How to “Use” Brittain Autopilot

[Vance Harral]

That blue plug does connect to an autopilot unit, but the signals it carries are outputs from the autopilot to the TC100EVT, not the other way around.  As indicated up-thread, the nav logic in the autopilot has to have some way to command left/right turns as needed to intercept and track a heading or course.  In systems with the TC100EVT, the autopilot does this by sending electrical signals to the TC via that plug, which in turn biases the TC shuttle valve to direct vacuum to the servos.

Were you installing this with a B-5 autopilot, I could show you exactly where the plug goes.  I'm not familiar with the B-6.  Hopefully the B-6 has the same plug receptacle with the same functionality.  But the post upthread from Ross Taylor indicates his B-6 interfaces to a different TC, not the TC100EVT.  It's certainly possible that the B-6 can interface with different TC setups, and I hope that's the case for you.

Edited July 23, 2020 by Vance Harral

[Lawyerpilot]

Thanks Vance, great info.  You are correct the TC100EVT was introduced in 1967, the airplane is set-up for the 1967 installation.  Ross’s system is set up with the original 1966 remote gyro Between the firewall and panel. In 1966 it appears they moved the remote gyro from the tail cone and moved it to between the firewall and the panel, 1967 and after the TC100EVT replaces the remote gyro for the basic PC system mounted in the panel.  I am trying to find a wiring diagram or something that shows me the Pin out for the connector on both the B6 14 pin trapezoid connector, and this blue round connector with 7 pins.  Now that you confirmed that the connector is the interface with the auto pilot,  It seems to me that I need to set up a common connector with correct pin outs.  Does that 7 pin Blue round connector on the picture look like the female on your B5?  Thanks, Lee

Edited July 23, 2020 by Lawyerpilot

[Vance Harral]

This is probably what you're looking for, Lee. This page is from the installation manual for our B-5, my guess is the B-6 is similar.  Pins C/N/F/T/P from the B5 controller are wired to an Amphenol 7-pin female connector, which mates with that blue, 7-pin male connector from the TC100EVT.  My understanding is the "POT WIPER" and "DRIVE TORQUER" signals are the logic signals which allow the controller to command turns via the TC100EVT.  I don't know the nature of those signals, though.  Probably a DC analog voltage, but it's possible they could be something fancy like a PWM signal.

 

[Lawyerpilot]

I also noticed that Ross has a BI-603 and mine in a BI-601.  I think difference is the attitude hold.  

[Lawyerpilot]

I see you sent that while I was sending pictures, I think you are right!  That looks like what I need!  Thanks so much for the help

[Vance Harral]

My pleasure, glad to help.

The guts of your BI-601 ("B-6") controller look similar to our 3902-1 ("B-5"), just a little more compact.  I encourage you to be very cautious with the rotating multi-plane mode select switch I've circled in red below.  It's complex, and a little bit fragile in my experience.  If it fails, it renders the entire controller inop.  It's a custom Brittain component, and with Brittain in hibernation, no one is available to legally repair it.  We sent our B5 controller to Brittain twice for IRAN of that switch, both times over 10 years ago.  It's held up OK ever since, but I worry about it.

 

[Lawyerpilot]

Thanks for the cautionary note Vance

 

[Ross Taylor]

Hey @Lawyerpilot Lee, I'm happy to see you're making progress on that system and got some parts - right on!  And wow, @Vance Harral , what a wealth of knowledge you've got. 

[Lawyerpilot]

Hey Ross, great to hear from you!  I heard back from Brittain today and nothing quite seemed to be exactly right when comparing my airplane to all the manuals and installations i have been studying.  While reviewing model seriel numbers for various installations,  I discovered that even though my aircraft was manufactured in October of 1965, the serial number reveals it is actually a 1966 model year!  just like yours.  I am happy, i have a newer airplane than I thought!  this also explains why i couldn't find any evidence of an installation of a remote gyro in the tail cone as they were in 1965.  I now believe that your airplane and my airplane, both 1966 E and C had the same system except your had the altitude hold on the BI-603 while I had the BI-601 with just the navigation.  I feel I am really getting close.  The various components I have accumulated have really been great raining aids, but now I need to actually finally figure out what I am missing for a 1966 installation.  I bet it should look just like yours.  Good to have a 1996 buddy.  now I am changing my profile to 1966. Lol.

