ADVICE ON OLDER RV AVIONICS FULL UPGRADE

Oh Wise Wizards of the VAF - I am a recent buyer of Tom Whelen's 1994 built RV4, a wonderful machine, well maintained, low hour, impeccably built - in 1994. All steam, barely useful GPS, etc - and showing signs of wear on the various electrical systems. So. I've been obsessively researching (I am an engineer by training, so get ready for a nerdy post):

I am fairly settled, and have quotes from Stein, for a single 10" G3X based EFIS and mostly garmin parts including full ADSB in/out, etc. My mission is VFR only, but I do fly often cross country for work and personal travel. I fly in mountains a lot - based in Utah, fly over CO Rockies at lot, etc. Space inside is a big limiting factor in RV4's, and I'd love to delete the lower between legs stack altogether. I fly by myself 75% of the time, with a passenger 25%. I do light aerobatics but no competition - I mostly fly to and from places in the west, XC. I cruise often at 12-14K feet, and my airfields are mostly at least 4K feet ASL.

Plan to is install all electric, no more steam. Garmin G3x, w/XM (like the better resolution and reliability over ADSB only), engine monitor, GPS20 adsb complaint GPS, heated pitot/AOA replace, Garmin pitch and roll servos using on board G3X controls (only, plane has no autopilot or electric trim now), GTR20 remote com, integrate existing King Com as Com2, Garmin GTR45 ADBS source/out/transcvr, and G5 backup instrument with its own battery. Update/move analog switching, alternator, battery - but keep those analog breakers and switches, no solid state new control box for that (?) in a new panel.

My debates are a few:

1. GTR45/GPS20 combo for ADSB 2020 in/out compliance vs standalone box (Lynx,etc). It is more expensive that the Lynx or Stratus options, but it fully integrates with the G3. I prefer the XM source over the ADSB for weather, traffic etc - but having both is a good backup. But **** its expensive.

2. iPad/Lynx/Stratus as permanent, always live backup w/iPad on dash, VS. ADSB vs. Garmin Integrated ADSB/GPS2020 with G5 backup. Of course, again, the separate low cost solution for backup is probably not as reliable. But, it gives me another full EFIS style screen via an Ipad on my right next to the G3x screen, for a lot less moola.

3. Keep an integrate my old King Com with the G3X and GPR20 as Com 1/Com2? Or just pull that hunk of metal out, its big, heavy and in the way and not that easy to integrate without a separate audio panel?

4. Audio panel vs. just internal G3X touch? Budget is busted, so hard to argue for it.

5. Autopilot panel vs. just internal G3x touch?

6. Pay Stein to wire (a lot) of it or no? Worry about their wire and harness lengths being pre made and not to fit, etc?

Trying to remember to keep it simple, yet, consider usability, safety and pilot workload.

I have one radio, the GTR20 with my G3X system. It's fine for VFR - don't forget that the GTR20 / G3X Touch combo allows you to monitor the standby frequency if you like - I usually set it up to listen to AWOS / ASOS. If you really, really want to have a second radio, you *should* get a separate audio panel, although a simple switch *could* work, but I think it's a janky solution. But reusing the King with all your new avionics? Ewwww.....

When I finally add a GTN, I'll put in the remote intercom, but for now, the GTR20's internal audio is just fine - all it lacks is a Bluetooth audio source.

I redid all the wiring in my RV-8A that I purchased 3rd hand. I spent the winter building the wiring harness on my dining room table. It's not hard, you just have to pay attention to the wiring diagrams that Garmin provides in its install manual.

I prefer the separate autopilot control head.

IMHO

4. Audio panel vs. just internal G3X touch? Budget is busted, so hard to argue for it.

Internal, with monitor function one radio is all you need for VFR. Save that money(and panel space) and use it on the dedicated A/P panel


5. Autopilot panel vs. just internal G3x touch?

I have built 2 planes with the G3X Touch... one with and one without the A/P panel. Believe me when I tell you... you want the stand alone A/P panel

6. Pay Stein to wire (a lot) of it or no? Worry about their wire and harness lengths being pre made and not to fit, etc?

I think it's worth it to pay, unless you can use time when you wouldn't be flying anyway to do the wiring. (and it will take longer than you think I'd bet) It will take longer than you think, and probably more feet of wire than you initially purchase, meaning extra orders shipping and down time waiting for wire/pins, supplies

When I had my panel re-done (full remove and replace) by Jesse Saint, the labor was only about 13-14% of the total cost, and I didn't have to do anything. I'd say its worth it.

ansonfogel said:

....
1. GTR45/GPS20 combo for ADSB 2020 in/out compliance vs standalone box (Lynx,etc). It is more expensive that the Lynx or Stratus options, but it fully integrates with the G3. I prefer the XM source over the ADSB for weather, traffic etc - but having both is a good backup. But **** its expensive.

