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Oct 08, 2003, 12:57 PM
Fiberglass dont bounce???
RandyK1's Avatar

How do I reverse a servo?


I will be running 2 aileron servos off of a "Y" connector and I need to reverse 1 of the servos. Is there a easy way to do this? thanks....R....
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Oct 08, 2003, 01:00 PM
Closet Extrovert
Jim Poor's Avatar
Forgive the obvious question, but can you just mount it in the opposite direction?
Oct 08, 2003, 01:26 PM
Registered User
By far the easiest way is to get a Y harness with a reverser in one leg. Expert Electronics (http://www.horizonhobby.com) sells one.

The other option is to go in and reverse the outer two leads on the potentiometer, and reverse the two leads on the servo motor.

Just turning the servo around won't help. Remember, a servo's movement is angular; it moves around in a circle. No matter how you turn the servo around its axis, the servo will still move in the same direction.

On the side requiring the "reversed" servo, you need to mount your pushrod to the opposite side of the servo wheel, while maintaining the pushrod geometry so both surfaces move the same amount...

One option is to mount the servo upside down in the same place. This is often not practical, as the servo body would be protruding outside the plane.

Another option is to move the servo sideways so you can attach to the opposite side of the wheel, and keep the pushrod angle the same. As long as you keep all the distances the same (servo arm length, control horn length, pushrod length), and the pushrods are both parallel when both servos are centeredl, it will work fine.
Oct 08, 2003, 01:37 PM
Closet Extrovert
Jim Poor's Avatar
I was thinking of a wingmounted servo, guess it doesn't pay to assume. In the case I had in mind, if you mount one servo with the arm/wheel facing one way and the other opposite, the motion is reversed.

Randyk,
Where are you mounting the servos?
Oct 08, 2003, 02:42 PM
Fiberglass dont bounce???
RandyK1's Avatar
Servos are in the wing (ailerons). I just bought the plane from another "zoner" so I dont know if the servos are glued in or screwed in yet. I should get it in the mail tomorrow, I will look as soon as it gets here....R...
Oct 08, 2003, 05:59 PM
Registered Taranis User
Miami Mike's Avatar
Quote:
Originally posted by RandyK1
Servos are in the wing (ailerons).
You shouldn't have to reverse anything. If both servos face inward, or both face outward, an ordinary Y-harness will work fine. You can even get some aileron differential if you set up the linkage right.
Latest blog entry: Taranis: Aileron-To-Rudder Mix.
Oct 08, 2003, 11:08 PM
Fiberglass dont bounce???
RandyK1's Avatar
Quote:
Originally posted by Miami Mike
You shouldn't have to reverse anything. If both servos face inward, or both face outward, an ordinary Y-harness will work fine. You can even get some aileron differential if you set up the linkage right.
Miami Mike, I turned 1 servo upside down so its working so far, BUT how do I " You can even get some aileron differential if you set up the linkage right." I think I should have 12-15mm up and 2-3mm down. Is there anyway to do this on one channel? What would happen if I left it at 12mm up & 12mm down? Thanks for your help......R......
Oct 09, 2003, 02:52 AM
Single-task at best...
tim hooper's Avatar
Randy,

Assuming that your servos are mounted on their sides, then switch on your radio and let the servos centre themselves. Remove the arms and then cant them forward by one or two splines before re-attaching them. Instant differential!

Here's a pic of my Bandit, showing the set-up used.

tim
Oct 09, 2003, 06:00 PM
Registered Taranis User
Miami Mike's Avatar
That's what I had in mind, but I doubt that it's possible to get 12-15mm up and 2-3mm down that way. That's a ratio of 5 or 6 to 1 rather than the more common 2 to 1. Randy may have to settle for what he can get or else buy a new radio.
Latest blog entry: Taranis: Aileron-To-Rudder Mix.
Oct 09, 2003, 08:32 PM
Fiberglass dont bounce???
RandyK1's Avatar
I just gotta get this to hold me , untill I can save up for an Eclipse (very soon). Thanks, ..R..


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