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  #31  
Old 05-19-2022, 10:40 AM
Untainted123's Avatar
Untainted123 Untainted123 is offline
 
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Location: Azle, TX
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Quote:
Originally Posted by steveahler View Post
Have just installed Trio Pro in my RV-6. What a wonderful addition.
I talked with Steve last night, he installed a Trio Pro in his RV-6 and literally didn't change any of the settings, hooked to a Garmin 150, and said he was good to go without making any adjustments at all to the Trio (which lends weight to the manual stating "The default settings are acceptable for most light GA aircraft").

Quote:
Originally Posted by BobTurner View Post
I would start by watching your 400W on boot-up, and copy down the software version(s) it is running. Send these numbers to Trio, and ask if they are compatible with your Pro. This sounds like a software mis-match issue to me.
I will check the software version tonight at the hangar, and send an email to Trio to confirm any mismatch there (it would be nice if this is the answer). I believe my 400w is running the latest firmware already however, but will confirm.

Just to be clear though, it doesn't really climb nor descend acceptably on or off of an approach. It has it's own connections to Pitot and Static, so presumably it would do it's own calculations for Air/Data? I could try testing it with my GPS turned off, and see if that has any effect...

Quote:
Originally Posted by FORANE View Post
...In both cases I was unable to obtain acceptable results in climb or descent...
Does this mean you never did get it to do climbs and descents acceptably? If so, that is disappointing.

Quote:
Originally Posted by FORANE View Post
First thing I would do as untainted would be to make sure there isn't deadband in the elevator pushrod.
By deadband, do you mean essentially slop in the control? As in slop not even involving the autopilot? Would I check this by pinning the elevator and seeing if there is any play from the control stick? And then checking if there is any play in the attachment from the pitch servo?

Quote:
Originally Posted by FORANE View Post
It would be nice if the manufacturer of autopilots would incorporate a computer capable of learning the control necessary based on efis data. It seems like they react to altitude excursions after the fact and fail to predict excursions based on vs and altitude relative to setpoint.
I don't really get this either, why the computer in the AP can't figure out what's going on a little better. It obviously is hooked to pitot and static, and therefore doesn't even need the EFIS data from the GPS or anything else. But, in even the slightest turbulence, lufting or dropping, it immediately pushes over or pitches up. When it's altitude holding (when I mentioned earlier about monitoring it), if I hold the stick and "resist" what it want's to do for about 5 seconds (because we aren't actually climbing nor descending, the VSI swung because of turbulence, we stayed within about 20 feet of altitude), it will stop again and we continue on, equally distrustful of one another...

I am on a mission now to get this thing dialed in, I have lived with it being half baked for too long.
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  #32  
Old 05-19-2022, 12:02 PM
BobTurner BobTurner is offline
 
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Location: Livermore, CA
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These things are complicated, lots of possibilities.
1. Yes, it should fly in a wing leveler mode with no gps input. Try turning off the gps, see what happens.
2. Double check the wiring. ARINC A goes to A, B to B. If memory serves me, arinc speed in gps set to low. Check format. RS232 has correct format and has gps out to Trio in.
3. Check for static line issues. You might disconnect the static line right at the control head, use cabin air.
4. (More work). Open up the gold servo box. Inside there is a nylon gear (fail-safe if clutch malfunctions). Your slip clutch may have been over-tightened and in all the porposing now the nylon gear is stripped.

But ask Trio about software versions on your Trio and 430W. That’s my bet.
PS You didn’t mention it, but if you are controlling the Trio via an efis then there may be a software issue there, too.

Last edited by BobTurner : 05-19-2022 at 12:05 PM.
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  #33  
Old 05-19-2022, 12:36 PM
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Untainted123 Untainted123 is offline
 
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Quote:
Originally Posted by BobTurner View Post
These things are complicated, lots of possibilities.
1. Yes, it should fly in a wing leveler mode with no gps input. Try turning off the gps, see what happens.
2. Double check the wiring. ARINC A goes to A, B to B. If memory serves me, arinc speed in gps set to low. Check format. RS232 has correct format and has gps out to Trio in.
3. Check for static line issues. You might disconnect the static line right at the control head, use cabin air.
4. (More work). Open up the gold servo box. Inside there is a nylon gear (fail-safe if clutch malfunctions). Your slip clutch may have been over-tightened and in all the porposing now the nylon gear is stripped.