2. iPad/Lynx/Stratus as permanent, always live backup w/iPad on dash, VS. ADSB vs. Garmin Integrated ADSB/GPS2020 with G5 backup. Of course, again, the separate low cost solution for backup is probably not as reliable. But, it gives me another full EFIS style screen via an iPad on my right next to the G3x screen, for a lot less moola.

3. Keep an integrate my old King Com with the G3X and GPR20 as Com 1/Com2? Or just pull that hunk of metal out, its big, heavy and in the way and not that easy to integrate without a separate audio panel?

4. Audio panel vs. just internal G3X touch? Budget is busted, so hard to argue for it.

(Skip #5).

6. Pay Stein to wire (a lot) of it or no? Worry about their wire and harness lengths being pre made and not to fit, etc?
....

Click to expand...

I'm basing my suggestions on very similar goals. The major difference is that my RV-3B is single seat.

1. I vote for the Garmin integrated system. However, on my RV-3B (using Dynon) I'm planning on using a pingBuddy for ADS-B in, although it won't talk to the EFIS.

2. On mine, I'll be using the iPad/pingBuddy as the primary nav display, with the EFIS as backup to that for that purpose.

3. Ditch the King and go with an integrated system from Garmin.

4. Use the internal one.
......

6. I've seen Steinair wiring and it's very nice. You'll still have to hook it up to the airframe and route the cables hither and yon. On the other hand, DIY is merely a time and money choice since the job is totally doable.

Dave

Not exactly the same situation as you, but I am doing re-wiring now in my 9. I had an old 695 GPS panel mounted that I am replacing with a Garmin GDU470. I am also replacing a PM3000 (the PM3000 is for sale if anyone is interested) with a new GMA245 Audio Panel.

I have been talking with SteinAir almost every day for two weeks now. After talking with them I decided to do my own wiring. As Dave said:

I've seen Steinair wiring and it's very nice. You'll still have to hook it up to the airframe and route the cables hither and yon. On the other hand, DIY is merely a time and money choice since the job is totally doable.

Click to expand...

This is spot on. Wiring is not difficult. It just takes a lot of brain power to make sure every end of any given wire has the other end connected to its appropriate place. Even if you have Stein, or anyone else, build the harness, you still will have to route it appropriately behind the panel. There is still a lot of labor after receiving the prebuilt harness.

The other side of the decision to build yourself or not is the tools. It does take specialty tools to do a good job. Don't skimp on quality to save a buck when it comes to wiring tools. Then there is the issue of having to order multiple times stretching the time out. Definitely experienced with that part of things.

I am with the others concerning using older equipment. If you are going to go down this road you will not save any time trying to wire the older equipment so it communicates with the new stuff.

If budget is a primary concern your choice for ADS-B compliance is pretty expensive for sure. There are other less expensive options available to meet your goals. Of course, that kind of decision is a personal one. You might think about some of the new ADS-B equipment coming out. One example is the Garmin GDL-82 that will be an easy install with existing Mode C transponders. For anyone with existing equipment this is going to be a contender. There is also the Uavionics Echo out there too. Those are just two other options you may, or may not, have considered that may be worth thinking about.

Whatever you decide, know the wiring is quite an undertaking in terms of time to complete. Good luck with whatever you decide to do.

Regarding the audio panel and re-use of the King Com radio: I think you will need the audio panel to integrate the King radio. Instead, you might consider going with the single Garmin GPR 20 remote radio and purchase a hand held radio as a back-up. Certainly lower cost, and the hand held is not reliant on any of the aircraft systems/power to operate.

Just a thought.

Perfect VFR panel IMO with dual screen redundancy, the only change I would make to this would be to install the new 470 touch screens
Garmin G3X, GTR200 Com, GMC305 A/P control Panel, GTX23ES Xpdr tied to GPS-20A GPS position source, GDL39R ADS-B In. (Full ADS-B in/out)

Walt, could you describe in more detail that panel/install out to the system level?

ansonfogel said:

Walt, could you describe in more detail that panel/install out to the system level?

Click to expand...

More info added to original panel post. More panel pics and equipment info can be found on my website or feel free to call me.

