A Cavallo built THE CAROUSEL in Red Hook Brooklyn, with a crew of volunteers and the employees of Hyde Power Systems.  It took 8 weeks to construct, with the two crews working day and night.  We made it happen.

The division of labor worked really well- the volunteers would come to the shop at night, and do the 'grunt work' of edge grinding all the waterjet parts, jigging them together, and tacking them up.  When the day crew came in, they could get right to work welding and assembling the parts.  We had two welders going full time.

The volunteers also built the horses, and did a lot of 'non-structural' welding on other parts of the machine.  They also installed the hardwood flooring, and did all the assembly work.  Pretty much everyone got to do a little of everything - welding, grinding, bolting, playing with fire, and so on.  By the end of the build, things really starting rolling- the skills were picked up quickly.

The best part of the build was the community that coaelesced, and that everyone worked and sweated and it was good and fun.  And, we pulled it off- most amazing of all.

ENGINEERING

The machine was engineered for ease of build, structural simplicity, ease of assembly, compact shipping and storage, and mechanical durability.

I design everything using AutoCAD.  I work in 2D for the design, with 3D models to help with visualization and comprehension, especially with the more complex parts.  A word about design - once you've got something figured out, and you think you're done, start over again from scratch.  You'll do much better the second time around.  And hold no idea sacred - it leads to blind spots, and trouble in the finished product.  Criticize everything, question every step.  Consider the way things interact - how they're built, how they function, what they're supposed to do, and lastly, when you're done with the mechanical design, consider how the parts feel, how they come across aesthetically- if it looks good, it is good.  Look a the fasteners, the welding, the assembly - can it be built?  Will wrenches reach the bolts?  And then, when it's ready, add some decoration, make it sparkle.  Detail is the key to reaching people on a gut level.

THE VISION

Steel horses, appaloosas back from hell, carouseling on a coney island pirate ship, with a stage on the back, shooting fire out the top.  A nomadic wagon, built by a crew of post-apocalypse gypsies, roaming the world looking for the lost horse, and having a good time while they do it.

DESIGN CRITERIA

Build as big as possible, using the fewest materials.  Space constraints: build in a 25'x70'x13' shop floor, ship in a 26' non-CDL box truck towing a trailer, store in a container. 

Design for a sensible, efficient build, using unskilled labor wherever possible.

Assemble onsite with no mechanical aids or lifts.

Fit a stage on the back, with a sound system.  Provide storage, controllable access, and make it rockstar compatible.

Life size horses, sturdy and simple, with a robust drive system.

A hardwood deck, big enough to safely hold 100 people.

A simple, sturdy suspension, with airbags and shocks for a smooth ride - built as cheaply as possible.

Interactive fire effects, with unusual features and a coney island aesthetic, with safe and simple fuel storage, plumbing, and controllers. 

Maintain a shiplike feel - have an elegant, tough, but flexible overhead catwalk, with clean and simple rigging, bracing, railings, awnings, and so on.

BUILD PHILOSOPHY

The piece is completely custom, built around steel tubing frames and trusses, using waterjet cut metal for the splice plates and attachment points.  This design approach is very efficient in time and materials- the welded tube frames are easy to make, and very strong for their weight.  Using CNC manufacturing for the rest is the key to a quick build and a solid finished piece.  Of course, you have to draw every detail.

In practice, the tube frames and tubing lengths are all precut while the cnc order is processed.  When the cnc metal comes in, it is checked, deburred, and then welded to the tube structures.  Wherever two things have to mate, or align, the plates are bolted together, the parts clamped into the proper relationship, and then welded.  This assures alignment, and is very tolerant of real-world discrepancies in the tubing weldments. 

Wherever possible, parts and fasteners were standardized.

HORSES

The horses were designed with CAD.  The goal was to build a horse model as a 3D mesh, composed of flat polygons.  Unable to figure out any easy way to do it, we drew it one polygon at a time.  It took forever.  We used model horses (thank you model horse artists), photographs, and 'feel' to get the shape right as it evolved.  Once the model was worked up, we translated it into a pattern for the cnc metal cutters.  The horses on the carousel were CNC plasma cut from 1/8" thick steel plate.  The plates come as partially cut assemblies, with the fold lines cut out, so that the horses are literally folded up and welded.  

The horses are phenomenally strong, with their semi-monocoque construction.  As many people as can fit, they can hold.  People climbed and danced and boogied all over them, and they didn't care a whit.  Tough as can be.

