Per the Aero manual, I can save trims (after a gyro off trim flight) to the unit using the F: Set Trim function. After powering off the unit and resetting the transmitter trims to zero then powering up the unit the amount of control surface deflection is about half the amount of deflection I observed after the trim flight before storing the trims.

I experimented on the bench to confirm this behavior. I set a huge about of trim in the transmitter (so it would be easy to see) then used the Set Trim function to save this trim value to the unit. Sure enough, after completing the process and repowering the unit, the deflection was about half.

Two questions:

1) has anyone else experienced this and if so can you explain what I'm doing wrong?

2) If, after storing the trims from a trim flight, I perform another trim flight and activate the Set Trim function, will the new values replace the previously stored values or will they be added to the previously stored values?

Thanks in advance for any help you can provide.

Ray

In case it's of any value in diagnosing this behavior, I'm running a Spektrum AR8010T receiver connected to the Spirit via SRXL. DX9 radio with Trim Setup set to 2 (two clicks of trim for each press of the trim button).

Another observation that seems odd to me (probably I just don't understand) is, after saving a trim value from the TX of say +22 I see a value displayed in the Trims page of the Android software of +5. I've observed that the values displayed in the Trims page are much smaller numbers than the values in the TX. I would have expected the numbers in both Spirit and TX to be very close.

Ray

The silence is deafening on this very good question. Could you please respond Tomas?

Hello,

I am sorry for delayed reply.
The trims are being saved, but there is certain limit for them. If deflection is too big it will be limited by this amount (which should be more than enough). If model require more it will be not saved. So even if you will set big channel deflection it will end up as smaller always.

Trims from your radio will have always different value from Spirit Aero software. The amount is interpreted very differently even by each radio so unfortunately it will not match each other. Another brand will have values different to do the same trimming.

Next problem could be that Stick Deadband will make trim changes near center ineffective. So you will need to make more trim clicks I guess.

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Spirit System developer