High Strength Anti Drone Rope Net

A high strength anti drone rope net is a passive interception barrier: a rope mesh hung across the line a small unmanned aircraft would fly through, with an aperture smaller than the part that would pass first and joints strong enough to take the aircraft’s momentum without opening. We build it two ways – high strength polyester webbing or rope for light interception duty, and knotted aramid (Kevlar-type) rope where a real impact has to be stopped. It is light enough to handle by hand, it does not melt, and it asks for no power, no detection and no operator.

The number that separates a barrier from a gesture is not the strength of the rope. It is the strength of the joint. A 10 mm aramid rope breaks at about 7 t; knotted into a net it gives roughly four times the joint strength of the same rope held in a clamp, because four rope ends meet in every knot and share the load before it reaches the border. On a wire rope net pressed together with aluminium ferrules, the joint holds 200-300 kg – and the panel repeats that joint hundreds of times across the opening.

What the net is asked to stop

A drone arriving at a barrier brings mass multiplied by velocity, and the net has one short distance in which to take it away. A 0.9 kg quadcopter at 20 m/s carries about 18 kg·m/s of momentum and 180 J of energy; that does not sound like much until it has to be absorbed in the 100 mm of sag a taut panel allows. The aircraft either stops in the panel, or it converts the panel into a hole and carries on.

Five things decide which of those happens, and only one of them is the rope:

• The aperture – has to be smaller than the part that would pass first, usually the propeller disc or a wing leading edge.
• The joint – where the load leaves one rope and enters the next; on most netting this is the weakest element by a wide margin.
• The border – which takes everything the mesh collects and passes it to the anchors.
• The anchors – a panel that is strong enough and tied to 2 m posts will fail at the posts.
• The stand-off – clear space behind the panel for a caught aircraft to deform into, instead of reaching the asset.

That is the whole of the engineering, and it is why a drone net of this kind is quoted per opening rather than against a blanket capacity. It is also why a net sold on the strength of its rope alone is being sold on the one number that rarely governs. The full range of panels, meshes and edge details sits under öryggisreipi net.

Two builds, one decision

Polyester and aramid are both sold as high strength netting and they are not interchangeable. The choice is made by the threat, not by the price per square metre.

Where the fire case rather than the impact case governs, the decision moves to the brunavarnir gegn drone möskva, which is built around flame-retardant polyester and the standards it has to meet. Where the flight is fast and the mass is real, the answer is the knotted aramid panel described below.

The aramid rope: 10 mm and 7 t

A drone net is judged on its joints, so start with the rope. It is a 12-strand braid with no core. The strands are interwoven rather than twisted, so the rope stays round under load instead of flattening into an oval, it cannot unlay if a strand is cut, og – the part that matters here – it keeps its strength as it turns through the curvature of a knot. A twisted rope loses more in the knot because its lay opens under load; a braid holds its section and lets the strands share the bend.

Kl 10 mm the aramid braid breaks at about 7 t. Other diameters are braided to order, and every consignment is tested, so design from the batch certificate rather than from this page. What the figure does not tell you is how the rope behaves on the way there: aramid elongates about 3.5 percent before it breaks and under 1.5 percent at working load, which means an impact is transferred to the joint and the border almost as quickly as it arrives at the panel. There is no long stretch to buy time with, and that is exactly why the joint, and not the rope, is the subject of this page.

The same fibre is what carries heat. Aramid has no melting point in service: it carbonises from roughly 400 °C and holds its geometry, so a drone arriving on fire is caught in a panel that does not become fuel and does not drip onto whatever is below. The rope is braided in our own works from aramid braided rope, which is also supplied on its own for lashings and heat-exposed lines.

Why the knot gives four times the strength

Look at a single knot on the panel and count the rope ends going into it: four. Each mesh leg terminates in a knot that wraps around its own turns, so the load entering from one direction passes through the curvature of the knot and out through the other three legs. It never travels through rope sliding on rope, and it is never gripped by a device that can slip.

That is where the multiplier comes from. A clamped joint holds one rope end and holds it at the clamp; a knot holds four and lets them share. In practice a knotted aramid panel is specified at about four times the joint strength of the same rope in a clamped panel, on a fraction of the weight – and the same mechanism is what makes the panel behave well after a hit, because a struck mesh pulls its neighbours through defined knots rather than through friction, so the load spreads over an area several meshes wide.

It also decides how the net fails. A knotted panel degrades: one mesh takes the damage, the surrounding meshes hold, and the panel can be re-knotted and put back. A clamped or knotless panel tends to unzip from the point of impact along the line of least resistance. The construction, the mesh options and the strength table per braid are set out in full on the aramid net with knots síðu.

