Rigging Problem

[Wistarmo]

I have been through this problem. My A/C had a very left-wing low problem. Several attempts were made to adust the ailerons, etc. The problem is that in order to rig an A/C correctly, the first step is to make absolutely certain that the rudder trim is correct. Instrument panels sag over time. After changing mechanics, the first thing we did was to level the aircraft and look at the turn coordinator ball. It was well out of position. We then put in new instrument panel mounts and that brought the ball back to the center position. When the rudder trim is out of whack because of a faulty turn coordinator ball indication, every adjustment made after that will be in error and worsen the problem. Once we got the rudder trim corrected and the ball centered in level flight, the rest was easy.

[marks]

Well N900AT now flies straight!! We checked dangling gear and the right flap and the ailerons and everything seemed to check out. So we put her up on jacks and checked the rudder again. We locked the pedals in neutral and found that the rudder was one degree left, but the book says it should show one degree right. So we made that adjustment and things improved but were not perfect. So I landed and mentioned that someone on Mooneyspace (Dan) had mentioned that we should check to see that the ball is centered when the plane is level, and with no prompting my mechanic got out his level and put it across the seat tracks and once level we could see that the ball was eclipsed by the left line while there was a gap to the right. So after adjusting the instrument the plane flew straight! - Thank you everyone for your suggestions. I thought because right rudder seemed needed in climb but that a little left seemed to be needed in cruise that all was well, but left rudder just made the plane left wing heavy. Also compared to my old Beech Sierra the Mooney doesn't seem "seek" straight flight. I think there's less dihedral in the Mooney wings and the longer body and shorter wings of the Beech contribute to a noticed go-straight quality that has always seemed more vague in the Mooney. Once we removed the ADF antenna and the larger rotating beacon from near the back of the Mooney, the left-wing heavy sensation just got out of hand. Now I can fly at altitude and once things settle down I can put on the autopilot and the plane flies straight with my feet flat on the floor and the ball is centered. Next, I'm going to look into new panel mounts.

[Shadrach]

Marks,

You've gotten some very good advice here. Be slow and methodical. I want to reiterate that a gear swing is a good idea. I once had one of the gear door heim joints freeze and it caused my gear door to bow/flex down into the slip stream. It was not blatantly obvious unless you did a thorough examination of the plane with the gear up and locked. It manifested itself with a slight right roll tendency and 1/4 ball off center to the right.

[Guitarmaster]

Interesting topic.  I have the opposite problem.  The right wing is heavy.  

It takes right rudder to keep the heading from drifting and of course, that increases the right wing low.

 

The roll is far more pronounced with the flaps out.  Clearly there is a flap alignment problem.  We already pulled the left flap up a few degrees, yes, you read that right , a few degrees and it needs more.  

The airplane rigging was all jacked up.  In the annual, we re-rigged the ailerons so they are even with the wing and the yoke is straight.  After we did this, the left flap was hanging about 1 inch down from the back of the aileron!  Pulled the flap up, and got five knots extra speed!  

 

She is still rolling to the right and pulling to the left, albeit not as bad.  I.E.  If I keep the wings level, feet on floor, the airplane will flat-turn to the left.  

With the airplane wings-level and no heading change, the ball is hugging the left lubber line with right rudder pressure being applied.

We are attacking this issue in the upcoming week.  We will figure her out eventually!
 

to be continued....

[Hank]

Don't forget to check your PC servos and lines. I replaced all of the cracked plastic fittings in mine, then a couple of years later the plane began pulling to the right; in a couple of months it went from straight to almost 20° required on the heading bug, then I had to keep left aileron and/or rudder all the time. Turned out to be a torn boot on an aileron servo. Brittain redid it for $124 plus roundtrip shipping to Oklahoma.

[Guitarmaster]

The pc system is totally rebuilt. The lines were crumbling and the boots were leaking.

It works like a charm now!

[Hank]

I love a simple solution! Congratulations, now go enjoy your plane.

[philiplane]

I find I don't get reliable information from pilots when they have an out of rig plane. I have developed a flight test profile and checklist that I use. I do the test flight myself, with the plane loaded evenly, and then fill in all the blanks on my list. I usually make just one set of ground adjustments and one verification flight to solve any rigging problem. If you are trying to get your mechanic to fix an out of rig condition, and he's not an instructor, or at least  seasoned pilot, then you will spend too much time figuring each other out. 

[Llcrt]

Marks,

I also have a J that has to put in right aileron to fly straight, but my plane is rather slow and I think its because of the rigging issues.  Do you recall what your airspeed was when you had your issue and did you get it resolved?

[Guest paulie]

As someone who has rigged flight controls on B727s it is imperative that the rig steps be followed exactly. Centering the yokes and rudder pedals is step one. Skip a step or do it out of order and you'll be chasing your tail. As far as a mechanic who "eyeballs" stuff I would kick him out of my hangar. I assume you're paying him through his learning curve.

[gsxrpilot]

A Don Maxwell rigging job made all the difference on my first Mooney. Don made it fly straight and fast.

[RLCarter]

9 hours ago, gsxrpilot said:

Don made it fly straight and fast.

 Need to get his guys to do mine. What kind of speed gain did you get and were they able to get it done while you waited?

[Guest paulie]

Never used Maxwell but his reputation is excellent. It is a poor bargin using a mechanic that may work cheap but spends the time your paying for trying to figure out what he's doing and never getting it right. Don't get me going on the ones that do cheap, pencil whip annuals. They are a menace to aviation.