One of the major changes poised to sweep through theatres and other performance buildings in the next decade is the move to automation. At conferences in London, industry leaders, those involved with major theatres and opera houses, representatives from Cirque du Soleil, and engineers from most of the major stage engineering companies have described the benefits, approaches, and pitfalls of these developments. Many US venues have forestage lifts or orchestra pits operating on Serapid Rigid Chain or Spiralift mechanisms, and companies like JR Clancy, PDO, Texas Scenic, and Vortek are handling increasing numbers of motorized rigging installations. Powered movement of scenery, lighting, floors, and even walls is becoming more widespread in medium-scale and smaller venues, and with this, comes a greater need for knowledge and understanding.

Papers from the London conferences have been published in six full-color volumes, Theatre Engineering And Architecture, providing a unique resource for everyone involved with performing arts buildings. Two books focus particularly on stage machinery and rigging. There are descriptions of stage lift mechanisms and of differing designs of powered hoists, with details of stage control systems and determination of Safety Integrity Levels, a concept that will have an effect in the US in the future. The strain imposed on the body by handling counterweights and the restrictions imposed in the Netherlands on manually-operated flying are examined. Some extensive modern stage engineering and different forms of grids and rigging systems, both from the US and Europe, are examined. The need for regular inspections of rigging systems and how maintenance needs to be carried out is also stressed — all in all, very relevant information which is not available elsewhere.

Many of these topics, and others, will be picked up and developed at NATEAC, if not by speakers, by the specialist engineers, consultants, and delegates attending. As a preview, we reproduce some edited excerpts from the books that are relevant to what is being done internationally in overstage rigging.

Louis Janssen Of theateradvies bv On What Is Happening In The Fly Tower

Many conventional grids have the roof trusses running across stage from left to right with the pulleys on the grid floor (see Figure 1). In my opinion, this is not a good grid; to walk on it is like a minefield with all those trip wires — not very user-friendly, but there can be worse. Where the pulleys are on the floor, the roof is fairly low, and you don't have a lot of flying height. It is natural that, in a refurbishment, you want to leave the grid where it is. This can be made worse after the installation of a power flying system where they have installed walkways over the wire-ropes and other equipment (Figure 2). The height restriction makes it unpleasant for the people who have to work there. Even if you can integrate pulleys into the top of up-downstage roof trusses, you have a curtain of wires to pass through, and the grid space is not easily usable.

As a result of all this, we thought, “We have to get rid of those wires.” This led to the concept of putting the wire ropes under the floor of the grid. We designed it so that the pulleys are under the floor, and the wire ropes run across-stage under the grid channels. The channels are 140mm (5½") wide, and the opening between them is 60mm (2½") wide, so they are set out at 200mm (8") centers. Chain hoists or point hoists can be rigged through the openings without worrying about hitting the wire ropes, and the pulleys can be serviced from above, because you can take up sections of the floor. By using a perforated channel, we allow water from sprinklers to pass through. As the pictures show, the grid is a very clear space (Figure 3). In some installations, we have hinged the floor channels so that adjacent panels open against each other, so you can get a good size opening if you need to lower large electrical plugs through.

John Hastie Of Stage Technologies On Beamhoist

One of the major costs of a power flying system is installation. So if the equipment is simple to install, this will minimize the overall cost. Our new design also had to have no special components determined by the number of lines used; we didn't want to be making four-, five-, and six-line header pulleys, and so on. We wanted standard components. We also wanted to meet British Standard 7905 and other European legislation.

It had to be practicable to install some units one year and then add bars, year after year, possibly utilizing theatre production budgets. And it also had to be at a low enough price to open new markets, but without compromising safety or our own standards. To keep cost to a minimum, Beamhoist comprises only four major components (Figure 5). These are the aluminum beam, the fixed drop pulley, the ball screw, and the running pulley, all of which are illustrated in the picture. The hoist uses 5mm (0.2") diameter wire rope for each suspension line which is reeved around the drop and running pulleys at a ratio of either 4:1 or 8:1. The line nearest to the motor has its running pulley driven directly from the screw. The motor is connected to the ball screw actuator, without the requirement for a gearbox, and that drives the running pulley (Figure 6).

Reind Brackman Of Trekwerk On SynchroDisk

People sometimes ask us, “Why did you make a big drum?” To be honest, the basic reason why we made a big-drum winch is because it was different! If we had done the same as other manufacturers, there was no way we could start in the business.

However, the spinoff was quite interesting. We started designing the winch from the motor up. We contacted many motor manufacturers and worked with their development teams to make a compact unit. The SynchroDisk concept is that of an asynchronous motor and a large drum around it, and on top, a removable box with the electronics.

After a couple of different prototypes, we approached a “norm” for the design (Figure 7). Almost all the theatres in Holland have winches lifting 500kg (1,100lbs) which move the bar at 1.8m/sec (6'/sec), regardless of who makes them. This limits the amount of diversity in the product range and increases the production volume. As a result, almost all parts are the same in all versions of our big drum winch.

To achieve a 20cm (8") pitch of the bars, the winch had to be no wider than 40cm (1"- 4") in total for an installation with only two rows of units. That is quite difficult, as a 15kW asynchronous motor is actually a large item. However, we succeeded in getting the motor and drum within this dimension (Figure 8). In most of the installations, the winches are up in the roof, on the grid, or on a side gallery. The drives operate at 600V DC because we regenerate the energy from a winch when it is lowering and put that power back into the electrical supply. As a consequence of this, there are no braking resistors on the winches in our system.

Don MacLean Of Cirque Du Soleil On Future Trends In Stage Automation

Why are we moving from counterweight to automated flying? There have been comments about health and safety, and many people referred to the new Dutch legislation that forbids the use of counterweight systems over certain weights. A maximum flying load of 75kg (165lbs) is obviously not practical for the theatre industry. Then there are the costs of maintenance and of replacements — the 40-20-10 rule. We have, therefore, more or less debunked the idea that cost saving is a real factor in making that choice.

Faster turnover — now there is a point. Faster turnover is really critical for a lot of operational people and for theatre planners. This gives us improved ability to program the venue. With faster changeovers, we can have a more varied program and more rehearsal time, which can directly impact the bottom line in terms of the revenues from the shows.

Another reason why Cirque du Soleil, in particular, wants to employ automated flying systems is because of the increased repeatability. We want to make sure that the cues are done exactly the same every day, twice a day; no matter who is behind the console or who the flyman is, the show has to be consistent, so we need that repeatability.

But the main reason we are moving to automated flying is to support the artistic vision. Certainly, Cirque du Soleil could not do the type of shows that we do without the advanced and sophisticated controls of our flying systems, automation, and motion control systems. So we are seeing technical development in terms of support of the artistic endeavor, and that, above all, is the critical reason why we are developing automation systems. Lighting, audio, all our backstage teams, and technical specialists are supporting the artistic vision, and now we have a new department, the automation department, which also has a key role in that area.

The books referenced will be available for purchase at NATEAC, held July 20 and 21 at Pace University in New York City. Information on NATEAC can be found at Information on the TEAC publications can be found at