FPV — Tuning and flying

#fpv/tune · Note 6 of 7 · part of Drones

First: do not tune

Modern Betaflight defaults fly well on almost any sane 5" build. If the quad feels bad, the cause is nearly always mechanical:

• A bent prop or a bent motor bell
• A loose motor screw
• A cracked arm
• A soft-mount that has hardened or torn
• A battery sagging under load

Check all of those before you touch a PID. Most "tuning problems" are a £2 prop.

When tuning is actually warranted

When the quad is mechanically sound and you can reliably fly the drills from FPV — Simulators, and then something specific is wrong:

• Oscillation on hard throttle — usually a filter or motor-noise problem
• Propwash on descents — the classic D-term and dynamic-idle territory
• Bounce-back after a fast flip — D too low relative to P

Blackbox is the only honest feedback

Guessing is slow. Log a flight and look at it:

1. Enable blackbox logging to onboard flash or an SD card.
2. Fly a set piece: hover, a few hard throttle punches, a couple of flips, a descent to trigger propwash.
3. Pull the log and open it in PID Toolbox or the Betaflight Blackbox Explorer.
4. Look at gyro noise spectra first, then step response.

Noise → filters and mechanics. Step response → PIDs. In that order, always: PIDs tuned on top of a noisy craft are a tune for that noise.

Filters and the cost of them

Every filter adds latency, and latency is what makes a quad feel disconnected. The whole game is removing the least filtering you can get away with. If you have low noise — good motors, balanced props, soft mounts — you can lower filtering and the quad gets sharper. If you have noise, filtering is the only thing keeping the motors from cooking.

Rates

Rates are personal and not a performance setting — there is no "fast" rate. Start around 600–700°/s max, keep the same numbers in your sim, and change them slowly. Changing rates resets your muscle memory, so do it rarely.

Flying: the progression

Same as the sim, then extended:

1. Hover, one spot, sixty seconds
2. Figure-of-eight, both directions
3. Orbits at constant radius
4. Dives with a smooth arrest
5. Power loops
6. Split-S, Immelmann, and then linking them into a run

The thing that separates people who look good from people who look frantic is throttle smoothness, not trick vocabulary.

Keep a log

Every flight that taught you something is worth a line: pack, conditions, what broke, what you changed. That log is the single most useful note in this whole vault after a year — see FPV — Claude Code in the loop for keeping it without it becoming a chore.

← Previous: FPV — The first build · → Next: FPV — Claude Code in the loop · Series: Drones