ALL Surfaces Binding
 

Hey all, I'm at a loss. I finally put all the radio servo's in for my first plane and connected them, besides for the ailerons, and they all bind. The only one I can say I know how to attempt to fix is the throttle, as I believe it is only a matter of adjusting the offset. Before I go on, let me pose a question: On the other servos, when I go to the extreme, I hear the bind noise drone on and on, however when I am moving slightly in either direction from neutral, I also hear this noise, but at the rate I am moving and it immediatly stops after I stop, does this mean its binding in all movement?

Now to the specifics, my rudder servo binds [with both nose gear an rudder on], and my elevator binds. Now, I think I see one problem with both of these, that is at one extreme of the movement, The R/C link is being bent by the X-style servo arm I have. But this only explains one cause of the binding, possibly, as it binds at other points too. I have looked for causes, but I'm at a loss, and as a beginner I'm not exactly sure how to troubleshoot these problems. Thanks to those who tackle this one!

ALL Surfaces Binding
 

on the rudder and elevator pushrods did you cross the rods. In other words if looking in the radio compartment from the nose of the aircraft does the pushrod on the left side of the compartment exit the fuse in the rear at the right side and vice versa for the other. if not this could be the cause of the binding. Also have you tried moving to the outer most hole on the the control horns and or the inner most holes on the servo control arm? this can limit travel and sometimes reduce or elminate binding if you have a computer radio check the end point adjustment and servo travel. I would suggest solving this mechenacially rather then electronically if at all possible

ALL Surfaces Binding
 

NCLights,
The first thing to do is take the servo wheel off of the servo and see if you can move the rod freely to it's full travel. If not, find where it is rubbing. Maybe just bending the rod slightly will help.

Put the servo back on and try again. If the servo tries to turn further than the control surface can move, then you're pushrods are in the wrong holes. Use the outermost hole on the control surface. If it still tries to move too far, move the rod inward at the servo end.

Some servos just like to buzz. If it only does this at mazimum stick movement, it's not a problem. You won't be keeping the stick there anyway.

Tom

ALL Surfaces Binding
 

Ok, I'm not totally sure I know what you mean when you say "binding". (I know what I mean whey I say "binding", I'm just not sure you'r "binding" and my "binding" are the same "binding"). Now that we have that cleared up:

Binding usually means one of a couple of things.

1) that the servo is trying to move the control surface farther than the surface can move, causing the servo motor to be stalled before it reaches full travel. If this is what is going on, move the pushrods in a hole on the servo arm, closer to the center screw. This will cause the pushrod to move less and not excede the available movement of the surface. You can also fix this eletronically on some radios, but it's best to fix it mechanically.

2) the pushrod or other part of the linkage is getting stuck on something, or isn't moveing freely. In this case, disconnect the pushrod from the servo and move it by hand. Does it feel nice and smooth all the way thoug the travel? If not, figure out what is getting stuck and unstick it. Common causes of this are hinges out of alignment, pushrods bent at the wrong angle or wrong location, etc. This one takes detective work and paying attention to details, but it needs to be done if there is a problem. Getting someone local to you to go over it might be the best way to go about it, it's almost impossible to diagnose over the web.

Ok, if you think things are binding by the buzzing sound of the servo, that's a good way to discover a problem, that's for sure. It is a normal noise for a servo to make while it is moving. But once it reaches the end of it's travel, it should quiet down.

Also, as a side note, inexpensive servos are not always very good at handling very small movements, espeically around the center. It's referred to by two terms, "deadband" and "resolution". So a little oddness and buzzing with very small movements is normal and to be expected. If it the buzzing stops when the servo gets to the end, you are likely ok. Here's a test, take the servo arm off the servo and see if you hear the same kinds of things when the servo isn't moving anything else.

Oh, back in the days before CA hinges, you could tell if your surface was free enough by disconnecting the pushrod. The surface should "flop" around freely if you pick the airplane up and move it upside down, or side to side, depending on the surface. CA hinges do add a bit of resistance to the control surface movement, and that will cause some buzzing as the servo moves. I remember when CA hinges were first introduced and a lot of people saying they were garbage because of that extra resistance.

I really think you should get someone to check it out in person if at all possible.

ALL Surfaces Binding
 

Hi NC

First, check to see if the rods are binding themselves. To do this, disconnect them from the control surface and the servo, and move the rod back and forth. They should move very freely. If not, you should work on getting them to do so. The path from the servo to the control surface should be as straight as possible, with all bends happening as smoothly as possible.

Next, I would connect the rods to the control surfaces, and try moving them again, and see if they increase the friction dramatically. If so, check out your hinges to make sure that they aren't binding, and get the control surfaces to move freely.

Now with all of that done, you can connect the servos. When you do this, first center the servo with your transmitter, and place the servo arm so that it is centered for the particular throw of the surface you're trying to move. The idea is to have equal travel in both directions, and when the control is centered, the control surface is in it's neutral position. Depending on your equipment, you can adjust the travel length for each direction, but the end results is at both ends of travel, the servo shouldn't bind, or try to move the control surface farther than it physically can, if you know what I mean.

Sometimes you have to play with this stuff quite a bit. My suggestion to you is after you check all of this stuff, find a local club and bring the plane out with you, and ask some of the more experienced flyers to check it out for you. They'll be able to point out any problems with the linkage you might have.

ALL Surfaces Binding
 

Guys thanks for you help. I'm going to take a break for the weekend while I go into the city for an Opera and then try and manage finishing the crossword. I think your advice will help me solve my problems. And as for the in-person check, I entirely plan to have my plane checked out by the guy at the hobby shop just as soon as I'm done and have diagonosed the problems as much as I know how.

Thanks again.

ALL Surfaces Binding
 

No one mentioned this ,? but if the four way servo arm is hitting the control rod , cut off the un-used arms

Highlander