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G3X RV-8 upgrade

rotary57

Member
I have benefited from some of the installation threads already started, so I thought I'd start my own in case some particular detail proves beneficial to someone else.

Here is the original panel:
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Nothing super fancy, but very functional. The attitude indicator started to wander around a bit, and rather than replace it I thought I'd make the jump to a two screen G3X and all the benefits that would provide. There is very little room to work with, so I'm not retaining any of the steam gauges. The radio stack is remaining in the same spot, and I'm pulling out the CD player as I don't use it at all. I'll replace it with a jack for my iPhone wired into the audio panel.

Parts arrive, hurrah!
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After playing around with some printouts and a blank panel, I picked a layout, put it into CAD and CAM, and stuck it in the CNC.

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I used the mounting holes to locate the panel, i suck an appropriately sized drill bit in backwards for a perfect fit.

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I had to keep moving it around on the table as it's a little wide for my mill.

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Checking the fit

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I reused the radio stack mounting bracket from the old panel. This was actually the trickiest part of this phase, more art than science as there wasn't anything to really make absolute measurements off of and the alignment and work holding were kind of a pain.

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I admit it - I don't have real riveting tools... I just used a piece of round bar and beat it with a sledge. There is a piece of aluminum flat bar underneath the panel to preserve the surface finish from such a primitive method.

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Picking out locations for the modules - the GEA24 should fit where the AFS is now, which keeps me from having to extend any wiring.

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I carefully took pictures of all the connections, then labeled each wire as I took it off. I then wired them up to the GEA24 connectors.
 
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The GSU 25 I'm having more problem with, I'm planning on placing it on the forward side of this structure:

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Anyone have any better ideas?? It does yield slightly to a hard push, I'm hoping it's stiff enough to keep any undesirable motion from interfering with the unit.

I've done some of the harness work between the units, and that's about where I am in the process. I'm going to try to devote more time to it in the coming weeks and hopefully be done before Christmas so I don't have to fly commercial.

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Looking good so far. I am doing the two screen system with the autopilot. It is a really great value for the capabilities. I had a couple of questions for you. One, the stack on the right- how do you like that setup? Seems like most pictures I see have it on left, though I am accustomed to using my right hand for radios and throttle. Having the throttle on the left and the radios on the right and all the changes that get made in the climb with both things, makes me wonder. Second, are you using anything for back up?
 
I have never had a problem with the radio stack on the right, I find that in the narrow -8 panel, I can operate them with either hand equally well. With two active and two standby frequencies, I'm also usually prepared enough that I don't have to fiddle with the knobs much. Going from my experience flying into KHAF and KSQL under the San Francisco class B, I think my biggest workload in tricky areas is my vertical navigation: look at ipad, calculate needed descent rate to get under the next ring of class B while staying above class C, enter it into autopilot, repeat constantly - and DO NOT forget and let your autopilot set at -300 fpm take you past the correct altitude while you are busy navigating laterally or checking weather or something. I've come close. It's kind of stressful, and one of the reasons I'm upgrading to the G3X and it's nicer autopilot.

As far as backup goes, I have the second screen for single screen errors and a backup battery for electrical woes. For system or AHARS failures I have a angle of attack meter that will be installed on the glare shield for airspeed information in the pattern and an iPhone and iPad for altitude and navigation. This leaves me lacking an attitude indicator for total system failure in unintentional IMC. I think I'm comfortable with that for now, this is honestly never going to be a true IFR platform, at least in Colorado weather where IMC means icing conditions exist.
 
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I've gotten a lot done, and the plane is flying again!

GEA24 mounted
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removed trutrak servos (the Garmin ones came in yesterday, I'll be putting them in soon)

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No smoke!

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Make sure to upgrade your screens as soon as you get to this point! I had communication between the PFD and MFD, but I could not get the GEA 24 or GSU 25 to communicate at all - it was late at night, I was tired, and after checking and rechecking wiring, manuals, etc. I found my firmware was incompatible with the new units and went to bed. Somehow all my SD cards disappeared but I stole one from my wife's camera, got the screens updated, and all was well.

Here begins one of my few gripes with the system: I had a full set of working sensors for my AFS that I planned on using with the G3X - for instance this .5 to 4.5 volt, 0-100 gauge psi transducer which I verified is fully compatible with the GEA24 hardware. However it is NOT compatible with the software!! The manual lists a few choices of pressure transducers for manifold pressure, oil, etc. such as a .5 to 4.5 volt, 0-150 gauge psi transducer for oil pressure - exactly the same as my existing transducer except it has a span of 0-150 instead of 0-100. I figured I'd hook it up, set the calibration values, and be on my merry way.... except you can't calibrate oil pressure in the G3X. Or manifold pressure. Or fuel pressure. All you can do is pick part numbers from a list, it's ridiculous. Everything worked, it's just the values were skewed by the difference in span, so for example my oil pressure would read 75psi instead of 50. My AFS-2500 had no such problems - just like the industrial control systems I design at work you enter the output characteristics of the sensor and it displayed accordingly. I was pretty frustrated forking over another few hundred dollars for the Garmin transducers. Sigh.

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I raised the plane up for the AHARS calibration with a strap slung over a beam and down to the tailwheel. Once you get them a little bit off the ground, it's surprisingly easy to lift it the rest of the way by hand.

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And I'm back in the air! :D I'm going to start working on a shelf for the magnetometer, getting the autopilot installed, interfacing the GNS430, etc. but it feels wonderful to be done with the big stuff.
 
Small world....

I've been following your progress on this thread (I follow all RV-8 threads) but it wasn't until you posted the pic of your entire airplane that I realized... I've ridden in that airplane! And it was that ride in your airplane about 2.5 years ago that convinced me to buy an RV-8 of my own.

Congratulations on the G3X upgrade... you'll love it!

BTW, I have a couple nice pix of N678SR if you're interested. Just PM me with an email address to send them to.
 
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Wow! I wasn't expecting to see that, thank you both for the pictures! I guess she's covered a lot of ground since she was built 11 years ago. September 2011 was just 6 months before I took a ride in it - I sold practically everything I had, bought it as a student pilot and used it to get my license. I've had untold adventures in it since then. I even met my wife on a long cross country to California. Planes are great.
 
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