Configuration clarity: The source material combines a 40 kW maximum SG50 ground power unit with an airborne WF36 configuration rated up to 42 kW peak. This rewritten page keeps those ratings separate instead of presenting “42 kW ground power” as one number.
Why Continuous High Power Matters in Emergency UAV Operations
Firefighting and emergency-response aircraft can be asked to hover over the same incident for long periods while carrying heavier payloads than a normal inspection drone. A tethered architecture changes the energy model: grid or generator power stays on the ground, is converted to high-voltage DC for efficient cable transmission, then stepped down onboard to the aircraft bus voltage.
For a DJI FC300-class platform, this architecture can support three broad mission families: persistent observation/communications, heavy-load support, and aerial suppression tools. The actual payload, altitude and endurance remain dependent on the aircraft configuration, tether length, environmental conditions, power source and applicable operating rules.
Mission Roles Supported by the Architecture
| Mission role | How tethered power helps |
|---|---|
| Persistent incident observation | Maintains an elevated EO/IR, illumination or communications position without routine battery-change cycles. |
| Heavy-lift support | Provides continuous aircraft power while payload margin is used for emergency supplies, tools or mission equipment. |
| High-rise suppression support | Can be integrated with a separately engineered water/agent delivery path for elevated application of water-based or foam agents. |
| Wildland / perimeter monitoring | Supports long-duration overhead observation of evolving fire lines, access routes and hot spots. |
| Hazardous-area observation | Keeps operators farther from the immediate scene while maintaining a stable aerial viewpoint. |
Reference Power Architecture
SG50 Ground Power Unit
| Parameter | Source Reference |
|---|---|
| Input voltage | 380 V AC |
| High-voltage output | 1,000 V DC / 1,400 V DC |
| Maximum output power | 40 kW MAX |
| Tether length | 150-220 m |
| Power supply box weight | 49.3 kg ± 1 kg |
| Cable box weight | 32.9 kg ± 1 kg |
| Power supply box dimensions | 498 × 472 × 440 mm |
| Cable box dimensions | 498 × 471 × 440 mm |
Separating the power electronics from the cable-management box helps distribute weight and makes high-power field handling more practical than forcing the complete system into one enclosure.
Reference high-voltage tether reel and cable-management hardware.
Airborne Conversion Options
Reference airborne power-module family for heavy-lift UAV integration.
| Module | Input | Output | Peak Power | Weight | Dimensions |
|---|---|---|---|---|---|
| VF24 regulated series | 800-1,000 V DC | 50 / 60 / 73 / 100 V DC (source maps to multiple battery-equivalent buses) | 24 kW MAX | 9 kg ± 100 g | 370 × 223 × 127 mm |
| WF36 high-power series | 1,200-1,400 V DC | 40-60 V DC in the source configuration | 42 kW MAX | 11 kg ± 100 g | 326 × 280 × 143 mm |
Output voltage must be matched to the actual propulsion bus and aircraft integration. The table is a reference from the supplied solution; it is not a universal plug-and-play claim for every FC300 configuration.
Engineering sketch used during high-power configuration work.
System-Level Engineering Checks Before Deployment
Ground source capacity - confirm grid or generator rating, starting behavior, grounding and site distribution for the requested continuous load.
Tether voltage and cable length - transmission voltage, conductor size, cable mass and voltage drop must be solved together.
Airborne thermal margin - high continuous power requires cooling capacity at the expected ambient temperature and altitude.
Aircraft payload budget - the airborne converter, cable force, mission payload, hose or delivery equipment and mounts all consume payload margin.
Water/agent delivery - if suppression fluid is required, the hydraulic circuit is a separate engineering problem with its own hose weight, pressure loss and pump sizing.
Emergency behavior - define power-loss response, landing logic, tether management and ground emergency shutoff before field use.
Regulatory envelope - operating height, payload, firefighting substances and flight authorization must be checked for the actual jurisdiction and mission.
Reference electrical distribution cabinet used in a high-power ground-side setup.
Typical Deployment Concepts
| Scenario | Possible tethered role |
|---|---|
| Urban high-rise incident | Persistent thermal/visual observation; communications relay; integration with an engineered aerial suppression payload. |
| Wildland-urban interface | Long-duration overwatch of fire perimeter, access routes and hotspots. |
| Chemical or industrial emergency | Remote elevated observation and thermal monitoring while keeping crew farther from the immediate hazard. |
| Emergency logistics | Heavy-lift support for selected supplies or equipment where the aircraft and tether configuration retain adequate payload margin. |
| Night incident command | Persistent aerial camera/illumination node above a defined response area. |
Frequently Asked Questions
Is this a 40 kW or a 42 kW system?
The source architecture uses an SG50 ground unit specified at 40 kW maximum output. A WF36 airborne module is listed at up to 42 kW peak. Those are different points in the power chain and should not be described as the same rating.
Does tethered power mean the drone can fly 24/7 without stopping?
It removes routine battery endurance as the primary limitation, but aircraft inspection, motors, bearings, cooling, weather, tether handling and mission procedures still set operational limits. Continuous electrical supply does not equal maintenance-free continuous flight.
Can the tether also carry firefighting water?
Electrical power and water can be integrated into the same mission architecture, but the water hose is a separate hydraulic path that must be sized for pressure loss, flow, weight and working height.
Can the system support communications relay or EO/IR monitoring instead of suppression?
Yes. Persistent observation, communications and illumination are natural tethered roles because they benefit directly from long-duration hover.
What information is needed to configure a heavy-lift system?
Aircraft bus voltage, real and peak power, MTOW/payload budget, working height, site altitude/temperature, desired mission payload, ground power source and any water/data-tether requirements.
Talk to TethPower About Your Configuration
For a DJI FC300-class project, start with the aircraft bus voltage, continuous/peak power, target tether length, mission payload and available 380 V AC or generator source. TethPower can then size the ground, cable and airborne conversion chain around the mission.