Aerial spray calibration
Know what your aircraftactually puts on the ground.
Aerial Cal reads your water-sensitive paper cards and turns them into a measured pattern — droplet size, coverage, uniformity, drift risk, and the swath spacing your aircraft really supports. For drone, aeroplane, helicopter and fixed-wing UAV applicators.
Runs in any browser · installs to your home screen · subscription required
The loop
Card, photo, analysis, decision.
Five steps in the field, and a sixth when you want to prove a change. The analysis runs on the phone in your hand — no signal required once the app is loaded.
- 01
Lay the cards
Water-sensitive paper across the swath, perpendicular or parallel to the wind. The app records the layout and which card sat where.
- 02
Fly the pass
Fly it the way you actually spray. Enter aircraft, delivery system, rate, speed, height and the weather at the time.
- 03
Photograph each card
Photograph the cards with a calibrated camera. Analysis runs on the device — full-resolution photos are never uploaded.
- 04
Read the pattern
Deposition profile, CV%, uniformity, droplet spectrum, coverage and drift risk — for the swath you actually flew.
- 05
Act on it
The optimiser shows the swath spacing that matches your pattern, and what the numbers would be if you flew it. Then save, print or share.
- 06Optional
Truth-test the change
Prove it. Fly a second pass with exactly one variable changed and the report puts the two passes side by side — so you know whether the change earned its place.
What a Truth Test shows →
Readouts
Numbers you can put in a file.
Every figure comes with a guide explaining what it means and what it should make you do differently. Estimates, not certainties — you still fly the aircraft.
VMD
Droplet size
Volume median diameter and the full droplet spectrum, read from the stains on the card.
CV%
Pattern uniformity
How evenly the pass laid down across the swath — the number that decides your spacing.
%
Coverage
Percentage of the card covered, per card and across the whole pass.
SWATH
Effective swath
The spacing your measured pattern actually supports, not the one on the spec sheet.
RISK
Drift risk
Rated from your droplet spectrum and the weather you entered at the time of the pass.
RATE
Rate reconciliation
Measured deposit checked against the rate you metered, so you can see when the two disagree.
Built for the field
Designed for sunlight, gloves and no signal.
Built by people who have stood in a field trying to read a phone at midday. Large type, hard contrast, big targets, and analysis that runs on the device rather than waiting on a bar of signal.
- On your device
- Your passes, aircraft, products and card photos stay on the phone. Full-resolution photos are analysed in memory and are never uploaded.
- Camera-calibrated
- A one-time check against a printed reference sheet proves your camera is fit to measure — not just to take a picture.
- Every platform
- Drones, aeroplanes, helicopters and fixed-wing UAVs, each with their own delivery systems and swath ranges.
- Printable reports
- A full report with charts, card photos and the numbers behind them — for your file or your customer's.
Community Library
Contribute to view.
Filter de-identified results from other applicators by aircraft, delivery system and settings. It works because everyone in the pool feeds it — a library of spectators would be worth nothing.
Shared: the agronomic numbers, aircraft make and model, delivery system, settings and the weather you entered. Never shared: your name, operator, aircraft nickname or tail number, products, location and card photographs.
Two gates, neither about money
- 01Sharing is onYou see the pool because you are in it.
- 02Your camera is calibratedSo every number in the pool was measured, not guessed.
Crowd-sourced and unverified by design — a reference point, not a recommendation.
The umbrella
Aerial Cal is the first product from App.Op.
App.Op builds software for agricultural aviation — tools made by people who have stood in the field holding the cards. Aerial Cal is the calibration half of that. More is coming, and it will work the same way: measured, honest about its limits, and usable with gloves on.
For one applicator
Start calibrating
Open Aerial Cal in your browser and add it to your home screen. A subscription is required to use the app — there is no free tier.
For an operation
Licence your pilots
Businesses, universities and research groups are licensed by invoice, with seats you assign by email address and reassign when people change.