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Old Apr 29, 2015, 04:54 PM
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Throttle Servo Moves w/Rudder Input?

Hi All,

I have a Futaba FG12 (set-up Mode 2). When I move the rudder, the throttle servo moves a little (plus/minus 8 points on the servo monitor screen on Tx). Rudder is Channel 2, Throttle Channel 3.

Normal? Remedies?

Thanks!

EJ

P.S.: Radio was sent to Futaba and given a clean bill of health last November. Haven't flown it since it came back.
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Old Apr 29, 2015, 05:53 PM
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Is this on a clean model with ACRO model type selected? Make sure you do not have any mixes enabled.
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Old Apr 29, 2015, 06:21 PM
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Thanks.

No, I checked the mixes, all at are "Inhibited". Under "Model Type", I have the selection of "Airplane", Helicopter", or Glider". "Airplane" is selected.

EJ
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Old Apr 29, 2015, 07:20 PM
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You could try increasing the tension on the throttle stick.
I fly smooth throttle and I just went out to the work bench and put my 8FG in servo monitor. I was hard pressed to keep my rudder to throttle interaction that low
To test the gimbals, don't directly touch the stick with your fingers or thumb (me). Take something like a little screwdriver and use it to move the stick in the rudder axis while looking at the servo monitor, and see if you still get any coupling. With my 8FG throttle stick centered at 0%, if I move the throttle plus or minus 8% there is no visible movement in the analog display, I need to hit about 10% to see the bar move off center on the display, though your display may have better resolution than my 8FG.
I'll stay tuned for your update
Pete
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Old Apr 29, 2015, 07:41 PM
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Thanks Pete.

The throttle tension is moderate, and the travel is indexed (tick-tick-tick). Because of the indexing, throttle does not wander when rudder inputs are made.

I just checked my elevator/aileron servo movement (right stick) and while there's a twitch of movement of the opposite servo, it's not near as much as the throttle servo movement, when the rudder is moved. BTW, there is no rudder servo movement when changing the throttle setting.

EJ
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Old Apr 29, 2015, 09:42 PM
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Have you tried to calibrate the gimbals?
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Old Apr 29, 2015, 09:48 PM
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Hold the throttle all the way down and move the rudder. Still Doing it?

It is hard to move one without the other moving just a tad.
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Old Apr 29, 2015, 11:05 PM
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Quote:
Originally Posted by ivanc View Post
Have you tried to calibrate the gimbals?
Yep. Went to the menu and selected "Neutral", which centered all the servos. Interestingly, when I exit the page, the rudder offsets a little.

Once again, I sent the radio in for a check-up last November, and it was given a clean bill of health. Maybe this is normal? I really never paid this much attention to this behavior in my last radio (JR), so I can't relate experience-wise.

EJ
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Old Apr 29, 2015, 11:06 PM
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Quote:
Originally Posted by BHOFM View Post
Hold the throttle all the way down and move the rudder. Still Doing it?
Yep.

EJ
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Old Apr 30, 2015, 12:03 AM
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Quote:
Originally Posted by EJWash1 View Post
Yep.

EJ
I would take the back off the transmitter and look for something loose. the pots
or bad bearings.
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Old Apr 30, 2015, 12:30 AM
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Quote:
Originally Posted by BHOFM View Post
I would take the back off the transmitter and look for something loose. the pots
or bad bearings.
New radio. Worth a look though.

EJ
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Old Apr 30, 2015, 05:34 AM
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How to set up the stick tension and length to avoid interaction is described in this video
Tactic TTX650 set up video 2 (19 min 39 sec)


While the video uses the Tactic TTX650 for demonstration, it applies to all transmitters.

I've been flying RC for a gazillion years, 55 or more in human years, and always had my sticks too long for the way my wrist rolls with my hand.

The video could have used a bit more editing, but it is certainly worth the view.

The setup procedure does indeed translate into smoother flying with little or no interaction of the stick's axises.
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Old Apr 30, 2015, 05:52 AM
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I got my old mode 2 12FG that I seldom use anymore because I have a Taranis Plus telemetry system now and tested the rudder throttle. As expected there is absolutely no interaction between the rudder and throttle or any other control.

The 12FG was a great radio in its day, but Futaba let it die and has never replace it with a newer system with the same powerful features unless you buy a 18MZ.

Mike
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