Help! Sub trim changing? FlySky FSi6X

[luvmy40]

This morning I found my channel 1 sub trim would change during or after a flight. I set the subtrim to deal with a little left yaw. It was better, but not right. After the short flight, the rudder(3 channel setup) was in a distinct left position. I used the sub trim to bring it back neutral, thinking I had forgot to save the subtrim the first time. This time I made sure to save the setting and powered down and back up to check. All good.

Next flight was the same left yaw tendency. I brought it back from the crash sight and found the rudder defaulting to a left position. I added more sub trim to get it at a slight right angle and flew again. Still pulling left. The rudder was back to the left again and my subtrim was maxed to the right.

This has me scratching my head. Any thoughts?

 

[Merv]

Is your trim reversed?

 

[luvmy40]

I'm not adjusting with the trim tabs at all. This is all in the subtrim settings. I do believe the channel one servo is reversed, but Like I said, this was all set visually on the ground in menu, subtrim, channel one.

I just powered it back up, set the subtrim to neutral and repositioned the servo arm. After the wing repair is set, I'll try to make time for another session this weekend.

 

[Bricks]

Did you check your servo, gear may be stripped?

Your not using a flight stabilizer are you?

 

[luvmy40]

No stabilizer. A stripped servo was my first thought. I am using 9g metal gear servos and this one is not stripped.

Thanks for the reply!

 

[danskis]

When you figure it out let us know. Thanks

 

[Bricks]

Dumb thing try rebinding your receiver and keep your radio at least six feet away, when I bind I put my body between the radio and receiver. Don`t forget to calibrate the throttle.

 

[Tench745]

A thought: This may be a pushrod/control surface issue and not subtrim.

On my Spirit I have the rudder pushrod running through a guide tube and a slit in the fuselage, so there is a little bit of friction and very slight pushrod flex. Because of this, the rudder won't center reliably. If I give left rudder then neutral, the rudder tends to center just slightly left because the servo is pushing the pushrod to center the rudder. But, if I give right rudder then neutral it centers just fine because the servo is pulling the pushrod to center the rudder.

The same thing can be caused by under-powered servos, or low precision servos that don't or can't center themselves as accurately.

You can quickly test this on your model by giving a rudder input and seeing if the control surface centers properly, then give the opposite input and see if the rudder centers at the same place or not. Then do the same thing and see if the servo arm centers at the same place each time. This will help tell you whether the servo, the pushrods, or both are possible issues.

 

[luvmy40]

Thanks for the ideas!

Hopefully, I will get out for some flying Saturday morning.

 

[RossFPV]

Thanks for the ideas!

Hopefully, I will get out for some flying Saturday morning.

At least on the fs-i6, you need to hold cancel to save the settings.

 

[luvmy40]

The settings are saving.

Here's what happened. First short flight, No subtrim adjustments, lots of left yaw. I brought it down and adjusted the rudder(which was visible at a left turn position) subtrim to set the rudder at neutral.

Second flight, still left yaw tendency. I brought it down and the rudder was back in a left position. I again, adjusted the subtrim to neutral and made sure I saved the settings.

Third flight, still turning left! I brought it down and the rudder was back to a visible left position. The last adjustment maxed out the subtrim setting and gave me a bit of right rudder.

Next flight, still turning left and I had to hold full right rudder to fly close to straight. I ended of crashing this time and doing enough damage that I couldn't try again. When I powered the radio and receiver back up, I had no coms. I ended up installing a new receiver, but I haven't gotten it back in the air since.

All of these adjustment were made on the ground and verfied viually. Yes, the rudder channel is reversed. No adjustments were made with the trim tabs.