Importance of the Positive Control

[MBDiagMan]

The PC on my F is not working.  I did not bother fixing it because the TruTrak is going to be available next month.  At least for the last year and a half it has been available next month.  Anyway, I’ll get away from the sour grapes and move on to the issue:

Today I was on flight following and lost contact.  In the course of looking down trying to find a frequency, a wing kept falling off.  My wife would point it out, and I probably should have let her hold it level.  Anyway after all said and done no harm, but I understand that at bare minimum, the mid bodies need a wing leveler.  My C would fly straight and level hands off, but this one is not Al’s design.  It is a facsimile.

I think this must be why the mid bodies all got the PC if my impression is correct.

[Shadrach]

33 minutes ago, MBDiagMan said:

The PC on my F is not working.  I did not bother fixing it because the TruTrak is going to be available next month.  At least for the last year and a half it has been available next month.  Anyway, I’ll get away from the sour grapes and move on to the issue:

Today I was on flight following and lost contact.  In the course of looking down trying to find a frequency, a wing kept falling off.  My wife would point it out, and I probably should have let her hold it level.  Anyway after all said and done no harm, but I understand that at bare minimum, the mid bodies need a wing leveler.  My C would fly straight and level hands off, but this one is not Al’s design.  It is a facsimile.

I think this must be why the mid bodies all got the PC if my impression is correct.

Your plane needs to be rigged. It’s not a long, mid, short body issue. Also, the PC is very simple system. The little reading on it find someone who knows what they’re doing and have it fixed. Good chance that someone  who didn’t know what they were doing misroutedthe  hoses.

Edited July 25, 2019 by Shadrach

[kpaul]

39 minutes ago, MBDiagMan said:

The PC on my F is not working.  I did not bother fixing it because the TruTrak is going to be available next month.  At least for the last year and a half it has been available next month.  Anyway, I’ll get away from the sour grapes and move on to the issue:

Today I was on flight following and lost contact.  In the course of looking down trying to find a frequency, a wing kept falling off.  My wife would point it out, and I probably should have let her hold it level.  Anyway after all said and done no harm, but I understand that at bare minimum, the mid bodies need a wing leveler.  My C would fly straight and level hands off, but this one is not Al’s design.  It is a facsimile.

I think this must be why the mid bodies all got the PC if my impression is correct.

My F flys just fine without the AP engaged, trims out well.

[MBDiagMan]

36 minutes ago, Shadrach said:

Your plane needs to be rigged. It’s not a long, mid, short body issue. Also, the PC is very simple system. The little reading on it find someone who knows what they’re doing and have it fixed. Good chance that someone  who didn’t know what they were doing misroutedthe  hoses.

The PC is not working at all.  I am in the process of having it fixed.  Should be back to Maxwell in a few weeks.

By the way, thanks for the feedback guys.  Hope to hear more.

[carusoam]

My M20C flew perfect straight lines with no PC being connected...

It would drop a wing based on how heavy it was compared to the other side...

Fuel loading would start the low wing turn that would develop into a spiral if left unchecked....

1000 wonderful hours without a PC...

PP observations only...

Best regards,

-a-

[Shadrach]

14 hours ago, MBDiagMan said:

The PC is not working at all.  I am in the process of having it fixed.  Should be back to Maxwell in a few weeks.

By the way, thanks for the feedback guys.  Hope to hear more.

One misrouted hose can take the system totally off line. To complicate matters, Brittain’s vintage mx manual leaves a bit to be desired in terms of illustration quality and clarity.. 

[Shadrach]

3 hours ago, carusoam said:

My M20C flew perfect straight lines with no PC being connected...

It would drop a wing based on how heavy it was compared to the other side...

Fuel loading would start the low wing turn that would develop into a spiral if left unchecked....

1000 wonderful hours without a PC...

PP observations only...

Best regards,

-a-

I find the M20 airframe to be more tolerant of asymmetrical fuel loads then anything else I’ve flown. 

[gsxrpilot]

Get Maxwell to rig it when it's there. He's one of the best at getting Mooneys to fly straight and true. 