[carusoam]

Build date... End of its actual construction.

Air worthiness date... detailed in the first log book after meeting test flight requirements...

Model year... All the variables that get included for a particular model... some parts bins need to be emptied.... some parts bins emptied before the end of the model year... no parts go to waste...

It helps to know each date... often they can be confusing... as some serial numbers get pulled out of the production line for various reasons and get put back in at a later date...

PP thoughts only, not a mechanic...

Best regards,

-a-

 

[Missile=Awesome]

On 6/29/2020 at 1:03 PM, Nukemzzz said:

Ok, so since buying my 66’ E In December I’ve only been able to fly it for 10hrs and I’ve not had much time to play with all the knobs. The 10hrs was mostly training and it’s been down for a couple of months now as the engine gets rebuilt. See my other thread on that one. While waiting on the engine I’m sorting other things. See my other posts on the flap pump and instrument panel overhaul. 

Next on my list is Autopilot. A couple of times I flipped switches and turned knobs and nothing happened so I put and InOp sticker on it and noted it for future investigations. The PC system is also inop  

I’d like to start with something I can’t find anywhere on the intertubes, including here... how in the heck to you operate this system?  It looks to me like I have a well equipped version and it’s worth saving. It’s an Accutrak 1... I’ve established that. However, next to it I have strange knobs that indicate pitch and altitude. I think they are vacuum pull switches, I’ve not seen this on other’s panels. 

What am I looking at here?  What does those knobs do?  What is the glass with two lines on the right of those knobs?  What can it do and how do I do it?  Is this likely connected to my King VOR?  My Narco HSI?  I don’t have GPS yet, but apparently it can connect when I do.  

Lastly, the wing leveler seems too evasive time me. I’d very much like a switch on the dash that disables it, once I actually get it working. Anyone else do this?  I don’t like the idea of having to remember to hold down that button down on the yoke while slipping on landing and such . I also worry about what it will do during a stall (lead to a spin maybe). My version has the remote gyro BTW. Not the TC type. 

Help me to be excited about fixing this thing so I can motivate myself. Lol 

You SHOULD get excited.  You have the makings of a great auto-pilot!  You first need to inspect the boots for ailerons and rudder to make sure they are not leaking.  Yes the rubber gasket in the yoke button can also need replacement.  The main control (you stated not turn coordinator) may also be non-functional.  If it is I would replace with a TC100 turn coordinator controller.  The accu-Trak will track a GPS heading very well.  Or a VOR.  The Accu-Flite uses a DG with heading bug and is EXCELLENT!  To use altitude hold you pull the pitch and trim for level flight (or climb). Once trimmed you pull the altitude hold and it will HOLD altitude.  There is an adjustment in the tailcone under a rubber boot (flat screwdriver) to adjust if the sight window is NOT aligned.  Result is that when you cancel the pitch you are out of trim and plane will pitch up or down.  Not sure why you are so concerned about a stall with autopilot on?  The Brittain stuff is NOT approved for approaches JUST for cruising.  The wing leveler alone is a nice safety feature.  There is an electric (under panel) solenoid that eliminates the need for the yoke button.  You flip a panel or yoke switch and it uses pressure to hold vacuum open or closed.  It is OFF no use of solenoid when pc is on (most of time) when maneuvering you flip the rocker and it uses electricity to shut off vacuum to PC system.

[Missile=Awesome]

On 7/23/2020 at 8:40 AM, Lawyerpilot said:

Thanks @carusoam, the TC100EVT is powered from the inverter on one side, but this plug comes out the other side, like it should connect to something else.  It is not needed to operate the PC.  It is directly inline with the power input.  One thought I had is that maybe it is just an extension of the inverter power to daisy chain to something else for power.  The schematic doesn’t show anything else attached.  The other thought is that this could be output to the B6 autopilot.  

