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  #21  
Old 11-22-2020, 07:07 PM
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bruceh bruceh is online now
 
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Lon, got your PM. Let's talk! Sure sounds like a communication problem with the ADAHRS and/or GPS.
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  #22  
Old 11-22-2020, 07:37 PM
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Glad that somebody is able to help, it will be interesting to hear about what you find. Must be something amiss on the Skyview Network but puzzling that the display internal diagnostics don't seem able to provide more info?
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  #23  
Old 11-23-2020, 08:13 AM
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rleffler rleffler is offline
 
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Quote:
Originally Posted by lon@carolon.net View Post
I don't know exactly what the avionics shop did while my plane was there (for 6 weeks). I assume they used a voltmeter to check voltage on the power pins and continuity to the ground from the ground pins. (And, yes, I do remember my flight instructor telling me that the word "assume" should never appear in a sentence about anything having to do with flying.) The avionics shop checked something with a voltmeter, because they concluded my battery had a dead cell, and they replaced it with a new battery, though that didn't help at all.

When the Dynon "failed," the HDX displays did not go dark. They continued to work perfectly. It was the information they displayed that made me say the system "failed." The failures were the altimeter, airspeed, GPS location, and attitude failures that I described in my original post. The data displayed during these failures was confirmed by the Dynon internal "black box" files, by ADS-B Out reports, and by ForeFlight -- all of which showed just what the HDX displays showed.

I have wiggled the wires connected to the HDX displays, but doing that did not trigger any failures.

Thanks Bob. I will follow through with the manual verifications that you and Joe have advised must be done. Because I'm not the builder, and don't even have a hangar in which to work (my plane is tied down outside), I've been looking for another avionics guy near Santa Monica who is able and willing to do the work. I pay my bills promptly. But mechanics and avionics specialists are so busy here in Southern California that I'm struggling to find one that will take on the job or even return my calls.
Youíve provided some really valuable information. Did your engine data remain displayed? With the gps did the magenta line on you map disappear or just the lat/long data stream?

Many of the Dynon connections are through the sv-network. Itís looking like that may be your common denominator. The adahrs are on the sv-network. The flight plan data from the gps (magenta line displayed on your map) comes through the Sv-Arinc box, which is attached to the sv-network. The engine sensors are also connected via the sv-network, which is why I asked if they were affected. The gps lat/long data is a rs-232 connection, which is direct to the EFIS.

Identification of the specific data the is affected and then knowing how that data gets to the EFIS is going to be key to isolating the root cause of the problem.

While there are great avionics shops out there, many are also jacks of all trades and master of none. Because of the volume of different solutions out there, some shops just donít keep up with all the various vendors products.

I would focus first on a bad crimp, intermittent open circuit, pin not completely inserted, etc, on the cable going from your EFIS to your sv-network hub. The odds of multiple connections going into the sv-network being bad are slim, so thatís why the single cable between the hub and you EFIS would be a good starting point.

Are your cables the white ones with black plastic shells from Dynon, or did somebody custom make the wiring harness? Iíve never seen an issue with the Dynon cables, but that doesnít mean that canít have an issue. Taking the shells of the db connectors isnít that difficult, but if youíve never done it before it could be overwhelming. Is there somebody in your local EAA chapter that can mentor you?

If you have two EFIS, then swapping the sv-network cables between the two EFIS would be another great troubleshooting step. The the problem stay on the same screen or did it move with the cable swap?


Even if you donít understand all the information right away in the install manuals, I highly recommend getting a copy and reading it. It will help you understand your systems better.
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  #24  
Old 11-23-2020, 04:56 PM
lon@carolon.net lon@carolon.net is offline
 
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Quote:
Originally Posted by rleffler View Post
Youíve provided some really valuable information. Did your engine data remain displayed? With the gps did the magenta line on you map disappear or just the lat/long data stream?

Many of the Dynon connections are through the sv-network. Itís looking like that may be your common denominator. The adahrs are on the sv-network. The flight plan data from the gps (magenta line displayed on your map) comes through the Sv-Arinc box, which is attached to the sv-network. The engine sensors are also connected via the sv-network, which is why I asked if they were affected. The gps lat/long data is a rs-232 connection, which is direct to the EFIS.

Identification of the specific data the is affected and then knowing how that data gets to the EFIS is going to be key to isolating the root cause of the problem.

While there are great avionics shops out there, many are also jacks of all trades and master of none. Because of the volume of different solutions out there, some shops just donít keep up with all the various vendors products.

I would focus first on a bad crimp, intermittent open circuit, pin not completely inserted, etc, on the cable going from your EFIS to your sv-network hub. The odds of multiple connections going into the sv-network being bad are slim, so thatís why the single cable between the hub and you EFIS would be a good starting point.

