Hi all

This question is NOT about the rudder trim, but a rigging/yaw trim issue. My '79 M5-235C has started pulling right (starboard) over the last couple of years. This year, after hibernation, it seems somehow worse (about half a ball). I replaced the rudder return springs thinking this might be the cause.

Nope.

Any suggestions? There has been no damage/hard landings or anything like that to bend the airframe.

Quote from a post by Jeremy (maules.com) at this post:

http://www.maulepilots.org/Hangartalk/v ... g&start=15

Starting at the beginning and setting everything to factory spec is worth doing. Over time, cumulative effect of minor tweaks to control surfaces, bending or warping of flaps and ailerons, spring tensions changing etc etc leave you chasing conflicting adjustments.

Wish we could make some posts, like this one, a sticky.
Kirk
quote=maules.com post_id=47199 time=1505410919 user_id=36]
It seems about once a year the rigging comes up.
It is pointless chasing a rig problem without starting from scratch.
Yes, you can fix a situation but at the expense of drag from the next situation.

1. Level the plane laterally using wing root carry through tube behind top of windshield, and by jacking the gear.
2. Check that the tailplane hinge line matches laterally.
3. Run a stringline from inboard edge of composite wing tips and check it is level laterally.
4. Adjust front wing struts to achieve level lateral stringline, and a 3" gap above wingspar roots.
5. Adjust rear struts to achieve the washout in each wing, 1/2 degree trailing edge up at outboard rib.
6. Check the vertical stabilizer is 90 degrees to the elevator hinge line which you have leveled by checking and if necessary changing tail struts.
7. Run a stringline from top of rudder and vertical stab when faired and the line should extend to a point 1 3/4" to left of centre of wing root carry through tube.(This combats left turning tendency in cruise).
8. Adjust the elevators so that the balance portion is equal and flush with stabilizers at BOTH sides otherwise it will roll the plane.
9. Place light upward hand pressure on flap trailing edge and adjust with pushrod until faired correctly with bottom of wing.
Check Both ends of each flap.
Do Not use wing root fairing for reference.
10. Tie a stick across bottom of both control yokes catching four points.
Adjust with turnbuckles.
11. Using above headliner turnbuckles adjust ailerons individually until flush with bottom of wing, checking at both ends of aileron.
IF any of flaps and ailerons is not close to flush with wing bottom at BOTH ends, there is a twisted control surface and the correct rigging will be compromised.
12. Adjust rudder trim bungee so that the spring is slack with T handle fully in (this is for right turn tendency in descent) and light tension on spring when T handle is at one and a half marks on shaft showing.
13. Adjust tail steering springs correctly with a little slack or they will affect the rudder trim.
14. Adjust the rudder servo tab flush with rudder when ailerons are locked together with the stick.
15. Be sure that with no load on either the tailwheel or the nose wheel, the swivel is not too sticky otherwise the wheel will act as a rudder.
It can be kicked loose to go in trail when in flight prior to setting rudder trim.
16. Adjust the rudder centering springs (not on M4 and M5) to be no shorter than 4.5" and to hold the rudder centered when no load on the tail.

Only now can you test fly the rigging as you will be starting from square One, and fine adjustments can be done for roll or yaw.

All the above is in your Maule Maintenance Manual
[/quote]

Thanks, Kirk. Greatly appreciated.

Might be way off base, but you might check inside the wing for wasp nest, birds nest etc. Apparently this is common and it will seriously throw things off.

Can't hurt...

I know you said it's not about the rudder trim but have you checked to make sure the rudder trim spring under the right kick panel isn't hanging up on insulation wiring etc? Mine was hanging up at one point so it constantly was adding spring pressure even though the handle was fully pushed in to the panel.

Make sure the tailwheel isn’t too stiff in the pivot. If it is, it can end up cocked off to one side, acting like a rudder.

Solved!

Greg was the closest (which is kinda funny as he has the exact year and model I have). I put the tail up on a jack, disconnected the rudder return springs and STILL had the issue of the rudder pulling right. I took a closer look at the rudder trim spring and saw there was enough tension on it to pull the rudder even though the handle on the panel was all the way in. There is a Bowden cable that comes from the handle to the spring to actuate it and the cable had either slipped or was installed (by somebody over the last 42 years) too high in its clamp. I loosened the clamp, slid the Bowden cable down about 3/8", tightened it all back up and problem solved.

Thanks for your help, everyone.

Awesome. Glad it worked out. I've been down the re rigging road trying to get mine to fly straighter and faster hands off but it's a long fought battle. It now is fairly hands off but still skids a bit.