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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 ONSPEED solid tone
  4. Below approach speed — you should hear high-pitch pulsing that speeds up as you slow further
  5. Near stall — you should hear the stall warning buzz (rapid high-pitch 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.