Matronics Email Lists :: View topic

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

Elevator Trim Servo

Matronics Email Lists Forum Index -> RV10-List

View previous topic :: View next topic

Author Message

n520tx(at)gmail.com
Guest

Posted: Sat Jul 08, 2017 5:18 am Post subject: Elevator Trim Servo

Doing some T&G last evening in the 10 ... with just me on board, final 

typically has me full nose up on the trim - even with that, I still need 

some back pressure ... but that's not the story.



Anyway, on roll-out, I was moving the tab back to neutral and realized 

it was taking a LOT longer to reset than usual. Eventually I determined 

that it was not moving at all. The trim had stopped in the full nose up 

(tab down) position.



Some troubleshooting after shutdown revealed the mechanism is not 

jammed, it still gets power - when activated, the unit does some 

"whirring" - but the jack screw does not move. It appears something 

INTERNAL to the unit has failed.



In all my years flying RV's, I've never heard of a single failure in 

this manner. Anyone ?



Really wish I had used a DB9 or some other quick connect for this ...



--Ron

philperry9

Joined: 23 Nov 2011
Posts: 381

Posted: Sat Jul 08, 2017 5:28 am Post subject: Elevator Trim Servo

We just replaced one on a -10 on our field.  Exactly the same failure after some T&G's in the evening.  There was noise but no movement as a gear broke inside the unit.  



It was ~10 years old, FYI.  



I suspect this servo gets more use (and high pressures on the mechanisms) than any other servo (Aileron and rudder for those who have rudder trim). 



 



Sent from my iPhone



 	  Quote: 	
		   On Jul 8, 2017, at 7:18 AM, Ron Walker <n520tx(at)gmail.com> wrote:

 

 

 

 Doing some T&G last evening in the 10 ... with just me on board, final typically has me full nose up on the trim - even with that, I still need some back pressure ... but that's not the story.

 

 Anyway, on roll-out, I was moving the tab back to neutral and realized it was taking a LOT longer to reset than usual. Eventually I determined that it was not moving at all. The trim had stopped in the full nose up (tab down) position.

 

 Some troubleshooting after shutdown revealed the mechanism is not jammed, it still gets power - when activated, the unit does some "whirring" - but the jack screw does not move. It appears something INTERNAL to the unit has failed.

 

 In all my years flying RV's, I've never heard of a single failure in this manner. Anyone ?

 

 Really wish I had used a DB9 or some other quick connect for this ...

 

 --Ron

philperry9

Joined: 23 Nov 2011
Posts: 381

Posted: Sat Jul 08, 2017 5:33 am Post subject: Elevator Trim Servo

Last message send too early.   



So I have been disabling auto-trim on my auto pilot.  Just to keep it from working up a down until I can learn more about how much input it's putting into the system.   I really don't want to go on a 3 hour flight and have the auto-trim running the tab the whole time when the trim is close enough that servo is close enough to handle the loads.  



So I've been using auto trim to get level and then shutting it down until it's needed.  



I don't know if it helps much, but I'm just hoping to extend the life of the servo by running it when it really doesn't need to be running. 



Phil





Sent from my iPhone



 	  Quote: 	
		   On Jul 8, 2017, at 7:18 AM, Ron Walker <n520tx(at)gmail.com> wrote:

 

 

 

 Doing some T&G last evening in the 10 ... with just me on board, final typically has me full nose up on the trim - even with that, I still need some back pressure ... but that's not the story.

 

 Anyway, on roll-out, I was moving the tab back to neutral and realized it was taking a LOT longer to reset than usual. Eventually I determined that it was not moving at all. The trim had stopped in the full nose up (tab down) position.

 

 Some troubleshooting after shutdown revealed the mechanism is not jammed, it still gets power - when activated, the unit does some "whirring" - but the jack screw does not move. It appears something INTERNAL to the unit has failed.

 

 In all my years flying RV's, I've never heard of a single failure in this manner. Anyone ?

 

 Really wish I had used a DB9 or some other quick connect for this ...

 

 --Ron

cooprv7(at)yahoo.com
Guest

Posted: Sat Jul 08, 2017 7:15 am Post subject: Elevator Trim Servo

Phil,

    What kind of autopilot do you have? Just curious as I currently have the TruTrak which tells you a trim change is needed but doesn't actuate the trim.  However, I am about to do a big panel upgrade which includes going to a Garmin G3X and Garmin autopilot servos and am wondering if it also ties into the trim?



