A Cable That Keeps the Aircraft Aloft
Tethered unmanned aerial systems solve one of the most persistent limitations in drone operation: endurance. Instead of relying only on an onboard battery, the aircraft receives continuous power from a ground station. The same physical connection can provide a direct path for command, telemetry, video and other mission data. That combination supports persistent surveillance, emergency response, temporary communications, inspection and defense applications in which frequent landing and battery replacement are unacceptable.
The tether can appear to be a simple cable, but it is one of the most demanding components in the system. It must transmit power efficiently, preserve data integrity, carry mechanical load, tolerate weather and abrasion, and travel smoothly through a reel system. It must accomplish all of this at the lowest practical mass and diameter because every additional gram becomes part of the aircraft’s lift requirement.
These design requirements interact. Increasing conductor size reduces resistance and voltage drop, but increases mass and aerodynamic drag. Adding shielding can improve electromagnetic compatibility, but may increase diameter and stiffness. A heavier jacket can improve abrasion resistance, but may reduce altitude or payload capacity. The best tether is therefore not the cable with the maximum value in every category. It is the cable optimized for the aircraft, ground power architecture, mission altitude, tether-management system and operating environment.
Why the Tether Defines System Performance
In a battery-powered drone, the energy source and wireless link are separate subsystems. In a tethered platform, the cable becomes a combined electrical, communications and mechanical lifeline. Depending on the architecture, it may contain high-voltage power conductors, low-voltage control conductors, shielded copper data pairs, drain wires, grounding elements and a tensile strength member. Some tether systems also use optical elements for high-bandwidth data.
The finished cable affects the aircraft mechanically as well as electrically. Cable mass increases the required thrust. Wind acting on the tether creates lateral load and drag. Excessive stiffness can disturb station keeping and increase stress at the aircraft termination. A construction that does not spool consistently can create kinks, localized tension or unstable payout.
For these reasons, cable selection should begin while the drone and tether-management system are still being engineered. Waiting until the end of the design process often forces compromises in voltage, reel size, aircraft payload or operating height.
Integrating Power, Data and Signal
A hybrid tether consolidates multiple functions inside one protected construction. Power conductors are selected according to system voltage, current, total tether length, acceptable voltage drop and thermal rise. High-voltage power transmission is frequently considered because higher voltage can deliver the same power at lower current, allowing smaller conductors. The tradeoff is increased insulation, spacing and conversion requirements.
Data and control circuits require a different set of decisions. Twisted pairs can help reject common-mode noise. Shields and drain wires can reduce coupling from power electronics, motors and switching converters. Conductor lay, pair geometry, shield coverage and grounding strategy all affect electromagnetic performance. The physical relationship between power and signal components matters; simply placing unrelated wires in a common jacket does not create an optimized hybrid cable.
Pelican Wire’s cabling, bunching, stranding, tape-wrap, overbraid and extrusion capabilities allow engineers to evaluate the construction as a complete system. Materials and geometry can be selected around the required electrical behavior, flexibility, environmental resistance and finished diameter rather than around the nearest catalog cable.
Visit Pelican Wire at CUAV in Las Vegas Sept. 1-3
CLICK THE IMAGE BELOW & and enter UAVA2630145 when prompted to enter a promo code to receive a Free Exhibit Hall Only Pass or $100 off a Full Conference registration.
BOOTH 1384
The Weight-Loss vs. Durability Tradeoff
Low mass is one of the most visible design goals, but the lightest cable is not automatically the best cable. Conductors must still carry current without excessive loss or temperature rise. Insulation must maintain dielectric performance across the operating voltage and environment. Shields must protect sensitive circuits. Reinforcement must control tensile loading so the electrical conductors are not forced to become structural members.
Fine-gauge conductors, compact insulation walls and efficient cabling geometry can reduce diameter and weight. Conductor alloy, plating, strand count, strand diameter and lay length can be adjusted for conductivity, flexibility, corrosion resistance and termination method. A high-strength nonmetallic member may carry tensile load, while the electrical elements remain optimized for current and flexing.
The jacket binds the construction together and protects it from the operating environment. It must be strong enough to resist abrasion and handling damage without making the tether unnecessarily rigid. The correct answer is a balanced design supported by calculations and physical testing, not a single material chosen in isolation.
Flex Life and Tether-Management Compatibility
A drone tether is repeatedly paid out, tensioned, exposed to wind and rewound. This produces bending, torsion and cyclic tensile loading that differs from the motion experienced by a stationary cable. Strand construction, conductor lay, component placement and reinforcement all influence dynamic life.
The finished cable must also be compatible with the reel diameter, level-wind mechanism, guide surfaces, payout speed and tension-control strategy. A cable that is too stiff may resist spooling or transmit higher loads to the aircraft connector. A construction with insufficient internal stability may allow components to migrate, flatten or become damaged during cycling.
