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Jamie
07-22-2008, 01:11 PM
I have a Trio EZ Pilot I just can't get quite right. It's supposed to be easier than this. :-)

Problem:

In cruise (160+ kts) it will wag the wings to the point of making me sick. It holds course fine, but it still wags the wings rather badly. The stick is constantly hunting. I have flown with others and their performance is so smooth you can't even tell their Trio is flying the airplane! My servo is mounted in the outter-most wing bay with the SafeAir1 mounting kit.

Attempted Fixes:

I have double-checked all the control linkages...everything is snug and there is no slack. There is no binding in the pushrods and everything moves freely. I sent the servo and head back to Trio. They re-worked my Servo, replaced the printed board, updated the software on the head and bench tested everything, but the behavior is unchanged.

I have followed the calibration procedures outlined in the manual as accurately as possible, including setting the center position and course and track gains.

It seems that at slower airspeeds the servo behaves a lot better but up at cruise it will make you sick.

I'm not bashing Trio...they have gone above and beyond to help me work this out. I'm posting here in hopes that someone else has had this problem that may have a good idea.

638RS
07-22-2008, 02:07 PM
Does it do this in all modes? Track, Course and intercept?

My Trio behaved badly when first installed and it turned out to be a bad input from the GPS that was driving it.

Jamie
07-22-2008, 03:22 PM
Yes, it does it in both track and course modes and with the GPS turned off.

Sam Buchanan
07-22-2008, 03:57 PM
I have a Trio EZ Pilot I just can't get quite right. It's supposed to be easier than this. :-)

Problem:

In cruise (160+ kts) it will wag the wings to the point of making me sick. It holds course fine, but it still wags the wings rather badly. The stick is constantly hunting. I have flown with others and their performance is so smooth you can't even tell their Trio is flying the airplane! My servo is mounted in the outter-most wing bay with the SafeAir1 mounting kit.


Jamie, the gains may be set too high. Our RVs only need very low gain since the control system is so low-friction.

Here are the settings that have worked great with all the EZ-Pilots I have flown in my RV-6:

FINE CRS QLT=2
FINE TRK QLT=1
PULL IN=8

Try those settings and see if you like the system better.

Jamie
07-22-2008, 04:46 PM
Jamie, the gains may be set too high. Our RVs only need very low gain since the control system is so low-friction.

Here are the settings that have worked great with all the EZ-Pilots I have flown in my RV-6:

FINE CRS QLT=2
FINE TRK QLT=1
PULL IN=8

Try those settings and see if you like the system better.

Thanks, Sam. I'll give those numbers a try and see what happens. I'm fairly certain I have tried those numbers before but I'll give it another try just to be sure.

roadrunner20
07-22-2008, 07:47 PM
Call Jerry @ trio.
He will be happy to help you.

Kahuna
07-22-2008, 08:12 PM
Jamie,
You want to borrow my head?
Takes 5 minutes to swap out. Ill put yours in mine and we will have another data point.
Id be happy to try yours on the way to Osh if you want. It will gimmie time to play with yours.
Ill only charge you the fuel for my time playing with it:D
Ill back back in a few days from sunny San Jose....
Best,

Jamie
07-22-2008, 09:06 PM
Call Jerry @ trio.
He will be happy to help you.

Yep, Jerry has been a saint. Just wanted to see if others had similar problems.

algrajek
07-28-2008, 09:42 PM
Talk to Jerry, but it sounds like the internal gain(adjustable pot inside the servo), needs tweaking
Nordo

Jamie
08-19-2008, 05:25 AM
Here's the latest update on my saga:

I tried Sam's recommended gain/pull-in settings and that doesn't resolve the problem.

I flew the plane and turned EVERYTHING off, including the GPS. I did not turn the alternator off.

When I'm in setup mode and setting the aileron neutral value, the autopilot is rock solid. In CRS or TRK mode, it will CONSTANTLY oscillate the stick, just like it does on the ground when you turn on the servo. I can find no slop in the controls.

I took Mike up on his offer and installed his EZ pilot head in my panel then calibrated it. This didn't appear to improve anything.

Next I installed a new servo from Trio. Same thing....no improvement. So it appears that the problem is something on the airframe or electrical.