It will be faster as well.

[N201MKTurbo]

Your PC will work much better if the plane is rigged right. Getting rid of a heavy wing is not hard to do.

 

[BigD]

My C had an “inop” PC system when I picked it up after purchase. After a long flight across county home, I looked into PC system. I found one of the aileron Servos had a tear. This was an easy fix and the system immediately began working again. I was amazed as difference with a working PC system. There is some great advice here on the PC systems and occasionally parts for sale.


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[jamesm]

I had a PC system  in my '67C the turn coordinator when out on it about 2 years ago.  I initially  though no big deal so I didn't have the TC repaired thinking the Tru-Trak, Trio, or Garmin would have a replacement autopilot on the market  shortly. Boy was I wrong,  sure miss having the wing lever.

 

James '67C

[steingar]

I always thought they put the PC system in so folk didn't crash swinging the bar.

Mine is long gone, I've an Stec roll control autopilot in its stead.  An autopilot I rarely use.  A properly rigged aircraft should fly straight.

[Seymour]

mine works nicely (nice and level; rigged for single pilot so I draw from the right tank first if I have a passenger).  From what I heard from a previous owner, the rigging took several efforts to get right.

I assume it will have to be re-rigged after a paint job.   Is there anything I can do before dropping it off at the paint shop to make the job easier?

[MBDiagMan]

Well, I got it back from Maxwell last week rigged well and PC operational.  The PC didn't feel the way I expected but is working perfectly.  I tried flying a heading this morning and love how it works.  I took up my heading and kept it on course with a little rudder input.  The track log looked like I had drawn it with a straight edge.

It’s not a Trutrak, but since they won’t sell me a Trutrak yet, this will help until the miracle happens and the Trutrak is made available for Mooney’s.  I’m glad I got it working.

Edited September 5, 2019 by MBDiagMan

[Bob_Belville]

2 minutes ago, MBDiagMan said:

Well, I got it back from Maxwell last week rigged well and PC operational.  The PC didn't feel the way I expected but is working perfectly.  I tried flying a heading this morning and love how it works.  I took up my heading and kept it on course with a little ruder input.  The track log looked like I had drawn it with a straight edge.

It’s not a Trutrak, but since they won’t sell me a Trutrak yet, this will help until the miracle happens and the Trutrak is made available for Mooney’s.  I’m glad I got it working.

My first Mooney had only the PC which was really a great help, I never understand why some folks disable their or don't bother to repair if it is not working. 

Do you have the trim knob to fine tune the unit to hold a heading quite well?

[MBDiagMan]

Yes, but I have yet to have the need to turn the knob.  I will experiment with it a little Saturday.  I will get the feel for how sensitive it is.

[Jerry 5TJ]

The basic Brittain PC system is simple enough. If the turn coordinator / shuttle valve is working properly about the only other trouble-shooting involves chasing down leaks in hoses and bellows.  Decent documentation is available online.  

[Bob_Belville]

7 hours ago, MBDiagMan said:

Yes, but I have yet to have the need to turn the knob.  I will experiment with it a little Saturday.  I will get the feel for how sensitive it is.

It's been many years but I recall you can use the trim know to do something of a command turn. Try turning it full deflection and leave it there long enough to stabilize... I don't suppose it will be more than a 15 deg bank.

[Hector]

My 67C has the PC and the Accutrak AP. Love the combination. The Accutrak is slaved to the GPS and will fly the flight plan loaded in the GPS effortlessly. I do help it lead the turns to keep it from chasing the needles. Just recently my PC stopped functioning after years of working great. After some simple testing I determined the right Aileron servo was leaking. Bought a replacement servo from Alan Fox here and was in the middle of replacing that servo when I noticed the rubber part of the old servo had no tears but had actually separated from the can. Spoke with Alan on the phone and he told me how to re-tape it which I accomplished easily. Working like new again and flew yesterday from Jacksonville Florida to Oxford Ohio while letting the Accutrak do most of the flying. I fully intend to install a Trutrack when available, but I can wait as long as it takes because, frankly, what I have does most of what I need.


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