Reverse Servo from inside

If the only difference is the bearing, then how can one turn in the reverse direction??? Reading your post indicates that they are both mounted with the shafts pointing the same direction. If this is the case, both should move the same direction when on a Y harness. If they don't then the servos are not the same.

Now, if the servos are mounted so that the shafts are opposite (mirror image) then that is a design flaw in the model as it would require either having flaps taking up two channels, or needing a reversing circuit to operate properly.

If the horn on one of the flaps could physically be moved, it's just a matter of flipping the servo arm 180', since when the right side is pushing, the left side is pulling, but apparently that's not an easy option. At least that's how World Model's J-3 is handling the situation with my FIRST RC model, being assembled as we speak (and makes me a bloody authority on the matter :-), with opposite offsets of the pushrods for the ailerons. Assuming on my part that most servo's are the three wire variety, with most likely a common ground, and cw/ccw movement, couldn't the two wires simply be snipped and reversed? In my case there's black/red/yellow, and logically (famous last words) black would be the common. However, I just added 3" to the length of my aileron servo's to prevent having extension plugs left in the wings, and it was no easy task pulling the wire nuts through those little holes in the ribs, let me tell you!!! (kidding - solder splice w/heat shrink :-)

Cheers'n Beers.. [_]) Don

Go ahead, you'll blow the servo board. What you need to reverse the servo is a

180 degree phase shift on the signal, not a voltage reverse, unless it's AFTER the PC board, at the motor and feedback pot.

Black is negative voltage, red is positive voltage, yellow is signal. Dr.1 Driver "There's a Hun in the sun!"

Yep - out of curiousity I did a google on servo's about the same time you posted, and discovered the error in my thinking (lack of :-). I was "assuming" the "Y" mentioned simply did a wire swap on one leg, but they actually added a buffer. Another step in the RC learning curve! Is it "live & learn", or "learn or burn"? d:->))

LOL And the plot thickens - the "Y" with reverser is reverseing both legs, is it not (the discription doesn't elaborate), so this wouldn't solve the problem either, unless you simply added it in series with one leg of the existing "Y" only using one leg. Didn't see one listed, but surely someone makes one for a single servo... Amazing how things look so simple at first glance!!

All transmitters can reverse any channel. The trick is to operate two servos in opposition on one channel. What would be the point otherwise?

Is anyone really still running 4 channel radios? It seems a programmable mix would obviate all the problems, and add opportunities as well (flaperons, for one).

No, Tower Hobbies shows EMT part # LXAFN1 as a Y harness with a reverser on one servo leg. Dr.1 Driver "There's a Hun in the sun!"

If all you need is 4 channels, yes. I'm flying a Hitec Flash 4 on my two Piranha IIs. They don't use the mixing, but I do have the exponential dialed in, servo reversing, and use the ATV to equalize throws. I could change the linkage a little and do away with the ATV and reversing. A softer touch on the sticks eliminates the exponential, so now you have a plain old 4 channel radio of yesteryear. Dr.1 Driver "There's a Hun in the sun!"

No. Those wires also power the electronics inside the servo. Electronics do not do well with regards to reversed polarity.

The only TRUE way to reverse a servo internally is to swap the wires to the motor, and swap the outer two wires on the potentiometer. If the motor is soldered directly to the PCB, then you either need to be really good at soldering, or you need an external reverser.

That direct solder connection is also the rear mount for the motor. Changing it at all might loosen it. Dr.1 Driver "There's a Hun in the sun!"

Is he saying the servos are moving in different directions, or that the flaps are moving in different directions? If the servos are moving in different directions, it's probably the Y harness. If the servos move the same way, but the flaps are moving in different directions, perhaps because he put the connector on the outside, or inside, of each servo. I'm really surprised you are not able to think of these possibilities on your own.