How tethered drone cleaning works, step by step
A cleaning drone is not a flying pressure washer. It is a tethered aircraft fed with power and purified water from the ground, flown by a pilot who never leaves the pavement. Here is what happens on a job, from the van to the dry glass.
Short answer: a ground unit in the van produces heated purified water and supplies power through a tether to a drone under 25 kg. The drone hovers a few metres from the façade and sprays at low pressure, then rinses. The pilot and ground crew stay inside a closed perimeter on the ground. The glass dries without streaks because purified water leaves no minerals. Cleaning rate: 500 to 800 m² per hour depending on dirt and protocol.
- Site survey. We check the façade materials, the height, where the van and ground unit can stand, the tether path, the perimeter, and the permits the site needs. Nothing is flown before this.
- Water production. The van carries a reverse-osmosis unit and a heater. Tap water goes in; purified, heated water comes out. No detergent is used on glass.
- Perimeter and briefing. Cones, tape and a ground operator close the area under the flight path. The building manager is told which entrances are affected and when.
- Tethered flight. The drone takes off from a pad, linked to the ground unit by a tether that carries power and water. It cannot fly beyond the tether, and it can stay up as long as the job needs.
- Spray and rinse. The pilot works the façade panel by panel, a few metres away, spraying at low pressure so that no glass or seal is stressed. A rinse pass leaves the surface to dry streak-free.
- Check and report. The ground operator checks the result from the ground and with the drone camera. The client receives photos before and after.
What the drone can and cannot do
It is excellent on large, tall, flat or gently curved surfaces: curtain walls, cladding, glass roofs, metal roofs, solar arrays. It is a poor choice for small or very detailed façades, deep balconies, and anywhere without a safe ground area below. For those, we use a 17 m water-fed pole or a 40 m aerial platform, and we say so in the quote.
Safety in one paragraph
The tether is the first safety device: the drone cannot fly away. The second is the perimeter: nobody stands under the flight path. The third is the crew: a pilot and at least one ground operator, both trained, with a written flight protocol and the permits for the site. In France we work under prefectoral authorisations in central Paris; in Thailand we will work under CAAT rules and NBTC registration, with the same discipline.
See it
Questions about the method
What is a tethered drone?
A drone linked to a ground station by a cable that carries electrical power and, for cleaning, a water hose. It can fly for hours and cannot leave its tether radius.
Why purified (osmosed) water?
Tap water leaves minerals that dry as white marks. Purified water carries none, so the glass dries clean without wiping and without detergent.
How close does the drone fly to the façade?
Usually two to four metres, depending on the jet and the wind. The pilot adjusts the distance panel by panel.
What happens if the wind picks up?
Above the wind limit set in the flight protocol, the drone lands and the job waits. That is in every quote.
Investors, property groups and corporates
We present the Thai launch plan and the figures in a direct meeting, under NDA. Building owners can also apply for a documented pilot job.