What rope for the zip-line descent

Hello.
I would like someone to advise me on a certain issue. I am planning to build a rope slide on the plot. The descent will be about 70m long, the rope will be 10mm thick steel, but I'm not sure what weave to choose the line. There are ropes with various strands on the market and, as far as I know, not all of them are suitable because of the weave. Does anyone know about this topic?

The rope must be able to withstand transverse loads. It's once. Must be certified.
The surface must be smooth to facilitate the movement of the block. Such ropes can be made, for example, of wires with a trapezoidal cross-section. Or from round wires, but with a filling between the strands.
Its tearing strength MUST be greater than the maximum expected load. Some even recommend a multiplier of 5 times more.
The maximum stresses result from the design of the descent and its length and slope. A rope that works well on a 20-meter descent at a low angle may crack on a slightly longer descent. These are variable forces, but they are quantifiable.
This is where the transverse stresses that the rope must withstand must be taken into account.
However, I think that for a small zip line, at a not too high angle, a rope with a strength of between 55 and 100 kN of breaking strength is sufficient. Well, unless you will be swinging "right guys" 150 kg each. Or you are planning a descent of 200 meters with a height difference of 30 meters. This is a different story.
Therefore, do not only look at the thickness of the rope, but its exact parameters.

And if the zip-line is to be commercial, forget about the self-made. You must have a design made by a designer with appropriate permissions, certified equipment, periodically inspected and controlled, and maybe even tested for loads. Otherwise, if someone even cuts a finger, PIP and the rest of the company will hang you for jewels on the nearest lamppost, or you will do it yourself out of desperation, when they tell you everything.
Such charms of service provision.

But even if it is only a ride down from the balcony on the first floor and 20 meters - you better count your endurance. Like the force needed to anchor the rope. 100 kg of weight, on a long lever it is no longer a fairy tale and you can even smash the wall of the house. In general, zip lines are, contrary to appearances, a really extreme sport and it is very easy to get hurt. This is one of the most traumatic sports.

Thanks a lot for your extensive reply.

The rope will be tied to 2 healthy ash trees with a trunk diameter of at least 1m. As I mentioned above, the total length of the descent is 70m. Zipline will be for private purposes only and will be used only by people weighing less than 40 kg (my two daughters). I do not want to make an angle that is too high so that the speeds are not achieved too high. I also want the person descending to be relatively low to the ground.

According to the manufacturer of the rope, the breaking strength is 5 tons.

Is it really such an "ordinary" steel rope, on which the kids will ride and not be so heavily exploited, will not be suitable for this purpose?

Added after 33 [minutes]:

Referring to my post above, he gives the parameters of the rope. The rope is certified.
- Diameter [mm]: 10
- Strength: 58.4kN
- Tensile strength [N / mm?] [Mpa]: 1770
- Weave RHRL: 6x37 + FC
- Breaking load [kg]: 5955
- Weight [g / m]: 346

Can I use this?

It should be good. Select only the appropriate pulley according to the rope diameter. It would be best with a brass or bronze roller. The least damage to the rope surface will be the least and the roller itself will have the least wear. At 70 meters, it would be worth considering a fastened harness. It is a long bit of a descent and a simple stick to hold on, like on playgrounds, may not work (hanging for a long time).

The block will be dedicated to zip lines of a reputable company, so it should be ok.

manix-76 wrote:

Referring to my post above, he gives the parameters of the rope. The rope is certified.
- Diameter [mm]: 10
- Strength: 58.4kN
- Tensile strength [N / mm?] [Mpa]: 1770
- Weave RHRL: 6x37 + FC
- Breaking load [kg]: 5955
- Weight [g / m]: 346

I'll warm it up a bit, but well ....
I am not a specialist, but for such applications, 6mm is enough for me.
For example: Weave: 6x19 + FC has tensile strength [N / mm2] [MPa]: 1770 and breaking load [kg]: 1960 and weight [kg / m]: 0.12.

manix-76 wrote:

The rope will be tied to 2 healthy ash trees with a trunk diameter of at least 1m.

