Rudder Trim vs. Rudder Rigging Problem - Which is it?

Joe Cabral

Joe Cabral

Filing Flight Plan
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I hope this forum can settle an ongoing conversation with my A&P...

I've owned an Archer for 3 months, and the rudder trim has to be adjusted all the way to the right (clockwise) in flight and on stands to make the rudder straight and the pedals aligned.

I've asked, is this a rudder rigging problem?

My A&P insists it is not because when the rudder trim control is removed, the rudder is centered, and the pedals are aligned. Visual inspection of the removed rudder trim control doesn't reveal anything wrong with it.

I will buy another rudder trim control, but I'm wondering if I'm wasting money - if this is just a rudder rigging problem.

Is it rudder rigging or rudder trim control? Thanks!
 
Joe Cabral said:
I've owned an Archer for 3 months,
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What specific year and model Archer?

Has the nose wheel steering and rudder rigging been independently verified by the mechanic?
 
Bell206 said:
What specific year and model Archer?

Has the nose wheel steering and rudder rigging been independently verified by the mechanic?
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It's a 1979 Archer and the steering and rigging has not been independently verified. It has only been verified by my mechanic that I'm having the conversation with...
 
Bacho said:
Are the wings level?
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They appear to be level but I know appearance can be deceiving. I haven't had a real test for wings level... I suppose I'll need to have that done.
 
The rudder trim setting for hands-off straight & level cruise depends on airspeed and total weight. Since airspeed & weight determine AoA which determines the angle of the propellor plane, cruising slowly at max GW at low power requires more R rudder than cruising fast at high power when light. Those without cockpit trim controls but a semi-flexible fixed tab on the rudder, can bend that tab to increase or decrease its curvature to fine tune the rudder neutral position to suit typical payload & airspeed. Is your rudder trim control fully to the R all the time, even when flying solo (lightweight) and cruising at high speed / high power?
 
Joe Cabral said:
the steering and rigging has not been independently verified.
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Well, until you know the nose steering rigging and rudder rigging is good, I wouldn't buy a trim control yet especially since you see the problem in flight. Perhaps the mechanic has already checked both?

For reference:

1709858367761.png
 
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Bell206 said:
Perhaps the mechanic has already checked both?
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Thank you, yes the mechanic said he checked both but I didn't get a second independent check of that assertion. He doesn't have the rigging equipment/jig but he said he tightened cables and aligned the nosewheel. I don't think his adjustments were thorough and completed with the 'book' open. I'm therefore contemplating a second opinion but I don't want to get off on the wrong foot with this mechanic. I'm a newcomer to plane ownership and to this small airport where he is the sole A&P. My plan for now is to get a salvaged trim control, they're not that expensive, and if that doesn't help I'll be more convinced (and hopefully he too) that there is an underlying rigging problem, or something else requiring investigation... He suspects it's the wrong trim control but it matches photographically with every picture I've seen of a 65837-02. Besides, the trim controls for hershey bar winged Piper PA-28s is markedly different so it doesn't seem likely there was a mix-up in the hands of the prior owner (pre-Dec 2023).
 
MRC01 said:
The rudder trim setting for hands-off straight & level cruise depends on airspeed and total weight. Since airspeed & weight determine AoA which determines the angle of the propellor plane, cruising slowly at max GW at low power requires more R rudder than cruising fast at high power when light. Those without cockpit trim controls but a semi-flexible fixed tab on the rudder, can bend that tab to increase or decrease its curvature to fine tune the rudder neutral position to suit typical payload & airspeed. Is your rudder trim control fully to the R all the time, even when flying solo (lightweight) and cruising at high speed / high power?
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MRC01 said:
Is your rudder trim control fully to the R all the time, even when flying solo (lightweight) and cruising at high speed / high power?
Click to expand...
 
MRC01 said:
Is your rudder trim control fully to the R all the time, even when flying solo (lightweight) and cruising at high speed / high power?
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Yes, that is the case at all times, unfortunately.
 
I doubt the control is faulty and agree with Bell.

However; my recall of the Service Manual is that it has a “ merry go round”

to rigging . Rudder, trim and nosewheel are Al supposed to be done first.

It is a task best addressed by an experienced CHEROKEE Tech.

Rigging one portion doesn’t work.
 