I believe that plugs into a DG with heading bug

[Nukemzzz]

36 minutes ago, Missile=Awesome said:

You SHOULD get excited.  You have the makings of a great auto-pilot!  You first need to inspect the boots for ailerons and rudder to make sure they are not leaking.  Yes the rubber gasket in the yoke button can also need replacement.  The main control (you stated not turn coordinator) may also be non-functional.  If it is I would replace with a TC100 turn coordinator controller.  The accu-Trak will track a GPS heading very well.  Or a VOR.  The Accu-Flite uses a DG with heading bug and is EXCELLENT!  To use altitude hold you pull the pitch and trim for level flight (or climb). Once trimmed you pull the altitude hold and it will HOLD altitude.  There is an adjustment in the tailcone under a rubber boot (flat screwdriver) to adjust if the sight window is NOT aligned.  Result is that when you cancel the pitch you are out of trim and plane will pitch up or down.  Not sure why you are so concerned about a stall with autopilot on?  The Brittain stuff is NOT approved for approaches JUST for cruising.  The wing leveler alone is a nice safety feature.  There is an electric (under panel) solenoid that eliminates the need for the yoke button.  You flip a panel or yoke switch and it uses pressure to hold vacuum open or closed.  It is OFF no use of solenoid when pc is on (most of time) when maneuvering you flip the rocker and it uses electricity to shut off vacuum to PC system.

Thanks for the info. Not worried about a stall, just curious. 

Im still not clear on what the pitch pull does. Also, it seems to be a vacuum switch but hardly moves. 

[Missile=Awesome]

50 minutes ago, Nukemzzz said:

Thanks for the info. Not worried about a stall, just curious. 

Im still not clear on what the pitch pull does. Also, it seems to be a vacuum switch but hardly moves. 

Pull pitch in a climb or decent and it holds that pitch/decent level.  Can also pull in level flight and trim it is “locking in that pitch”. Will stay close to level without pulling altitude hold.  THAT will adjust if plane goes a little up or down to the level you set.

[Vance Harral]

1 hour ago, Missile=Awesome said:

I believe that plugs into a DG with heading bug

This is an interesting comment.

The B5/B6 systems which use the TC100EVT are not really designed to interface with a DG.  The controllers themselves have a heading select knob, and they interface to a remote compass in the tail which "tells" the autopilot controller the current heading.  However, I know from a casual conversation with Brittain some time ago that it's possible to interface a DG with a heading bug to the B5 controller if desired (I asked because I don't really care for the separate heading select and remote compass arrangement, we've had calibration issues with ours).  I don't know the details of how this would work, except that Brittain said for the arrangement to be legal it would require a mode switch to select between the autopilot controller and the DG for heading information.

So... one wonders if that switch simply switches the inputs to the TC100EVT between outputs from the autopilot controller and outputs from the DG.  If so, then it might be possible to connect a DG with heading bug directly to TC100EVT.  Whether that would be legal or not is a separate issue.

Looking at pictures of the Sigmatek 4000-series DGs that are used with the Accutrak system, it appears they require a 5-pin female ampherol connector to mate with the DG.  That doesn't match the 7-pin male connector on the cable from the TC100EVT, but perhaps there is an adapter.

[Vance Harral]

35 minutes ago, Missile=Awesome said:

Pull pitch in a climb or decent and it holds that pitch/decent level.  Can also pull in level flight and trim it is “locking in that pitch”. Will stay close to level without pulling altitude hold.  THAT will adjust if plane goes a little up or down to the level you set.

That describes the user operation of the pitch hold button in layman's terms.  The implementation is pretty clever: it actually senses changes in airspeed and/or "G" load, and applies elevator to counteract them.  I've attached a page from the NAV-FLITE II/B-5/B-7 Operating manual that describes the mechanism.

 

[Missile=Awesome]

7 hours ago, Vance Harral said:

This is an interesting comment.