I do not recommend imitators. You can pay for the destruction of two ash trees, there will be no small bill.

retrofood wrote:

manix-76 wrote:

The rope will be tied to 2 healthy ash trees with a trunk diameter of at least 1m.

I do not recommend imitators. You can pay for the destruction of two ash trees, there will be no small bill.

I don't think it will be so bad ... just give wooden spacers.

Tomek79 wrote:

I guess it won't be that bad ... just give wooden spacers.

I hope I just wanted to signal the need to pay attention to it.

Actually, I hope so too

I have had a 35 m long zipline in my garden for 10 years. I did not buy the block, but I made it with the use of 2 100 mm diameter polyamide rollers: http://www.marlonstal.pl/rolki-profilowane-na-linke-poliamidowe-i-metalowe-c-47.html Their advantage is quiet operation when descending and lower rolling resistance. I also made a brake of my own idea in the pulley with blocks made of beech wood, they cover the rope from above and below. You can then build a zipline with a greater rope slope and the descender (s) brakes before the end. However, I have to replace the lower brake pad once a season.

How did you do this brake? Any photo can you upload?

When I am on the plot, I will take a photo of the block from the outside and throw it in. To see the brake I would have to disassemble the pulley, for now I will try to describe it. It works similar to a disc brake on a car (motorcycle, bicycle) with the difference that the disc is a zip-line rope. In my case, only the lower block is movable, mounted on a two-sided lever with a ratio of about 1/4. The top block is fixed. Braking efficiency is determined by the play between the rope and the upper block and the force with which we act on the lower block. I have the top block from the beginning, you have to set this clearance once in a few years. I replace the lower one, as I wrote once a year, because it wears out faster. The blocks must be adjusted to the diameter of the rope, i.e. the grooves must be sawed out with a round file. With the speed of the zip line at the end of the rope about 1.5 - 2 m / s, such a brake is more than enough. At higher speed, you can be tempted to build a brake with two movable blocks with a cable or hydraulic drive. Once I tried to find out why brakes are not applied to pulleys of professional zip lines? On another forum I received the answer "and what we will do if the descendant panics and brakes in the middle of the route, we will have to take him off by helicopter"

I am building a 40m zipline on a 6mm rope.
Everything is fine, but how is the block supposed to return to the starting point?
I am thinking of attaching a 2mm rope to the pulley, which will automatically pull the pulley to the starting point. Some motor drum or something. Maybe someone has already done something like this?

A loop of rope and two wheels above the lifting line.
I can send you photos.
I'm making a drive for this ..

I will connect to the topic Zbigniew, if you can post a photo.
Now the question about the pulley, why do there have to be two rolls and where, for example, as for a colleague, take the diameter of 100mm? there can be no such thing as in the picture? I do not plan to save, also take it easy I am asking for a technical approach.

Solution example

Thanks for the photos - is there no resistance to going down?

There is no electric clutch.

To m-blue. Two wheels because the brake is built between them, in the middle. The diameter of the rolls 100 mm so that they were smaller rev. and then quieter at the exit. The roller that you showed is about 40 mm in diameter and does not have a rolling bearing (there will be a high rolling resistance) My rollers are on ball bearings.

Zbigniew 400 wrote:

A loop of rope and two wheels above the lifting line.
I can send you photos.
I'm making a drive for this ..

I'll warm up the topic ;)

can we ask for these photos? - I am most interested in the drive

Post 18.............

Madrik wrote:

100 kg of weight, on a long lever it is no longer a fairy tale and you can even smash the wall of the house.

Leverage on elastic rope? Could you please elaborate on the topic. I am trying to build and somehow such an aspect did not occur to me. Until now, I have believed that the static force pulling the anchorage away is never greater than the gravitational force of the object suspended on the rope. Of course, with the swaying, something needs to be added, but leverage? I would really be grateful for developing the topic.

Hello.
In turn, I wanted to ask if anyone has knowledge about the construction of commercial zip lines exceeding 500 m in length. Namely, it concerns the issues of construction (thickness of the rope, degree of inclination of the rope so as not to be too slow).
Thank you in advance for any information provided