The G3X touch is great for lots of functions but you WILL want to have a dedicated Auto pilot to touch the wheel and quick access to buttons. I would strongly suggest at least leaving room for a GTN650. You will very likely want to move to some IFR flying based on safety and the cross country style you mentioned. Congratulations.

Ditch the King

Go with single GTR20. It has built-in stereo ICS and standby monitoring

Buy the G3X 10" GDU WITHOUT Sirius/XM built in.

Buy a GDL-52 portable and semi-permanent mount it for Sirius XM weather & music combined with dual-channel ADS-B "in" weather and traffic. It wires right into the GDU. Uses same interface plug as the GDL-39. And talks wirelessly to ipads, phones, aeras etc...

By all means go with the GMC 307 dedicated autopilot control panel.

Buy a used GTX 327 or better yet GTX 32 (remote) Mode C transponder. $400 either one all day long.

Buy a 2020 conpliant GDL-82 ADS-B UAT "out" and install with remote anonymous switch on panel.

Woola!

JLITD -

I love this way of thinking - would you mind terribly if I picked your brain via the old telephone (OK, not analog, but, well voice none the less)? Or email? I am [email protected]

My vote - have your panel built

RVbySDI said:

Not exactly the same situation as you, but I am doing re-wiring now in my 9. .................

Whatever you decide, know the wiring is quite an undertaking in terms of time to complete. Good luck with whatever you decide to do.

Click to expand...

Steve,
I agree with everything you said however my vote is to have someone like Steinair, Aerotronics, Jesse St. James, or Walt A. build the new panel and if possible even install it. Time and experience equals money. My panel was professionally built by Aerotronics in 2008 when the original owner built my RV7A. I have since (as you know) done a number of aircraft and avionics upgrades that frankly would not have been possible without a well designed and built panel with good schematics and plenty of picture documentation. All my wires are labeled or numbered and connected to plugs that are also labeled and grouped.

This well made panel allowed me to swap out my grips to military style grips and easily wire up A/P, Comm swap and freq swap grip buttons, transponder ident, CP push to talk trigger, and a flap extend/retract switch to the pilot's stick. It also facilitated conversion of my manual trim system to electric trim and wire it to both grips. All this was doable because my original panel wires were labeled and grouped together in well label cannon plugs. Schematics identified the appropriate plugs to connect to and what wires to tap or plug into. Pictures showed where these plugs were and what they looked like. Any time I had a concern or needed help Aerotronics was there to guide me and answer stupid questions.

As you know I recently upgraded to ads-b out with a Garmin 335 purchased from Steinair. I had Steinair build me a conversion harness which again made this upgrade much easier than all the rewiring that the upgrade required. It again provided a harness that was appropriately labeled for further upgrade if desired.

I'm all for saving money but I've discovered the real value of having professionals due the challenging work and me just connecting the dots (so to speak). It's also really great to have knowledgeable people to talk to who are willing to help you because they know your panel.

ansonfogel said:

1. I prefer the XM source over the ADSB for weather, traffic etc - but having both is a good backup. But **** its expensive.
2. iPad/Lynx/Stratus as permanent, always live backup w/iPad on dash, VS. ADSB vs. Garmin Integrated ADSB/GPS2020 with G5 backup. Of course, again, the separate low cost solution for backup is probably not as reliable. But, it gives me another full EFIS style screen via an Ipad on my right next to the G3x screen, for a lot less moola.
3. Keep an integrate my old King Com with the G3X and GPR20 as Com 1/Com2? Or just pull that hunk of metal out, its big, heavy and in the way and not that easy to integrate without a separate audio panel?
4. Audio panel vs. just internal G3X touch? Budget is busted, so hard to argue for it.
5. Autopilot panel vs. just internal G3x touch?
6. Pay Stein to wire (a lot) of it or no? Worry about their wire and harness lengths being pre made and not to fit, etc?
* Trying to remember to keep it simple, yet, consider usability, safety and pilot workload.

Click to expand...