The B5/B6 systems which use the TC100EVT are not really designed to interface with a DG.  The controllers themselves have a heading select knob, and they interface to a remote compass in the tail which "tells" the autopilot controller the current heading.  However, I know from a casual conversation with Brittain some time ago that it's possible to interface a DG with a heading bug to the B5 controller if desired (I asked because I don't really care for the separate heading select and remote compass arrangement, we've had calibration issues with ours).  I don't know the details of how this would work, except that Brittain said for the arrangement to be legal it would require a mode switch to select between the autopilot controller and the DG for heading information.

So... one wonders if that switch simply switches the inputs to the TC100EVT between outputs from the autopilot controller and outputs from the DG.  If so, then it might be possible to connect a DG with heading bug directly to TC100EVT.  Whether that would be legal or not is a separate issue.

Looking at pictures of the Sigmatek 4000-series DGs that are used with the Accutrak system, it appears they require a 5-pin female ampherol connector to mate with the DG.  That doesn't match the 7-pin male connector on the cable from the TC100EVT, but perhaps there is an adapter.

The more I thought about my comment, the more I believe I am incorrect.  I did not have the TC100 installed.  I had the remote controller for PC with accu-flute and Accu-Trak add on’s installed later...

[Missile=Awesome]

7 hours ago, Vance Harral said:

That describes the user operation of the pitch hold button in layman's terms.  The implementation is pretty clever: it actually senses changes in airspeed and/or "G" load, and applies elevator to counteract them.  I've attached a page from the NAV-FLITE II/B-5/B-7 Operating manual that describes the mechanism.

 

LOL.  I am thinking I was the layman Vance.  Your explanation found is much more precise and detailed...and of course correct.  My response was as a “user layman” in how I used the system in our old ‘66 E.  Pitch and altitude hold were very nice features and worked “pretty well”.  Our Accu-Trak System 20 with add on System 60 PSS is far superior in function.

[Nukemzzz]

8 hours ago, Vance Harral said:

That describes the user operation of the pitch hold button in layman's terms.  The implementation is pretty clever: it actually senses changes in airspeed and/or "G" load, and applies elevator to counteract them.  I've attached a page from the NAV-FLITE II/B-5/B-7 Operating manual that describes the mechanism.

 

Awesome sauce.   So this explains why the pitot line is T’d with one line going back towards the tail. Ive been wondering what system beyond the airspeed gage would need this as an input. 

[Lawyerpilot]

Thank you soo much Vance for the technical manuals that you sent me!  These are exactly what I was looking for!  Now that I understand all of the installations for the various autopilot systems (B5, B6, Tru Trac, Nav Flite, Tru Flite) Here is my problem, I have the 1966 installation that had the gyro P/N 11900-30 mounted between the firewall and the panel.  This gyro was only used one year (1966), and I can't find one.  In 1967 and thereafter the TC100 EVT was used as both the PC gyro and the interface for all of the navigation systems.  in 1966 the link to the auto pilot was a Shunt valve (P/N 860005-1), I cant find that either.  I cannot find an STC that authorizes installation of the TC100EVT back one year to 1966. I purchased a TC100EVT just as a training aid and it is certainly superior to the 1965 (P/N 11900-25 installed in tail cone) and 1966 (P/N 11900-30 installed between firewall and panel) and I think the reason they were not backward compatible is that the panel cut outs for 1965 and 1966 were not laid out for another instrument head.  The turn coordinators in these years were much smaller and the TC100EVT instrument face and could not just be swapped.  You would need a whole new panel and molded plastic, in 1967 and subsequent they designed the panel with the TC100EVT in mind.  I can see no reason why the TC100EVT couldn't be installed in a 1966 model because the airplane structure and operation is the same. In fact I have heard from several pilots that they replaced their 1996 (P/N 11900-30) with a TC100 and the system works as designed.  Has anyone ever installed a TC100EVT in a 1966 that you know of?  Thanks so much for those last few manuals for clarity.  I am really educating myself on all of the systems as try to get mine working, right now the best option would be a 1967 M20C installation in a 1966 M20C if that was actually a possibility.  Once I get a TC100EVT installed it seems to work with many systems with minimal installation.  Lee

