Tuning guide

Why does my quad dip in fast turns?

Q: Why does my quad only dip in fast turns?

A fast turn combines several demands at once: high throttle, a sustained yaw input, a large pitch or roll command, and often a voltage sag. It is the condition where the motors are closest to their limit and where I-term relax is most active. A quad that holds attitude in a hover can still run out of authority here, so the turn exposes the limit rather than creating it.

Q: Is yaw washout a PID problem?

Not entirely. Yaw authority comes from motor inertia rather than differential thrust, so small, light or heavily loaded quads can run out of yaw authority before roll or pitch does. Prop direction, motor health, battery voltage and weight all change it. A yaw gain alone may not fix a build that does not have enough yaw control to begin with.

Q: Can I-term relax cause a dip in a turn?

Yes. Relax holds I down during fast setpoint changes. In a long, sustained turn that can mean the integrator is not helping to hold the attitude, so the quad sags. The log sign is a response that settles below the commanded rate while the stick is still held, especially if the dip disappears when the turn is slower or shorter.

Q: How do I log a turn properly?

Fly a sustained banked turn in each direction at a similar throttle, then a straight reference pass. Keep the sticks smooth enough that the setpoint is a command rather than a series of spikes. Repeat a few times and note the wind. One dramatic turn is not enough to separate a tune fault from a gust or a battery that was already sagging.

A dip in a turn can come from the yaw axis, the pitch axis, the motors, the battery, or the air. They feel similar from the goggles and need different fixes. The log shows which one is actually losing.

1. A turn is several tests at once

In a fast banked turn the quad is holding a high throttle, a sustained yaw input, a pitch or roll attitude, and often a voltage sag. It is the point where the motors are closest to their limit and where I-term relax is most active. A quad that holds attitude in a hover can still run out of authority here, so the turn exposes a limit rather than creating one.

"It dips" is not enough to choose a fix. Ask which axis lost: did the nose drop (pitch), did the quad yaw or wash out (yaw), did it lose altitude while staying level (thrust), or did it shake through the turn (propwash)? The answer changes the family of settings entirely.

2. Five causes, five log signatures

Cause	What you feel	What the log shows
Yaw washout	The quad yaws or skids through the turn instead of holding the line	Yaw gyro lags or overshoots the yaw setpoint while roll and pitch track. Motors may be near their limit. Common on low-authority builds and small whoops.
Pitch droop	The nose falls in the turn; the quad loses the attitude you asked for	Pitch gyro settles below the commanded rate while the stick is still held. You may also see the integrator being held down by relax.
Motor saturation	It feels like the quad has no authority left; more stick does little	Motor outputs are pinned near maximum, often on a diagonal pair. The controller is asking for more than the motors can give.
Voltage sag	The dip gets worse as the pack drains or at the end of a punch	Battery voltage falls under load beyond what the cell count should allow. The tune cannot outperform the pack.
Propwash / disturbed air	A shake or bounce through the turn, worse when descending into your own wake	A burst of oscillation that starts with the disturbed air and decays. It is not a steady tracking error.

Two or more can be true at once. A heavy quad at low voltage can be saturated and sagging in the same turn, and no gain change fixes either.

3. Why the yaw axis is different

Roll and pitch are controlled mostly by differential thrust. Yaw is controlled by the reaction torque of the spinning motors, so it depends on motor inertia and has less authority to spare. Small, light or heavily loaded quads can run out of yaw control before they run out of roll or pitch. That is why yaw washout shows up in turns and power loops, and why adding roll/pitch gain does not necessarily help it.

Motor direction and propeller orientation also change how the wake behaves in a hard corner. The community has argued about "props in" versus "props out" for years; the useful point is that it is a build choice with a real aerodynamic effect, not a universal PID fix. Change it deliberately, then compare logs.

Do not tune a turn from one turn. Wind, a battery that was already sagging, a mid-air bump or a single aggressive input can all look like a tune fault. Repeat the turn in both directions, at a similar throttle, and compare.

