Just setup a new quad copter with the APM 2.5 and firmware 2.7.3.  Have done the initial PID tuning  and the copter flies stably and well in Stabilized mode.  Flight characteristics are very good.  Self leveling is working well.

Flight mode 1 is "stabilized".  Switch 7 is set to enable disable Simple Mode.  However when we enable Simple Mode the aileron and elevator reverse stick control actions.  The copter is still self leveling correctly so correction inputs are still being handled correctly but not stick inputs.

Would appreciate any input as how to resolve.

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  • Thanks Randy,

      In this build the copter has a power backplane circuit board where the entire board is used for power distribution.  The ESC wires are removed to the very outside of the board.  The APM was mounted very close to the distribution board.  The current flowed though the distribution board to each of the ESCs and this caused the rotation of the magnetic field as power increased.  Moving the APM up a inch basically solved the issue.  No apparent deviation occurs with power increase.

    Based on what is was seeing the nulling might have a hard time working as the deviation shifted with power.  Now it should be able to work to eliminate any magnetic declination error based on location.  At least I hope so.

  • Tried some more test flights.  I used the telemetry to compare actual flight performance to what was shown in telemetry.

    The complete reversal did not happen but significant change did happen.

    With the aircraft initialized the GCS magnetic heading and aircraft orientation are consistent.  When the throttle is increased to hover the magnetic heading and actual heading begin to diverge and reach about 90 degree variation.  The controls are shifted in Simple mode according to the perceived magnetic heading.  This is not the complete reversal seen in the first test but the copter was being flown more aggressively just prior to switching to Simple mode.  The amount of magnetic divergence from actual seems to be dependent on current / throttle.  This would make sense if the sensor is being affected by the magnetic field of the power supplied to the ESCs.


    Landing and reorienting doesn't sound like a fix for me.  In order to use it must be consistent or a crash could ensue.  Has this been a issue?

    Regarding the reversed comment - actually in simple mode a beginner finds this intuitive compared to normal orientation style of flying.  Right aileron moves right, forward elevator moves forward etc.  Just like driving a car.  We have several customers who use this t do AP in some situations where they can manipulate the camera by yaw and still easily pilot the copter.  What happened was a actual reversal of controls. The copter was facing in the direction it was initialized in and the controls completely reversed.

    So we are looking at moving the flight controller. although no wires are close to it it is near an "back plane" that could be generating the interfering magnetic field.  Alternatively we will remote the compass as done in some other systems.

  • Well aircraft are normally "reversed" to someone who has not flown them. When you engage simple mode do the stick movements make more sense for someone who has never flown an aircraft?

  • Developer

    Just land re-orient the copter and disarm then arm again. Does it still have the issue?


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