[Missile=Awesome]

20 minutes ago, Lawyerpilot said:

Thank you soo much Vance for the technical manuals that you sent me!  These are exactly what I was looking for!  Now that I understand all of the installations for the various autopilot systems (B5, B6, Tru Trac, Nav Flite, Tru Flite) Here is my problem, I have the 1966 installation that had the gyro P/N 11900-30 mounted between the firewall and the panel.  This gyro was only used one year (1966), and I can't find one.  In 1967 and thereafter the TC100 EVT was used as both the PC gyro and the interface for all of the navigation systems.  in 1966 the link to the auto pilot was a Shunt valve (P/N 860005-1), I cant find that either.  I cannot find an STC that authorizes installation of the TC100EVT back one year to 1966. I purchased a TC100EVT just as a training aid and it is certainly superior to the 1965 (P/N 11900-25 installed in tail cone) and 1966 (P/N 11900-30 installed between firewall and panel) and I think the reason they were not backward compatible is that the panel cut outs for 1965 and 1966 were not laid out for another instrument head.  The turn coordinators in these years were much smaller and the TC100EVT instrument face and could not just be swapped.  You would need a whole new panel and molded plastic, in 1967 and subsequent they designed the panel with the TC100EVT in mind.  I can see no reason why the TC100EVT couldn't be installed in a 1966 model because the airplane structure and operation is the same. In fact I have heard from several pilots that they replaced their 1996 (P/N 11900-30) with a TC100 and the system works as designed.  Has anyone ever installed a TC100EVT in a 1966 that you know of?  Thanks so much for those last few manuals for clarity.  I am really educating myself on all of the systems as try to get mine working, right now the best option would be a 1967 M20C installation in a 1966 M20C if that was actually a possibility.  Once I get a TC100EVT installed it seems to work with many systems with minimal installation.  Lee

I would think Cee Cee at Brittain could get language for installation.  It is just an improvement on the remote controller.  Jerry wanted to install one in my ‘66 when plane was at Tulsa, but ours was working great.  Gentleman that bought our plane with a functioning PC and Accuflite/AccuTrak and Altitude hold pulled ALL out for dual G5 install.  The equipment would likely be for sale.  I can reach out if you or anyone else is interested...

[Lawyerpilot]

Hey Missle, thanks for chipping in.  Did your 66 originally have the 11900-30 mounted between the panel and firewall on the pilot side?  Lee

 

[Lawyerpilot]

The "blind" remote gyro without a face?

[Vance Harral]

19 hours ago, Missile=Awesome said:

The Brittain stuff is NOT approved for approaches JUST for cruising.

FYI, the B-5 system is approved for approaches, see below.  The APP setting on the mode select wheel effectively implements high sensitivity to the CDI needle, and logic in the controller will fly an intercept when within 60 degrees of the inbound heading.  There is no vertical nav on the approach, just lateral, but it will follow a localizer or VOR reasonably well.  A little hangar fairy once told me it does passably well on an GPS LPV approach as well.  I wouldn't say it flies approaches better than your average proficient IFR pilot could hand-fly them, but I would not hesitate to use it in the actual soup.

[Missile=Awesome]

2 hours ago, Vance Harral said:

FYI, the B-5 system is approved for approaches, see below.  The APP setting on the mode select wheel effectively implements high sensitivity to the CDI needle, and logic in the controller will fly an intercept when within 60 degrees of the inbound heading.  There is no vertical nav on the approach, just lateral, but it will follow a localizer or VOR reasonably well.  A little hangar fairy once told me it does passably well on an GPS LPV approach as well.  I wouldn't say it flies approaches better than your average proficient IFR pilot could hand-fly them, but I would not hesitate to use it in the actual soup.

NOPE 4 me...HARD NOPE.