Jump to content

Flying wires


jackthebuilder

Recommended Posts

Having often had to cobble together an assortment of flying wires in some venues, I'm trying to establish the spec for a 'general purpose' stock of (professionally made and tested!) identical flying wires that I can have made.

 

I'm thinking about something that would cover most of the requirements for flown scenery in venues with a height-to-grid of up to 40 feet - nothing super-heavy or specialised!

 

Basically what you think, in terms of length, wire diameter, all steel or fibre core, colour, and terminations, that would cover most scenarios.

 

Any thoughts appreciated. Many thanks.

Link to comment
Share on other sites

We (as a user of other peoples theatres) have six off 6m 2mm lines.

 

Regular users of wire know that it only comes in two lengths, so we opted to have the "too long" variety, so we could wrap the excess round the bar...

Link to comment
Share on other sites

Thanks to David and Paul for that, and to those that replied privately in a considerably more helpful and friendly manner than the first 2 replies.

 

It seems that being in a new environment, and unsure of the protocol, I have been the hapless victim sent for a 'long stand' or a tin of tartan paint.

 

I thought this might be a reasonably safe place to ask a serious, polite and - admittedly - open-ended question which might encourage some useful discussion.

 

The 'Welcome - hope we can help' mat seems to be tainted by a couple of regulars perpetuating an exhausted joke that no-one seems to want to tell them isn't funny any more.

 

Ho hum - I wonder if they recall the time when they were new to all this themselves, and maybe received helpful and friendly advice, and whether they will either have the courage to respond in more helpful terms, or resort to further humbug?

 

Or maybe just say nothing, which will speak volumes in itself. Watch this space...

 

Thanks again to those who replied courteously.

Link to comment
Share on other sites

With a grid height of about 40ft presumably you have a maximum height of flown piece as something a bit less than 20ft. So I would suggest you would need some flying wires which are about 20ft long (for flatage where the attachment point is at the bottom) plus some wires that are quite short - perhaps 3 or 4 mt - for items where the attachment is at the top. The gauge of wire needs to be worked out based on how heavy the flown pieces are and how many wires are used for the piece (and the SWL of your bars obviously has an impact on the maximum weight you can fly). The number of wires depends on how many pieces you think you might fly.
Link to comment
Share on other sites

I would recommend something like 6mm 7x19 construction black steel wire rope (SWL 8:1 270kg) hard eye both ends and some 1 tonne shackles, in the lengths that Lee has pointed out above. Rope Assemblies will be able to help with both of these items:

 

http://www.ropeassemblies.co.uk/category.asp?id=1&t=Theatre%20Ropes%20and%20Rigging

 

I also recommend buying one of these for each drift, so as to prevent damage to the hard eye that wraps the bar:

 

http://www.flints.co.uk/acatalog/Black_Web_Links.html

 

And a bottlescrew/turnbuckle for each drift to level the piece

 

If you wanted a flexible solution, you could go for long drifts with a hard eye at one end, fused and tapered at the other and use bullets or wedge sockets to terminate at the piece. This would require a little more time on fit up to fly a piece and obviously someone competent to make off the free end.

Link to comment
Share on other sites

Just a quick thought - whatever you end up purchasing, if you do, is also going to need regular inspections. The advantage of using the stock found in the venue is that it's distinctly their responsibility to maintain and keep to a inspection schedule. You might find it tricky/expensive to get a relatively small number of items regularly tested.

 

I would probably opt for some* at 4ft, 12ft and 20ft

 

*where some is defined on the basis of how many, in your experience, you have needed for previous shows + a wiggle factor for whatever might reasonably occur in the future

Link to comment
Share on other sites

Sorry I've been Out on a gig and I'm responding from an iPhone so spag issues are likely. I've also been up for almost 24hrs straight so I'll respond properly when I've slept on it.

 

However; I find the op's response extremely rude. I appreciate that we all have the occasional sense of humor failure, but his response further up the thread is frankly borderline trolling. My friend, by all means come in here and ask for help, you will get it. You will also find that there are charachters here that you may or may not like. Calling into question my character is unacceptable however, when you do not know me from Adam. Likewise with David.

 

We are all here so that we may give something back. And I take slight umbrage that you feel as you do to post so vehemently over such a trivial and trifling manner. Would it be fair to suggest that it speaks volumes about your character ?

Link to comment
Share on other sites

Sorry I've been Out on a gig and I'm responding from an iPhone so spag issues are likely. I've also been up for almost 24hrs straight so I'll respond properly when I've slept on it.

 

However; I find the op's response extremely rude. I appreciate that we all have the occasional sense of humor failure, but his response further up the thread is frankly borderline trolling. My friend, by all means come in here and ask for help, you will get it. You will also find that there are charachters here that you may or may not like. Calling into question my character is unacceptable however, when you do not know me from Adam. Likewise with David.

 

We are all here so that we may give something back. And I take slight umbrage that you feel as you do to post so vehemently over such a trivial and trifling manner. Would it be fair to suggest that it speaks volumes about your character ?

