Hi,
I have pull pull rudder installation on my 90 size, and i want to make sure that the cable tension is ok.
in the curren setup the centerning isk ( 1mm devation around the center ), and the cables looks tight.
but i can move the rudder against the servo for about few degrees for each side any suggestions ?

Thanks,

What servo? It appears that the servo is not strong enough?

Vince

Tighten the cables in the centered position until the rudder doesn't move or have play, of course if the servo has play then take it in consideration, also, the servo horn shuld be the same size as the rudder horns distance.

Hi,
I am using digital airtronics 74751, if i will tight the cables till the rudder won't move against the servo
then it will put stress on the servo shaft is that ok ? ( i guess that it will wear the servo is that so ? )

Thanks,

sorry the servo model is airtronics 94751Z ( 73oz at 4.8V )

It's ok, there is not that much tension on it any way,you have to increase the tension a little at a time and check, if you do it like that you will get the correct tension and that's ok with the servo, remember the output shaft has one or two bearings and it can handle a lot more tension.

Regards

On a digital tighten it enough that the servo is not buzzing/hunting after power up and its has been moved, I.e. switch on and then move the servo by the Tx and if you have it right any buzzing will stop, but it will buzz when you first switch on, any play in the servo should dissapear when the power is on.

If you are worried about the servo output shaft load, put an auxillary arm in front of the servo and connect that to the rudder, it can then take a lot of tension as the servo has no direct tension on it only the rudder load.

Mike

My digital servo is buzzing constantly ( ~ 2 buzz / sec ) even when the servo arm is disconeccted
from the pull pull cabels !

If your servo's buzz when not even connected then the centering/reolution may be off and the servo is constantly hunting for the correct centre position, I would put an Amp meter on it to see if its drawing excess power when stationary.

Mike

Hi,
What do you mean "centering/reolution may be off " ? i mean what could cause the centering to be off ?
i have been told that it's related to the transmitter signal width is that make sense ?

I think he meant centering/reSolution. It is possible that these problems can be caused by the transmitter, but more than likely the pot is worn in the digital servo. One thing I have heard of being done to stop this (and keep in mind this is just a temporary fix) is using the sub-trim in your transmitter to re-define what center is, and adjusting the servo arm accordingly. The digital servos are constantly searching for center, which can account for a certain degree of buzzing, but when it gets to where the control surface is being moved by this search for center, it's time to repair or replace.

The servo is new ! i bought it one week ago it has 30 minutes total working time.

Then it's probably just the normal buzz, I wouldn't worry about it unless it starts to move on its own. What kind/how old is your transmitter? What kind of servo is it?

It might need a new pot. Irregardless of how much 'time' is on it.

Quite right, I dislocated my shoulder two days ago and its very tender, makes it difficult to type, anyway that's my excuse and I am sticking to it. LOL

The newer Hitec Digital servo's can be programmed for centre and resolution on either side of center, isn't technology wonderfull.

Mike

mjfrederick
The servo is sanwa 94751Z, and the transmitter is Sanwa RDS8000 2.4GB, as you understand i am sanwa favor..

Thanks,

Hmmm... no experience with Sanwa products here. Hopefully someone else could chime in.