Thanks,

Marcus 



 	  Quote: 	
		   On Jul 8, 2017, at 9:32 AM, Phillip Perry <philperry9(at)gmail.com> wrote:

 Do not archive

 

 

 Last message send too early.   

 

 So I have been disabling auto-trim on my auto pilot.  Just to keep it from working up a down until I can learn more about how much input it's putting into the system.   I really don't want to go on a 3 hour flight and have the auto-trim running the tab the whole time when the trim is close enough that servo is close enough to handle the loads.  

 

 So I've been using auto trim to get level and then shutting it down until it's needed.  

 

 I don't know if it helps much, but I'm just hoping to extend the life of the servo by running it when it really doesn't need to be running. 

 

 Phil

 

 

 

 

 Sent from my iPhone

 

> On Jul 8, 2017, at 7:18 AM, Ron Walker <n520tx(at)gmail.com> wrote:

> 

> 

> 

> Doing some T&G last evening in the 10 ... with just me on board, final typically has me full nose up on the trim - even with that, I still need some back pressure ... but that's not the story.

> 

> Anyway, on roll-out, I was moving the tab back to neutral and realized it was taking a LOT longer to reset than usual. Eventually I determined that it was not moving at all. The trim had stopped in the full nose up (tab down) position.

> 

> Some troubleshooting after shutdown revealed the mechanism is not jammed, it still gets power - when activated, the unit does some "whirring" - but the jack screw does not move. It appears something INTERNAL to the unit has failed.

> 

> In all my years flying RV's, I've never heard of a single failure in this manner. Anyone ?

> 

> Really wish I had used a DB9 or some other quick connect for this ...

> 

> --Ron

> 

> 

>

Kellym

Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ

Posted: Sat Jul 08, 2017 3:40 pm Post subject: Elevator Trim Servo

I have the Dynon Skyview autopilot system, which shows on screen a trim 

command, which the autotrim then activates. At cruise the changes are 

rather minor and infrequent. In the pattern I hand fly anyway and do my 

own trimming.The Dynon autopilot panel adjusts trim motor speed 

automatically to be inverse to airspeed.



On 7/8/2017 8:15 AM, Marcus Cooper wrote:

 	  Quote: 	
		   

 

 Phil,

      What kind of autopilot do you have? Just curious as I currently have the TruTrak which tells you a trim change is needed but doesn't actuate the trim.  However, I am about to do a big panel upgrade which includes going to a Garmin G3X and Garmin autopilot servos and am wondering if it also ties into the trim?

 

 Thanks,

 Marcus

 

> On Jul 8, 2017, at 9:32 AM, Phillip Perry <philperry9(at)gmail.com> wrote:

> Do not archive

> 

>

> Last message send too early.

>

> So I have been disabling auto-trim on my auto pilot.  Just to keep it from working up a down until I can learn more about how much input it's putting into the system.   I really don't want to go on a 3 hour flight and have the auto-trim running the tab the whole time when the trim is close enough that servo is close enough to handle the loads.

>

> So I've been using auto trim to get level and then shutting it down until it's needed.

>

> I don't know if it helps much, but I'm just hoping to extend the life of the servo by running it when it really doesn't need to be running.

>

> Phil

>

>

> Sent from my iPhone

>

>> On Jul 8, 2017, at 7:18 AM, Ron Walker <n520tx(at)gmail.com> wrote:

>>

>> 

>>

>> Doing some T&G last evening in the 10 ... with just me on board, final typically has me full nose up on the trim - even with that, I still need some back pressure ... but that's not the story.

>>

>> Anyway, on roll-out, I was moving the tab back to neutral and realized it was taking a LOT longer to reset than usual. Eventually I determined that it was not moving at all. The trim had stopped in the full nose up (tab down) position.

>>

>> Some troubleshooting after shutdown revealed the mechanism is not jammed, it still gets power - when activated, the unit does some "whirring" - but the jack screw does not move. It appears something INTERNAL to the unit has failed.

>>

>> In all my years flying RV's, I've never heard of a single failure in this manner. Anyone ?