I checked voltage at the servo and it appears I'm getting a 0.1 volt drop from main bus voltage, which I calculate as being normal for that wire length.

I will check again (for the fifth time) if there is an obvious problem with aileron rigging. I will also temporarily disconnect my aileron trim and go and fly to see if that solves the problem. Yes, I'm grasping at straws here.

Any other ideas?

Kahuna
08-19-2008, 05:39 AM
Id look at 2 areas.
1. Interference. Is it possible to run everything off? I mean everything! Pull all fuses except for the trio. Even run the GPS on batteries. No alternator, no nothing. Rule out EMI and other voltage problems. It would also be a good idea to put a fluke on the bus during flight and measure the stability of the bus. Your digital readout on your engine monitor probably has some smoothing and you need more decimals than it can provide.
2. GPS. does anything change with GPS's? turn off GPS in flight and what does the trio do?

There are many successful installations with your rigging. This problem is solvable Dont throw in the towel yet!

Bryan Wood
08-19-2008, 06:35 AM
Jamie,

I'm following with interest because I'm having a similar issue. Like you Trio is not lacking for support, we just haven't found the problem yet. Out of curiosity are you fighting a heavy wing? How does your plane fly hands off?

Not that your problem is the same as mine, but I ruled out alternator noise after having a failure going into OSH and having to replace it in the grass in the RV parking. The hunting is still there on my autopilot. I also installed shims in the servo to take out play, no help. Please post your results if you figure out the problem.

ddurakovich
08-19-2008, 06:37 AM
I found when my rudder trim went a bit screwy (don't ask!) the Trio seemed to hunt quite a bit. If I kicked in sufficient rudder to center the ball, it was rock steady.

Jamie
08-19-2008, 07:10 AM
Jamie,

I'm following with interest because I'm having a similar issue. Like you Trio is not lacking for support, we just haven't found the problem yet. Out of curiosity are you fighting a heavy wing? How does your plane fly hands off?

Not that your problem is the same as mine, but I ruled out alternator noise after having a failure going into OSH and having to replace it in the grass in the RV parking. The hunting is still there on my autopilot. I also installed shims in the servo to take out play, no help. Please post your results if you figure out the problem.

Bryan:

Good to see someone else is having a similar issue (misery loves company :)). Yes, I have a slightly heavy right wing which I am slowly nulling out. I always trim it out before engaging the servo. I flew with Mike Stewart in his -8 and we were discussing this and he was able to run his aileron trim to the stops and the Trio held perfectly, so I discounted this as being a possible culprit. I then moved my trim to the stops and the autopilot continued it's abnormal behavior.

I also need just a touch of right rudder in cruise, but even centering the ball has no effect on nulling out the stick oscillations. At all stages of flight the stick is visually oscillating, just like it does on the ground when you engage the servo, although maybe not *quite* as much.

Sam Buchanan
08-19-2008, 07:25 AM
When I'm in setup mode and setting the aileron neutral value, the autopilot is rock solid. In CRS or TRK mode, it will CONSTANTLY oscillate the stick, just like it does on the ground when you turn on the servo. I can find no slop in the controls.

I took Mike up on his offer and installed his EZ pilot head in my panel then calibrated it. This didn't appear to improve anything.

Next I installed a new servo from Trio. Same thing....no improvement. So it appears that the problem is something on the airframe or electrical.

Swapping out control heads and servo was an important phase of the troubleshooting and eliminates the possibility (I think...) of your particular unit from being defective.

The part about the system being solid in setup mode is really intriguing. What is changing when the system goes from "setup" to "normal" mode??? The only thing I can think of is the GPS. If the GPS is off-line during setup and the system is stable, but starts oscillating when the GPS comes back online, it is probably time to try another GPS. Or could it be that some sort of EMI is being picked up on your NMEA data feed?

Sorry you are having problems, I know this is frustrating. It is worth the effort to fix because you will really enjoy a fully functional EZ-Pilot.

Jamie
08-19-2008, 07:37 AM
Hi Sam:

I tried turning off the GPS to allow the Trio to track by itself and the oscillation still exists. I also have two GPS units, a Garmin 496 and an Apollo GX-50. I have tried running the head with both GPS units and get the same result.

