Model Boat Mayhem

Technical, Techniques, Hints, and Tips => Radio Equipment => Topic started by: Hotglove on August 26, 2019, 04:02:40 pm

Title: Servo adjustment Spektrum dx6i
Post by: Hotglove on August 26, 2019, 04:02:40 pm
I have just fitted a new rudder servo and the rudder moves more in one direction than the other.
The servo centres OK and the linkages seem fine with no binding, but there is quite a marked difference, perhaps 30% using the trim switches is not an answer since that simply moves the unequal travel to one side or the other.
The more that I have read, the more confused I get.
Thanks in anticipation.
Title: Re: Servo adjustment Spektrum dx6i
Post by: john44 on August 26, 2019, 04:57:11 pm
Hi, have you tried going into your set up list scrolling to the servo adjustment list and having a look what the rudder settings are. They may be set for another model that requires a different %of movement.
I don,t mean the trimm settings. It's the main set up settings you may need to alter.


Hope that helps
John
Title: Re: Servo adjustment Spektrum dx6i
Post by: JimG on August 26, 2019, 09:35:18 pm
Do you have the linkage at 90 degrees to both the servo horn and the rudder horn? If not then you will have built in differential where it will move more in one direction.
Jimj
Title: Re: Servo adjustment Spektrum dx6i
Post by: malcolmfrary on August 27, 2019, 01:27:58 pm
Does the servo itself swing equally both sides with no linkage attached?
I so -

If you imagine a line between the pivot of the tiller arm and the center of the fixing screw of the servo, if both arms are the same side of the line as each other, they should both be at right angles to that line at center.
If they are opposite sides, they will need to be angled to compensate, but will still need to be parallel to each other at neutral.
In neither case has the center line of the boat got any relevance.
Just geometry, really.
Title: Re: Servo adjustment Spektrum dx6i
Post by: clockworks on August 27, 2019, 04:05:54 pm
If you can't sort it by adjusting the linkage and levers, have a look at adjusting the endpoints/rates in the Tx settings.


Most computer transmitters have adjustments for servo travel. By default it is set to 100% either side of centre. On my Futaba, I can set the travel between 0% and 140%, independently for each direction.  To get equal travel on the boat I'm currently building, I have set one direction to 90%, the other to 140%.  I couldn't fix it using geometry because the tiller would hit the hull in one direction if I set the tiller at right angles to the linkage, and the servo mounting plate wouldn't allow me to move the servo any further inboard without a complete redesign.
Title: Re: Servo adjustment Spektrum dx6i
Post by: Hotglove on September 21, 2019, 06:05:33 pm
Having read the comments and other threads I set up the new servo very carefully both physically and by TX adjustment, must have done something right because the boat responds equally and is much more manoeuvrable than before. I expect that the old servo had been failing gradually for some time without me noticing.
She looked great out on the lake this morning.
Thanks for the advice and interest shown.