>>

>> Really wish I had used a DB9 or some other quick connect for this ...

>>

>> --Ron

>>

>>

>>

>

>

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

cooprv7(at)yahoo.com
Guest

Posted: Sat Jul 08, 2017 7:42 pm Post subject: Elevator Trim Servo

Thanks, I'll keep, an eye out for a similar system on the Garmin although I don't think it has control of the trim motor. 



Marcus 



 	  Quote: 	
		   On Jul 8, 2017, at 7:38 PM, Kelly McMullen <kellym(at)aviating.com> wrote:

 Do not archive

 

 

 I have the Dynon Skyview autopilot system, which shows on screen a trim command, which the autotrim then activates. At cruise the changes are rather minor and infrequent. In the pattern I hand fly anyway and do my own trimming.The Dynon autopilot panel adjusts trim motor speed automatically to be inverse to airspeed.

 

> On 7/8/2017 8:15 AM, Marcus Cooper wrote:

> 

> Phil,

>     What kind of autopilot do you have? Just curious as I currently have the TruTrak which tells you a trim change is needed but doesn't actuate the trim.  However, I am about to do a big panel upgrade which includes going to a Garmin G3X and Garmin autopilot servos and am wondering if it also ties into the trim?

> Thanks,

> Marcus

>> On Jul 8, 2017, at 9:32 AM, Phillip Perry <philperry9(at)gmail.com> wrote:

>> Do not archive

>> 

>> 

>> Last message send too early.

>> 

>> So I have been disabling auto-trim on my auto pilot.  Just to keep it from working up a down until I can learn more about how much input it's putting into the system.   I really don't want to go on a 3 hour flight and have the auto-trim running the tab the whole time when the trim is close enough that servo is close enough to handle the loads.

>> 

>> So I've been using auto trim to get level and then shutting it down until it's needed.

>> 

>> I don't know if it helps much, but I'm just hoping to extend the life of the servo by running it when it really doesn't need to be running.

>> 

>> Phil

>> 

>> 

>> 

>> 

>> Sent from my iPhone

>> 

>>> On Jul 8, 2017, at 7:18 AM, Ron Walker <n520tx(at)gmail.com> wrote:

>>> 

>>> 

>>> 

>>> Doing some T&G last evening in the 10 ... with just me on board, final typically has me full nose up on the trim - even with that, I still need some back pressure ... but that's not the story.

>>> 

>>> Anyway, on roll-out, I was moving the tab back to neutral and realized it was taking a LOT longer to reset than usual. Eventually I determined that it was not moving at all. The trim had stopped in the full nose up (tab down) position.

>>> 

>>> Some troubleshooting after shutdown revealed the mechanism is not jammed, it still gets power - when activated, the unit does some "whirring" - but the jack screw does not move. It appears something INTERNAL to the unit has failed.

>>> 

>>> In all my years flying RV's, I've never heard of a single failure in this manner. Anyone ?

>>> 

>>> Really wish I had used a DB9 or some other quick connect for this ...

>>> 

>>> --Ron

>>> 

>>> 

>>> 

>> 

>> 

>> 

>>

philperry9

Joined: 23 Nov 2011
Posts: 381

Posted: Sat Jul 08, 2017 8:04 pm Post subject: Elevator Trim Servo

Marcus,

Sorry I missed our message.  Fortunately I saw it on Kelly's reply.  

I have the Garmin GX Pilot (TruTrak) with the G3X.    It will tell you if you need trim up or down and then you just add it manually.  

For Auto-Trim, you have to get the Auto-Trim module from TruTrak and install it.   I can look at my AP head and see when trim inputs are being sent from the TruTrak to the trim servo.  Right now mine are fairly frequently and have experienced a couple if moments where it was putting inputs in so quickly that be plane never had time to respond before the next input was made.   That created and pretty aggressive oscillation of about 30 ft high to 30 ft low as the auto-trim thought it was playing catchup, when in reality it was behind. 

Before my next flight, I'm going to make an adjustment to reduce the frequency of the auto-trim inputs.  That will (should) give the plane some time to react before the next trim command is issued. 