1. XM weather works at all altitudes, everywhere. If you're low over the mountains out west and really need weather info, XM will be there, ADS-B might not. And as you know, sometimes the nearest airport is on the far side of the next mountain. (I used to live in the Arizona high country.) Garmin's newest GDL52 has XM, ADS-B, attitude, and battery backup, pretty sweet.
2. I've got an older iPad that was never very readable in the RV-8. Plus, if you are going to use it for backup attitude, you *need* a quick mount on the panel. Flying with it on your lap for attitude information will probably not work. I no longer even carry the iPad with me in flight, although I used it in the Cessna (which had control wheels, not sticks.) I'd go with the G5, or, if you have the GDL52, maybe an aera660 for backup attitude display. Dunno. I've played with the GDL39/660 combo and it seems to have enough bandwidth as a backup attitude indicator, but then you'd not have it for backup nav.
3. One comm radio with the monitor function (newer Garmins) works just fine, says I with 100+ hours in the -9A.
4. The GTR200 has its own audio panel that is supposedly pretty good. And the panel mount radio can be controlled from the G3X, so you don't need to buy the remote version. Gives you a little extra redundancy.
5. You'll really want the autopilot control panel. If you don't have room for the one with the knobs, the 307, I'll trade you my 305 plus cash for a 307.
6. I bet if you are careful and complete in telling Stein what you want, you'll get it. I was very pleased with them when they cut new metal for my panel. And if you don't have the correct crimping tool$, don't even think about doing your own wiring.

I know that there are solutions for mounting Garmin servos in the RV-8, and I vaguely recall that the -8 and the -4 have the same control stick, but you might want to double check what it will take to get the servos to fit. Hopefully not much, but just to be safe...

In my old RV-4, I had the GPS under the panel behind the stick, and the location was *terrible.* (Did the panel before GPS came out). I think you're wise to put everything you can on the panel. However, you should be able to put the GTR200 and the GDL52 under the panel behind the stick as you wouldn't be accessing them (much) in flight. And I had so much junk on my panel that I made it 2" deeper or so and shortened the control stick -- didn't seem to make much difference in the feel of the plane.

And guess who wants to make those same kinds of upgrades to his RV-8...

Ed

Opposite opinion

Ed_Wischmeyer said:

1. XM weather works at all altitudes, everywhere. If you're low over the mountains out west and really need weather info, XM will be there,

Ed

Click to expand...

Except when it's not.
I've had two completely different xm radios require "re-initialization". Apparently this is not uncommon, as there's a dedicated page on xm's web site to do this.
Unfortunately for me, the last time I really wanted it - crossing AZ/NM in monsoon season - the thing wouldn't work. And my fuel stop was out in the boonies with no cell service, no internet, so I couldn't get hold of xm to get it re-initialized. I was so angry I junked the subscription, got adsb-in, and haven't looked back. I do try hard to avoid being low over the mountains and really needing wx info.

Works for me

I just installed a basic G3X touch system in my 16 year old 8.

I had Stein do the harness, made life easier and would recomm no it. Also, get the drawing, you will need it!

No audio panel needed for a single comm. I am surprised at the audio quality of music through the aux input, my wife loves to crank up some music!

Scott A Jordan
N733JJ

Bring it to Redline at KHAO (Cincinnati), and get a turn key install in about three weeks..... Experts at G3X installation on RV's.

ansonfogel said:

JLITD -

I love this way of thinking - would you mind terribly if I picked your brain via the old telephone (OK, not analog, but, well voice none the less)? Or email? I am [email protected]

Click to expand...

ansonfogel,

I am a true proponent of using a Mode C transponder linked to a UAT-out transmitter for ADS-B out compliance. Cheap, effective and the ability to squawk anonymous when VFR to maintain personal privacy. The new GDL-82 combined with any legacy Mode C transponder is perfect for this. You even use the same single original transponder antenna. And don't over-pay for 1090ES "out" equipment not required unless you have twin turbos in your RV-4 or plan on crossing the pond to Europe (with 12" N Numbers - - rare for an RV). Be advised Mexico has no current plans to implement ADS-B out requirements and at this time Canada plans to mandate for only one geographic area. Again, you probably don't have 12" N numbers anyway. Finally, with 1090ES out you pay more to loose your privacy option for VFR operations. Nothing to hide but if you're flying around VFR letting the world knows where you are, how high you are, and how fast you are going that should suffice, thank you. They (ATC and FlightAware, directed marketers, kid on a computer etc...) don't need to know your personal details that don't have anything to do with your flight. Anonymous mode under UAT gives you your privacy without affecting safety.

Don't ever ask an avionics manufacturer or avionics retailer if you should buy the latest new avionics gee whizz box. Their answer is predictable. I proudly count myself within their ranks as a technology geek and system installer. In their defense they are generally good folks who are consumed with the latest technology and their enthusiasm for the shiny boxes and blinking lights can cost you money.