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Joe Cabral said:
Thank you, yes the mechanic said he checked both but I didn't get a second independent check of that assertion. He doesn't have the rigging equipment/jig but he said he tightened cables and aligned the nosewheel. I don't think his adjustments were thorough and completed with the 'book' open. I'm therefore contemplating a second opinion but I don't want to get off on the wrong foot with this mechanic. I'm a newcomer to plane ownership and to this small airport where he is the sole A&P. My plan for now is to get a salvaged trim control, they're not that expensive, and if that doesn't help I'll be more convinced (and hopefully he too) that there is an underlying rigging problem, or something else requiring investigation... He suspects it's the wrong trim control but it matches photographically with every picture I've seen of a 65837-02. Besides, the trim controls for hershey bar winged Piper PA-28s is markedly different so it doesn't seem likely there was a mix-up in the hands of the prior owner (pre-Dec 2023).
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You fly in this thing and you can die in it. Get a 2nd opinion and screw his feelings.

People fly fair distances to go with a good mechanic for their planes. Get use to that idea.

Also, in my experience up here in Canada having a good mechanic is hard. Most can do the basic, but specific things like rigging and even figuring out a vibration issue in our engine? We had to go to 2nd and even 3rd opinion.

Don't buy bits just to see if that's the problem. What if next time you have some engine problems? Overhaul? I mean that is literally what one guy told us to do. I called the engine shop and they said are you insane? What if the issue is outside the engine? You just wasted a lot of money. Luckily the engine shop guy knows our mechanic and they talked and we moved away from that idea. Eventually we found a very grumpy and hard to nail down guy who does stuff on the side from the flight school, and he figure it out. I'd have insisted we stick with the grumpy but he was really hard to work with he'd say he would swing by to do something and never show. As such we get our basics done with our long term mechanic and if we have bigger issue, we know we might have go somewhere else.
 
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I highly doubt the problem is in the trim control and buying a new one will not fix it. Exactly what is the problem you notice in flight and in what flight regimes? The trim control itself is dead simple and I've never heard of one being "broken". The rudder neutral check is also pretty simple, block the rudder pedals and look at the rudder. Is it straight or not? Same with the nose wheel. I'd be suspect of the nose wheel being out of alignment in flight acting as a "rudder". Was the nose jacked up when checking the rudder rigging? Does it track OK when taxiing?

You really need to very clearly articulate the problem and when it's happening. Was the rig checked on the flaps for example? Are you sure its yaw that is the issue and not roll? (flaps checked?)

OP, you seem to jumping to replacing the trim as the solution. There are so many other and more likely, possibilities.
 
All good points here and I appreciate it. I will definitely take it to another larger service center out of the area -- probably the SkyTech Piper service center in MD (nearby). I'll come back to this thread with how it turns out.
 
If you have checked everything and failed to find a problem then you need to start all over because you missed something. I know that doesn't help but it's impossible to answer your question from our perspective, other than to just guess. As noted the rigging procedure is a linear step by step process. You can't jump into the middle of it and start adjusting things. I assume the airplane has been this way since you got it are there any entries in the logbook that mention control surface removal or replacement or rigging adjustment?
 
Joe Cabral said:
I don't think his adjustments were thorough and completed with the 'book' open.
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That right there. I have found way too many airplanes with controls out of rig because the mechanic didn't consult the manual. Half the time they don't even have the manual, and I think the other half don't read and comprehend well. So they just "tighten the cables" and mess everything up.
 
IIRC The Cherokee Trim System is not “ More Left vs More Right “ set up.

It is More Right to Less Right adjustment that exerts varying pressure

on the Right Rudder Pedal.
 
Dan Thomas said:
That right there. I have found way too many airplanes with controls out of rig because the mechanic didn't consult the manual. Half the time they don't even have the manual, and I think the other half don't read and comprehend well. So they just "tighten the cables" and mess everything up.
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When I rebuilt my Decathlon and rigged it per the service manual, I was amazed at how much better it flew. 40 years of accumulated tweaks can really get things out of whack.
 
You are new to the plane...did you speak to the previous owner and see what their take on it is?
 
Something I noticed from the service manual (pg 2C9) is that it is possible to install the trim w/o the spring being in the neutral position. "Install rudder trim mechanism and set it at neutral (no load on spring) position." notice that the "and set it at neutral" comes after the install. It is possible the mechanic thought it wasn't needed and didn't double check the position before connecting it to the system.

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I just saw something else in the manual. To remove the rudder trim control, you need to "Rotate trim knob to the extreme left (counterclockwise) trim position." (pg 2C9 step E(1)(c)). I wonder if the mechanic may have considered an install step to include "Rotate trim knob to the extreme right (counterclockwise) trim position" (not in the book)?

This would at least seem plausible especially if the mechanic was doing it memory rather than by referencing the service manual.
 
Joe Cabral said:
All good points here and I appreciate it. I will definitely take it to another larger service center out of the area -- probably the SkyTech Piper service center in MD (nearby). I'll come back to this thread with how it turns out.
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If you're talking about the one I'm thinking of, you might try Plane Care at Hagerstown, too.
 
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