PC system hoses

[TheTurtle]

just an FYI for mooneyspacers.  Talked to Brittian today and they recommend 7/32" windsheild wiper hose for the lines under the dash from turn coordinator to pilot valve etc.

I had my pilot valve tested and as I suspected it was holding vacuum and making my plane very John Deere like.  asked him about sending me some new lines to replace the aquarium tubing thats there now and he suggested just going to the auto parts store and getting the wiper lines.

[cctsurf]

I love aircraft parts companies that take a real-world attitude toward parts and don't expect you to purchase the same thing from them with a blessing from the pope, the faa and themselves...

[MyNameIsNobody]

My perspective is that I don't want to buy your plane.  I want to buy the plane serviced by a licensed A&P replacing parts with certified parts.  If I ever catch a hanger fairy I will de-capitate it and put the head on the vertical stab to warn away other fairies...

[TheTurtle]

1 hour ago, MyNameIsNobody said:

My perspective is that I don't want to buy your plane.  I want to buy the plane serviced by a licensed A&P replacing parts with certified parts.  If I ever catch a hanger fairy I will de-capitate it and put the head on the vertical stab to warn away other fairies...

cool im not selling so we should be ok.  friends still?

[geoffb]

Good thing nobody asked you.  Also, I'm not sure there's such a thing as "certified" medical tubing as originally installed by Brittain.  If his mechanic will supervise and sign off him replacing his tubing, he's legal.

[cctsurf]

2 hours ago, MyNameIsNobody said:

My perspective is that I don't want to buy your plane.  I want to buy the plane serviced by a licensed A&P replacing parts with certified parts.  If I ever catch a hanger fairy I will de-capitate it and put the head on the vertical stab to warn away other fairies...

I'm not talking hangar fairies, I'm talking about how much of our planes came straight off of cars (door handles, alternators, gas tank vent valves--out of a holley carburetor, and those are just a few things I have personally dealt with) or off of the shelf and yet the parts must first be blessed by the oem many of which haven't "manufactured" one (by which I mean, put a sticker on one from an auto parts store) in years.  I know that's not true of Brittain, but as geoffb said, 

 

1 hour ago, geoffb said:

Also, I'm not sure there's such a thing as "certified" medical tubing as originally installed by Brittain.

They know that the tubing manufactured for windshield wipers is adequate for their system, why have to touch every piece of tubing, charge extra for it, and waste their time?

1 hour ago, geoffb said:

If his mechanic will supervise and sign off him replacing his tubing, he's legal.

 

[TheTurtle]

yep all is inspected by my IA.

[cliffy]

It all comes down to being approved by the manufacture.  It still has to be signed off by an A&P but it should be no issue with him as long as Brittain approves of it. It's legal, just like door handles and alternators. Brittain, because they are damn good at what they do, makes it easy for us in the after market, ancient world to maintain our airplanes. Ya think STEC would do something like that?  NOT!

[Gary0747]

The original hoses were latex surgical type tubing and would deteriorate with oxidation fairly quickly. Most Windshield washer tubing is made from EPDM elastomer which is superior to the original larex and may not have been available 50 years ago when the Brittain systems were originally installed. 

Edited January 4, 2017 by Gary0747

[Yetti]

You mean like the Fram G12 filters on the Brittian system?

Edited December 20, 2019 by Yetti

[211º]

Not sure what you meant by "John Deere like" – sluggish, stiff, something else?

I ask as I am doing a very slow analysis of my Britain B6 auto pilot.


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[TheTurtle]

Just now, 211º said:

Not sure what you meant by "John Deere like" – sluggish, stiff, something else?

I ask as I am doing a very slow analysis of my Britain B6 auto pilot.


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felt like the vacuum wasnt disengaging even with the thumb button pressed in or removed.  so I was always fighting the PC system.  Made it very stiff to move the alierons, a lot like driving a tractor or an old farm truck with no power steering.

I called Brittian this AM to let them know a package was on the way.  They said they had already gotten it, put me on the line with the guy working on it and he said he had already tested, diagnosed and fixed it.  shipped back out same day!!.  He said pilot valve (the thing hanging under the instrument panel) wasnt releasing all of the vacuum when the button was pressed.  I had sent the pilot valve and the thumb disconnect button.  He said the button was fine but he went ahead and replaced the orings on it as well.

[211º]

felt like the vacuum wasnt disengaging even with the thumb button pressed in or removed.  so I was always fighting the PC system.  Made it very stiff to move the alierons, a lot like driving a tractor or an old farm truck with no power steering.
I called Brittian this AM to let them know a package was on the way.  They said they had already gotten it, put me on the line with the guy working on it and he said he had already tested, diagnosed and fixed it.  shipped back out same day!!.  He said pilot valve (the thing hanging under the instrument panel) wasnt releasing all of the vacuum when the button was pressed.  I had sent the pilot valve and the thumb disconnect button.  He said the button was fine but he went ahead and replaced the orings on it as well.

Sounds very familiar to what is going on with mine. Thanks for the information.

And all of those people out there in Tulsa are pretty awesome. I have already had a few conversations with them and they have been great with the information and pointers.


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[MyNameIsNobody]

You should ask them about the electric solenoid disconnect for PC system.  Very nice as you flip a toggle switch and the electric solenoid blocks PC vs. holding button down to cancel PC.  I fly with PC always on (unblocked) unless maneuvering.  I did NOT like holding down the button.  The solenoid was NOT that expensive (.1AMU's) and install was straight forward.  I did with updated yokes.  Toggle on left handle of pilot yoke in similar position to PC button.  100% agree that Brittain is awesome to work with.

[MyNameIsNobody]

20 hours ago, TheTurtle said:

cool im not selling so we should be ok.  friends still?

