An 85mm whoop with the same PID tune as a 65mm flies like it’s drunk — wallowy on pitch, oscillating on roll recovery, overshooting every gap. Whoop tuning is a different animal from 5-inch tuning. The physics scale down but the problems don’t: propwash on a 19g whoop kills lap times just as surely as on a 600g freestyle rig, and the fixes are completely different.
Whoop Tuning: PID Profiles by Size Class
After tuning over 30 whoop builds across all three size classes, here’s what I’ve found actually works. These are starting points — every build differs, but these numbers get you 90% of the way there before fine-tuning.
65mm Whoops (31mm Props, ~19-25g AUW)
The lightest class. Inertia is so low that the quad responds to PID corrections almost instantly. This means lower P gains than you’d expect — the quad doesn’t need aggressive correction because it responds immediately to small inputs.
PID Profile — 65mm (Betaflight 4.5, Bluejay 48kHz ESC):
- P (Roll/Pitch): 45/47. If you see oscillations in forward flight, drop P on pitch first — 65mm frames tend to be pitch-resonant around 180-210Hz.
- I (Roll/Pitch): 70/75. Higher I than a 5-inch because tiny whoops drift noticeably with low I-term windup. Without enough I, the quad won’t hold angle through an entire indoor lap.
- D (Roll/Pitch): 35/38. D below 30 creates propwash bounce on snap roll stops. D above 42 makes the motors run hot on 31mm props.
- Feed Forward: 80 transition, 0.5 gain. Too much feed forward on a 65mm creates overshoot — the quad is light enough that stick input alone moves it fast.
- TPA: 0.15 starting at 1300. Most 65mm racing happens between 30-60% throttle — TPA doesn’t kick in much, which is fine.
- D Min: Off for 65mm. The default D is already low enough that D Min isn’t needed.
Motor Output Limit: Set to 80% for 0802 25000KV motors on 1S. These tiny motors overheat fast at 100% output with aggressive D gains. The 80% limit costs you about 0.3 seconds per lap but saves motors and keeps voltage sag manageable.
Rates: Actual rate 800 deg/s on roll and pitch, 700 on yaw. RC Rate 1.0, Super Rate 0.72, Expo 0.2. You need fast roll for tight indoor gates but yaw authority is naturally limited on a ducted 65mm — 700 deg/s is about the mechanical max before you’re fighting the ducts.
75mm Whoops (40mm Props, ~28-38g AUW)
The sweet spot for indoor racing. Enough mass for stability, light enough for tight gaps. This is where whoop tuning gets interesting — the ducts are generating real aerodynamic effects now.
PID Profile — 75mm (Betaflight 4.5, Bluejay 48kHz ESC):
- P (Roll/Pitch): 52/55. Higher than 65mm because the extra weight needs more correction authority to arrest momentum. 75mm frames with 40mm props can oscillate at 165-185Hz on pitch.
- I (Roll/Pitch): 80/85. The extra mass means more drift at low I. Push I until you feel a slight “sticky” feeling on the sticks, then back off 5 points.
- D (Roll/Pitch): 38/40. D term is your propwash weapon on 75mm. Under 35 and every hard 180 dumps you into a bounce. Over 45 and the 40mm props start screaming.
- Feed Forward: 90 transition, 0.65 gain. 75mm whoops benefit from feed forward on sharp stick inputs — the extra mass needs a predictive push.
- TPA: 0.18 starting at 1250. These whoops spend more time at mid-high throttle during racing.
- D Min: On, D Min gain 20, advance 50. Helps with propwash recovery after sharp maneuvers without cooking motors in straight-line flight.
Motor Output Limit: 85% for 1002 20000KV on 1S or 1102 14000KV on 2S. 75mm whoops can run motors harder than 65mm thanks to better cooling from the larger ducts.
Rates: Actual rate 750 deg/s roll/pitch, 650 yaw. RC Rate 1.0, Super Rate 0.70, Expo 0.25. Slightly slower than 65mm because the larger quad needs more deliberate line choices.
85mm Whoops (40mm Props, ~38-50g AUW)
Bordering on a micro drone rather than a true whoop. Flies outdoors comfortably but still raced indoors on larger courses.
PID Profile — 85mm (Betaflight 4.5, Bluejay 96kHz ESC):
- P (Roll/Pitch): 58/62. Highest P in the whoop class. The frame is stiff enough and heavy enough to need aggressive correction.
- I (Roll/Pitch): 90/95. The weight demands strong I hold, especially in wind.
- D (Roll/Pitch): 42/45. 85mm whoops propwash badly on 40mm props at this weight. D is your primary counter — don’t be afraid to push it.
- Feed Forward: 100 transition, 0.75 gain.