For the RV4, space is tight. So remote mounting whatever you can makes sense. I have transitioned from a die hard steam guage type to a mix of glass panel with good old analog ASI, Altimeter still in place as backups. I also had liked seeing my avionics and twiddling knobs. And now I am at the point of the more integrated approach with as little on the panel as possible with a few exceptions, like the dedicated GMC 307 autopilot controller.

If I were doing a personal RV4 I would go pretty much as I described in my "Woola!" post above with the addition of an aera 660 surface mounted with a RAM ball base. Alternatives (or additions) to the 660 could be your smart phone or a small tablet running Garmin Pilot or ForeFlight (which are compatible with the GDL-52). Your passenger could link their smart phone, tablet or aera to the GDL-52 also. The new GDL-52 is a magic box with everything included. I do have an Aviat Husky where I dedicated an aera 660 mounted in the rear cockpit. I would save that for later, if ever, in your RV4. The area 660 is basically a mini G3X without the flight instruments or air data. It was designed by the same team. The GDL-52 has a backup battery and provides horizon/AHRS and synthetic vision on top of the prior mentioned music, weather and traffic features to the aera 660 and Android or Apple devices.

I might spring for Sport version of the VPX system but that is attributable to my geeky tendancys. It is costly and you strike me as a more practical type. The main advantage of the VPX is electrical systems monitoring integrated into the G3X display. If you were outfitting a full IFR set-up in a less sporty more higher market value airframe then I would encourage the VPX. But for a fun low-cost very capable VFR RV4 i would suggest conventional breakers and busses. Especially on a budget.

With a makeover of this scope it will be faster and easier to re-wire the whole panel including bus bars, etc. Trying to salvage any existing wiring or switching out circuit protection designs is folly and will cost more in the long run. Using one of your mentioned panel builders will take care of that with a turn key replacement. Another advantage of using a professional panel shop is they will supply complete schematic diagrams with labeled wiring. Don't get too hung up on harness lengths. These guys know their stuff and can consult best and common placement of LRUs with appropriateness service loops. Once consulted you can run a string or seamstress measuring ribbon between components for harness lengths. With the G3X CAN Bus design the panel builder will designate beginning and ending devices (terminations) at the ends of the daisy chain. Again, let them help you with the design as that, along with aftermarket support, is a big part of what you get for your money.

I would guess that if you call around you might find different levels of accommodation from different panel shops. Reputation via word of mounth and community experience is important. It's also important to work with one who is open to giving you exactly what you want and not try to steer you into doing what they want. A friend of mine had a "our way or the highway" response from one shop who was insisting on only certain components from certain manufacturer with expensive options my friend didn't need or want.

Finally, if you have any desire to install all or a portion of your panel and you have the wherewithal and time you may well consider attending the AEA's Experimental Avionics Installation class in October in Lee's Summit, MO. Lots of fun. Highly recommended.

The GDL-82 ADS-B out unit and GDL-52 portable everything in unit, announced at OSH can be pre-ordered but will not be ready for delivery for about a month minimum. Your RV4 is functional for now so you have the luxury of time on your side to fully explore the possibilities. Upon which you have started in this thread by your initial post.

Jim

P. S. The GTX 327 and GTX 32 are functionally equivalent. The only differencenis the tray and the GTX 32 doesn't have a face plate. So if you have a conventional GTX 327 it can be remote mounted, just like the GTX 32. The G3X won't know the difference and will remote control either the same way.

jliltd said:

I am a true proponent of using a Mode C transponder linked to a UAT-out transmitter for ADS-B out compliance.

Click to expand...

Anyone know if someone out there makes an all-in-one 978 out box? I really want to be able to squawk VFR and not have everyone know my tail number, but it seems kind of silly go to buy two separate boxes for that.

It seems like the market is mostly dominated by 1090 boxes.

Tankerpilot75 said:

Steve,
I agree with everything you said however my vote is to have someone like Steinair, Aerotronics, Jesse St. James, or Walt A. build the new panel and if possible even install it. Time and experience equals money. My panel was professionally built by Aerotronics in 2008 when the original owner built my RV7A. I have since (as you know) done a number of aircraft and avionics upgrades that frankly would not have been possible without a well designed and built panel with good schematics and plenty of picture documentation. All my wires are labeled or numbered and connected to plugs that are also labeled and grouped.

This well made panel allowed me to swap out my grips to military style grips and easily wire up A/P, Comm swap and freq swap grip buttons, transponder ident, CP push to talk trigger, and a flap extend/retract switch to the pilot's stick. It also facilitated conversion of my manual trim system to electric trim and wire it to both grips. All this was doable because my original panel wires were labeled and grouped together in well label cannon plugs. Schematics identified the appropriate plugs to connect to and what wires to tap or plug into. Pictures showed where these plugs were and what they looked like. Any time I had a concern or needed help Aerotronics was there to guide me and answer stupid questions.

