Brittain Autopilot Flight Tips

[tsuttles]

Ok guys it is installed and working but I need some real world flight experience to help with the system. I have the PC wing leveler, Accu track II NAV and Accu Flite HDG system. What is YOUR sequence of activation and what have you found that works with the system. I am going out for a flight tomorrow with the sole purpose of playing with the system again to try and learn it. My sequence so far has been:

 

1. Activate PC and trim for wings level

2. Activate the Accu Trak when on course but it seems to roam and does not really hold any kind of course. (BUT) I was reading more tonight and it says I should set my AccuFlite to the heading that it is tracking and activate the Accuflite system so I will try that tomorrow.

 

The Accuflite system alone seems to S turn a lot around the heading is that normal?

 

Please help.....

 

Tim

 

[Hank]

My PC system is on all the time. I don't use the thumb cutoff switch in the pattern because I like the high yoke forces to remind me to bank gently. I do not have the cutoff switch in the panel.

 

The AccuFlite system is stone simple. Set the heading bug first, then turn it on and the plane should do a good job of going in that direction. It does not compensate for winds, though, you have to do that by adjusting the bug. If it banks consistently to one side, then you have a leaking servo on that side. Brittain rebuilt my left wing servo for $124 a  year ago, and I retaped the rest of them using their instructions and recommended materials.

 

AccuTrak is more complicated. Mine used to make sweeping turns, sometime S turning, sometimes just banking right and staying there. Then I read somewhere that they both should be turned on. Set the heading bug, turn it on, then turn on the AccuTrak. That makes it work much better. But I have flown very few approaches with it; guess I need to practice some once I get the plane moved down here. [soon, I hope!]

 

Hope you enjoy your Mooney as much as I do my slightly older version. C's are great machines, and the Brittain systems just make them even more pleasant.

 

 

P.S.--I had to find a panel shot to see which is the AccuFlite and AccuTrak. I use the heading bug religiously, but sometimes leave it turned off, just because. The AccuTrak is used much less often, but I guess I really should practice. That's why I didn't know how to use it for a long time, and just thought it didn't work.

[takair]

The S turning is because the gains are not quite right. The install manual has a flight test section. Ref the AccuTrack, what radio are you coupled to. I almost always have it running off my GPS. I set the AccuTrack to HI gain. Mine sometimes S turns a little, typically in still air. This is because the gain is a little off. I almost always use it with both Accutrack and AccuFlite on at the same time. In extreme cross winds you will need to offset the bug a little to keep the CDI centered. This is normal. You can also do intercepts using the heading bug. Go fly it and Have fun with it. Once set up, it is a great system.

[tsuttles]

Wow all this really helps!! Keep em coming

[N601RX]

You can also play with the CDI deflection range on the gps, this is where it gets it signal from. Most gps's can be set between 5 miles down to .3 miles. I like the .3 mile range better, but you will have to back the gain down a little to use the .3 mile setting.

Also give it a minute or so to settle in. It has a large rc circuit inside that needs a little time to stabilize.

I've also found that a good lube job on the flight controls will help keep it working smoothly.

[N33GG]

My accutrak ll with the pc is tied to my 430w. It works incredibly well tracking gps, VOR, ILS , or whatever is being fed to the cdi. I don't have a heading bug or capability. I didn't have to adjust anything, it just worked after the 430 install. So I can assure you it is quite capable of intercepting and tracking very well, and I have a fair amount of autopilot experience to judge from. It will never be a century 41 or king 150 or 200, but for single pilot IFR or vfr, it is awesome for flying courses. I am very impressed and love it. No need for me to spend anything for upgrades.

Good luck and let us know how it turns out.

[tsuttles]

601RX I will try that tomorrow also. How do you "back the gain down a little", where do I adjust that?

[N601RX]

Look in the back of the install manual. Too low it will wander off course, too high and it will oscillate back and fourth. Be sure the flight controls moves freely before trying to adjust anything.

[tsuttles]

The S turning is because the gains are not quite right. The install manual has a flight test section. Ref the AccuTrack, what radio are you coupled to. I almost always have it running off my GPS. I set the AccuTrack to HI gain. Mine sometimes S turns a little, typically in still air. This is because the gain is a little off. I almost always use it with both Accutrack and AccuFlite on at the same time. In extreme cross winds you will need to offset the bug a little to keep the CDI centered. This is normal. You can also do intercepts using the heading bug. Go fly it and Have fun with it. Once set up, it is a great system.

I have it running off my 430W as the NAV1 and SL30 as NAV2. I will look through the manuals for adjusting gain. 

[scottfromiowa]

Since we installed the Accu-Flite w/heading bug the AccuTrak rarely gets used. The Accu-Flite just does a great job of ttracking the bug that is set. I agree that the Accu-Trak needs a little warm up. I hold the yoke for about ten seconds after turning on as it will sometimes do an aggressive turn to Trak. Settles down though. Yes, ours will do some lite turns left and right as it tracks. NOT a big deal though. We are not talking big S turns. if it is really hunting agree gain (adjustment is INSIDE the unit) needs adjustment. We run of a Garmin 300 with gain set to high. Altitude (Brittain) hold going in first week of April at Tulsa-Brittain. Will do full report on installation/function soon after.

Have fun learning/flying your Brittain's. You CAN adjust heading bug with it on too. Need a little more track left, just adjust the bug....that easy. Of course getting plan trimmed for hands off and getting wing-leveler trimmed for wings level is first before setting GPS Track and powering up Accu-Trak. I always do a re-entry of destination on GPPS/center it right before turning on Accu-Trak.

[cliffy]

Yes make sure your needle is centered before engaging the Accutrak- by resetting your GPS. I have the Accutrak only coupled to a Garmin GPS155 TSO. It works great. If you look you will read in the Brittian book that it is not certified for approaches. At least my book says that. Will it track them, in a word YES, is it legal? In a word NO, I wouldn't do it with a Fed on board. Now, that being said, mine will land on the painted center line of the runway from a GPS appraoch at my home airport. 

[tsuttles]

Thanks guys for all the information. I went up today and got more and more frustrated until I tried the L and R manual turn (cloud) knob on the accutrak and there was the problem. The servo control valve was wired backwards. After landing and a phone call to my AP I switch the red and green wires leading to the servo control valve. On the return trip home it flew the magenta line like a dream. All problems fixed and the unit is working flawless. I can see the problem, the airplane tracking right of course so the servo control opens the left when in fact it was opening the right taking me more off course and increasing the wrong signal. The accuflite system is nice for heading assignments for sure I feel like I have a more capable airplane already. Not sure I would want to be in Hard IFR yet without alt hold but this would be a great tool on those easier IFR days and single pilot.

 

As of right now glad I saved the 20,000.00 and went with the Brittain....  

 

Thanks again....

[takair]

The old switcharoo. For future reference, one way to ops check is to turn AccuFlite On, on the ground, with the engine running: With the heading bug centered the yoke should stay near center. Heading bug left, yoke biases left, heading bug right, it biases right. This is a good ops check for the system before launching hard IFR. The taxi test is also a good check of basic leveler function. Yoke should move opposite of a taxi turn. I've had the disconnect button and the pneumatic relay stick and then only noticed it when airborne. These checks prevent that.

[N601RX]

It's also possible that he crossed the plumbing lines and not the wires. Might want to double check just to make sure everything is per the install manual. It might save some confusion later on.