Guy Prevost
08-19-2008, 09:58 AM
Jamie,

This is just a WAG, but one problem I've run into on other projects (home-made CNC equipment, etc) is an overall stiffness problem. You've stated that you don't have play in your control system and I can't remember where your servo is mounted.

If you have just a few thousands of an inch of deflection in the servo mount, it could easly cause this problem. Say for instance you have it mounted to a wing rib. The wing rib could be flexing a bit with every movement of the servo arm. This would cause the servo to hunt back and forth, because from its perspective, it thinks the controls are moving.

Worth what you paid for it...

Guy

Jamie
08-19-2008, 11:00 AM
Yes, Guy that is something I considered. I'm using the SafeAir1 mounting kit.

Here is my install:

http://rv.jpainter.org/images/2007-03-23.1994.jpeg

This is before securing wires, etc. Anyway, what's not pictured here is an angle piece behind on the forward side of the spar web to provide rigidity. I have investigated the sturdiness of the mount issue after seeing a post here on VAF about a guy having a similar problem with his Trio altitude hold. His solution was to stiffen his mount which solved his problem. He mentioned that he could see the servo flex when he applied pressure. I have push/pulled/prodded mine and I don't see any movement at all.

Rockyjs
08-19-2008, 08:56 PM
Jamie,
Not sure if this is pertinent, but I had a problem in my Trio Altitude system on the first flight I used it. It was porpoising. When I engaged the altitude hold on the ground and bumped the stick it would oscillate forward and aft. After troubleshooting with Trio they said to send the servo back. When I went to remove the servo, I grabbed where the pushrod was connected to the elevator mid-ship bellcrank and moved this back and forth with what I felt was excessive effort. I made a new pushrod and installed the servo in a different location, that gave it a better mechanical advantage. This appears to have solved the problem.

You may want to check where the servo pushrod is connected to the aileron bellcrank for any adverse loading/binding. It seems like your servo is getting some feedback in your control linkage causing it to oscillate. Is that the stock servo arm? It maybe just the picture, but it looks bigger than the ones I have.

N908RV
08-19-2008, 10:21 PM
Jamie,

I have the exact same set up - gold standard servo and Trio AP head and SafeAir mount, SafeAir pushrod and that same extended SafeAir crank arm. Works like buttah.

That said, I didn't start out that way. I had a Navaid servo at first which would work fine using my old Navaid head. When I switched it out for the new Trio head, the problems began. It was very jerky and no matter what setting I used I couldn't get that out. In my quest to do the least amount of work (because I had already spent inordinate amounts of time messing with that Navaid servo to get it perfect for the Navaid head) I decided to just buy the new Trio Servo and throw money at the problem. They did offer to check out and "tighten up" the old style Navaid servo, but I decided I wanted a one shot install because I had lots of upcoming long flights and little time to experiment.

And, as you guessed, that solved my problem.

Everyone mentions EMI and all these other things (and that could be), but I have unshielded strobe wires running to my power pack out on the wing tip running in the same conduit as my unshielded (yes, you are supposed to shield the Gold Standard servo wires, but I figured I'd only redo those wires if I had an issue) and I don't have any issues at all.

I am thinking you need to return the Gold Standard servo and ask them to take a look at it. It may be need to be checked out by the factory - could be just something minor wrong with the unit.

Like I said, a WAG, but I have been following this thread and was very surprised at your experience given that my stuff worked from the word go once I used the Trio servo.

And yes, their customer service is simply the best.

Good luck,

Rob

PS: In your picture, I see that you don't have a safety washer and cotter on the servo shaft. Highly recommend that. Trio now recommends that in their literature too. In the event of a roll pin failure, if you have a washer or two and a cotter pin installed on that servo shaft, in the event of failure this will keep everything on the shaft so that there is no possibilty of a loose pushrod hanging up. There was an earlier thread on that re: wingtip servo install and a roll pin failure of the old Navaid servo. Same basic concept. Just wanted to mention that as a easy safety item to implement.

Kahuna
08-20-2008, 05:40 AM
Rob,
From Jamies previous post "Next I installed a new servo from Trio. Same thing....no improvement. "

Jamie
08-20-2008, 06:34 AM
Rob, you make some good points. As mentioned by Kahuna, I had Trio re-build/bench test my servo and they also sent me a new one -- all with no luck.