As you know I recently upgraded to ads-b out with a Garmin 335 purchased from Steinair. I had Steinair build me a conversion harness which again made this upgrade much easier than all the rewiring that the upgrade required. It again provided a harness that was appropriately labeled for further upgrade if desired.

I'm all for saving money but I've discovered the real value of having professionals due the challenging work and me just connecting the dots (so to speak). It's also really great to have knowledgeable people to talk to who are willing to help you because they know your panel.

Click to expand...

Jim,
Yep that all sounds good.

I'm all for saving money but I've discovered the real value of having professionals due the challenging work and me just connecting the dots (so to speak).

Click to expand...

Saving money is not the driving motivator. I don't think I am saving very much money at all as a matter of fact.

It was just over 12 years ago when I started my build project. At that time I knew precious little about building an airplane. I could have very easily bought a quick built kit and bypassed most of the construction needed for an airframe. I didn't do that. I bought a slow build kit. In the span of 5 years building I met a lot of new people I now call friends. I had a lot of help from those friends in building an airplane. During that time and the process of building I learned more than I could have ever dreamed I would have about building. More importantly though, I learned a lot more about me than I ever dreamed I would have.

8 years ago I embarked on the process of building my panel. I knew precious little about wiring an airplane. Again, I could have very easily bypassed the panel construction process. I didn't do that either. I bought a slew of expensive electronic gizmo boxes from SteinAir and began the process of learning what it takes to make them all work in an airplane.

I am interested in KNOWING how everything was installed in my panel. I am all about the EDUCATION part of experimental aircraft. I welcome that 'challenging work'. It gives me more knowledge and allows me to better understand how, and more importantly, WHY things work the way they do. That goes for retrofitting as I am doing now. Because I made great efforts to label and document everything 8 years ago, I am doing quite well in installing these upgrades.

Everything you said about labeling and documentation you ended up with in your plane holds true for mine also. That includes having support from SteinAir. A different company from your plane's builder went with but still the same level of support just the same. The same level of support whether they built the panel or I built it. I pick up the phone and ask them a question. They answer it. As you and I have discussed just a couple of weeks ago. I cannot imagine a company supporting experimental aircraft doing business any other way. In my opinion it is the only way any company should do business when selling to the 'general public'/non-professional builder/pilot if they wish to be successful.

Live Long and Prosper!

rmartingt said:

Anyone know if someone out there makes an all-in-one 978 out box? I really want to be able to squawk VFR and not have everyone know my tail number, but it seems kind of silly go to buy two separate boxes for that.

It seems like the market is mostly dominated by 1090 boxes.

Click to expand...

Sure. The Garmin GDL-82 will do what you wish. The Uavionics box will do so also. I would expect any UAT only box will have that capability to do so.

rmartingt said:

Anyone know if someone out there makes an all-in-one 978 out box? I really want to be able to squawk VFR and not have everyone know my tail number, but it seems kind of silly go to buy two separate boxes for that.

It seems like the market is mostly dominated by 1090 boxes.

Click to expand...

Yes. The Sandia Aerospace Sentinel. All-in-one Mode C andd UAT trNsponder.

install houghts

Think about a wing-x battery, a must weight savings. I have 2 in my RV12.

A systems engineering perspective

You're seeing lot of box-level input on function, integration, and long-term support.

You might consider human factors as well:
do the displays work for you?
does the information make sense to you?
can you see what you want, and need, when you need it?r

Step Back

Just thought I'd offer a counter point.

I flew a 4 with steam gauges for 13 years. Had that stack between the legs. Although it reminded me of the fighters I flew, it was too restrictive on long cross countrys.

However! Why not just get a kneeboard with an iPad mini and foreflight? There will be lots of $$$ surprises as you tear things apart, including unexpected down time. Just think of what else you could do with that cash - buy more gas, fly more, put it into the engine overhaul fund, vacations with the kids, etc. If you're building then it's a different story, but if it works fine now...

We all think when we buy an airplane that we will have it forever, but you won't. You're just a custodian and you won't get much back in your eventual sale price anyway and the next buyer may not like your choices. If everything works fine as is then just look out the window and enjoy the view!

Probably anathema to the folks on here, but just thought I'd throw out that unpleasant dose of pragmatism lol

Mike