 

Not bad for someone been up for 24 hours Smiffy!! You must have slinky fingers. I only saw 3 SPAG errors!! :P

Link to comment
Share on other sites

Many thanks to Tris, Jonathan and Lee for that. I've concluded:

 

Wire rope:

 

Safety factor of 6 - 8 seems to be an acceptable standard, and given that most of what I've flown is around 150 Kg max, with 2 or more flying steels, 4mm wire, 7 x 19, hard eye both ends, would seem reasonable. Less chunky than 6mm (obviously!), a bit more flexible, and I could always add another steel (or 2 for 'balance' if already 3-point hung) if I was close to the limits.

 

Black wire would seem sensible so I can cope with anything visible (flown signs, for example), but it doesn't seem to be available with fibre core, which I have found to be a bit less likely to kink than all-steel. But at 4mm, and careful handling (!), that shouldn't be an issue.

 

The ferrules I have seen most are about 1 inch long, with one at each termination, but I understand that rigging experts would prefer to see 2 No. at each termination. Would it be fair to say that the additional cost of the second ferrule would not be that much and worth doing anyway?

 

Length:

 

6 metres/20 feet would seem the best option. Add in the length of whatever flying iron is used, and a straining screw for adjustment, and you're up at 21 feet or so.

 

I suppose for headers, signs etc you could avoid having to use shorter steels by going down, across, and back up again - remembering that you're effectively halving the SWL of the wire for each vertical used in this way.

 

But if I'm going to spend a few bob building up - and maintaining, I take that point - a decent stock, it would make sense to add a few at 1 and 3 metres, just to make it quicker and more efficient to rig.

 

I'm thinking of 12 No. at 6 metres, and 6 No. each at 1 and 3 metres for starters.

 

Rigging:

 

I like Jonathan's idea of the 'web links' - neat and tidy, but doesn't allow the flexibility of going round the bar a few times to shorten the steel.

 

Usually the steel goes round the bar (once or more times) and shackled onto itself. I've always been a bit uneasy about this as it must put a distortion strain on the wire rope at the point where the shackle meets the rope. But that seems to be the way of it very often. Maybe a compromise would be to knock a few Kg off the SWL, or allow a safety factor of (say) 10, to be safe.

 

Shackles often seem a bit untidy to me somehow - they often sit at an angle, because of their shape, but I'm sure they're safe enough - 1.5 ton shackles seem to be recommended. I've not used them, but maillons rapides seem to be a neater solution.

 

Suppliers:

 

I have Rope Assemblies, Flints and Cosalt as potential suppliers. Any others I should consider?

 

Many thanks again, and any further thoughts appreciated. All the best.

 

 

 

 

Link to comment
Share on other sites

Regular users of wire know that it only comes in two lengths, so we opted to have the "too long" variety, so we could wrap the excess round the bar...

 

 

I like Jonathan's idea of the 'web links' - neat and tidy, but doesn't allow the flexibility of going round the bar a few times to shorten the steel.

 

Usually the steel goes round the bar (once or more times) and shackled onto itself. I've always been a bit uneasy about this as it must put a distortion strain on the wire rope at the point where the shackle meets the rope. But that seems to be the way of it very often. Maybe a compromise would be to knock a few Kg off the SWL, or allow a safety factor of (say) 10, to be safe.

 

Shackles often seem a bit untidy to me somehow - they often sit at an angle, because of their shape, but I'm sure they're safe enough - 1.5 ton shackles seem to be recommended. I've not used them, but maillons rapides seem to be a neater solution.

 

 

 

Hi, just thought I'd weigh in with a little concern over the practice of wrapping steels around a bar and terminating with a shackle. I know it happens but really it shouldn't, in my opinion if your needing to wrap a steel then your using the wrong length! Likewise if a shackle looks messy then it to is either the wrong size for the job or has been installed incorrectly. Below is an extract from the British Standard 7906-1 specifically addressing these issues. Whilst it may be "common Practice" is it safe? My biggest concern is that many inexperienced people in our industry are using equipment as basic as a piece of SWR and a shackle believing that they are using it within safe limits when in fact a simple lifting operation has many facets that need to be taken into account and missing some of the basic principals can cause catastrophic results.

If looking to shorten a length of SWR there are a few methods that have already been mentioned that I'd like to second bullets (automatic dead ends), wedge sockets and cable gliders.

 

8.10.2.5 Installation

Wire ropes should not be kinked or twisted. Wire ropes should not be knotted to form a connection. Wire ropes should be properly terminated (see 8.13.1) and attached to the load and/or lifting machine using an appropriate lifting accessory (see 8.13.2).

 

8.13.1 Terminations

Terminations generally reduce the SWL of the rope. The efficiency of a correctly fitted termination is stated as a percentage of the strength of the rope itself; thus a 60 % efficient termination reduces the MBL of the rope by 40 %. The highest efficiency termination should be used wherever practicable.

8.13.2 Lifting accessories

All lifting accessories should be certified and the SWL known. Lifting accessories used for flying should have a safety factor of at least 8. Slings, sling terminations, hooks, shackles etc. vary considerably in size

for a given SWL. It is essential that lifting accessories are compatible both in size and capacity. It might be necessary to add an intermediate link or shackle in order to achieve compatibility. However, the minimum

number of components necessary should be used to achieve compatibility between the lifting machine and the load.

 

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.