Another question! When the throttle is WOT to prime, I am getting servo feedback- those quick, micro-movements. Is this normal? Thanks again.

You may be binding the servo. ie.. the servo still has more travel but the throttle is all the way open already.
If your radio has the capability you can try end point adjustments, if not try moving the control rod in 1 hole on the servo or out one hole on the carb.
This is only one possibility, there are others.

Thanks for the response. Can this "binding" damage the servo?

Yep ! If not fixed !

It will also drain the battery... FIX IT!

You can either fix it mechanically by adjusting the linkage so that the throttle is full open when the servo just reaches it's full throw, or you can set the end-point from within your computer radio menu for the throttle. If you don't have a computer radio, then you are stuck with doing it mechanically. But, as said, it has to be done or else you chance stripping gears in your throttle servo.

This goes for other servo's and linkages on your planes as well. Binds can drain batteries very quickly and can cause problems with stripped gears very easily by breaking teeth off of the gears when stressed like that. The servos should move freely from end to end without any binding from linkage or from control surfaces. The primary ane preferred way to fix this is mechanically. You can change the holes that the clevis or the connecting rod on the servo end is connected to either on the throttle arm or the servo arm. Closer in on the servo end will shorten the throw. Further out on the throttle arm will effectively do the same thing.

Also, keep in mind that this may not be the cause for our jitter. It is a cause, but there are others. Examine this one first because it is the most obvious.

CGr.

Sometimes they get the jitters from the transmitter antenna being close to the plane as on start-up. Then, when you get a few feet away it stops. Sometimes it helps to use a plastic clevis on the throttle arm of the carb as well. Ross

I am getting feedback on all of my servos now when *****g out the throws. Does this mean it's simply the fact that the transmitter is so close to the plane?

Could be, back about 5 feet away and see if it goes away.

Nope. And it's an RTF, too. I already tried messing with the throttle rod, but I messed that up, so I downloaded the Avistar ARF directions and followed them, but it says nothing about how to ajust the rod for idle.

How the heck do you get the brass piece off of the servo arm?!?

Nevermind, i somehow got it. I'm not mechanical. I study philosophy.

So you are not really sure you even have an airplane? Sorry couldn't resist

NO, i know for sure I have a plane. I'm also sure that I also messed around with a beautiful girl about 15 mins ago. I also know that I have a Negra Modelo in front of me. Damn, I smell like her. Damn, nothing like nitro in the morning!

While it is very likely that as everyone says, you are either experiencing "binding" or the servo is prevented from full movement, because the linkages cannot move any further ( you can correct this by adjusting the endpoints via the TX )....

... you also may need to consider that your servo or system is getting RF interfernce from the engine.

Are you using mechanical metal linkages and pushrods from the engine to the servo?

These can act as antennas directing engine RF noise towards the servo, and causing it to glitch.

I've also had a servo or two that would do this even with plastic linkages, when the engine was within a specific RPM range.

The problem was with the servo itself, as changing it out for another of the same brand, make and revision level, solved the problem.

He never said if the engine is running when this happens, is it?
If it is not running than the engine won't be the cause.

I did assume that WOT pointed to the engine running, but that may not be the case.

Quote from original post.
"When the throttle is WOT to prime"
I gathered that to mean he opened up the throttle to prime the engine before starting. But who knows?
Part of what makes it hard to troubleshoot online.

Sorry for the late response. No, the engine was not on. I have an avistar, so the throttle is pushrod. I somehow fixed the throttle servo binding, though. My next concern is that when I move the rudder full throw left or right, there is binding as well. I have moved several feet away from the plane, too, but they still bind. I'm not sure what it is. All of this was factory installed.

Of course, depending on the radio, you can always change the EP (end point) if computer. If not, then you will have to do this mechanically. You gotta remove that bind or your battery will not last very long.

Move the control rod closer to the center on the servo or further out on the control horn on the rudder, or both if needed. This will reduce the throw and hopefully remove binding.

CGr.

Yeah, I don't have a computer radio, but a 4ch Futaba that came with my plane. I tried to move the control rod, but I was unable to remove the brass piece from the servo arm. What's the trick? Thanks again!

The clevis you mean? It should just spread apart and slide off the control arm. If you are unsure, take a digital pix and post it so we know what you are referring to when you say "brass piece".

CGr.

I think you are merely hitting the maximum movements of the control surfaces.

With most computer controlled radios, you can set the "end point" adjustments to prevent you from bottoming out the servos, eliminating the noise you hear as the servos try to push past where the control surface is permitted to move.

On non computer controlled TX equipped trainers, you cannot set an end point adjustment.

Many people just fly the planes this way as you rarely ever max out any control...

However if you wanted to you could adjust the linkages or change the control horn holes used to stop this.

First of all, thanks for your patience. I really appreciate it.

I don't mean the clevis. I mean the piece on the servo arm that holds the rod in place. That is, the rod runs through the piece, and there is a screw on top of it that can be tightened or loosened to adjust the rod. I don't have a camera, or I would post a picture. I hope that is a bit more clear.

Opjose, that makes a lot of sense. Besides, it's the rudder, which I don't frequently use in the air, anyway. YET.