PA28-181 Archer trim indicator

[Joe_B1]

A couple of days ago I took the archer up for a few circuits around the pattern. When I did my run up, I set the trim to neutral. When I was done flying, I noticed that the trim indicator wire was missing. I ran the trim wheel from full up to full down but no indicator. So I guess it somehow broke off. My question: Is there a way to determine takeoff position of the trim tab without the indicator wire before I get this fixed? The A&P's are backed up at my shop and can't get to it for a while.

 

[Hang 4]

Try gently pushing the plastic cover towards the passenger side. You might find it visible. Sometimes the cover can tilt a bit and cover it.

 

[Domenick]

I assume this is an Archer with a trim wheel between the seats.
The plastic cover is relatively easy to remove. Perhaps the wire indicator has slipped out of its spiral groove in the wheel. See the MX manual under Section V Surface Controls/5-20 Stabilator Trim Controls.
There's a marginally helpful diagram in the section.

A photo may help:

Also here are a couple links I saved on setting the trim indicator.
https://www.piperforum.com/threads/rigging-trim-wheel-indicator.22800/
https://www.piperforum.com/threads/trim-position-indicator.20868/

 

[Magman]

If it in fact fact broken you may want to find another Archer and see how many cranks from either stop puts you at Neutral.
IIRC Looking at the Stab from outside the aircraft the tab should be neutral when stab is also.
Either way; be prepared if you are not neitral.

 

[Joe_B1]

If it in fact fact broken you may want to find another Archer and see how many cranks from either stop puts you at Neutral.
IIRC Looking at the Stab from outside the aircraft the tab should be neutral when stab is also.
Either way; be prepared if you are not neitral.

Thats what was looking for! No problem visually checking for neutral at the stabilator. Thank you.

@Domenick, I will check the scroll, I can't see the threads you quoted but thanks for the photo of the wheel.

If I get any answers on where the indicator went, I will check back.

 

[Unit74]

It’s a quick fix for an AP. I don’t know what the prob was, but I had a similar issue on my PA32. Maybe 10 min to fix. No clue what he did.

 

[Domenick]

Once you find neutral by external inspection, count the turns (or quarter turns or whatever) from stop to stop. You may also want to mark the wheel in some temporary way (old-fashioned white-out works well).

 

[Joe_B1]

Once you find neutral by external inspection, count the turns (or quarter turns or whatever) from stop to stop. You may also want to mark the wheel in some temporary way (old-fashioned white-out works well).

That was my plan if the pointer is actually broken, thanks!

 

[Joe_B1]

It's fixed!

I took off the plastic cover and heard a loud "sproing" and the little indicator popped back into position. It apparently got caught under the cover. Still, I trimmed it to neutral and noted the position of the trim tab just in case it happens again.

 

[RonP]

Joe_B1,

Since the trim tab on the stabilator moves with the stabilator how do you know where neutral is on the trim tab relative to the indicator?

 

[Joe_B1]

Joe_B1,

Since the trim tab on the stabilator moves with the stabilator how do you know where neutral is on the trim tab relative to the indicator?

After it was fixed, I set it to neutral. Then I moved the yoke until the tab was in line with the elevator. I measured the distance from the yoke to the panel. Now I know if I set the distance from the yoke to the panel to that value, I can move the trim wheel until the tab is in line with the elevator and that will always be the neutral position.

 

[RonP]

Joe_B1,

Can’t that same relationship with the trim tab in line with the elevator occur at any trim setting other than neutral trim?

 

[Joe_B1]

Joe_B1,

Can’t that same relationship with the trim tab in line with the elevator occur at any trim setting other than neutral trim?

Right, but measuring the distance from the yoke to the panel will establish a neutral elevator position and then moving the trim tab to be in line with the elevator will get everything close enough. At least thats what I think will work in case the indicator decides to play hide and seek in the future.

 

[Domenick]

Try this.
Run the trim out to a full stop. Set the yoke until you have neutral by visual inspection. Measure yoke chrome exposed. Mark with black felt pen.
Count turns to the other stop. Set the yoke until you have neutral by visual inspection. Measure yoke chrome exposed. Mark.
Divide by two for both trim turns and yoke chrome. Mark.
Set trim wheel to middle position. Measure chrome. Visually inspect.

Now, the most important question is, does the plane take comfortably

 

[Joe_B1]

Try this.
Run the trim out to a full stop. Set the yoke until you have neutral by visual inspection. Measure yoke chrome exposed. Mark with black felt pen.
Count turns to the other stop. Set the yoke until you have neutral by visual inspection. Measure yoke chrome exposed. Mark.
Divide by two for both trim turns and yoke chrome. Mark.
Set trim wheel to middle position. Measure chrome. Visually inspect.

Now, the most important question is, does the plane take comfortably

Essentially what I did but did not do the middle thing. It seems like mine has much more up trim travel than down. On the trim indicator on the floor the neutral position is not in the middle, its closer to the front.