Phil

Sent from my iPhone

 	  Quote: 	
		   On Jul 8, 2017, at 5:38 PM, Kelly McMullen <kellym(at)aviating.com> wrote:

 I have the Dynon Skyview autopilot system, which shows on screen a trim command, which the autotrim then activates. At cruise the changes are rather minor and infrequent. In the pattern I hand fly anyway and do my own trimming.The Dynon autopilot panel adjusts trim motor speed automatically to be inverse to airspeed.

> On 7/8/2017 8:15 AM, Marcus Cooper wrote:

> 

> Phil,

>     What kind of autopilot do you have? Just curious as I currently have the TruTrak which tells you a trim change is needed but doesn't actuate the trim.  However, I am about to do a big panel upgrade which includes going to a Garmin G3X and Garmin autopilot servos and am wondering if it also ties into the trim?

> Thanks,

> Marcus

>> On Jul 8, 2017, at 9:32 AM, Phillip Perry <philperry9(at)gmail.com> wrote:

>> Do not archive

>> 

>> 

>> Last message send too early.

>> 

>> So I have been disabling auto-trim on my auto pilot.  Just to keep it from working up a down until I can learn more about how much input it's putting into the system.   I really don't want to go on a 3 hour flight and have the auto-trim running the tab the whole time when the trim is close enough that servo is close enough to handle the loads.

>> 

>> So I've been using auto trim to get level and then shutting it down until it's needed.

>> 

>> I don't know if it helps much, but I'm just hoping to extend the life of the servo by running it when it really doesn't need to be running.

>> 

>> Phil

>> 

>> 

>> 

>> 

>> Sent from my iPhone

>> 

>>> On Jul 8, 2017, at 7:18 AM, Ron Walker <n520tx(at)gmail.com> wrote:

>>> 

>>> 

>>> 

>>> Doing some T&G last evening in the 10 ... with just me on board, final typically has me full nose up on the trim - even with that, I still need some back pressure ... but that's not the story.

>>> 

>>> Anyway, on roll-out, I was moving the tab back to neutral and realized it was taking a LOT longer to reset than usual. Eventually I determined that it was not moving at all. The trim had stopped in the full nose up (tab down) position.

>>> 

>>> Some troubleshooting after shutdown revealed the mechanism is not jammed, it still gets power - when activated, the unit does some "whirring" - but the jack screw does not move. It appears something INTERNAL to the unit has failed.

>>> 

>>> In all my years flying RV's, I've never heard of a single failure in this manner. Anyone ?

>>> 

>>> Really wish I had used a DB9 or some other quick connect for this ...

>>> 

>>> --Ron

>>> 

>>> 

>>> 

>> 

>> 

>> 

>>

bob(at)thelefflers.com
Guest

Posted: Sun Jul 09, 2017 1:35 am Post subject: Elevator Trim Servo

Phil,

 It sounds like your  vertical gain setting on the AP may be set too high.  The indication of gain being too high is a rapid over correction.

 Have you flown the in the AP mode and tested to see if a manual turn or altitude change is responded to appropriately?  I.e.  Does it turn out within 1 degree of the heading or within a couple feet of the altitude without overshooting?   If the gain is too high you'll see what you are experiencing.   Setting even one or two numbers high and you'll think you are on a roller coaster.   Too low and the AP will seem sluggish and unresponsive.

 I'm not familiar with the Garmin screens, but on the AFS there is additional set of gain controls in the EFIS.   This allowed me to even further fine tune the settings after getting them as close as possible in the manual AP mode.

 In the four years of flying with the Trutrak auto trim, I've never noticed it working.   It made appropriate corrects without any movements that that passenger can notice.

 I don't have my settings handy at the moment, but I have them and can share them with you as a comparison.  There almost identical to Rob Hickman's recommendation on where to start for a RV-10 using a AFS pilot, which is basically  the same AP that you have.

 Bob

 Get Outlook for iOS

 _____________________________

 From: Phillip Perry <philperry9(at)gmail.com (philperry9(at)gmail.com)>

 Sent: Sunday, July 9, 2017 12:11 AM

 Subject: Re: Elevator Trim Servo

 To: <rv10-list(at)matronics.com (rv10-list(at)matronics.com)>

 --> RV10-List message posted by: Phillip Perry <philperry9(at)gmail.com (philperry9(at)gmail.com)>

 Marcus,

 Sorry I missed our message. Fortunately I saw it on Kelly's reply. 