Your comments on EMI are very interesting. I too doubt it could be EMI. I have my serial line from the GPS split to the Trio, my Dynon EFIS/EMS and my SL-40 com (for sending frequencies) so I have thought that maybe the interference could be coming from one of those devices, but turning them all off has had no effect.

I have checked the pushrod and it does not appear to be binding. I can grab the pushrod and have plenty of 'twist' available before the bearings hit their 'stops'. Pushing and pulling on the pushrod I do not feel any load.

Thanks for your mention of cotterpinning the shaft -- sounds like a very simple thing to do. That pushrod coming off would be an absolute day ruiner -- it looks like it could get hung up very easily.

Jerry from Trio called me yesterday and gave me a few other ideas to try, mostly pertaining to the head. They've apparently had this problem on a very few number of airplanes and I am going to try and help them resolve it as best I can.

N908RV
08-20-2008, 05:45 PM
Jamie and Mike, thanks for clarifying - I missed that part. Well, you really have run the gauntlet then.

I'm still head scratching.

Thanks for continuing to post on this - we might all learn a good lesson from it hopefully. Sorry you get to be the guinea pig, Jamie.

Rob

flyinmonque
08-28-2008, 12:18 AM
So has there been any headway with your problem?

rocketbob
08-28-2008, 05:07 AM
Sounds to me like there's not enough torque at cruise to smoothly move the ailerons. The clutch could be slipping causing erratic behavior. Maybe if you tried moving the pushrod down on the pivot arm to give you more torque, it might help a bit...of course you would have to make sure you have enough travel available to allow the full range of aileron movement.

The torque will drop off drastically as you move up the arm, and you couple that with the 7's 1:1 ratio at aileron bellcrank which makes for heavier ailerons... I think that's the only thing you haven't eliminated.

I've had friends modify the aileron weldments, to make the ailerons lighter, with good success...

Jamie
08-28-2008, 05:19 AM
Since my last post I have tried exactly what you mention, Bob. I used the original bracket that came with the Trio. I'm not sure why the SafeAir1 people have you use the longer bracket. I have plenty of clearance remaining with just the original one. Anyway...

It didn't help. It's still just a mess.

I tried adjusting the aileron trim -- it was sort of loose and wasn't tight enough to offset a large fuel imbalance. I tightened it up and this didn't help.

I tried disconnecting aileron trim entirely. This was my attempt to eliminate any sort of possibility that the aileron trim was having an effect.

The folks at Trio have asked me to do a couple of tests regarding modifying some things on the head -- which I'll do but right now the remnants of Fay have kept most of us Southeasterners grounded.

rocketbob
08-28-2008, 07:08 AM
The other thing you can do is temporarily tighten up the clutch, and see if that helps.

If the servo works fine at slower speeds, without a doubt you have a mechanical issue.

RV4er
08-28-2008, 07:34 AM
I have not read all the post in this thread so this may have been covered before. I installed the same set up in my RV 4 using the Safe Air installation kit. When I tried to set up the EZ Pilot on the ground before the first flight I noticed that the servo kept searching and moving. I also was not getting the required aileron throw each direction. In my case I found out that the servo base plate I got from Safe Air had been drilled incorectly. This caused the push rod to be too long. I can't remember how much I had to remove from the push rod but I am thinking it was around 3/4 an inch.

This may have nothing to do with your problem but is just a thought.

In addition, Trio and Safe Air customer support was outstanding.

Jamie
08-28-2008, 09:55 AM
The other thing you can do is temporarily tighten up the clutch, and see if that helps.

If the servo works fine at slower speeds, without a doubt you have a mechanical issue.

Yep. Good idea. Already tried that one too. :-)

rocketbob
08-28-2008, 10:18 AM
hmmm. How about moving the rod end down on the servo crank to a lower hole?

Jamie
08-28-2008, 11:17 AM
hmmm. How about moving the rod end down on the servo crank to a lower hole?

I may try that Bob, but I don't know if I'll have any luck with it. Looking at my logbook, I estimate I have spent about $500.00 in avgas just trying to get this problem worked out. I'm honestly at the end of my rope on this one.

