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G3X autopilot in RV-8?

Robert Anglin

Well Known Member
We are making changes to the all new Garmin G3X system. One of the things that has been used in both the old as well as the new tough is auto pilot control panel GMC 305. The question would be. Is it worth it to put this unit in, given the small panel space of an RV-8. The new tough system G3X has a pretty good auto-P function built into it as it is. What are you guys seeing out there that have this GMC 305? Does it only come into its own when used IFR or does it get used a lot for VFR as well? I guess I am looking for what others think of this unit and its impact with respect to flying RV's?
Thanks for you time on this one.. Yours as always. R.E.A. III #80888
 
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Waiting to hear the answers with great interest myself.
Just at the beginnings of my panel planning so this is very timely.
 
We've been flying with G3X systems for close to three years Robert. We installed the 305 in the RV-6 about a year and a half ago, and it is simply outstanding - intuitive, easy to operate, easy to see. We just installed a Touch system this past week, and have to fly it, but while I have played with the Touch interface for the A/P in the hangar, I'll reserve judgement until I am in the air for awhile.

I did fly a factory RV-12 a couple of weeks ago with the Touch and the 305 - I used the 305 for all of the mode controls, and the Touch interface on the PFD to set altitude pre select, hdgs, etc. That seemed very natural - but then again, I am used to the 305. So....jury is still out on the Touch interface - will let you know what I think after a few trips.
 
GMC305

What Paul said! I flew the autopilot via the soft keys on the G3X for two years and then the GMC305 came out. I installed it and it is wonderful. My RV-8 has a two screen early G3X. Garmin GTN 650, GTX 330es and GMC 305. In addition I have three backup gages: Airspeed Attitude. Altitude. It all fits fine.


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GMC 305 Question.

Thanks Danny and Paul. We have maid up our mind at this juncture in time to install one of the 10" G3X tough screens and the auto pilot servos. These new G3X units are a good step up from the older units. We know that we can add a GMC 305 after the fact if we get to a point of adding a flight director at some point or find that the tough G3X dose not do as much or work as well as having both up front. I guess it boles down to having the independent unit if the 460 faults. And how the work load is made more fluid in flight, with only having the one or both at the same time. As we all know panel space and placement of doodads is high on the list of planning these changes. Thanks for the input, keep it going. Yours. R.E.A. III #80888
 
Another vote for the GMC 305. It really adds to the package and makes operating the AP a no brainer. Having dedicated AP controls just makes a lot of sense.
 
GMC 305

Almost every installation we do includes a GMC 305 even though the touch screen interface works great. The GMC 305 just saves one key push, and provides a more familiar look and feel for autopilot control. I've got almost 300 hours with a GMC305 and absolutely love it.
 
Sleep fixed it.

OK, I slep on it and read a few more posts like the one above, on do I need another A.I. and the response from our good friends at Garmin.
It is amazing how you can fix your problems in your sleep sometimes.
We will get the GMC 305 and find a place for it, "top left side of panel-free hand and all.". I think this will free up the EFIS "that" just a little more on the display side of manipulations and add that little bit more safety if the EFIS should happen to go fault and we need to go back-up A.S.A.P.. Thanks guys, and the Sand-Man, for this one. Yours as always. R.E.A. III #80888
 
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Is it worth it to put this [GMC305] unit in, given the small panel space of an RV-8. #80888

I have a G3X Touch panel in an RV-8 without the GMC305.

Having flown it for a few months, I wish I had dedicated AP buttons. There's more screen switching than I'd like under IFR, relying on the touch interface page.

Odds are good, if/when I have to pull the panel for anything, I'll find a way to fit the GNC305.
 
Pahan (Avionics Installations, in Spruce Creek) put his up on top of his G3x panel:
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I have a G3X Touch panel in an RV-8 without the GMC305.

Having flown it for a few months, I wish I had dedicated AP buttons. There's more screen switching than I'd like under IFR, relying on the touch interface page.

Odds are good, if/when I have to pull the panel for anything, I'll find a way to fit the GNC305.

I will also add a vote to install it (even though it looks like you have made up your mind to do so). I now have 10 hours on my plane and I wish this thread was out while I was building my panel:(. I will also install one if I ever decide to change my panel.
 
I have a G3X Touch panel in an RV-8 without the GMC305.

Having flown it for a few months, I wish I had dedicated AP buttons. There's more screen switching than I'd like under IFR, relying on the touch interface page.

Odds are good, if/when I have to pull the panel for anything, I'll find a way to fit the GNC305.

I have a GMC305 with G3X Touch installed with around 100h on it of which 40h are IMC. The main reason for the upgrade from the previous EFIS/AP was to reduce button pushing IFR. I love the GMC305.

Now IFR, I rarely touch the screen at all, using the GMC for all the AP controls and the knobs on the G3x for bug control.

I personally like to minimise using the touch during busy IFR - so more dedicated buttons/knobs the better IMHO.

Cheers
 
Odds are good, if/when I have to pull the panel for anything, I'll find a way to fit the GNC305.

Good thing no one took bets on those odds.

I had reason to pull my panel and true to my prediction, I called Stein and had him ship me out a GNC305.

Wiring was easy (although I have now run out of RS232 portion the G3X).

It took me about 2hrs to remove my panel and 4hrs to put it back in. RV-8's are for contortionists!

As others have said, the GNC305 is very intuitive. I'm glad to have dedicated buttons again.
 
You will love it.

If you ever need another serial port, you can just use the connection to the roll servo although you will lose the connection redundancy.
 
Thanks Brian, but I'm not following. My roll servo has a CAN BUS connection fre the G3X and a serial connection direct from the GMC305.

My G3X is serial from the GMC305, GTN MAPMX, GTN Connext, GDL39, and my backup COMM.

If I drop anything it would be the serial connection to by backup COMM.
 
Up-Date

You guys may like to hear of the progress on this one. We looked at putting the 305 on top of the glair shield, but liked it better below the glair shield. On the far left side we put the 305 at the top as high as we could. Just bellow that we put 340 audio panel and just below that GNC-255B. Then moved over as close and high as we could and placed the GDU-460.
By making the 3/4" angle rails on the radio stack a little long we found that we had room for A GTN-650 if we want to install one at a later date and we still had room below the radio stack to place all the little push-pull breakers to go to these new black boxes. This hole system is under construction and is all new world to us so it well be a couple of months before we understand how it all wires together. Placing the units in this order gave plenty of air space on top of the stack and putting 3/16" gaps between the units will get air around everything for good cooling. Sorry I am not good at posting JPG's to this site, but it is looking to be a great system if an old man like me can ever understand all its full utility. Thanks for the help on this. Yours as always. R.E.A. III #80888
 
Thanks Brian, but I'm not following. My roll servo has a CAN BUS connection fre the G3X and a serial connection direct from the GMC305.

My G3X is serial from the GMC305, GTN MAPMX, GTN Connext, GDL39, and my backup COMM.

If I drop anything it would be the serial connection to by backup COMM.

If you ever find yourself needing another port, you can disconnect the GMC305 from the GDU and just use the connection to the servo...it works fine that way although you do lose the redundant connection.
 
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