- TPA: 0.20 starting at 1200. 85mm whoops fly at higher average throttle.
- D Min: On, D Min gain 25, advance 60.
Motor Output Limit: 90% for 1103 11000KV on 2S. At 85mm, you have the cooling and prop disc area to run motors near their limits.
Rates: Actual rate 700 deg/s roll/pitch, 600 yaw. The bigger quad needs smoother inputs — high rates just create overshoot and wasted momentum.
ESC Protocol Note: 96kHz PWM on Bluejay for 85mm whoops. 48kHz is fine for 65/75mm but the larger motors on an 85mm benefit from the higher switching frequency — cooler running and slightly more torque at low RPM.
Parameter Comparison Table
| Parameter | 65mm Whoop | 75mm Whoop | 85mm Whoop | What Happens if Wrong |
|---|---|---|---|---|
| P Gain (Roll) | 45 | 52 | 58 | Too high: oscillation at 180-210Hz. Too low: mushy roll stops |
| D Gain (Pitch) | 38 | 40 | 45 | Too low: propwash bounce on hard stops. Too high: hot motors |
| Motor Limit | 80% | 85% | 90% | 100% on 65mm burns 0802 motors in ~30 packs |
| Feed Forward Gain | 0.5 | 0.65 | 0.75 | Too high on 65mm = overshoot. Too low on 85mm = sluggish |
| TPA Start | 1300 | 1250 | 1200 | Starting too late means TPA never activates at racing throttle |
| ESC PWM Freq | 48kHz | 48kHz | 96kHz | 96kHz on small whoops can cause desync on rapid throttle changes |
Common Whoop Tuning Mistakes
Mistake 1: Copying 5-inch PIDs onto a whoop. This never works. A 5-inch quad has roughly 30x the mass and 10x the prop disc area of a whoop. PID values that are aggressive on a 5-inch are comically high on a whoop — the quad will oscillate itself to death. Whoop P gains are typically 40-60% of 5-inch values. Start from whoop-specific presets (UAV Tech whoop preset, Betaflight community whoop presets) and tune from there.
Mistake 2: Running motor output at 100% without checking motor temperature. After a 3-minute race heat, whoop motors should be warm — not too hot to touch. If you can’t hold your finger on the motor bell for 3 seconds, you’re overworking it. Reduce motor output limit by 5% and retest. Burnt motor windings on a whoop are almost always from D-term heat buildup, not crash damage.
Mistake 3: Ignoring the throttle curve. Whoop racing is conducted almost entirely between 25-60% throttle. A linear throttle curve wastes resolution — half your stick travel covers throttle ranges you never use. Add throttle expo (0.3-0.5) or use a throttle mid point of 0.35 with expo 0.4. This gives you finer control in the range you actually fly and makes altitude management through tight gates far easier.
Mistake 4: Running D Min with the wrong advance value. D Min’s purpose is to reduce D gain during steady flight (less motor heat) and boost it during sharp maneuvers (propwash control). If D Min advance is too low, the gain boost arrives after the propwash event — useless. Set advance to 50-60 for whoops so D ramps up fast enough to catch the bounce before it develops.
Mistake 5: Overlooking frame resonance from bent ducts. Whoop ducts take abuse. A slightly bent duct changes the frame’s resonance frequency and introduces vibration that no amount of filtering fully suppresses. After any crash that deforms a duct, bend it back and do a quick hover test. Listen for changes in motor pitch — a new whine or buzz means the frame isn’t resonating cleanly anymore.
⚠️ Regulatory Notice: Whoop-class drones under 250g may have different registration and operational requirements depending on your jurisdiction’s 2026 regulations. In the US, sub-250g recreational drones have fewer restrictions but must still comply with airspace rules and Remote ID requirements for certain operations. EASA Open Category A1 covers sub-250g drones with fewer operational constraints. Always verify the current rules for your location and drone weight class before flying.
Internal Links
Whoop motor behavior is fundamentally different from larger builds — our FPV Motor KV and Cell Count Matching guide explains how KV selection changes with prop size and voltage.
For understanding the Betaflight filtering pipeline that interacts with whoop PIDs, see our Betaflight Gyro Filtering guide.
If you’re building your first whoop from scratch, our AIO vs Stack Flight Controller Builds guide covers the all-in-one board options that dominate whoop builds.
Video Guide
Recommended Hardware
The Happymodel X12 AIO flight controller is purpose-built for whoop racing — 12A ESCs with Bluejay 96kHz support, built-in ELRS receiver, and a layout that fits every 65/75/85mm whoop frame with standard 25.5mm mounting. uavmodel stocks the X12 in both 1S and 2S variants. If you’re building a race whoop, this board removes every excuse for a bad tune.