Looking for Opinions for adding Alt Hold to my Setup

I am building an RV-6 that I am setting up for IFR. I have a Trio EZ Pilot with a Navaid Servo. After more research, I have learned that Alt Hold is highly desired for IFR in the 6, so I am looking at options to add one. I found an affordable Trio Alt Hold, but will need to buy another servo. Cost will be 800-900 (will be used).

I have a Dynon D-100 and was thinking of adding a Dynon Servo and Using the Dynon AP for Alt Hold. I have the HS-34, so I have a knob for easily setting the alt. I can also easily engage the AP via the Disconnect switch. The potential down side is that I have two different autopilots with two disconnect switches. I am also afraid it could impact resale value. This option would be about $700. I suppose I could add a combined disconnect switch also, allowing to disconnect either or both.

Third option is to sell the Trio setup and buy two Dynon servos. The upside is that I can use the ARINC interface from the KLN-90B that I have. I am told the RS-232 output is slow and the Trio will not be solid when connected to this. The downside here is that I lose my Turn Coordinator on the Trio. This is part of my backup strategy if the D-100 fails. It would be my only Attitude backup. I do have the Garmin 396 and it has a turn coordinator display, but I am unsure if this is a reliable as the Trio. Net of selling the Trio, this option should be about $700-800.

I am hoping the community can help me a bit here. I do not have my IFR ticket yet and this is my first build.

Thanks in advance.

Larry

I don't see any reason not to do what you propose and put in a Dynon servo for pitch. You can always put in a second Dynon servo down the road if you get ahold of a cheap backup attitude indicator. You can use the same disconnect switch to kill both. When killing the auto pilot in a hurry, you don't want to have to think about it. I would definitely hook them up together. You should be able to kill either individually on the controller itself.

I did that very thing in my VFR 9A. I have a Trio for roll then added a Dynon for pitch controlled by my D180. I wired both disconnects to a single button. Works fine.

Start saving your money, because a lot of people are now going to tell you how to spend it!
If you intend to fly ifr it is all about back up capability.
Get the Trio altitude hold. Then, if the Dynon dies, back up #1 is the autopilot (not the Trio turn coordinator. The -6 is tough to fly partial panel. Not saying it can't be done, but...)
But you really should have a real back up, too. Something like a Dynon D6, GRT mini, etc. Forget the 396. And that backup should have its own battery, too.

I would suggest not buying anything until you are well along in your training; then you will be in a better position to decide for yourself.. Of course the down side of this is no actual IMC until you have back up flight instruments.

I'm doing the same thing. I have a navaid wing leveler. I bought ge mini x this summer for A&P fuctions and plan on adding pitch servo when I can afford it. The mini is so awesome ! And after I sold a few steam gauges it was only 1000$ ish.

Larry,

I would echo the advice to get your rating first and then design your panel around what makes you comfortable. I have an RV6 also that was equipped with the Trio EZ pilot for roll and and Tru-Trak for ALT HOLD. This was an excellent set up for easy VFR flying and would have been pretty good (my opinion) for IFR. When I got my IFR training (at GATTS in Manhattan KS, using a 172RG) I discovered that the Turn Coordinator was a pretty important item during my training. At GATTS they cover up the Attitude Gyro for your entire training time (I am not kidding, the whole time). The only time I saw the Attitude indicator was on the check ride, where I found it to be an slight distraction from the task at hand.

When I got home I tried to fly the RV with the TC feature on the Trio and did not find the response fast enough to be useful. It is a good cross check in a steady turn, but for me to try to roll into a standard rate turn using it as a primary reference did not work well. Using it in combination with the Attitude Indicator is probably okay, but from a redundancy standpoint it did not meet my safety requirements. I ultimately replaced the Trio 3 1/4 inch unit with a Tru Trak Vision 385 (2 1/4 inch) unit. This allowed me the space for an electric Turn Coordinator (I have an old school six pack panel). This set up works much better for me. Also with the Vision I have GPSS which allows it to fly the holding patterns which the EZ Pilot does not do (Pro Pilot can). The GPSS, Alt select and Vertical Speed select are all very helpful for IFR type flying. This is not a meant to be a slam on Trio, if they had a 2 1/4 inch control head, I would have very seriously considered the Pro Pilot.

All of these choices are personal and your mileage my vary! The main point to my post would be that what I thought I wanted prior to training was somewhat different than what I felt I needed after getting my ticket.

If possible put off the panel choices until you have your rating in hand. Training will likely change your thoughts. I suspect that there will be another shift in my own preferences after gaining more experience in the IFR world.

For what it is worth...

Bill

I fly an RV-6 with a Tru Trak auto pilot and added the stand alone
Altrak VS Altitude Hold . Works great. Also have Dynon 100 & 120, and
wanted a separate stand alone system for redundancy . Also people at
Stein Air are a great source of info and equipment.






Doug
RV-6
KOWI

agree with Doug

We have the TT altrak and it works great, but only as altitude hold. In the near future we are going to upgrade to the TT vizion or their Gemini with AP functions. This will give us altitude pre-select and climb/descent rate control that will be a huge help in the RV in actual IMC.

Love the TT also because it is a standalone backup in case our GRT system has an issue (which it never has).

As others have said, this stuff is changing so fast, wait as long as you can!