Let me ask a question: Do the other autopilots (Trutrak, etc) "hunt" for load on the ailerons like the Trio does? See this video (http://video.google.com/videoplay?docid=-6091595923961913674&hl=en). Even in a climb, it appears as though the servo is working itself to death. It appears that it is wagging the ailerons like in this video, just not quite as much.

rocketbob
08-28-2008, 11:45 AM
My Navaid hunts like this on the ground if I turn it on. Its fine in flight.

Looking at your pic again it looks like the pushrod is way too high up on the arm to have good torque.

I remember in the Navaid manual they gave you torque values based on the hole, the further away you go the more torque you lose.

videobobk
08-28-2008, 11:55 AM
First, glad I haven't had this problem with my Trio. Very happy with it all. Not wanting to disagree with a fellow Hoosier, but I think RocketBob has it wrong; lengthening the arm at the servo will increase the required torque at the servo to operate the ailerons. If, while the servo is hunting, you add some resistance to the stick, does the hunting go away? I know that mine will quit hunting on the ground if I hold it lightly. If this is the case, a longer linkage may be in order.

The only thing that doesn't make sense to this is that the ailerons have more resistance at higher speed, or at least they did on the 7 I flew. Most planes do. Something mechanical has to be wrong.

The only time I have had my Trio "hunt" is if I turn it on at pretty low speed. Then it will for a moment.

Bob Kelly

rocketbob
08-28-2008, 12:05 PM
Bob, I think you may have misread what I said, moving the rod end closer to the servo shaft will give you more torque from the servo at the expense of travel.

Sparky
08-28-2008, 01:50 PM
The part about the system being solid in setup mode is really intriguing. What is changing when the system goes from "setup" to "normal" mode??? The only thing I can think of is the GPS. If the GPS is off-line during setup and the system is stable, but starts oscillating when the GPS comes back online, it is probably time to try another GPS.

Jamie, I think Sam hit on a key element of troubleshooting this problem. The problem MAY be with the loading of the RS-232 feed between the GPS and the Trio control head. You said you turned off the other items that are connected to this RS-232 signal, but if they are still connected they are still loading the signal. I think you said you had 4 or 5 items connected. Some RS-232 drivers can't handle this many loads. Have you tried physically disconnecting all the RS-232 loads with the exception of the GPS and the Trio?

Jamie
08-28-2008, 01:56 PM
Jamie, I think Sam hit on a key element of troubleshooting this problem. The problem MAY be with the loading of the RS-232 feed between the GPS and the Trio control head. You said you turned off the other items that are connected to this RS-232 signal, but if they are still connected they are still loading the signal. I think you said you had 4 or 5 items connected. Some RS-232 drivers can't handle this many loads. Have you tried physically disconnecting all the RS-232 loads with the exception of the GPS and the Trio?

Paul:

I have not tried this yet, but it has been on my list of things to try. I know that in the setup mode (turning off the head, holding down the servo button, turning the power back on) when engaging the servo to set the servo center position it is smooooooth. On the ground in this mode I see the same wagging as in the video I posted. I'm thinking this is the key to my problem. In the servo center positioning mode GPS is being ignored.

I think I will try the RS232 thing next. There are really only three things connected -- my SL-40, Dynon and the Trio, but who knows -- it could be something there.

Sparky
08-28-2008, 02:05 PM
It could also just be a poor connection.

rocketbob
08-28-2008, 05:27 PM
I don't think an impedance mismatch on the RS232 line going into the AP is a likely problem. NMEA sentences have checksums, and if the Trio is validating the checksums and if they're incorrect I would assume they would display some sort of error.

Otherwise flying the airplane with the Trio in heading mode would eliminate the serial lines as a problem.

n2prise
08-30-2008, 10:10 PM
Jamie,

You mentioned that you have your SL-40 tied to the serial bus. That means you are probably using something other than PURE NMEA 0183 output (VHF out along with NMEA). One of the modes in 396/496 also has TIS input from the Garmin 330 transponder. When I was helping Wendell Folks setup his Trio EZ Pilot, we had to default to just plain old NMEA to get it to follow the GPS 396 course line, and work with the Dynon D10-A.

