Reading a drone spec sheet — which numbers mean something and which are just marketing

Drone sales brochures are usually full of numbers. This article helps you sort out which ones are really worth looking at.

Maximum take-off weight (MTOW)

This tells you the total weight the aircraft can carry. It matters because it is the real limit of the structure, not a number to fly right up against every day. Flying at full capacity all the time wears out the motors and batteries quickly.

Flight time per battery

The advertised figure is often for flying empty with no spray. The figure to ask for is "how many minutes can it fly with a full tank", which is much shorter, and is the number that sets the real pace of work.

Nozzle flow rate

This tells you how many litres per minute it can spray. It is used together with flight speed to work out the volume per rai. If the seller cannot give you this number, be careful, because it is the most basic number in spraying work.

Spray swath width

This tells you how wide one pass covers. This number must come with conditions, such as at what height, because the swath gets wider when flying higher, but droplets also drift more.

Obstacle avoidance and terrain-following radar

Really useful in fields with power poles, trees or steep slopes, but ask what conditions it works in. Some radar types do not work well with tall crops or in fog.

Numbers that are more marketing than use

A maximum signal range of several kilometres: in real spraying work we always fly within visual line of sight as required by law, so this number is hardly used. The same goes for top speed, because spraying needs a speed that matches the flow rate, not the fastest the aircraft can go.

What is not in the spec sheet but matters more than half of it Can you get parts, and at what price? Where is the service centre, and how many days do repairs take? Is there someone to teach you how to use it? A drone with great specs that waits three weeks for parts in spraying season is a drone that cannot earn you money.

Ask the seller about both parts fully, then compare using the same set of information.