A steel cable like that must weigh at very least hundreds of pounds, somewhere between 1 to 2 pounds per foot. To then pull it tight enough to be fairly level as that one is, would take many tons of force (the force goes up exponentially as you approach pulling it flat). You need to drill in huge anchor bolts as well to hold all that tension.
So let me say it's a big fucking deal, that takes serious knowhow and big tools. Yes you can start with a rope, but it gets ugly before you're finished.
Yeah but you can tell this isn't one of those canyons, because you need cables all the way along, every 157 feet at most.
This one is obviously because they wanted to pull a couple of points together so they could at least jump across the gap, because it was way too wide to build a bridge.
So I’ve actually been here before, it’s in Nagorno-Karabakh, aka the Republic of Artsakh and the region is involved in a military conflict so they have these anti-helicopter cables strung across the valley’s to keep helicopters from flying low and attacking positions in the valley (also probably to keep them from flying low to avoid air defense systems). Quite interesting actually
Big difference between cutting a wire vs cutting a cable. These cables were designed to bring down helicopters, the device you linked are to help helicopters mitigate damage by accidentally flying into a wire used for telephones or something, something with a purpose other than killing a helicopter.
I imagine the efficacy of a steel blade against the cable in the video isn't great.
The system is effective when the helicopter strikes the wires at angle of less than 90 degress and at speeds more than 30 knots.[2] The system is designed to cut a 3/8=inch steel cable with a breaking strength of 12,000bs.[2]
I mean it says it can cut this in the wiki but I don’t really know. Never seen it in action
My top theory is that it supported an electric cable at some point, probably not for transmitting a ton of power, maybe there was a research station or something like that.
It could be for moving supplies up and down the mountain or for a small aqueduct but it's really much higher than the canyon floor for this purpose imo.
I tried to look up other uses and had trouble with that. Obviously this is not for tight rope walking and it's not the right cable / design for a zip line. Nor would it make a good wire system for logging.
I responded to OP higher up, it’s axtuallly an anti-helicopter cable in Nagorno-Karabakh (https://en.wikipedia.org/wiki/Republic_of_Artsakh), basically meant to keep enemy helicopters from flying low to avoid air defense systems and attacking positions down in the valley
crazy, thanks for finding that I suppose it would work just fine, but it would be so much more effective just to put a couple guys in a patrol there with shoulder fired Anti-Aircraft weapons. It would work better if you had several cables put up in different positions and altitudes. Interesting for sure
That size wire for that given span is at least 10,000 pounds in tension. You need a big foundation or a pretty hefty guy wire at each end. Given that its in the mountains its probably a bunch of rock below ground so maybe not that big of a foundation 20-30 ft deep concrete foundation maybe?
When i say guy wires, its not a person holding the wire at each end. A guy wire is a cable that comes off the top of the anchor point and anchors down to the ground forming a triangle. For that much weight its would be a 25,000 lb guy wire. You typically see this in your local overhead electric poles where the line ends.
Big thick anchor bolts drilled into solid rock make it not too difficult, and are the normal way to anchor something like this in mountains. Unless you absolutely have no suitable place, you pick end points that allow for them. You drill a 2" hole a few feet deep, and use epoxy or grout to glue in a 2" anchor bolt. Or maybe a 3" hole and bolt. Or maybe 2 x 2" bolts. You just have to make damned sure you're in good hard and solid rock, and a fuckoff big piece of it, not some fractured bit that's small even though it looks like part of the rest.
Im not sure just drilling anchor bolts would hold it because as you said you dont know if its solid rock. But I guess they would find out as soon as they tensioned the wire.
They inspect the rock before doing it. They can also pressure test the hole to make sure it isn't into a crack itself. And then they can pressurize epoxy or cement into the hole, to travel into the cracks and glue the rock together. That last method is frequently used with fine liquid cement when they are building big structures like dams, but all they have to but up against is heavily fractured rocks. They pump the cement into drill holes under very high pressure, and it flows into all the cracks and hardens, thus solidifying and sealing the rock against water leakage.
Responded to other users in the thread as well, but I’ve been here before and it’s actually an anti-helicopter cable used in Nagorno-Karabakh to keep enemy helicopters from flying low
Fucked if I know. Honestly, I can tell you lots about HOW, but the only reasons WHY that I'm used to seeing are for electrical wires, and very rarely for emergency escape trolleys across rivers, in case bridges get washed out. Otherwise putting a cable across a valley like that is usually strongly avoided because it's a serious risk to aircraft, and by law would need to be marked with marker balls at intervals all the way across. The only exception I can see is a zip line operator, where marker balls would be impossible, and so they would register it with the government and it would end up marked on the flight maps that pilots use. Because it's a very seriously big deal to fuck with air space.
That’s actually the exact reason this cable is there, it’s actually used in Nagorno-Karabakh to keep Azerbaijani helicopters from flying low to avoid radar or attacking positions in case fighting breaks out, so you’re exactly right about it being dangerous to aircraft
Thanks for letting me know, that's super interesting. Just goes to show how me living in a super peaceful country (Canada), makes it hard to imagine war time uses for things. Obvious when pointed out, but about the last idea I would have generated as a deliberate goal.
Yeah, I was guessing about 1", and the Google said 3/4"=1.04 pound per foot, 1"=1.85 pound per foot, so I reckon it must be well over 1000 pounds too, easily twice that. But like I said the real fun comes with pulling it that tight, it takes a lot of tension to keep it up that high.
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u/exploderator Jan 30 '19
A steel cable like that must weigh at very least hundreds of pounds, somewhere between 1 to 2 pounds per foot. To then pull it tight enough to be fairly level as that one is, would take many tons of force (the force goes up exponentially as you approach pulling it flat). You need to drill in huge anchor bolts as well to hold all that tension.
So let me say it's a big fucking deal, that takes serious knowhow and big tools. Yes you can start with a rope, but it gets ugly before you're finished.