Seeking Opinion - Brittain Accutrak (B-11) & AccuFlight (B-12) install

[Zippy_Bird]

Hi All,

Hope everyone is enjoying some good Spring flying!

Seeking opinions today from folks that fly the Brittain AccuTrak and AccuFlight systems in their Mooneys.  Specifically I am trying to understand if folks have one or both installed, and in the case of both, is one more useful than the other?

My bird came with a basic Brittain wing leveler which I love and over this past year I have been wanting to enhance my basic system with more advanced features.  I don't have piles of cash right now to buy a fancy new autopilot, so instead I have been collecting components piece-by-piece to install the Brittain Accutrak (B-11) & AccuFlight (B-12).   The MS forums and resident expert K.W. have proven priceless in understanding these systems, and I am grateful to all who have shared knowledge.  Currently I am at the point where I need to make my final install decisions and send components off to Porter-Straight for rebuild and yellow tag.

My question to the forum is this... Should I install both systems (the AccuTrak AND the AccuFlight) or just one system (the AccuTrak OR the AccuFlight)?  If just one, why?

Always appreciate the diversity of thought and opinion on the forums, and often discover things I never considered.  Thanks in advance to anyone who throws in a word!

Sincerely,

Zippy_Bird

 

 

[takair]

I have both and love it.  The two together offer better performance than one alone, but any version is better than none.  If you look at some of my flight tracks, you can see how well it can perform.  It takes some initial patience, tweaking it, and it takes a little learning ton how to use it all together, but once you do, performance is on par with some of the more expensive systems.  There are a few threads about this…or happy to discuss on via phone….

[Hank]

I have both, too. AccuFlight follows the heading bug, great for straight-line flight. AccuTrak follows whatever I program into my WAAS GPS--straight lines, turns, instrument approaches, etc. But neither one does anything with the elevator, you still have to watch and manage your altitude.

[cliffy]

I had only the Accu-trak in my Mooney and didn't need anything else. It followed my course from the old GPS 155 TSO that I had. 

Didn't care about flying a heading as all I did was cross country point to pint straight line. 

I think 2 wires were pulled from the 155 TSO for left -right steering and all was good. Easy Peasy

If I needed a heading for ATC or something just the wing leveler and turn knob  sufficed  My airplane flies straight. 

Lots less install if you just go Accu-trak 

I think I have 2 systems in boxes on the shelf -1 Accu-trak /Accuflight combo and one Accutrack only  that I'm going to put up for sale here on MS soon.

Both were working when removed.  

[Echo]

i had both and only used Accu-Flite heading bug.  Worked fantastic.  You could compensate for wind drift with it.  Being able to quickly dial in a heading from ATC, or to program a heading that kept you out of weather was a common requirement that the Accu-Flite performed well.  Of course you could see the "magenta line" and set the bug to follow it.  I fly out/into Class C airspace and being given headings is common for me so I prefer to the AccuTrak.

[0TreeLemur]

I fly 1000 mile cross-countries several times a year.  At first did it all in my C by hand.  Arrived at my destination too tired.  Then like you I gathered the parts and installed an Accutrak II first in our C.  It was a fantastic magenta line follower.  But, after I finished my IR and started asking for diversions around buildups I started to covet the Accuflite.  Installed that my nav problems were all solved.  Life was so good, except for altitude hold.

Next I pieced together the parts for the Brittain AH system, and with the help of some resident knowledge here, got it working.  Ended up with a full two-axis autopilot, all done by tubing and rubber bands!

Now I fly a J with a "modern" autopilot- the 1980's vintage Bendix-King KFC-150.  Honestly, the Brittain wing leveler does a better job than the BK at keeping the wings level in turbulence because it is more responsive and smoother.  The dynamics of the Brittain wing leveler are just unbeatable it seems.  The altitude hold on the BK system is very aggressive at maintaining altitude within 20 ft.  The Brittain altitude hold had more like a +/- 60 ft variance, and provided a much smoother ride.  In mountain wave turbulence I just have to turn the BK altitude hold off or it will make my passengers (or me) puke.  The Brittain altitude hold, while responsive, seems a better match for the flight dynamics of a small airplane.

The Accutrak II would sometimes wander a bit.   Seemed random, but more likely to happen after several hours of a long trip.   The Accuflite of course depends on the rate of gyro precession on your DG- that would make long distance flights without the Accutrak a little zig-zaggy.

If you can find all the parts, I'd recommend putting in both.  You can use the Accuflite to help in maneuvering (e.g. holds) too if you need to look at an approach plate or weather data on your iPad while shooting an approach.  It's all great for workload reduction.

[Zippy_Bird]

Thank you all for the valuable insights.  Installing both is the way to go.  Decision made!

Question for the AccuTrak (B-11) folks... What methods are you guys using to drive the AccuTrack NAV1 and NAV2 inputs and with what hardware?

I currently have two old-school Bendix-King VOR/ILS/GS heads driven by KX-155s that should play nice with the AccuTrak NAV1 and NAV2 inputs.  I am however looking to add IFR GPS navigation as soon as possible given budget constraints.  May do it at the same time as this install if I can swing it.  Based on comments above it sounds like most have GPS navigation paired with the AccuTrak, but how and with what?

My understanding of the documentation suggests an analog output capable navigation/CDI head MUST BE INSTALLED to serve as an intermediary between a given navigation source and the AccuTrak controller for the purpose of generating the required volts/amps input signals for the AccuTrak.  Upstream from the NAV/CDI head, one can have their avionics of choice, but the signal MUST pass through an analog output capable CDI... or so that is my understanding.  In other terms, if one is rocking a modern WAAS GPS they also have a modern GPS/VOR/ILS/GS CDI (like a Midcontinent GI-106A) routing signal to the AccuTrak?

Is this understanding of a modern GPS setup correct, or are there other methods?

As always thanks so much for the comments.  Getting excited for the install!

Sincerely,

Zippy_Bird

 

[takair]

I have my GNs-430 coupled to mine.  Just uses the analogue left-right outputs which are switched by the GNS.  I never bothered hooking up my number 2 nav and have never missed it.  It might be of value when flying pure VORs or under failure of number 1….although then you still have heading…

[0TreeLemur]

The setup in my C involved a Mid-continent GI-106A connected to the GNS430W, and a BK KI-209 connected to the KX-155 nav/com.  The analog outputs from those two indicators were connected to the Accutrak II as NAV1 and NAV2.  I almost never used the VOR nav functions.  I'd say you can get by with just the GI-106A connected to the Accutrak.

 

[Zippy_Bird]

Hi All,

One last question before this thread slides into history... has anyone used a Garmin GI-275 to drive a Brittain AccuTrak?

It seems to me that if this were possible, it could help bridge a gap when upgrading avionics, particularly if one plans to get a GFC500 eventually, but can't muster the funds to do it all in a single install.  

Thanks to everyone who added to the discussion!

Z

[LANCECASPER]

15 hours ago, Zippy_Bird said:

Hi All,

One last question before this thread slides into history... has anyone used a Garmin GI-275 to drive a Brittain AccuTrak?

It seems to me that if this were possible, it could help bridge a gap when upgrading avionics, particularly if one plans to get a GFC500 eventually, but can't muster the funds to do it all in a single install.  

Thanks to everyone who added to the discussion!

Z

It might drive it but it's not on the compatibility list: https://static.garmin.com/pumac/gi275_autopilot_compatibility_c.pdf