FIELD DEPLOYMENT REPORT  |  INDUSTRIAL GRAIN FACILITY CLEANING

Removing Human Risk from Grain Silo Maintenance:
SF-91X-100M Tethered UAV at Lianyungang Yihai Liangtian

On-site deployment at Yihai Liangtian — SF-91X-100M operating on the grain storage building exterior, March 2025.

Deployment Context: The Grain Industry’s Altitude Problem

Grain storage facilities present a specific set of maintenance challenges that differ from urban high-rise cleaning. Structures are often located in semi-industrial zones with limited service vehicle access, facades are tall and repetitive, and cleaning cycles are driven by regulatory hygiene requirements rather than aesthetic standards. Rope-suspended cleaning crews — the conventional solution — must be sourced, insured, and safety-certified, creating scheduling friction and significant per-square-meter cost.

At Lianyungang Yihai Liangtian, the facility operates grain storage buildings whose facades require periodic exterior cleaning to meet hygiene and structural maintenance standards. On March 10, 2025, Kitefly Tethered completed a full deployment of the SF-91X-100M tethered drone cleaning system at the site — the first aerial tethered cleaning operation at the facility.

The deployment objective was to demonstrate continuous 24/7 aerial cleaning capability while eliminating all personnel from working at height. Both objectives were achieved in the field operation.

Equipment Selection: What the SF-91X-100M Brings to This Application

The SF-91X-100M is a fully integrated tethered cleaning system comprising three major subsystems: a heavy-lift hexacopter airframe, a ground power station with high-voltage tether, and an airborne power conversion module. These three components together replace the traditional combination of scaffolding, rope crew, and pressure cleaning equipment — while operating continuously without battery-swap interruptions.

AF-J30 — Heavy-Lift Hexacopter Platform

AF-J30 heavy-lift hexacopter: maximum takeoff weight 65 kg, 30 kg effective payload, carbon fiber and aerospace aluminum construction.

The AF-J30 provides the airframe backbone of the system. Its 65 kg maximum takeoff weight and 30 kg effective payload capacity give it the margin to carry high-pressure water jetting tools without compromising flight stability. RTK-assisted positioning (4G version) delivers centimeter-level hover accuracy across large facade spans — critical for maintaining consistent nozzle-to-surface distance during cleaning passes.

AF-G30 — Ground Power Station with Tether Winch

AF-G30 tethered ground power station: 16 kW output, 120 m high-voltage tether, Kevlar-reinforced cable with 50 kg tensile strength.

The AF-G30 is the energy source that enables the SF-91X-100M’s unlimited flight endurance. It accepts 380V AC from the grid and outputs 1,000V DC via a 120-meter tether cable to the aircraft. An automatic winch manages cable tension throughout the flight profile; the Kevlar-reinforced cable is rated at 50 kg tensile strength, providing both electrical and mechanical tether security. The complete system (including cable) weighs 41.5 ± 1 kg.

WF-12K — Airborne Power Conversion Module

WF-12K airborne module: 239 × 204 × 139 mm, 3.21 ± 0.5 kg — converts 800–1,000V DC tether input to 59V / 200A propulsion power.

Mounted aboard the AF-J30, the WF-12K steps down incoming high-voltage tether power (800–1,000V DC) to the 59V / 200A supply required by the aircraft propulsion and cleaning payload systems. At 3.21 ± 0.5 kg and 239 × 204 × 139 mm, its size and mass are designed to minimise impact on the drone’s effective payload budget. Standardised XT90 input and XT150 output connectors ensure broad compatibility.

Operational Comparison: Tethered Drone vs. Conventional Cleaning Methods

The following comparison reflects the key differences that drove the selection decision for the Yihai Liangtian deployment. The data points are representative of field conditions rather than manufacturer-stated values where indicated.

Field results at Lianyungang Yihai Liangtian — facade cleaning completed March 2025, zero safety incidents recorded.

What the Yihai Liangtian Deployment Confirms

Kitefly Tethered has been developing industrial tethered UAV systems since 2013. The March 2025 deployment at Yihai Liangtian adds a grain storage facility to a growing list of validated application environments that includes transportation hubs, construction sites, commercial towers, and industrial plants.

Three operational findings from this deployment are worth documenting for reference:

• Cable management in open industrial yards: The AF-G30’s automatic winch maintained consistent tether tension throughout vertical and lateral flight profiles across the grain building facade — no manual cable management was required.
• Continuous endurance under sustained cleaning load: The WF-12K held stable 12 kW output to propulsion and cleaning systems without thermal interruption across the full test duration.
• Zero personnel at height: The entire operation was conducted by a ground-based operator team. No working-at-height certification, fall arrest equipment, or height permits were required for the cleaning phase of the project.

For operators evaluating tethered aerial cleaning for grain facilities, food processing plants, and other industrial structures where hygiene maintenance cycles are regulatory rather than cosmetic, the SF-91X-100M provides a validated entry point.

Additional Application Environments for the SF-91X-100M

• Grain storage depots and agricultural processing facilities
• Power generation infrastructure — cooling towers, turbine housings
• Port and logistics terminal warehousing
• Chemical plant and refinery exterior maintenance
• Stadium and arena exterior glass and cladding
• Bridge deck and structural surface maintenance

Enquiries and Technical Consultation

For project scoping, system configuration guidance, or export documentation, contact Kitefly Tethered directly.