4. Reading the turn in the log

Find the sustained part of the turn. Ignore the entry spike and the exit. The sustained section is where droop and authority problems show.
Look at each axis against its setpoint. Yaw error with roll/pitch tracking points at yaw authority. Pitch error with yaw tracking points at pitch droop. Both axes losing together points at thrust or saturation.
Check the motors. If they are pinned at maximum, the controller has no headroom. A gain change cannot create thrust.
Check the battery. A sagging pack makes every authority problem worse and can make a good tune look bad.
Check the I-term and relax behaviour. If the dip appears only in long, fast turns, relax may be holding I down for too long for the build.

5. What to change, by cause

Yaw washout: inspect motor health and prop direction, confirm the build has enough yaw authority, and only then look at yaw tuning. A yaw gain cannot fix a quad that is physically short of control authority.
Pitch droop: the integrator and relax. The question is whether I is too low or is being suppressed too long. Those are different fixes and the log distinguishes them.
Saturation: reduce the demand — weight, prop size, battery health, throttle management — or accept that the corner is outside the build's envelope. Do not raise gains to ask for more than the motors can deliver.
Voltage sag: pack condition, connector, capacitor and cell count. The log can show the sag; it cannot tune around a tired battery.
Propwash: mechanical cleanliness first, then damping and filtering. See the frame-versus-prop guide.

6. What Easyquadtune measures in a turn

The analyser reads the step response per axis, including the steady-state plateau, so a pitch response that settles below the command is reported as droop rather than overshoot. It checks motor output for saturation and battery voltage for sag, because both cap what a tune can honestly promise. It also records when a log is angle-dominant or has no clean yaw step, and it does not pretend to have measured yaw when the log did not contain a yaw test.

That matters for a turn-specific problem: a log full of banked turns may contain no isolated yaw step at all. The honest output is "yaw not measured", not a yaw gain pulled from noise.

Questions pilots actually ask

Why does my quad only dip in fast turns?

Because a fast turn combines high throttle, sustained yaw, a large attitude command and often voltage sag. It is where the build is closest to its limit, and where relax is most active.

Is yaw washout a PID problem?

Not entirely. Yaw authority comes from motor inertia, so small or heavy builds can run out of it. Prop direction, motor health, voltage and weight all matter.

Can I-term relax cause a dip in a turn?

Yes. If it holds I down through a long turn, the quad can sag. The log sign is a response below the command while the stick is still held.

How do I log a turn properly?

Fly sustained banked turns in both directions at a similar throttle, plus a straight reference. Repeat, note the wind, and do not judge from one dramatic turn.

Where these questions come from

r/Multicopter: BetaFPV Meteor 65 dipping — the exact "dips on aggressive turns, is it the tune?" question, with yaw washout and prop-direction answers.
r/fpv: Undesired yaw — a pilot tracing a post-powerloop yaw spin to washout.
r/fpvracing: Does my QX95s need PID tuning? — yaw authority, motor condition and prop direction as competing explanations.
Oscar Liang: FPV drone tuning — anti-gravity and I-term relax in the context of throttle changes and turns.
Betaflight 4.3 Tuning Notes — wobble at the end of fast moves, dynamic idle and low-authority behaviour.
Betaflight PID Tuning Tab — the official descriptions of tracking, damping and I-term relax.

Find out which axis is losing in your turn

Easyquadtune reports roll, pitch and yaw separately, flags motor saturation and voltage sag, and does not invent a yaw measurement when the log has no yaw step. First log is free per browser.

Analyse your log Or watch it work on a demo flight first

More guides: how to read a blackbox log, wobble on hard stops, overshoot vs droop, frame resonance vs prop noise, I-term relax, when a log is not good enough.

Easyquadtune is not affiliated with the Betaflight project. Always fly responsibly and perform an initial hover test in a safe environment after any tuning change. The worked example on this site is an illustrative render, not a customer log.