Profiles¶
The Profiles tab manages PID tuning profiles -- the actual stabilization gains that control how tightly the flight controller holds your commanded attitude.
Multiple profiles can be configured and switched between in flight (via an Auxiliary mode mapping), which is useful for having distinct tunes for, e.g., calm cruising versus aggressive 3D/aerobatic flight on the same airframe.
PID Gains¶
The PID Gains table holds the actual per-axis P, I, D, F (Feedforward), and B (Boost) terms -- the static tune itself, as distinct from Master Gain below, which scales it live rather than editing it directly.
Most people tune by feel in the air, not by reasoning about control theory, so here's what each one is actually doing to the way the plane flies rather than a textbook definition:
- P is how locked-in the plane feels to your stick and to gusts. Too little and it's floppy/mushy -- slow to respond, wanders off your line. Too much and it gets nervous: a fast buzz or bounce-back right after a sharp input.
- I is what holds a turn, a knife-edge, or a heading exactly, rather than approximately. Too little and it slowly bleeds off the line in wind or if the CG's slightly off. Too much and it wallows -- a slow wandering oscillation, or the plane keeps rotating a beat after you've already centered the stick.
- D is the shock absorber: it stops P's correction from overshooting and soaks up a gust before it upsets the plane. Too little and inputs overshoot, and gusts knock the plane around more than they should. Too much and servos start to growl, buzz, or run hot -- D is by far the most noise-sensitive term, so if you're chasing heat/buzzing here, check Gyro filtering first.
- F is what makes stick input feel instant instead of rubbery -- it pushes toward where you're asking the plane to go the moment you move the stick, rather than waiting for it to fall behind first. Too little feels delayed, and the plane keeps rotating briefly after you let go of the stick. Too much snaps past where you wanted and kicks back ("strikeback") as the stick returns to center.
- B is a finishing touch on top of F, reacting to how fast you move the stick rather than how far. Too little and quick flicks feel soft/rounded; too much and quick flicks get twitchy, sharing D's noise sensitivity.
Quick troubleshooting¶
| What you're seeing in the air | Try |
|---|---|
| Floaty/mushy, wanders off your line | Raise P |
| Bounces or buzzes right after a sharp stick input | Lower P (or raise D) |
| Overshoots a gust or fast input before settling | Raise D |
| Servos growl, buzz, or run hot | Lower D, check Gyro filtering |
| Stick input feels laggy or rubbery | Raise F |
| Keeps drifting/rotating a moment after you center the stick | Lower I; if it's only on quick inputs, raise F instead |
| Snaps past the input and kicks back as you release the stick | Lower F |
| Quick flicks feel twitchy/nervous | Lower B |
| Quick flicks feel soft, no snap | Raise B |
Master Gain and its curve (below) scale P, I, and D together as one percentage -- F (Feedforward) and Boost are tuned independently per-axis and aren't affected by Master Gain.
Why these defaults¶
Out of the box:
| P | I | D | F | B | |
|---|---|---|---|---|---|
| Roll | 50 | 16 | 0 | 100 | 0 |
| Pitch | 50 | 16 | 0 | 100 | 0 |
| Yaw | 80 | 20 | 0 | 100 | 0 |
The standout choice is D = 0 on every axis. A fixed-wing control surface doesn't live in a particularly noisy, high-vibration environment, so the default tune leans on Feedforward (already set to a meaningful F = 100 out of the box) for a responsive, instant-feeling stick rather than D-driven damping. Add D deliberately if a specific airframe overshoots or wallows in gusts -- and check Gyro filtering first, since D is the term most likely to expose noise once it's non-zero.
I is also deliberately kept low relative to P (16-20 vs. 50-80) -- don't read that gap as I being "weak." I isn't left to accumulate freely the way a raw integrator would: I-Term Decay Time (6s by default) continuously bleeds accumulated I-term error back off, capped by an I-Term Decay Max Rate (35°/s), and I-Term Relax (level 22, cutoff 10Hz by default) specifically suppresses I buildup while the stick is moving quickly, to avoid bounce-back at the end of a roll or other fast maneuver. Because something else is actively managing decay, a small I gain is enough to hold a steady bias (wind, a CG offset) -- pushing I up to "match" P instead just reintroduces the slow wallowing oscillation the decay/relax defaults are there to avoid.
Yaw runs a bit hotter than Roll/Pitch (P 80 vs. 50, I 20 vs. 16) since rudder authority and yaw stability vary more from airframe to airframe than aileron/elevator response typically does.
Boost defaults to 0 -- it's a finishing touch layered on an already-working Feedforward tune, not something you'd want fighting an airframe that hasn't been flown and trimmed yet.
Master Gain defaults to 100% (no scaling) with no curve assigned on every axis, and Throttle (TPA) likewise defaults to 100% with no curve -- so the PID Gains table above is exactly what flies until you deliberately assign a curve or an Adjustments knob.
Master Gain¶
Master Gain sets one overall gain per axis (Roll, Pitch, Yaw) that scales the P, I, and D terms of that axis's PID loop -- F (Feedforward) and Boost stay at their static configured values -- each with its own optional gain curve so the scaling can vary with stick position rather than applying a single flat multiplier. In expert mode a fourth row, Throttle (TPA), attenuates gains across the throttle range using the same shared gain-curve pool.
Any of these gains can also be mapped to a transmitter switch/knob from the Adjustments tab for live in-flight tuning -- when a gain is under live adjustment control, its row shows the current effective value being commanded in place of the static configured number.