Hi,

I am building a plane from a plan and I have completed it's rudder assembly. When the control surface is moved to the extreme end's and released back the rudder does not center again. I think it's most probably an issue with the servo not centering back again, or is it due to some other reason. I got a programable radio. Can I do some "settings" on the radio to cancel of this effect.

In any case how do I rectify it? ... 




Ashutosh

(a) a newbie rarely uses rudder

(b) Your quick connector should be able to swivel, the purpose of it is that, it is not swiveling

(c) Did you hear the jitter, your servo is on high load, reason could be your connector not swiveling or your horn to servo arm imbalance (Fulcrum load effort funda,)

(d) the throw itself is too much

(e) Why is servo overloading ? check that first

(f) If you keep doing this movement the servo will give up soon.

also move the connector on the horn to the top most hole

Yup, a newbie rarely needs to use the rudder  , but I want RET+Aileron, all four of them to be functional. At a later date, I can just plug in the servo into the receiver to activate the control. Also the servo did jitter. That may be due to the thread locker I used on the Linkage stopper  Will check on the jitter.

So I disconnected the push rods from both the servo arms of rudder and elevator to check if there is servo centering issue. And I think there is an issue. Please confirm by looking at the video. Can this be resolved by doing some programming on the radio. If i am not mistaken "differential" throw's can be set for this servo.

And yess ... the push rod connector is put on the top most notch of the servo arm ... .



Thanks !

On second thoughts ... diff throw won't work as it's amount of throw a servo will give in either direction and not related with servo centering.

Quote from: ashutoshn on October 23, 2011, 01:14:53 PM
And yess ... the push rod connector is put on the top most notch of the servo arm

He meant top most hole on the control horn not the serve horn, to reduce load on a servo you move the connector to the lower hole on servo horn and/or higher hole on the control horn.
BTW that servo looks bad, you might have to replace it.

Which servo are you using? Asking just for the information......

Thanks.

It could be a problem with the pushrod( the pushrod might be bending after moving nd hence when u leave the sticks it could be assuming off centered position. Tats wts was happening on a scratch built of mine. Is the rudder neutral before u move the rudder?

The servo is not centering even with the push rods removed

@SLS: During the build, the thought of replacing the servo never came to my mind and it would be real pain to replace it. Any suggestions on rectifying it? The bottom screws of the servo are accessible from the underbelly. Would opening the servo, help?

@Sumeet: Because of one faulty servo, one can't consider the brand to be bad. The rudder servo is bad but elevator servo works fine. Anyways both the servos are Power HD - 1900A.

@sravan: Thanks for your concern. I had earlier built a push-rod set out of a material which flexed and did not track straight. I then later rebuilt the set with 2mm CF rod,  1/32" and 1/16" piano wire. This combination is good as they provide longitudinal strength to the push rod and lateral flexing is very less. The rudder was neutral before i moved the rudder.

i'm not sure about opening up the servo, all i can suggest test it one more time by swapping it with the other servo; i mean swap the servos on the rx. if its still not centering then replace it. not worth risking a model for a servo. 

with my limited knowledge ... you should try

1) same test with some other servos
2) same test with some other ESC

I faced similar issue and with other set of servos + ESC it worked fine.

Good luck!