How to tune a Betaflight quad by size: whoop to 7 inch

Quad size changes what you tune first, not the method. Small whoops and toothpicks care most about the master multiplier and noise from tiny, fast motors. Cinewhoops are limited by their duct and weight. 5 inch quads are where the Betaflight defaults fit best. 7 inch long range quads run slower props, so filters sit lower, filter delay matters less, and TPA matters more. Whatever the size, a measured flight beats any size rule.

Why does quad size change the tune?

Bigger props are heavier and spin at a lower rpm, so they respond more slowly and make noise at lower frequencies. Smaller props spin fast, respond quickly and put their noise higher up. That shifts three things:

• Gains. How much P, D and feedforward the quad takes before it overshoots.
• Filters. Where the noise sits, and how much filter delay you can afford.
• TPA and D max. How much the quad needs to back off at high throttle, and how much extra D helps in fast moves.

The Betaflight defaults are a compromise. The directions below describe which way public presets for each size usually move from the defaults. They are starting points for thinking, not values to type in.

How do I tune a tiny whoop (65 to 75 mm)?

Whoops have little thrust to spare, so the tune is about response and noise from small, fast motors.

• Master multiplier. Presets for 65 mm whoops sit moderately above default, with damping and P plus I about at default. Pitch gains run a little above roll.
• Dynamic notch. With RPM filtering on, presets at this size drop the dynamic notch to zero or one. Check first that your board’s ESC firmware supports bidirectional DShot.
• Feedforward. Presets disagree at this size: some raise it and some set it to zero. Decide from your own flight.
• Jitter reduction. Presets cut feedforward_jitter_factor well below the default of 7.

Whoop presets vary a lot, so treat these as a rough starting point and let your own flight decide.

What about toothpicks and 2 to 3 inch builds?

These are light and quick, and you can feel a small gain change. For 3 inch, presets point to:

• master multiplier somewhat above default and damping clearly above default, with D max only partly used;
• feedforward near or below default, and I slightly below default;
• a single dynamic notch plus the RPM filter at three harmonics (rpm_filter_harmonics default is 3);
• TPA rate (tpa_rate, default 65) a little above default.

The spread between tunes is wide here, because pilots want different things from the same size. For 2 inch and 2.5 inch there are few public presets, so the flight is the only guide.

How do I tune a cinewhoop?

Cinewhoops are ducted, heavy for their prop size and use slow motors. They are the least like the defaults. Expect these priorities:

1. Noise first. Duct and motor noise reaches the gyro, so get filtering right before pushing gains. See filter tuning.
2. Slow response. Weight and motor speed mean the quad reacts later. Over-aggressive feedforward shows up as overshoot at the end of each move.
3. Clean stops. A heavy ducted quad shows overshoot at the end of each move first, so get the stops clean before chasing a faster rise.

Fix mechanical causes first: loose camera mounts, a duct touching a prop, or bent props produce noise that no tune can remove.

How do I tune a 5 inch freestyle or race quad?

This is the size the defaults were built around, so changes are smaller and more about how you like it to feel.

Freestyle. Freestyle presets raise the master multiplier and P plus I moderately above default, keep damping near default, and switch the D max slider off. Feedforward goes up. Gyro and D-term filters sit slightly looser than default. Tunes use two to three dynamic notches, a lowered yaw lowpass and anti-gravity slightly above default.

Race. Race presets keep the master multiplier at default, lower P plus I and damping, and raise I. Feedforward sits modestly above default and I-term relax cutoff is raised a lot. Jitter reduction goes down and feedforward smoothing goes up for fast links. TPA kicks in earlier and filters stay near default.

Race tunes vary a lot with the pilot, so treat the gap between freestyle and race as a direction, not a rule. See feedforward, I-term and TPA for the throttle side.

How do I tune a 7 inch long range quad?

Big props at low rpm mean noise sits at lower frequencies and the motors respond slowly.

• Filter frequencies lower. Noise bands are lower, so lowpass and notch settings sit lower than on a 5 inch. The RPM filter’s minimum frequency (rpm_filter_min_hz, default 100) is worth checking against your lowest motor speed.
• More filter delay tolerated. Big props already respond slowly, so heavier filtering costs less than on a 5 inch.
• TPA matters. At high throttle, big props can pick up oscillation, so check tpa_rate and tpa_breakpoint (defaults 65 and 1350).
• Gains. Presets for 7 inch put the master multiplier above default and feedforward higher, with damping about default to slightly higher, and I slightly lower.
• Feedforward jitter and smoothing. Presets raise jitter reduction well above default and lower smoothing.

The 7 inch presets all assume the RPM filter is on.

Does a size rule beat my own flight?

No. Two 5 inch quads with different motors, props, frame stiffness and battery can need different tunes. A size row tells you the likely direction. The measured flight tells you where your quad actually sits: overshoot, propwash, motor temperature and noise. When the two disagree, follow the flight, in small steps, and check motor temperature after each change.

How FPV PID Tune handles it

FPV PID Tune uses a reference tune for your quad’s size only as direction, never as the answer. Values come from the measured test flight, inside fixed safety limits and small steps per round. A full tune is 4 rounds, one battery each, and the app says “Tuned” after the fourth. See how it works and the slider guide.