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65 M20E Controls and PC


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I took my E for a Taxi and run-up today after being in the Avionics shop for nearly 3-1/2 months, and had a couple of surprises. Are Mooney controls interconnected? When sitting still or moving, engine running and not running, applying rudder in either direction causes aileron deflection in the direction of rudder application. Was not expecting this.

I had dual G5's installed. Britten auto pilot was also removed. Left the PC system hooked up, mainly so it would provide vacuum to the step. The right aileron servo has a known leak. There is a noticeable deflection force to the left, easily (kind of) overcome, and goes away if the cut-out button on the yoke is depressed.

Is this due to the servo leak? What will happen in flight? Will I have to hold the cut out button continuously to keep if from doing something crazy?

My Mooney instructor and I are planning to fly it home tomorrow, depending on how we can resolve these issues.

I have a brand new (rebuilt by Britten) servo. Debating whether to install it, or remove/permanently disable the system, as autopilot is next on the horizon.

Any comments or advise would be appreciated.

 

 

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A produce rubber band or a 35 mm film canister will work to keep the button down as well. 
 
if you’ve got a good servo, swap it in. Should fix that leak. 
 

I fixed a series of leaks in mine which always revealed others. Took a little time to get it squared away, but the system is pretty straightforward once you’ve messed with it a little. 

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Aileron and rudder are interconnected by spring.  A working PC will actually cause the aileron to roll the opposite way when turning on the ground.  A leak in a PC that causes roll makes for long flights unless disabled.  You should see if you can eventually get it working.  A working PC and a working Brittain autopilot are as good as many modern units.  As a side note, the Pc is not required for the step, they are independent.  Also, retrofit electric kit for the step is also available should you decide you want to rid yourself of the vacuum altogether.

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Oh, also, I don’t recommend rudder movement on ground when not rolling.  I’ve seen the weld on the rudder bar break and that is a major PIA to change....  if you can easily move the rudder when sitting still, you likely have lots of wear in the system already.

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8 hours ago, oldguyscanfly said:

I took my E for a Taxi and run-up today after being in the Avionics shop for nearly 3-1/2 months, and had a couple of surprises. Are Mooney controls interconnected? When sitting still or moving, engine running and not running, applying rudder in either direction causes aileron deflection in the direction of rudder application. Was not expecting this.

I had dual G5's installed. Britten auto pilot was also removed. Left the PC system hooked up, mainly so it would provide vacuum to the step. The right aileron servo has a known leak. There is a noticeable deflection force to the left, easily (kind of) overcome, and goes away if the cut-out button on the yoke is depressed.

Is this due to the servo leak? What will happen in flight? Will I have to hold the cut out button continuously to keep if from doing something crazy?

My Mooney instructor and I are planning to fly it home tomorrow, depending on how we can resolve these issues.

I have a brand new (rebuilt by Britten) servo. Debating whether to install it, or remove/permanently disable the system, as autopilot is next on the horizon.

Any comments or advise would be appreciated.

 

 

What was your reasoning in removing the Brittain Auto pilot unit?

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Thanks to all for the replies!

After the comments, and looking at the schematics for the control and PC system, I have a better understanding of it all, and am more comfortable with doing the flight.

The rudder system is very tight, and just a slight pressure gave me the aileron movement while not moving.

The decision to remove the autopilot was mainly to eliminate the vacuum system. I am aware of the electric step conversion, and plan to do that. Also to make room in the stack for future autopilot, if BK or Garmin ever get it together for the E. It was also inop, according to the previous owner.

The avionics shop recommended keeping the PC system in place until we can move forward with an autopilot. The leak wasn't discovered until yesterday. My avionics guy rummaged around in his store room and came out with a still "fresh in the bag" from Britten servo, said he'd give it to me. I would imagine there would be other leaks to deal with also, though the tubing I can see looks to be in pretty good shape.

So that leads to a final question- does a working PC system enhance flight characteristics that much? Is it worth fixing, or since removal is pending (could be at least a year?) should I just permanently disable it?

Thanks to all....

 

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19 minutes ago, oldguyscanfly said:

Thanks to all for the replies!

After the comments, and looking at the schematics for the control and PC system, I have a better understanding of it all, and am more comfortable with doing the flight.

The rudder system is very tight, and just a slight pressure gave me the aileron movement while not moving.

The decision to remove the autopilot was mainly to eliminate the vacuum system. I am aware of the electric step conversion, and plan to do that. Also to make room in the stack for future autopilot, if BK or Garmin ever get it together for the E. It was also inop, according to the previous owner.

The avionics shop recommended keeping the PC system in place until we can move forward with an autopilot. The leak wasn't discovered until yesterday. My avionics guy rummaged around in his store room and came out with a still "fresh in the bag" from Britten servo, said he'd give it to me. I would imagine there would be other leaks to deal with also, though the tubing I can see looks to be in pretty good shape.

So that leads to a final question- does a working PC system enhance flight characteristics that much? Is it worth fixing, or since removal is pending (could be at least a year?) should I just permanently disable it?

Thanks to all....

 

I have an older C model that had the PC system install as an accessory, it has an on off button instead of the push button on the yoke. I love not having the PC system for most of my flights, infact the only time I turn it on is for longer flights when I want a bit of a break. I say a bit of a break because it still tends to wonder when engaged but the alt portion does a pretty good job once trimmed.

Brian 

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I love having the PC and AFCS. It takes a little getting used to pushing the button, but I’ve been doing it so long I don’t notice. The key is having it set up correctly. People are paying extra now for the blue wings level button. Britain was doing it over 50 years ago. Really reduces workload, in my opinion. I would have to pay over $5k, maybe $10k, to get the same features. 

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2 minutes ago, Yetti said:

Read the ground test section of the Brittian POH supplement.....  

I have a controller that has not been supported since I bought my plane, brittian said I could upgrade if I could find the parts but since I do not use it a lot it wasn't worth the expense. I will eventually install a newer autopilot when one gets certified for the older C models.

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Update-

First flight was uneventful, and the PC system preformed as expected, so I guess a lot of worry about nothing. We did have a battery charging issue, and was unable to bring her back home to KFCH. Since I had to leave the plane there, having the shop replace the leaking servo while they sort the electrical issue.

That being said, my first Mooney flight was wonderful! She flies straight and true, and was amazed at the speed/power settings. 1.5 hrs, and five landings, big smile still on my face two days later!

Flying the PA28R 180 back to Fresno seemed really slow lol

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When I purchased my 65 C I flew it from California to Ohio with a non-working PC which I had been told was inop. Once I looked into it, I found an easy to fix leaky aileron servo. I was amazed at how much easier to fly the plane was after that. I’d recommend trying to keep the Positive Control system if you can. If you do decide to take it out, you’ll find many here interested in it, a testament to how many of us enjoy the systems.


Sent from my iPhone using Tapatalk

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While involved with the alternator...

Take a look at the starter...

Its a very similar job...  old heavy one comes out, new lighter one goes in...

Make sure you get the seals adjusted to keep the airflow around / through the cowl for engine cooling...

PP thoughts only, not a mechanic...

Best regards,

-a-

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