Are your cables the white ones with black plastic shells from Dynon, or did somebody custom make the wiring harness? Iíve never seen an issue with the Dynon cables, but that doesnít mean that canít have an issue. Taking the shells of the db connectors isnít that difficult, but if youíve never done it before it could be overwhelming. Is there somebody in your local EAA chapter that can mentor you?

If you have two EFIS, then swapping the sv-network cables between the two EFIS would be another great troubleshooting step. The the problem stay on the same screen or did it move with the cable swap?


Even if you donít understand all the information right away in the install manuals, I highly recommend getting a copy and reading it. It will help you understand your systems better.
Bob,

Good questions, all.

My engine data does remain displayed. The gps magenta line disappears. I don't remember what color the cables are, but the builder bought the wiring harnesses from Van's. The cables must have been good to begin with, because the avionics were perfect for more than 2 years. The problems that appeared without warning show up in identical fashion on both displays. The altitude error shows up on FlightAware, as well as on the HDX displays. And the gps failure shows up on ADS-B Out reports as well as on the displays.

I'm working now with Bruce H, and his plan of attack is quite similar to yours, proving that "great minds think alike."

Thanks,
Lon
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  #25  
Old 12-05-2020, 12:52 AM
NinerBikes NinerBikes is offline
 
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Quote:
Originally Posted by lon@carolon.net View Post
Bob,

Good questions, all.

My engine data does remain displayed. The gps magenta line disappears. I don't remember what color the cables are, but the builder bought the wiring harnesses from Van's. The cables must have been good to begin with, because the avionics were perfect for more than 2 years. The problems that appeared without warning show up in identical fashion on both displays. The altitude error shows up on FlightAware, as well as on the HDX displays. And the gps failure shows up on ADS-B Out reports as well as on the displays.

I'm working now with Bruce H, and his plan of attack is quite similar to yours, proving that "great minds think alike."

Thanks,
Lon
Did you and Bruce H get this resolved, and what was the solution to the problem?
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  #26  
Old 12-05-2020, 09:45 AM
Pdtofly Pdtofly is offline
 
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Lon,

I have done quite a few installs, and have designed my own interconnect board. When I see a problem, I do a simple check. When you have the error, go to the Network Status page in setup up.

SkyView Network has redundancy and error detection features which allow it to detect and annunciate module and SkyView Network wiring faults. In the event that SkyView reports a problem with an ADAHRS, EMS module, autopilot servo, or a problem with the “standby network”, this NETWORK STATUS page will provide more information about the nature of the problem.

You can do this inflight. Go into setup, this will take you into the inflight setup screen. Select the bottom line which will take you into the ground setup screen. Then get into the Network Status screen. With the error shown, press the 2 and 7 button, and it will take a screen shot and save it to your thumb drive if installed, so when you get back on the ground, and if the problem goes away, you know where you need to start looking.

During install, if you simple swapped the white/blue with the white/green wires, it will show you the error in network status.

With my board design, I have a long SkyView Network test cable, and I just unplug the installed Network cables on both ends, replace it with my test cable and see what’s happens. If it starts working, I know the problem is somewhere in the installed cable, and then start checking the connectors on each end.

Hope this might help, and good luck. Report back what you find, as it might help someone else if they find they have a similar problem.

Brian

After rereading some of your posts, you might just have a screen with corrosion problems within the screen.

Last edited by Pdtofly : 12-05-2020 at 09:51 AM.
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  #27  
Old 12-06-2020, 04:55 PM
lon@carolon.net lon@carolon.net is offline
 
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Quote:
Originally Posted by NinerBikes View Post
Did you and Bruce H get this resolved, and what was the solution to the problem?
No, Bruce and I have not resolved the problem yet. Bruce helped a lot, via phone and text, by steering me towards the likely problem, and letting me know what to do to find and fix it. The problem is probably a short in the SkyView Network, possibly in the vicinity of the Van's Controller (i.e., the hub that SkyView components plug into). The exact location of the short is still unknown, though, because one possibility is that it's somewhere along the wires from the ADAHRS in the tail of the plane to the Controller in the avionics bay in the cockpit. The ADAHRS wiring harness is suspect, because the wires in that harness are zip-tied to a rib in the tail, to the sides of the tail and probably to the floor of the fuselage under the seats. This is the way the KAI tells builders to do it. But I've been advised that zip-tying to metal can cause chaffing and thus shorts. Searching for the short has been tough for me, for reasons I explain in my next post just below.
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Last edited by lon@carolon.net : 12-06-2020 at 04:57 PM. Reason: Correction
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  #28  
Old 12-06-2020, 05:26 PM
lon@carolon.net lon@carolon.net is offline
 