Where a wire rope net gives up: the ferrule

A wire rope net is pressed together with aluminium ferrules, and the ferrule is the whole problem. It grips the rope by deformation and holds only about 200-300 kg before the rope draws through it or the ferrule itself deforms and lets go. That figure is not the panel’s weak point in the singular – it is repeated at every joint in the mesh, and a drone that arrives with energy finds the nearest one.

Three further things work against it. Steel does not stretch, so there is no deflection to spread the impact over time and the shock arrives at the ferrule undamped. A wire panel is heavy for its area, which is fine on a fixed guard and awkward on anything that has to be lifted into place. And a ferrule cannot be re-made in the field: it needs a press, a die and a new ferrule, so a repaired wire net is a net with a joint nobody can inspect.

Wire rope nets are still the right answer for rigid screens, heavy debris and abrasion, and we make vír reipi slings and assemblies on the same presses. They are not the right answer for a fast, light aircraft, because the ferrule – not the wire – sets the limit.

Specifications

Mesh size: matching the aperture to the aircraft

Aperture is the first thing buyers ask for and the number most often quoted without saying what it has to retain. Vinna úr flugvélinni: the opening has to be small enough that the part which would arrive first cannot pass through it. On a multirotor that part is the propeller disc; on a fixed wing it is the leading edge.

Border, panels and anchors

The mesh collects, the border carries, the anchors decide. A knotted panel is only as good as the line that takes the load out of it, and that line is spliced rather than knotted because a knot in the border would put the whole panel through a 200-300 kg-class joint at its most highly loaded point.

• Border – the same braid or one size up, double-laid, spliced around the perimeter, with corner eyes or stainless thimbles.
• Anchor spacing – 2 m or closer along the border; the border rope spans between anchors and carries whatever the panel collects.
• Afstaða – at least 1 m clear behind the panel, so a caught aircraft deforms into space instead of into the asset.
• Panel joinery – border to border, laced or spliced. Mesh tied to mesh is not a joint and will fail first.
• Roof return – a vertical wall can be flown over; anything above about 6 m needs a return or a top curtain.
• Forspenna – take the slack out and stop. A knotted aramid panel sets under its first load; over-tensioning it creeps the knots and works the anchors.

Vindur, installation and inspection

On a tall vertical panel the governing load is usually wind rather than the aircraft. A 100 mm net is roughly 30 percent solid: calculate the panel as a porous surface at the local basic wind pressure, fix it all round with no gap at an edge or a corner, and never cut mesh for access – put a reinforced opening on the drawing instead.

• Before fitting – check the panel against the drawing: möskva, þvermál reipi, landamæri, corner eyes, batch tag.
• In service – inspect at a fixed interval for chafed strands where the panel crosses structure, togaðar eða bognar festingar, tæringu á innréttingum, og hnútar sem hafa losnað.
• Read the surface – a bleached, fuzzy rope is UV degradation; gljáður eða stífur reipi hefur séð hita. Either, if widespread, retires the panel.
• Eftir hlerun – meðhöndla spjaldið sem hlaðið sönnunargögnum vegna óviðráðanlegs atburðar. Inspect mesh, border and anchors before it goes back into service, and replace it if a corner or the border has taken damage.
• Life – aramid is more UV-sensitive than polyester; a coated panel, or shade above it, roughly doubles service life outdoors.

Where it is specified

• Airports, helipads and approach zones – interception as one layer of a wider counter-UAS design, not instead of it.
• Prisons and correctional sites – contraband delivery by air is the usual driver, and the panel has to be seen to be there.
• Hreinsunarstöðvar, tank farms and fuel depots – panels over bunds and process areas where a burning drone is the second hazard.
• Leikvangar, arenas and event sites – crowd protection and defined flight boxes during drone shows.
• Gagnaver, substations and water treatment works – a dropped payload or a crashed airframe is the risk, not the flight itself.
• Hafnir, terminals and rail yards – large openings closed with joined panels.
• Iðnaðarþök, skylights and cooling areas – where the approach is from above and a horizontal or angled panel is the only barrier that works.

Two neighbouring products cover the cases this one does not: the aramid fall protection safety net where the net has to catch a person, og fire rescue rope for the response team that has to reach the panel afterwards.

Five lines on the enquiry

Algengar spurningar

Where the rest of the detail lives

The pages below carry the neighbouring products, so this one can stay on the question of strength.

• Aramid net with knots – byggingu, mesh options and strength per braid
• Kevlar fléttað aramid reipi net – the load-bearing aramid net, 4-16 mm reipi
• Brunavarnir gegn drone möskva – where the fire case governs the fibre
• Kevlar / aramíð þráður möskva – fine aramid screen for sparks and debris
• Aramid fallvarnaröryggisnet – where the net has to catch a person
• Climbing net – the same knotting tradition, in a recreational build
• Safety rope nets – the full category, with panels, möskva og brún smáatriði
• Aramid fléttað reipi – the line our aramid panels are knotted from