In general pricipal, the hydraulic flying
system is much the same as the counterweight fly system
, except using hydraulic rams to control the movement of the arbor
Typically, a hydraulic fly system uses a double faced piston. That is, it has two rams and can be moved by fluid pressure on either side. Also, because the piston has a relatively short stroke, a complicated set of headers and pulleys is required so that a short movement of the piston can result in long movements of the batten.
In many ways hydraulic fly systems and other mechanical fly systems are more dangerous than the traditional manual fly system. They have considerably more power and give much less feedback to their operator, making it very difficult to recognize trouble spots. Great care should be taken when operating a hydraulic fly system.
Part of the Stage Rigging Metanode