Funny.

I'm not buying so Yes, we are cool honey bunny.

[cliffy]

I just wish that they gad enough time to get back into production on the alt hold "eyeballs". I think that is the only thing holding them back from being able to put out that system again. Same with resurrecting old on the shelf alt hold systems with a bad eyeball. 

[captainglen]

Automotive windshield wiper hose is rubber and will leak in a very short time. Aviation Tygon can work well but requires replacing all the fittings. Approved silicone tubing is the best choice for replacement although the wall thickness and O/D is much larger than the other two choices. Remember that a leaky Britin P/C autopilot can cut into your instrument vacuum making your horizon and DG unreliable.

[cliffy]

The "rubber" hose that the factory recommends lasts far longer now than it did back in the 60s.

The factory knows what it is doing. By using anything else you are stepping into the 'experimental" arena. 

Why is it difficult to go with what the factory recommends?

Why are we always trying to "out do" the guys who made the equipment?

Does anyone use  say a prop that is different than what the factory recommends just because they feel it's better than what the factory uses?

I just don't understand the thinking. I really don't. 

[DonMuncy]

2 hours ago, cliffy said:

The "rubber" hose that the factory recommends lasts far longer now than it did back in the 60s.

The factory knows what it is doing. By using anything else you are stepping into the 'experimental" arena. 

Why is it difficult to go with what the factory recommends?

Why are we always trying to "out do" the guys who made the equipment?

Does anyone use  say a prop that is different than what the factory recommends just because they feel it's better than what the factory uses?

I just don't understand the thinking. I really don't. 

No disrespect intended. I can't speak for everyone, but there are instances where the products, technology, etc. we have today is superior to what was available when the factory wrote the original specifications, etc.

For instance, with modern instrumentation and testing data, I think we can manage our engines better than some of the original recommendations.

We shouldn't do/buy something different, just to save a buck, but sometimes, there are products/procedures that are actually better.

The real problem is being able to tell the difference. And that is where a lot of our disagreements set in.

[cliffy]

Don

I agree with you to a certain extent. We do have better items now than 40 or 50 years ago when our planes were made. In this case, what the factory (Brittain) used 40 years ago is different than what they recommend now. It's a different material and they have checked it out and OK'd it. In fact, the auto industry had to improve their vacuum hose technology just to keep their own products working better. 

My concern comes from so much chatter about wanting to use "items" on certified airplanes that are not "certified" products just because they view the item as "obviously better than the certified product". or looks just as good but is cheaper. As an A&P I don't have the authority to go that direction nor does anyone else on certified aircraft. I agree that our current regs are elephantine and pedantic, the bureaucracy is outstanding in inefficiency and the FAA won't let go of any control even when the technology is used in other facets of "certified" aviation. It's plain stupid but that is what we are stuck with

 

[BigD]

Because my PC disconnect switch is disconnected and simply sitting in its place in yoke, I assumed the entire PC system was inop. However, reading this thread, I wonder: could an operating or partially operating PC system be the cause of my plane consistently wanting to roll to right? I’ve been thinking it was something else or just out of rig. Any ideas? 

[TheTurtle]

5 minutes ago, BigD said:

Because my PC disconnect switch is disconnected and simply sitting in its place in yoke, I assumed the entire PC system was inop. However, reading this thread, I wonder: could an operating or partially operating PC system be the cause of my plane consistently wanting to roll to right? I’ve been thinking it was something else or just out of rig. Any ideas? 

The disconnect switch just breaks the vacuum in the system.  I suppose if the line was capped it wouldnt be able to release.

[0TreeLemur]

13 hours ago, BigD said:

Because my PC disconnect switch is disconnected and simply sitting in its place in yoke, I assumed the entire PC system was inop. However, reading this thread, I wonder: could an operating or partially operating PC system be the cause of my plane consistently wanting to roll to right? I’ve been thinking it was something else or just out of rig. Any ideas? 

 I can't imagine a leak case that would cause it to consistently wanting to roll right.  That sounds like a bad vacuum valve on the gyro to me.

When I replaced the TC after installing a new panel in February, my son and I accidentally hooked up the vacuum lines backward.  Two engineers got it wrong!  I blame the fact that the manual uses vague and inconsistent notation, and the valve ports on back of my TC are not clearly marked.  For some reason the Red/Green notation becomes Left/Right.   Anyway, the improper connection was obvious when taxiing.   The PC system turned the yoke into the direction of turn, when it should have turned it away from the direction of turn.  That is how bad a misrigged system can get.  BTW we did fix it before the first flight.

[Hank]

2 minutes ago, Fred_2O said:

 I can't imagine a leak case that would cause it to consistently wanting to roll right.  That sounds like a bad vacuum valve on the gyro to me.

One of my aileron servo boots blew or wore a hole, and the plane turned consistently towards it, since the aileron wasn't deflecting properly. Some people either disconnect or remove their PC system for reasons I don't understand. There used to be much discussion about how to hold the button down all the time; seems the leading methods were 35mm film cannisters and broccoli rubber bands.

[0TreeLemur]

That's funny @Hank .   I can see how the film canister w/heavy rubber band would work, if you can find one today.   In lieu of that, I suggest an old 4 MP digital camera held on with a tie down strap as a modern equivalent.

I love the PC system.   When I first heard about it, I thought 'big deal'.   Now that I've done a few long trips, not having to worry about keeping the wings level, especially in turbulence, is such a relief.   Last week I flew 9 hours, most of it in rough air.  I had my seat slid back about mid-way with my right hand near the trim wheel and toes on the rudders just to provide a little nudge on the heading.  The PC system is a thing of wonder.