© Lucy Hosking. Photo
© David Huang.
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Satan's Calliope was inspired and conceived twenty minutes
into my first adventure at Burning Man in 1998; spawned of Art and
Science gone gloriously wrong together in the service of fun. She
began as an engineering thesis and became an evolving mechanical
sculpture used as the centerpiece of an hysterical performance of
fire and light and noise. She is musical in the sense of Stockhausen,
loud as Kiss and cannons, dangerous and complicated like aircraft and
women.
The calliope is centered around a cluster of 17 acoustic pulse jets,
tuned chromatically from G1 through B2. Fourteen aluminum organ
pipes tuned from C3 through C#4 fan out on the sides and are blown
with propane. Fourteen truck horns, lengthened for tuning, are
arranged among the pulse jets with their bells across the top and are
also blown with propane. Two large accumulator flares blast from the
top for percussive effect. This is mounted on an hydraulic jack which
raises and rotates vertically to a height of three meters for playing
and retracts horizontally for travel.
The vehicle was once a 1986 Harley Davidson / AMF electric golfcart,
and in this incarnation hopes to redeem the good name of Harley from
the taint of AMF. The body is sheet aluminum riveted over an
aluminum armature. All propulsion and organ systems are powered by
205Kg of lead-acid batteries, which also serve as ballast when the
organ is raised. 115 liters of propane carried in two long tanks in
the sides is strictly for the organ.
The organ is controlled by an industrial computer using an MC68332
that I designed for a former employer. It reads MIDI from any
musical keyboard and determines which valves and igniters to operate
for any desired note or effect. There are several regimens for the
pulse jets to achieve different effects sequencing air, fuel, and
ignition, and plans are a foot to servo the fuel pressure to the MIDI
volume control signal. The organ pipes, truck horns, and other
effects are simply played by on/off valves. This control information
is broken out into eighty or so individual control signals
transferred serially to a second small computer in the back of the
organ itself where the valve drivers and electrical igniters live.
Fuel is delivered to a manifold through safety valves and a CO2
purge system where it is pressure regulated separately for the pulse
jets, organ pipes, and the horns and other accessories. An electric
air compressor, reservoir, and regulator provide starting and boost
air for the pulse jets.
Every effort was taken to make the system safe, reliable, and legal.
Most of the gas handling hardware was taken from the semiconductor
industry, like the corrugated stainless flex fuel lines and the
manifold valve bodies in the organ. There is almost no non-metal
plumbing, and none in the organ itself. The body is open under the
machinery to prevent accumulation of unburned fuel vapor, and while
it is checked for leaks before every show, the entire fuel system is
designed to prevent even a large leak from ever finding a source of
ignition.
Satan's Calliope began as my PhD thesis in
putting fire and sound where I want them when I want them to go
there. She was a study in resonant structures and thermodynamics.
She became my introduction to art and a source of pleasure for all
who encountered her.
Lucy Hosking, lucyfer at calcentral dot com