But ask Trio about software versions on your Trio and 430W. That’s my bet.
PS You didn’t mention it, but if you are controlling the Trio via an efis then there may be a software issue there, too.
My Trio is an older model, so Trio said that the option to connect it to the G5 and use the G5 for altitude select etc was not available as an upgrade on mine, so I have to do all input on the control head itself. When I sent it in, they upgraded it to the GPSS/VS option (a different circuit board I think?) and updated the firmware to the latest as of end of 2021.

I'll try to work through this list and see what I can discover, you all have given me lots of good leads.
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  #34  
Old 05-19-2022, 02:23 PM
BobTurner BobTurner is offline
 
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The reason I keep harping on software mis-match is that your symptoms (roller coaster ride) sound exactly like mine during my phase 1 testing, but only when using my GRT efis for control. Turned out to be mis-matched software (I bought them a year apart). I sent the control head back to Trio, they updated the firmware, no problems since. Separate topic, much later I also had to update the software in my 430W so it would send the correct data for adsb-out. Everything these days is software!

Also, several posters commented on the need for many setting adjustments. While it’s true that the autopilot should ‘know’, after the fact, that it was too aggressive (or not aggressive enough), and could in principle ‘learn’ to fix it next time, machine learning is fairly complex, and probably not as reliable as manually entered parameters.
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  #35  
Old 05-19-2022, 07:39 PM
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FORANE FORANE is offline
 
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Quote:
Originally Posted by Untainted123 View Post
(which lends weight to the manual stating "The default settings are acceptable for most light GA aircraft").
The default settings would almost immediately result in a crash when used in my Lancair.




Quote:
Originally Posted by Untainted123 View Post

Does this mean you never did get it to do climbs and descents acceptably? If so, that is disappointing.
Yes, this is correct, never did in either aircraft. I used the pro pilot altitude hold in cruise only. I would use it during approaches, climbs, descents with roll servo on and pitch servo off manually controlling the elevator.



Quote:
Originally Posted by Untainted123 View Post
By deadband, do you mean essentially slop in the control? As in slop not even involving the autopilot? Would I check this by pinning the elevator and seeing if there is any play from the control stick? And then checking if there is any play in the attachment from the pitch servo?
Yes, any slop between the servo and elevator would result in pitch oscillations and excursions.



Quote:
Originally Posted by Untainted123 View Post
When it's altitude holding (when I mentioned earlier about monitoring it), if I hold the stick and "resist" what it want's to do for about 5 seconds (because we aren't actually climbing nor descending, the VSI swung because of turbulence, we stayed within about 20 feet of altitude), it will stop again and we continue on, equally distrustful of one another...
I do the same thing. It's frustrating. Trio has a few software versions for the pro pilot. It sounds like you have the most recent. The last time I had mine serviced, it was updated to the most recent at the time which added an overall gain setting; that helped some.
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Last edited by FORANE : 05-19-2022 at 08:00 PM.
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  #36  
Old 05-19-2022, 11:21 PM
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Untainted123 Untainted123 is offline
 
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Ok, so I started going through some things this evening.

1. My GPS software is 5.3, which Garmin indicates is the latest version
2. My Trio has the latest, confirmed by Chuck at Trio (more on this below)
3. There is zero slop in the elevator connection and none in the connection to the servo.
4. I didn't make it to opening the servo gold box, because I called Trio to get their thoughts on the software mismatch possibility.

Chuck at Trio (who has been super helpful) started going through my problems with me, and we talked about the software for a minute. He said there would be no mismatch in my software between the GPS and the Trio, apparently because my Trio is older and doesn't receive any altitude select etc commands from any type of EFIS, and relies on it's own pitot/static connections to do any type of EFIS calculations.

We then discussed VNAV servo gains, and a couple other things, but these seemed normal, or he said the defaults, especially for an RV-6, should be pretty close already (an RV-6 was used a test bed during the development of the Trio).

He then wanted me to blow or put some air past the static ports to verify that the Trio saw a climb or descent. When I told him it was going to be difficult to get under the wing to the pitot/static mast, because I have a Piper style pitot/static mast, he shut the whole thing down

He said that type of static port will never work correctly with the autopilot, because the Trio is able to detect changes of altitude to within 4 inches, and any change of the wing incidence shows up as a huge pressure change to the autopilot when the static port is located under the wing like that.

He was 99.9% certain this was my problem, and suggested I disconnect the static line to the Trio and use cockpit static pressure to test with, and in addition, since he was pretty confident that was the issue, to install the standard static ports in the rear fuselage location, in clean air.

So, I spent this evening installing the standard static ports in the fuselage, a very simple 1 hour job that so far has taken 5 Oh, well, once again too windy to fly.

