Airframes

Four aircraft classes cover all 19 capabilities. Most farms and most operators need two of them.

Class B is the one to build or buy first. It carries every survey payload in the catalog.

Buy or build

The honest recommendation: buy the first one, build the second. A DJI Mavic 3 Multispectral or Matrice-class aircraft gets you flying paid work almost immediately and comes with a class marking that simplifies the Open category case. Build when a payload you need is not sold on a turnkey aircraft, which in practice means radiometric thermal at a sane price, high resolution global-shutter RGB, or anything that has to sit on a dock you designed.

There is also a strategic argument for building: procurement rules in several markets have been tightening around Chinese-manufactured aircraft for public sector work. If you expect to fly for municipalities, forestry authorities or publicly funded restoration, an aircraft you assembled from open hardware is easier to defend.

Class B parts list

A 5 to 7 kg quadcopter with 30 to 40 minutes endurance and a 2 kg payload.

Roughly €2,200 to €4,500 before the sensor. Add the sensor and the positioning service.

The frequency mistake, which is easy and expensive

Radio hardware sold as standard on drone parts sites is frequently US-band.

• Telemetry: 900 MHz modules (RFD900x) are not legal in the EU. Buy the 868 MHz variant (RFD868x).
• RC link: 915 MHz ExpressLRS is US; the EU uses 868 MHz, with duty cycle limits.
• Video: the 5.8 GHz allocations differ by country and several channels used in FPV are not permitted for general use.

Check the band, then check the power limit, before ordering. This is the single most common compliance failure on a self-built aircraft.

Endurance, honestly

Manufacturer figures are hover time at 20 °C with no payload and no wind. Plan against two thirds of the advertised number, and hold 20% battery reserve or you will eventually pay for an aircraft with a shortcut.

Fixed wing and VTOL

For field mapping over very large areas, a fixed wing or VTOL covers several times the hectares per battery. It also cannot hover, cannot fly at 15 m for weed detection, and needs more space to launch and recover.

Worth it above roughly 300 hectares of contiguous mapping per outing, which in practice means cooperatives and restoration sites. Below that, a multirotor is more flexible and far cheaper to own.

Maintenance, which decides your real cost per hectare

Keep a per-airframe log with total hours, cycles per battery and every part change. It is what turns "the drone cost €4,000" into a defensible cost per hectare, and it is what an insurer or an authority will ask for.