avoiding collisions when flying...

[addaperle]

hope someone can help because this has been annoying me for ages...

 

what do you call the system whereby flys are attached to pulley's that allow them to be moved a little up or (occasionally) downstage in order for them to be out of the way of something flying past them?

 

and, more importantly, whats the best way of achieving this?

 

thanks

[gareth]

Do you mean brailling (which is where a line is attached to each end of a flying bar enabling it to be pulled little way up or downstage)? Or bresting (which is where a line is run from one fly gallery to the other, pushing the steel suspension lines of a flying bar up or downstage)?

 

I don't quite understand what you're referring to when you say that the flying bars are "attached to pulleys that allow them to be moved up or downstage" ...

[robloxley]

and, more importantly, whats the best way of achieving this?

We have permanent braille lines on our first counterweight bar, to allow LX1 to be brailled downstage hard against the pros. arch. For something like this, where the bar will be flown in/out with the brailles attached, go for a small wire rope block around the fly line, or you could get away with a hard eye with a metal thimble in the braille line.

 

Otherwise, any sensible sized bit of rope will do. A karabina is useful to clip the braille line onto the barrel flying wire. This is then tied off on the gallery handrail.

 

For a brest line, again any sensible length rope and some way to attach it at each end - probably to the gallery handrail. You can't really fly bars when brested else the wire ropes will chafe on the flying steels.

[addaperle]

I'm pretty sure I mean brailling. If, as suggested in the previous post, a rope is attached using a karabina to the flying wire and then tied off on the gallery hand rail, does it need to go via anything in order to be effective? (can I just run the rope directly from the wire to the handrail?)

 

Assuming that I have understood that part of it, once the ropes are attached I need to be able to move the flat several times during the performance to allow something else past it - is this just a case of pulling on the ropes going to the handrail? Also will the bar twist when I do this so that the end attached to the long moves further downstage than the short?

 

I'm sure this is all very simple but for some reason my mind isn't grasping it!!!

 

thanks for all your help.

[Rob]

will the bar twist when I do this so that the end attached to the long moves further downstage than the short?

 

You need brailing lines at both ends of the bar, or at least on two points. They just need to be equidistant from the centre, and reasonably far enough apart to keep the bar stable.

[Kevin Robertson]

Hi there,

 

Just a point.

You could Braille the bar using a running Braille on the lines. This involves 'Snatching' the line using a snatch block or similar. This enables the bar to still fly.

One point to note when brailling or breasting bars is that you must watch the angle of fleet. This cannot exceed 2.5 degrees. In reall terms this works out as for every metre from the grid to the bar you can move the bar 4cm upstage or dowstage. (even less if using a whinch...)

 

Good luck