 I have the Garmin GX Pilot (TruTrak) with the G3X. It will tell you if you need trim up or down and then you just add it manually. 

 For Auto-Trim, you have to get the Auto-Trim module from TruTrak and install it. I can look at my AP head and see when trim inputs are being sent from the TruTrak to the trim servo. Right now mine are fairly frequently and have experienced a couple if moments  where it was putting inputs in so quickly that be plane never had time to respond before the next input was made. That created and pretty aggressive oscillation of about 30 ft high to 30 ft low as the auto-trim thought it was playing catchup, when in reality  it was behind. 

 Before my next flight, I'm going to make an adjustment to reduce the frequency of the auto-trim inputs. That will (should) give the plane some time to react before the next trim command is issued. 

 Phil

 Sent from my iPhone

 > On Jul 8, 2017, at 5:38 PM, Kelly McMullen <kellym(at)aviating.com (kellym(at)aviating.com)> wrote:

 > 

 > --> RV10-List message posted by: Kelly McMullen <kellym(at)aviating.com (kellym(at)aviating.com)>

 > 

 > I have the Dynon Skyview autopilot system, which shows on screen a trim command, which the autotrim then activates. At cruise the changes are rather minor and infrequent. In the pattern I hand fly anyway and do my own trimming.The Dynon autopilot panel adjusts  trim motor speed automatically to be inverse to airspeed.

 > 

 >> On 7/8/2017 8:15 AM, Marcus Cooper wrote:

 >> --> RV10-List message posted by: Marcus Cooper <cooprv7(at)yahoo.com (cooprv7(at)yahoo.com)>

 >> Phil,

 >> What kind of autopilot do you have? Just curious as I currently have the TruTrak which tells you a trim change is needed but doesn't actuate the trim. However, I am about to do a big panel upgrade which includes going to a Garmin G3X and Garmin autopilot  servos and am wondering if it also ties into the trim?

 >> Thanks,

 >> Marcus

 >>> On Jul 8, 2017, at 9:32 AM, Phillip Perry <philperry9(at)gmail.com (philperry9(at)gmail.com)> wrote:

 >>> Do not archive

 >>> --> RV10-List message posted by: Phillip Perry <philperry9(at)gmail.com (philperry9(at)gmail.com)>

 >>> 

 >>> Last message send too early.

 >>> 

 >>> So I have been disabling auto-trim on my auto pilot. Just to keep it from working up a down until I can learn more about how much input it's putting into the system. I really don't want to go on a 3 hour flight and have the auto-trim running the tab the  whole time when the trim is close enough that servo is close enough to handle the loads.

 >>> 

 >>> So I've been using auto trim to get level and then shutting it down until it's needed.

 >>> 

 >>> I don't know if it helps much, but I'm just hoping to extend the life of the servo by running it when it really doesn't need to be running.

 >>> 

 >>> Phil

 >>> 

 >>> 

 >>> 

 >>> 

 >>> Sent from my iPhone

 >>> 

 >>>> On Jul 8, 2017, at 7:18 AM, Ron Walker <n520tx(at)gmail.com (n520tx(at)gmail.com)> wrote:

 >>>> 

 >>>> --> RV10-List message posted by: Ron Walker <n520tx(at)gmail.com (n520tx(at)gmail.com)>

 >>>> 

 >>>> Doing some T&G last evening in the 10 ... with just me on board, final typically has me full nose up on the trim - even with that, I still need some back pressure ... but that's not the story.

 >>>> 

 >>>> Anyway, on roll-out, I was moving the tab back to neutral and realized it was taking a LOT longer to reset than usual. Eventually I determined that it was not moving at all. The trim had stopped in the full nose up (tab down) position.

 >>>> 

 >>>> Some troubleshooting after shutdown revealed the mechanism is not jammed, it still gets power - when activated, the unit does some "whirring" - but the jack screw does not move. It appears something INTERNAL to the unit has failed.

 >>>> 

 >>>> In all my years flying RV's, I've never heard of a single failure in this manner. Anyone ?

 >>>> 

 >>>> Really wish I had used a DB9 or some other quick connect for this ...