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Thank you very much to all of you who have offered me suggestions and wisdom. I now believe the problem is a short somewhere in the SkyView Network, and all would be good if I could find it and correct it. Alas, therein lies the rub. The SV Network includes several wiring harnesses, each of which has several to many individual wires. In my plane at least, the wires connected to each D-Sub Connector are bundled together with zip ties, and those bundles are zip tied to other bundles. This makes everything in the avionics bay secure, but it makes it impossible to inspect most of the wires, and even harder to inspect the D-Sub pins. I know this, because I removed the top of the avionics bay to get a good look at the wiring, and realized that in order to do a close inspection, I'd have to remove the wiring from the plane entirely, in order to look at it on my desk at home under a bright light. (I don't have a hangar. My plane is tied down outside.) I began by unplugging Connectors from the Van's Controller box, before looking carefully to see where the wires go from there. After getting the Connectors unplugged, I saw (too late) that they went through grommets that were too small for the D-Sub connectors to pass through. I figured out how to get one of the grommets out of the surrounding metal J-slot, but in doing so, I broke the power wire to the fan on the co-pilot side of the avionics bay. Fixing that wire requires new clips and I'm waiting for those to be delivered; but in the meantime, that made me worry about what else I might break trying to get the wiring harnesses home. To compound things, I then realized that some of the wiring goes through grommets into the engine compartment where they are permanently soldered onto things there, like the GPS and (I think) engine monitoring sensors; so those wires can't be removed from the plane. Getting a good look at the ADAHRS harness required me to remove the pilot's seat, and I did. So, by then, my plane was practically back to being a kit, and I was getting worried I wouldn't be able to reassemble it properly, and that I was -- or was about to become -- the proud owner of a batch of airplane parts suitable only for sale to a salvage company. Fortunately, I'm pleased to be able to report that I was able to get everything reassembled properly. But I'm just as far from finding the short as I was at the beginning.
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  #29  
Old 12-06-2020, 06:47 PM
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PaulvS PaulvS is offline
 
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Hi Lon,
Dang, this must be getting quite frustrating!

The electrical system for your RV-12 is quite integrated and complex, according to the wiring diagram, assuming it has been built according to Vans plan:

https://www.vansaircraft.com/wp-cont...1_12-18-18.pdf

According to this wiring diagram, the ADHARS is connected via a 9 pin connector. The autopilot servos are also hooked into this loom, which finally connects to the Vans hub via a 37 pin plug. So the fault could be anywhere, I don't think it will be trivial to find it, unless there is a visually obvious break or chafe somewhere.

I certainly wouldn't remove any harnesses from the aircraft at this stage! Post #27 by Pdtofly has some good suggestions for testing in-place. Otherwise about the best you could do on your own may be to unplug and replug all of the accessible Dsub plugs that carry the Skyview Network, just in case the cause is a poor connection between pins somewhere.
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Last edited by PaulvS : 12-06-2020 at 06:52 PM.
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  #30  
Old 12-06-2020, 07:39 PM
John-G John-G is offline
 
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Lon-

Most of the ADAHRS wiring goes through grommets as you pointed out .... however, as a builder I can tell you the first two locations I would look for chaffed ADAHRS wires are in the tail cone.

Have a look at drawing 31B-20 figure 1 .... you can see that the ADAHRS wires enter the tail cone from the center tunnel and bend left towards the left side of the tail cone then make a bend aft and swoop up onto the J-stiffener. I feel this is potential trouble spot #1.

When assembling, I felt where the wires jump up onto the J-stiffener would be a possible area for wire chaffing and protected the wires at that location using a piece of split tubing as can be seen in the following photo link.
http://4.bp.blogspot.com/-4E7VX0IV1H...0/DSC09489.JPG

The next area I would have a close look at can be seen on drawing 31B-21 figure 1. The ADAHRS wires are wire tied onto the F-1208 frame. If care was not taken installing the wires they could rub on the edge of the F-1208 frame.

My last suggestion for you would be to have a very close look at the wiring transition above the rudder pedals as can be seen on drawing 31b-25 figure 3.

Remove F-12125 and have a VERY close look at this area .... and while in that area remove the wire tie from F-12125C (both can be seen in figure 3). The amount of wires running under F-12125 makes it very difficult to correctly install F-12125 without pinching wires. It is like trying to stuff 5 lbs of cra* into a 3 lb bag. Note: In this area I placed some heat shrink tubing over the threads of the screw that secures F12125 so the wires can't chafe on the screw's threads when the screw is in place.

All the above areas are potential problem areas and merit a good looking over.

Good luck,
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Last edited by John-G : 12-07-2020 at 07:53 AM.
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