From 69a5566a6f7e402b6725c945125ae53888f6df1f Mon Sep 17 00:00:00 2001 From: Mathieu Bresciani Date: Wed, 3 Apr 2024 10:24:44 +0200 Subject: [PATCH] Update en/config_fw/trimming_guide_fixedwing.md Co-authored-by: Hamish Willee --- en/config_fw/trimming_guide_fixedwing.md | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/en/config_fw/trimming_guide_fixedwing.md b/en/config_fw/trimming_guide_fixedwing.md index 69fae3a122dc..5f33e3a94e69 100644 --- a/en/config_fw/trimming_guide_fixedwing.md +++ b/en/config_fw/trimming_guide_fixedwing.md @@ -43,14 +43,17 @@ You can then trim your remote (with the trim switches) and report the values to -Auto-trimming continuously estimates the current trim of the aircraft during flight, uses it to reduce the constant load on the integrator of the angular rate control loop, and adjusts general trim parameters (`TRIM_ROLL`, `TRIM_PITCH` and `TRIM_YAW`) after landing. +Auto-trimming is enabled by default. +On first flight, auto-trimming estimates the current trim of the aircraft, and then updates the general trim parameters (`TRIM_ROLL`, `TRIM_PITCH` and `TRIM_YAW`) with calibrated values after landing. +The trim estimate is only updated when the aircraft flies with a bank angle of less than 10 degrees for more than 7 seconds. +So for the first calibration flight you should fly large circles or several phases of straight and level flight. + +On subsequent flights auto-trimming continuously estimates the trim and slowly updates the stored trim parameters. +This reduces the constant load on the integrator of the angular rate control loop. Auto-trimming is enabled using [FW_ATRIM_MODE](../advanced_config/parameter_reference.md#FW_ATRIM_MODE). This parameter is set to `(1) Calibration` (trim parameters are replaced by the trim estimate on landing) for the first flight and is then automatically changed to `(2) Continuous` mode (trim estimate is used to slowly update the existing trim parameters). -The trim estimate is only updated when the aircraft constantly flies with a bank angle of less than 10 degrees for more than 7 seconds. -During the first calibration flight you should fly large circles or several phases of straight and level flight to obtain best results. - ## Advanced Trimming Given that the downward pitch moment induced by an asymmetric airfoil increases with airspeed and when the flaps are deployed, the aircraft needs to be re-trimmed according to the current measured airspeed and flaps position.