Prototype testing should reproduce the actual bend radius, reel speed, tension and expected cycle count. Electrical continuity alone is not enough. A useful validation program also evaluates resistance change, jacket wear, component movement, signal performance, temperature rise and termination stress after repeated deployment.
Environmental Protection Without Unnecessary Bulk
Tethered drones may operate in rain, salt air, dust, ultraviolet exposure, temperature extremes and industrial contaminants. Cable materials should be chosen for the real environment rather than by temperature rating alone.
Abrasion resistance matters where the tether contacts rollers and guides. Low-temperature flexibility matters for cold-weather deployment. Moisture and chemical resistance support electrical reliability and dimensional stability. Ultraviolet resistance is important for systems used outdoors for long periods. Some platforms may also require flame resistance, low-smoke behavior or specialized material documentation.
Pelican Wire offers a broad range of extrusion and other wrapping & insulating materials, including fluoropolymers, cross-linked materials, polyurethane, TPE, PVC, nylon, polyimide and PTFE options. The engineering task is to match the material system to the required temperature, chemical, mechanical and electrical performance while controlling wall thickness and mass.
From Mission Profile to Prototype
A productive cable-development project starts with a complete mission profile. Key inputs include maximum tether length and altitude; ground-to-air voltage; current and power; permitted voltage drop; data protocol; allowable cable mass per unit length; minimum bend radius; reel geometry; target deployment cycles; tensile load; environmental exposure; and termination method.
Those inputs guide conductor sizing, insulation selection, shielding, cabling geometry, reinforcement and jacket design. The first prototype is not merely a visual sample. It allows the engineering team to test fit, voltage drop, temperature rise, signal integrity, handling and reel behavior.
Findings from the prototype can be incorporated before production tooling, process settings and inspection requirements are finalized. This is especially valuable for emerging UAS platforms, where aircraft weight, payload and power architecture may still be changing. Early feedback reduces the risk that the tether becomes the component that limits altitude, reliability or production readiness.
Why Custom Extrusion Matters
Extrusion converts the internal cable components into a unified, protected product. Precision is critical when the application calls for thin walls, a compact diameter, unusual geometry or a material with a narrow processing window. The jacket must be concentric and consistent without damaging the conductors, shields or reinforcement beneath it.
Custom extrusion can also control surface finish, color, print identification, friction characteristics and environmental protection. For a reel-managed tether, outside diameter and surface behavior directly affect spooling consistency. This makes extrusion a functional part of the tether-management system—not a cosmetic final step.
Pelican Wire’s custom capabilities include extrusion, precision stranding, cabling, bunching, tape wrap, textile serve and metal or textile overbraid. Bringing these processes together under one engineering review helps reduce interfaces and keeps the complete construction aligned with the mission requirements.
An Engineering Partnership From Prototype Through Production
Pelican Wire approaches custom cable as an engineering problem first. The company specializes in fine-gauge alloys and a wide range of insulating materials, with experience in aerospace, military, automotive, medical and other demanding industries.
A customer may arrive with a complete print, a partial cable specification or only the system requirements. In each case, the most useful discussion begins with the performance problem: how much power and data must move through the tether, what the aircraft can lift, how the reel operates, and which environmental and mechanical conditions cannot be avoided.
The objective is not to force the drone platform around a standard cable. It is to develop a manufacturable cable around the platform and then control that construction from practical prototype quantities through repeat production.
Start With Five Questions
Before selecting a tether cable, define five fundamentals:
- What electrical power must reach the aircraft?
2. What data and control signals must return to the ground?
3. What mass and diameter can the aircraft and reel accept?
4. How will the cable bend, spool and carry tension?
5. Where will the system operate?
When those questions are answered early, conductor, shielding, insulation, reinforcement and extrusion decisions can work together. The result is a tether designed to keep the aircraft powered, connected and airborne without becoming the limiting factor in the system.
Talk with Pelican Wire about a custom wire or multi-conductor cable for your tethered drone, UAS subsystem or ground-support equipment.
Article FAQ’s:
What does a tethered drone cable carry?
Depending on the platform, the tether may carry continuous electrical power, command and control signals, telemetry and video or other mission data. It may also include shielding, drain conductors and a tensile strength member.
Why not use a standard cable?
Standard cable often forces compromises in mass, diameter, voltage drop, signal protection, reel compatibility or environmental performance. A custom construction can be optimized around the complete mission profile.
What information is needed to design a drone tether?
Key inputs include power, voltage, current, tether length, data architecture, allowable mass, bend radius, reel geometry, tensile load, environmental exposure and target cycle life.
Can Pelican Wire support prototypes?
Pelican Wire’s engineering-first process can support practical prototype quantities used to validate fit, resistance, temperature rise, handling and reel performance before repeat production.
RELATED LINKS:
Precision Heating Wire for Aircraft & Aerospace Fluid Systems