The first thing you have to do is make everything straight. That means no up or down in the elevator and ailerons, and no left or right in the rudder. Straight.

How I do this is disconnect the linkage, then center the servos using the transmitter. If you have clevis's on there, slide a piece of rubber tubing over the rod. You will use these later. Make sure all the trims and sticks are in the absolute center position. Some radios have a little screen with a position indicator for each stick. If yours does, then center all using that indicator.

Next, insure that the servos are centered, meaning the control arms on each of the servos is in the center position. If not, you can remove the servo arm and rotate it 90 degrees (using the four arm servo arms). On one of the rotations, the servo arm will be straight and perpendicular with the direction of movement.

I then use a couple of paint stirring sticks (those you get free at the paint store that are about a foot long, about an inch wide, and about 1/8 inch thick. I use that to clamp the control surfaces straight with the stab/wing. I put a stick on each side of the surface then use a small clamp to hold it in place. This makes the control surface as straight with the wing or stab as possible.

With that done, you can now attach the linkage to the serovs, turning the clevis until the linkage slides easily into the holes on the servo arms without moving it (this is also done with the transmitter on to hold the servo in place).

When done, secure the clevis's or the rods into place using the little servo rod keepers, or those pieces of rubber tubing wrapped around teh clevis's before you started (slide them over the clevis to hold them closed).

Remove the clamps and the wood paint stiring sticks.

Move your sticks and all should be centered.

Now, once you fly the thing, all bets are off because you will most likely have to trim the plane for straight and level flight. We all have to do that, and usually on the first flight of each day, but that's just part of the hobby.

Good luck.

CGr.