I use a Garmin 296 with my Dynon D10-A and Navaid unit on serial port 1 with NMEA output at 4800 baud. The 296 has a second RS-232 output that goes only to my SL-30 with Aviation IN/NMEA & VHF Out sentences (9600 baud) to the memory of the SL-30 for COM/NAV frequencies from the GPS.

In the past few weeks, Wendell has started getting a glitch now and then when the EZ pilot will do an un-commanded roll to a high bank angle.

Has anyone heard of any changes to the EZ-pilot software configuration that address this issue? Wendell's unit had P53P2 then the serial number. Jamie, you might want to ask others here who are having good luck with their units what code appears on their units like the one I have listed above, P53P2.

Sam, what about your unit codes?

Sam Buchanan
08-30-2008, 10:18 PM
Jamie,

You mentioned that you have your SL-40 tied to the serial bus. That means you are probably using something other than PURE NMEA 0183 output (VHF out along with NMEA). One of the modes in 396/496 also has TIS input from the Garmin 330 transponder. When I was helping Wendell Folks setup his Trio EZ Pilot, we had to default to just plain old NMEA to get it to follow the GPS 396 course line, and work with the Dynon D10-A.

I use a Garmin 296 with my Dynon D10-A and Navaid unit on serial port 1 with NMEA output at 4800 baud. The 296 has a second RS-232 output that goes only to my SL-30 with Aviation IN/NMEA & VHF Out sentences (9600 baud) to the memory of the SL-30 for COM/NAV frequencies from the GPS.

In the past few weeks, Wendell has started getting a glitch now and then when the EZ pilot will do an un-commanded roll to a high bank angle.

Has anyone heard of any changes to the EZ-pilot software configuration that address this issue? Wendell's unit had P53P2 then the serial number. Jamie, you might want to ask others here who are having good luck with their units what code appears on their units like the one I have listed above, P53P2.

Sam, what about your unit codes?

Jerry, I'll have to check when I'm at the airport, don't recall software version but it will be a very late version since I got this particular unit just a few weeks ago.

I'm pulling in generic NMEA from a Lowrance Airmap 1000 and it works flawlessly.

I still think Jamie is working with data feed problems since the system is stable when the GPS is off-line.

n2prise
09-16-2008, 09:20 AM
Sam,

I talked to the folks at Trio and the unit went back for factory service to fix the "not-tracking a course problem" and a firmware upgrade. From the time of purchase to now, the new firmware change now gives it 9600 baud capability instead of just 4800 for NEMA 0183. The GPS 396/496 use 9600 baud when the VHF OUT and TIS IN function is added to the data stream options. Wendell's RV-8 has the GTX-330 transponder that can feed traffic information to any of the newer Garmin GPS's to display targets on the moving map.

We will post here when it comes home and gets a flight test.

Thanks,

Jamie
09-16-2008, 12:21 PM
I still think Jamie is working with data feed problems since the system is stable when the GPS is off-line.

Nope, this isn't the issue. When I turn the GPS off in flight the autopilot is still wagging the wings. The only time it doesn't wag the wings is when I'm in the mode to set the servo center position.

manolis
10-13-2008, 09:09 AM
I have bought the virus shortwind of pipistrel and also bought the odyssey.
From pipistrel they suggest me to install an autopilot, the Trio avionics. I read that there are problems with it when cruising in high speeds. My plane's cruise is 280 Km/h and VNE 310 Km/h. I have decided to use the Trio but i need you help. thank you in advanve

manolis

Sam Buchanan
10-13-2008, 10:05 AM
I have bought the virus shortwind of pipistrel and also bought the odyssey.
From pipistrel they suggest me to install an autopilot, the Trio avionics. I read that there are problems with it when cruising in high speeds. My plane's cruise is 280 Km/h and VNE 310 Km/h. I have decided to use the Trio but i need you help. thank you in advanve

manolis

Manolis,

Welcome to the forum! You didn't state what kind of aircraft you have but I have used the Trio autopilot for several years with cruise speeds the same as your plane (151 kts). 151 kt cruise is typical for Vans RV aircraft so there is a well-defined field history for all the current autopilots including the Trio system.

As long as your installation is sound you can expect to receive excellent results with the Trio. The EZ-Pilot has been flying for a few years now and the Pro Pilot will be shipping soon.

