Wing leveler troubleshooting

[yvesg]

Here is the schematic of my wing leveler. Does anyone knows how the 11900-25 (remote gyro) works? What is meant by “Sequenced Vacuum” and “Primary Vacuum”? The wing leveler was working fine until few months ago and now it pulls to the left side. Knowing how this works will help finding where the problem is. Thanks

Yves

Edited April 11, 2021 by yvesg

[TomM20F]

Is the airplane is rolling left, I would start by looking at the left wing aileron servo. The rubber boot is probably split. It really isn't a servo. The system is under vacuum so if the boot is split it is open to atmosphere. One aileron deflects. the other doesn't and the plane rolls. I would check this first before going crazy diagnosing under the dash.

[Hank]

^^^^ This first. 

Aileron servos are behind the inspection panel at the inboard end of the aileron. Helps to have small hands to remove them.

[David Lloyd]

Primary vacuum actually drives the remote gyro, sequenced vacuum is divided proportionally according to what the remote gyro sees.  There is a lever at the base of the remote gyro unit for more adjustment than the knob on the yoke can give.

Split boot, split line are the best bets after 56 years.

[yvesg]

7 minutes ago, TomM20F said:

Is the airplane is rolling left, I would start by looking at the left wing aileron servo. The rubber boot is probably split. It really isn't a servo. The system is under vacuum so if the boot is split it is open to atmosphere. One aileron deflects. the other doesn't and the plane rolls. I would check this first before going crazy diagnosing under the dash.

Hi Tom. I checked all 4 rubber boots and they seem to be OK. The aileron ones got replaced by new ones in 2008.

Yves

[yvesg]

If this can help: I recall when it was working better, I had to turn the yoke roll trim valve adjustment to the 3 o’clock position in order to keep the wings levelled. I checked the operation of the roll trim valve as well and it is ok.

I am setting up to have the appropriate equipment to troubleshoot this further. So do all agree if it rolls left, the leak is on the left side (red)? This info can help narrow the search area.

Yves

[TomM20F]

I am a new old Mooney owner so I am certainly not a Mooney expert but here is my logic. If there is a leak in the system on the left (red) circuit it is open to atmosphere. The aileron servo in the red left circuit does not pull on the aileron. The aileron then remains neutral. The right aileron (green circuit) servo that does not have a leak is under vacuum so it will pull on the aileron deflecting it down.  Right aileron down roll left. If you are rolling left the leak is in the left circuit provided it is a leak and not something under the dash. I think i have this right.

[FlyingDude]

I'm selling my old boots, if you decide you need them

[carusoam]

Yves,

how long til your next annual?

Expect that you may find that one of the plastic fittings holding the red and/or green PVC tubing together has decided to split...

many of them may be hiding under the the spring clamps they were originally put in place with...

 

Brittain was still selling the colored tubing... not sure about the other bits and pieces...  but they are easy to substitute...

As always... PP thoughts only, not a mechanic...

Best regards,

-a-

[Yetti]

2 hours ago, TomM20F said:

I am a new old Mooney owner so I am certainly not a Mooney expert but here is my logic. If there is a leak in the system on the left (red) circuit it is open to atmosphere. The aileron servo in the red left circuit does not pull on the aileron. The aileron then remains neutral. The right aileron (green circuit) servo that does not have a leak is under vacuum so it will pull on the aileron deflecting it down.  Right aileron down roll left. If you are rolling left the leak is in the left circuit provided it is a leak and not something under the dash. I think i have this right.

So there it a knob on the TC that can roll the plane left or right.  did you play with that yet.   Get a hand vaccum pump and start playing with the read and green lines.  There is a junction on the port side baggage compartment wall.

[Yetti]

The red tubing fails more often than the green tubing

[yvesg]

12 hours ago, carusoam said:

Yves,

how long til your next annual?

Expect that you may find that one of the plastic fittings holding the red and/or green PVC tubing together has decided to split...

many of them may be hiding under the the spring clamps they were originally put in place with...

 

Brittain was still selling the colored tubing... not sure about the other bits and pieces...  but they are easy to substitute...

As always... PP thoughts only, not a mechanic...

Best regards,

-a-

Anthony, annual was done a few months ago.

[yvesg]

11 hours ago, Yetti said:

So there it a knob on the TC that can roll the plane left or right.  did you play with that yet.   Get a hand vaccum pump and start playing with the read and green lines.  There is a junction on the port side baggage compartment wall.

Yes I did. It tests ok. Got a portable vacuum pump to step-up the investigation!

Yves