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Verifying Calibration

After calibrating, verify that the tones correspond to the correct speeds for your aircraft.

Ground Check

Before flying, verify basic sensor operation:

  1. Power on the controller
  2. With the aircraft stationary on the ground:
    • IAS should read 0 (or very close)
    • No tones should play (below mute-under-IAS threshold)
    • Pitch and roll should read approximately level
  3. Use the SENSORS console command to confirm all readings look reasonable

In-Flight Verification

Speed Check

The simplest verification: fly at known speeds and confirm the tones match.

  1. Cruise speed — you should hear silence (well above L/Dmax AOA)
  2. Best glide speed (Vbg) — you should hear the transition from pulsing to solid tone (L/Dmax region). For example, if your Vbg is 87 knots, the first tone onset should start around that speed.
  3. Published approach speed — you should hear the solid "on speed" tone
  4. Below approach speed — you should hear high-pitched pulsing that speeds up as you slow further
  5. Near stall — you should hear the stall warning (rapid high pulse)

If the tones are consistently at the wrong speeds (e.g., stall warning at approach speed, or silence at approach speed), the calibration needs to be re-done.

Flap Check

Repeat the speed check with different flap settings to verify each flap position's calibration:

  • The on-speed tone should correspond to approximately 1.3× Vs for each flap setting
  • The stall warning should occur at approximately the same AOA margin from stall in each configuration

Using Log Data

After a verification flight, download the log file and check:

  1. DerivedAOA values — should be reasonable angles (typically 0° to 20° for normal flight)
  2. Tone transitions — correlate tone changes with IAS to verify they match expected speeds
  3. Flap detection — verify the flapsPos column shows the correct flap setting for each flight phase

When to Recalibrate

Recalibrate if:

  • Tones are consistently at wrong speeds
  • You changed the mounting position or orientation of the controller
  • You changed the AHRS algorithm (Madgwick ↔ EKF6)
  • You modified the aircraft's aerodynamics (new prop, fairings, seals, etc.)
  • You changed the weight distribution significantly (new equipment, moved battery, etc.)
  • The R² of the original calibration was marginal (< 0.95)

Cross-Checking with Dynon Percent Lift

If you have a Dynon SkyView, you can compare OnSpeed's AOA against the Dynon's Percent Lift reading (logged as efisPercentLift). While the two systems measure differently, they should show consistent trends — both should increase together as you slow down, and both should peak near the stall.