By the way, I also am an Athenian................Alabama, USA. :)

Jamie
10-13-2008, 10:22 AM
Yes, don't let my experience discourage you from using the Trio. It is a fine autopilot and the folks there are great to deal with. I still do not know the cause of my problem.

manolis
10-14-2008, 01:55 AM
My plane is the Virus by Pipistrel. Is the plane tha won the CAFE - NASA 2008 GAT Challenge. I was thinking of buying the Pro pilot af Trio Avionics. I really dont wanna make a wrong decission.

Ron Lee
10-22-2008, 08:24 PM
I have what may the identical problem that Jamie has. Trio worked with me well to try things but nothing ever worked. After my engine was down for rebuild I have not worked with them to solve the problem. It may not wag as much as Jamie's does but still it would be nice if it were stable.

houndsfour
10-26-2008, 07:42 PM
I've been following this thread with intrest. I'm planing on replacing my Navaid system with the Trio EZ pilot.
Having said that, I have been flying my Navaid for 4 years and at first I also had the "Stick Shakes" at all speeds. After several emails (alot really) to Navaid, the cure was to add a small resistor directly across the motor teminals in the servo. That corrected my problem and the servo has worked ever since.
I'm planing on changing the system because on age of the gyro and I can't reach Navaid anymore.
Well, mabe I may have given you a different direction to look.

Sam Buchanan
10-26-2008, 08:19 PM
I've been following this thread with intrest. I'm planing on replacing my Navaid system with the Trio EZ pilot.
Having said that, I have been flying my Navaid for 4 years and at first I also had the "Stick Shakes" at all speeds. After several emails (alot really) to Navaid, the cure was to add a small resistor directly across the motor teminals in the servo. That corrected my problem and the servo has worked ever since.
I'm planing on changing the system because on age of the gyro and I can't reach Navaid anymore.
Well, mabe I may have given you a different direction to look.

Rich,

Navaid has closed the doors and I haven't heard of anyone offering service for the Navaid system. I flew my Navaid many hours, and enjoyed it. However, the capabilities of the new digital autopilots are going to astound you. :) You can buy just the control head of the EZ-Pilot for use with your Navaid servo, but the Trio Gold servo is so much more advanced I suggest you upgrade to it if the budget allows. Your current servo mount and linkage will probably work fine with the Gold servo.

Enjoy your new autopilot!

rodbower
10-27-2008, 07:52 PM
Trimming the RV.
Just a thought

There is a point when the aileron trailing edge radius gets too fat. This results in a very light aileron but may cause aileron snatch. The streamlined tubing on my starduster II that interconnected the upper and lower ailerons caused an unstable conditiion (snatch) that was fixed by taping a piece of stainless welding rod lengthwise to the strut. This solved the twitch in the stick.

Alot of people expand the trailing edge of the RV aileron to correct wing heavy conditions and go a little too far. I have the Trio in my 8 and have actually started compressing the trailing edge down on both sides and found the lateral stick movement (snatch) has improved.
The next time I have the floor boards out I plan to move the rod end on the servo closer to the pivot. May have too much leverage (sensitivity).
Love my trio
Rod

ShookieRV7A
11-21-2008, 11:25 AM
I hate resurrecting threads but I did not see any 'resolution' yet.

Jamie, you mention that you see the stick hunting around while you are on the ground. This tells me that even when the plane is at rest, the AP head or the servo may be getting erroneous information.

I also saw that you have checked for EMI and tried flying with minimal electrical loads and breakers pulled.

Have you tried checking your wiring and connectors between the head and the servo?

Jamie
11-21-2008, 01:31 PM
Hi Scott or Jenni: Thanks for the thoughts. My comments below.

Jamie, you mention that you see the stick hunting around while you are on the ground. This tells me that even when the plane is at rest, the AP head or the servo may be getting erroneous information.

Everyone who has a Trio, including the Trio folks, tell me that the ailerons wagging on the ground is completely normal. The servo is hunting for load on the ailerons. I swapped out the head and the servo and no change in behavior was observed.



I also saw that you have checked for EMI and tried flying with minimal electrical loads and breakers pulled.

Have you tried checking your wiring and connectors between the head and the servo?

Yes, I checked all of the wiring from the end to end, including installing all new connectors and carefully soldering them as well as crimping them.