HORSE DRIVE

Horses are driven by cranks below the deck, which travel on a 20" circle.  That's enough lift to get you pretty far up in the air.  They're driven in pairs, with each pair balanced on arms at the end of a lineshaft.  The lineshaft is driven by a DC motor and gear reducer.  A variable speed drive lets you adjust the speed to match the mood.  Slow and romantic, or fast and crazy.

In an attempt to save money, I used automotive rearends for Burning Man.  These were the only parts that broke- actually, they didn't break, but the welds to lock the spider gears did.  Turns out there's too much boogie in burning man - we would reweld them during the day, and the partiers would break them that night.  Good times.  So they're being replaced with what I wanted to use in the first place - solid shafts, roller bearings, and vee belts.  Boogieproof.

BASE WAGON

The wagon starts with two steel trusses, which come in halves.  Each half is 24' long, which happens to be the length of standard steel tubes.  The trusses are spaced apart by the horse drives, and the suspension pivots, with additional bracing where required to support the masts and transfer the rigging loads.

The trusses have attachment plates for the floor frames, the suspension, the stage, the tank boxes, and so on.  The attachments are all designed to be low profile, so that the total truss width is only 5-1/2", and they can nestle with eachother, reducing the truck pack.  The back half of the trusses is stepped up to support the stage, the subwoofers, and the firetanks.  The internal space is used for storage.

The floor frames are 4' x 15', with 2 inch square tubes for the perimeter, and 1-1/2 tubes for the stringers.  They bolt to eachother, and to the trusses. 

The flooring is 3/4" hardwood, which ships in panels that screw down to the tube frames. 

The bracing and railing posts are all steel tubing, with welded cnc cut endplates.

SUSPENSION

The piece rides on large agricultural implement wheels and hubs, and is floating on airbags, and stabilized by off-road shock absorbers.  The front and back wheels steer, with a middle row of straight wheels.

The front and back wheelsets are supported on crane bearings, which allows the wheels to pivot no matter the load placed on them.  The front and back are connected by aircraft cable, so that as the front wheels are turned by the hitch, the back wheels turn equally in the opposite direction.   This works great going forward- the wagon tracks right behind the tow vehicle.  Going backward, it's a lot more exciting.  So we avoided that.

FIRE SYSTEM

The propane flame effects are integrated into the tops of the horse poles.  Each pole has a pilot and an electrically operated effect head.  The pilots are fed by two 60 lb tanks, each feeding three poles.  The effect on each pole is fed from a separate 60 lb tank.  They are electrically activated, using a valve mounted on the pole top.  Additional valves are located back at the tank, so that the system can be shut down at the push of a button, in case anything gets out of hand.  Manual shutoff valves are also located adjacent to the tanks.

The tanks are housed in steel boxes, riding at the very back of the vehicle.  The regulators and valves are also mounted in a steel box, with easy access from the rear deck. Hoses run up from the regulator box to the catwalk, and feed off to the separate effects.

The effects are controlled using whisker limit switches (for fun, it could have been buttons, but these are cooler), which hang down from the catwalk for manipulation by the crowd.  When you flip the switch, the valve opens at the top of the pole, and a burst of flame erupts- some also blow whistles, throw cans up into a cage, spin, some spew colored flames.  Rock n roll.

ELECTRICAL SYSTEM

The propane valves are all 110VAC, as are the lighting and sound systems.  The horse drives are 220V.  After multiple generator failures due to the duststorms at Burning Man, we were down to just one 6500 watt generator, which actually handled all the load (although the lights would dim as the bass hit, or the horses got unevenly loaded).  So that's what we run.

A CAVALLO SPECIFICATIONS

Assembled Dimensions
Allow 60' length, 40' width, 45' height,
stage is 16' wide x 14' deep

Shipping Dimensions
26'-0" box truck, plus trailer or
40'-0" container,
total weight approx 10,000 lbs

Two days for Setup, two days for Breakdown

And we've got the following sound equipment ready to go:

16 channel mixer (Behringer MX3242X), 8 mics, with 6 mic stands, plus various short stands for amp mics, 2 guitar amps, 1 bass amp with a line out to main system, and a drum kit (2 toms, snare, ride, 2 cymbals, with pedals and whatnot).

The sound system is based around 4 EAW BH800 subwoofers, 4 EAW MR102 mid cabinets, 4 JBL horns, and 2 floor monitors (2x12 cabs with horns), powered by JBL Amps : MPX1200 for the subs (3200 watts), MX300 mids (900 watts) , MX300 horns (600 watts), and a Yamaha power amp for the monitors (300 watts).  Total system power is 5000 watts.  Keep in mind that the speakers are super-efficient folded horns, and make a lot of noise for the power.