Mooney M20C questions

[CJpilot316]

Hey all!

i just came out of a very extensive annual with my new-to-me '67 M20C. 

The last squawk that needs to be addressed is a leak in the fuel pressure gauge line, in front of the firewall. It appears a clamp has chafed it. Does anybody have a part number or a place to get the hose, or is it just a generic cut part?

Also, the plane has the positive control system, which I am not familiar with. How exactly does the system work, and how do I disable it? I do have the button on the yoke that I though was the disconnect. Anybody have some insight here?

 

-Cody

[Lrn2Fly]

The button on your yoke has 2 functions - press it to temporarily disable the PC, or pull the button out about 1/4" or so to keep it disabled.  The vacuum pump runs the entire system. There are 4 servos that are vacuum operated - one per wing, and 2 in the back for the rudder.  There is the gyro above your left knee that detects turn, just like your turn coordinator.  It directs each servo to either pull or release pressure to the airlerons and rudder to keep the plane flying level. You also have the trim wheel on your yoke to make fine adjustments, which merely balances the vacuum to the 4 servos.  When it's working, it's a pretty simple system. When it isn't working correctly, it is a real pain and must be fixed.

[Bob_Belville]

3 minutes ago, Lrn2Fly said:

The button on your yoke has 2 functions - press it to temporarily disable the PC, or pull the button out about 1/4" or so to keep it disabled.  The vacuum pump runs the entire system. There are 4 servos that are vacuum operated - one per wing, and 2 in the back for the rudder.  There is the gyro above your left knee that detects turn, just like your turn coordinator.  It directs each servo to either pull or release pressure to the airlerons and rudder to keep the plane flying level. You also have the trim wheel on your yoke to make fine adjustments, which merely balances the vacuum to the 4 servos.  When it's working, it's a pretty simple system. When it isn't working correctly, it is a real pain and must be fixed.

I've owned 2 '66Es. The first one had only the Brittain PC system when I bought it and I liked it a lot. Now that our Vintage planes are 50 years old it should not be a surprise that there might be leaks in servos and the plastic air lines. These are relatively easy to find and fix. And relative to anything aircraft related, cheap.

That PC is a life saver. I will permit you to look away for a while without the plane trying to do an aileron roll on you. Mooneys are slick, at least compared to Pipers and Cessnas. The knob to tweak the wings level can also be used for command turns. Play with it. 

[Yetti]

PHT hoses in Tulsa should have the hose.  Ask for the upgraded brown hose with integrated fire sleeve.

[CJpilot316]

6 hours ago, Yetti said:

PHT hoses in Tulsa should have the hose.  Ask for the upgraded brown hose with integrated fire sleeve.

They had it! Thank you!

[Raptor05121]

Cody, you need to update your tail number.

And tell the ladies and gentlemen who's plane you got to play with over the weekend.

[cliffy]

The correct PC tubing is color coded for each servo available from Brittain, The hose connectors are actually auto vacuum hose specified by the autopilot manufacturer (Brittain). Check with them and they will be able to help you out. They are real easy to deal with.   

[CJpilot316]

3 hours ago, Raptor05121 said:

Cody, you need to update your tail number.

And tell the ladies and gentlemen who's plane you got to play with over the weekend.

Don't worry brother, I'm gonna post a nice aircraft intro/story when I actually fly mine next week. Very few know the tail number and have seen the pics yet.

[Hector]

I would definitely try to fix the PC. Once fixed it is very reliable and very nice to have in IMC conditions. Also, at that point you can add a Britain Accutrack autopilot for little money. They show up for sale here once in a while. Additionally, and for added convenience, you can install a separate switch to turn the PC system on and off. I have it on my C and love it.


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[CJpilot316]

52 minutes ago, Hector said:

I would definitely try to fix the PC. Once fixed it is very reliable and very nice to have in IMC conditions. Also, at that point you can add a Britain Accutrack autopilot for little money. They show up for sale here once in a while. Additionally, and for added convenience, you can install a separate switch to turn the PC system on and off. I have it on my C and love it.


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To my knowledge, the system is working properly. What is required for parts to put the accutrak in?

[Hector]

To my knowledge, the system is working properly. What is required for parts to put the accutrak in?

You need a BI-805 servo control valve and an acutrack or accutrack II box. Your plane may already have the servo control valve but not sure. Go to the Brittain website for more details.


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