo Schoofs Email: info@largependulumwave.nl

New Way Air Bearing distributor IBS Precision Engineering BV applied New Way Air Bushings for a unique design into a kinetic light art experiment called Large Pendulum Wave for GLOW. In November the city center of Eindhoven, The Netherlands turns into a forum of interventions, installations, performances and events based on the phenomena of artificial light.

Large Pendulum Wave

The Pendulum Wave is a physical phenomenon based on a number of independent pendulums that are very accurately adjusted concerning swinging period (or frequency). On a steady frame 15 pendulums are mounted. Each pendulum can swing independently from each other. Due to the different length of each pendulum the swinging frequency is different for each pendulum. Once the frequencies are very accurately adjusted according to a mathematical sequence, the pendulums produce a dance of standing and running waves and quasi chaos. Most common is the small version that has 12 or 15 pendulums of approximately 30cm. The longest pendulum swings exactly 51 times per minute, the second exactly 52 times per minute and so on. There are some popular videos of the small versions available on the internet. The main theory behind the phenomenon can also be found here. A large version, on this scale, however, has never been built, correct me if I’m wrong…

How to deal with friction in the bearings

If the pendulums have pivoting points with variable friction coefficient, it is not possible to calibrate the swinging periods and consequently the patterns do not appear in the sequence. In the large version the bearings become even more important because of the longer sequence time.

For the small version the pendulums are often made of a small mass hanging on two strings. As mentioned above, strings are not possible as we want to speed up the swinging periods using a heavy mass on a rigid pendulum pipes. A bearing ‘quest’ eventually led to the most desirable solution: air bearings! These special New Way Air bushings are made of (porous) graphite that restricts and minimizes the air flow. Each pendulum has its own set of 3 bearings, one cylindrical main bearing and two flat bearings to prevent the shaft from horizontal movement. One pendulum weighs about 60kg and it is floating on a 0.004 mm layer of air!

Ivo Schoofs
Author Info:
Email: info@largependulumwave.nl