Model Boat Mayhem

Technical, Techniques, Hints, and Tips => Radio Equipment => Topic started by: knoby on July 17, 2011, 07:35:49 pm

Title: servo settings
Post by: knoby on July 17, 2011, 07:35:49 pm

Today I changed from 27mhz to 40mhz transmitter & receiver in my yacht. The sail winch is fine, but the steering servo is off centre now. pushing the trim tab all the way to the right almost straightens it out, but not quite. With the trim all the way over to the far right, the servo travel is less left than right. I can move the servo horn round 1 click, but this still doesn't give equal travel in each direction.
i should say the radio is futaba sky sport & its a futaba S3001 servo.
Is there anyway to adjust the centre position on the servo?
 Thanks Glenn

Title: Re: servo settings
Post by: Tug-Kenny RIP on July 17, 2011, 08:08:30 pm

I would remove the servo arm and  'switch on'  the set so that the servo is at neutral and the trims are in the middle, then refit the arm in this position.

It might swing out of line when you switch off but this will not matter as it should be corrected when you switch back on.

Hope this helps

Ken

Title: Re: servo settings
Post by: knoby on July 17, 2011, 10:31:40 pm

Thanks Ken, thats what i did in the end, although its still not sitting dead centre & doesn't throw equally either side of centre. I was wondering if anyone knew if it was possible to adjust the servo or receiver internally to fix the problem.

Thanks Glenn

Title: Re: servo settings
Post by: barriew on July 18, 2011, 09:15:26 am

Does the Tx have end point adjustment? Another suggestion - is the servo horn from the same manufacturer as the servo? There is a difference in the number of notches on the spindle of the servo between manufacturers. This can give problems getting the centre point correct.

Barrie

Title: Re: servo settings
Post by: John W E on July 18, 2011, 09:54:14 am

HI ya Glen
 
I see you are having problems lining your servo up.   If it’s a Futaba servo you will find that the servo horn has several positions marked on the top going from 1-4.  Each number represents a degree off-centre.  Here is a pic to explain– hope this helps.
 
Aye
 
John

Title: Re: servo settings
Post by: wibplus on July 18, 2011, 10:14:39 am

Hi, there are a couple of other things you might be able to try.

Does your radio have a "sub-trim" menu ? If so, you can adjust the sub trim to a small amount whilst the main trim is at centre and that will get it closer, or on to, centre.

The other thing to try is to remove the arm, then turn the whole servo around by 180 degrees and reset the arm with the servo in the new position. The splines on the servo shaft are usually offset to give a different position to the arm. 

Hope this helps.   :-)

Title: Re: servo settings
Post by: knoby on July 18, 2011, 06:31:04 pm

Thanks for all your ideas guys, the radio is just a standard with no end point or menu functions. Although there are several mechanical options to solve the problem, I was just curious if anyone knew of a way to adjust the electronics to reset the servo. With the older type Futaba servos, it was possible to adjust the pot inside to reset the centre point, however the pots inside the more modern servos are fixed in position. I assume they are now factory set to the same point & not adjustable without fiddling with the little black boxes inside.
i have some knowledge of little black electronic boxes, but, as little knowledge can be a dangerous thing, I will go for one of the mechanical solutions!!!

thanks again for your suggestions

Glenn