So BobTurner, looks like you were probably on the right track with the static line idea of using cabin air. The reason I didn't bother to test that first was:
1. too windy to fly, so I might as well tear something up instead
2. Made a lot of sense that that would cause that type of issue

As for the connections, when I put my GPS in config mode and checked the setting, it gives the flag to the CDI, and the autopilot comes alive like it's tracking a course, and the blue lights come on, and the display shows it's getting "GARMN" data, so I think that is all good to go there. It has also always correctly shown destination WPT and groundspeed, and the XT error from the GPS, so I think the serial is good. Also, previously, when I received it back from Trio after the upgrade, Chuck had walked me through the correct settings on the GPS for ARINC, which I confirmed are still set correctly.

So, Chuck suggested I report here about the sensitivity of the static location, and of course that the Trio was really developed and tested against a standard Van's setup for that, obviously they can't account for all the variations of what people do in practice, like my Piper pitot/static mast. He said obviously that may not explain everyones issues with the Trio, but he would definitely rank it high on the list.

I don't know if you checked into this static issue on your quest FORANE to fix yours in the Lancair and your 9A, but might worth a discussion with Trio and describing exactly how you have your static ports mounted. Maybe you could run a dedicated static port for just the autopilot, or find a way to test it similar to the cabin air idea? Chuck said the main thing is any changes in cabin pressure (opening a vent, turning on heat, etc) would obviously affect it, but would be at least be a test.

I will test all this in flight as soon as the WX clears up again with this horrible wind we have been having all spring.
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  #37  
Old 05-19-2022, 11:26 PM
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Untainted123 Untainted123 is offline
 
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Quote:
Originally Posted by Untainted123 View Post
1. My GPS software is 5.3, which Garmin indicates is the latest version
I stand corrected, the latest version is 5.4. Anyone know how I can get the latest version installed onto my GPS? Garmin website just says "Authorized dealer". I assume it's some special data or something?
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  #38  
Old 05-20-2022, 01:09 AM
BobTurner BobTurner is offline
 
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Quote:
Originally Posted by Untainted123 View Post
I stand corrected, the latest version is 5.4. Anyone know how I can get the latest version installed onto my GPS? Garmin website just says "Authorized dealer". I assume it's some special data or something?
With the 4xxW series, Garmin will not send software updates to owners, only dealers. Dealers can set their own prices, but $100 or so seems typical. They stick a data card into one of your data card slots, takes 10 minutes or so, depending on the upgrade.
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  #39  
Old 05-20-2022, 04:22 AM
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FORANE FORANE is offline
 
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Quote:
Originally Posted by Untainted123 View Post
I don't know if you checked into this static issue on your quest FORANE to fix yours in the Lancair and your 9A, but might worth a discussion with Trio and describing exactly how you have your static ports mounted. Maybe you could run a dedicated static port for just the autopilot, or find a way to test it similar to the cabin air idea? Chuck said the main thing is any changes in cabin pressure (opening a vent, turning on heat, etc) would obviously affect it, but would be at least be a test.

I will test all this in flight as soon as the WX clears up again with this horrible wind we have been having all spring.
Good luck. Depending on your current performance, this may not significantly improve the issue. Our 9a had the 2 static ports behind the baggage area on the side of the fuselage. I have tried venting Trio static port to the cabin. The cabin vent does cause issues like you cite (while possible eliminating other problems), but in my case it did not result in acceptable climb or descent performance.

I don't think the 5.4 version update on the 430 was a major change; ads-b was added in a previous update. I don't believe it would have any change whatsoever in the Trio performance.
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  #40  
Old 06-03-2022, 12:16 PM
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Untainted123 Untainted123 is offline
 
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Quote:
Originally Posted by Untainted123 View Post
So, I spent this evening installing the standard static ports in the fuselage, a very simple 1 hour job that so far has taken 5 Oh, well, once again too windy to fly.

I will test all this in flight as soon as the WX clears up again with this horrible wind we have been having all spring.
Finally got around to flight testing after changing my static port location to the standard instead of the piper pitot/static mast. I did use the Avery Tools static ports though, glueing them on the inside with proseal, instead of the normal Van's rivets.

Click image for larger version

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I can report that this has resolved any issues with the AP, and I am very happy. It does indeed work like we are on rails. It got a little porpoise'ey on the glide slope, but I was flying downwind, and ground speed was 140kts+. Chuck had suggested getting slow and configured well before the FAF, so I think that will take care of that problem.

I had also reset all values to their default, so at least for me, in my RV-6, the book values work almost perfectly from the get go, but you really have to have a standard airplane configuration especially regarding the static source for it all to work correctly from the get go.
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