 >>>> 

 >>>> --Ron

 >>>> 

 >>>> 

 >>>> 

 >>> 

 >>> 

 >>> 

 >>> 

 > 

 > 

 > 

 ===========

 -List" x-apple-data-detectors="true" x-apple-data-detectors-type="link" x-apple-data-detectors-result="11"> http://www.matronics.com/Navigator?RV10-List

 ===========

 ta-detectors="true" x-apple-data-detectors-type="link" x-apple-data-detectors-result="12"> http://forums.matronics.com

 ===========

 -detectors="true" x-apple-data-detectors-type="link" x-apple-data-detectors-result="13"> http://wiki.matronics.com

 ===========

 x-apple-data-detectors="true" x-apple-data-detectors-type="link" x-apple-data-detectors-result="14"> http://www.matronics.com/contribution

 ===========

jesse(at)saintaviation.co
Guest

Posted: Sun Jul 09, 2017 2:19 am Post subject: Elevator Trim Servo

The overshooting can be gains or auto-trim set too high. If your module has a knob, you can adjust it that way. If it is newer, it is adjusted using the trim switch (pg 9 in the auto trim manual). 

The Garmin G3X auto pilot does also have auto trim built in. You can adjust setting on it as well. 

The Dynon lets you set trim speed through the AP Panel, which also provides auto trim. It is not necessarily inverse to airspeed, but that is the correct way to set it. You set a max trim speed and the airspeed for that trim speed, then a minimum trim speed and and airspeed for that trim speed, then it makes a linear correlation between those two airspeeds. This is a very nice feature. 

In my experience, the trutrak usually trims a lot more than the Dynon and Garmin by default, but you can adjust that. Also, Dynon let's you trim manually even when the AP is on. Garmin turns the auto pilot off if you trim manually (unless fixed in a software update) and the Trutrak disables your trim switch when the AP is on. 

One other thing is that the Trutrak only offers auto pitch trim. The other two offer auto trim on pitch and roll, although I haven't ever used the roll trim portion more than just to realize it doesn't really need it. 

Jesse SaintSaint Aviation, Inc. 

jesse(at)saintaviation.com (jesse(at)saintaviation.com)

C: 352-427-0285

F: 815-377-3694

Sent from my iPhone

On Jul 9, 2017, at 5:34 AM, Bob Leffler <bob(at)thelefflers.com (bob(at)thelefflers.com)> wrote:

 	  Quote: 	
		           Phil,

 It sounds like your  vertical gain setting on the AP may be set too high.  The indication of gain being too high is a rapid over correction.

 Have you flown the in the AP mode and tested to see if a manual turn or altitude change is responded to appropriately?  I.e.  Does it turn out within 1 degree of the heading or within a couple feet of the altitude without overshooting?   If the gain is too high you'll see what you are experiencing.   Setting even one or two numbers high and you'll think you are on a roller coaster.   Too low and the AP will seem sluggish and unresponsive.

 I'm not familiar with the Garmin screens, but on the AFS there is additional set of gain controls in the EFIS.   This allowed me to even further fine tune the settings after getting them as close as possible in the manual AP mode.

 In the four years of flying with the Trutrak auto trim, I've never noticed it working.   It made appropriate corrects without any movements that that passenger can notice.

 I don't have my settings handy at the moment, but I have them and can share them with you as a comparison.  There almost identical to Rob Hickman's recommendation on where to start for a RV-10 using a AFS pilot, which is basically  the same AP that you have.

 Bob

 Get Outlook for iOS

 _____________________________

 From: Phillip Perry <philperry9(at)gmail.com (philperry9(at)gmail.com)>

 Sent: Sunday, July 9, 2017 12:11 AM

 Subject: Re: Elevator Trim Servo

 To: <rv10-list(at)matronics.com (rv10-list(at)matronics.com)>

 --> RV10-List message posted by: Phillip Perry <philperry9(at)gmail.com (philperry9(at)gmail.com)>

 Marcus,

 Sorry I missed our message. Fortunately I saw it on Kelly's reply. 

 I have the Garmin GX Pilot (TruTrak) with the G3X. It will tell you if you need trim up or down and then you just add it manually. 

 For Auto-Trim, you have to get the Auto-Trim module from TruTrak and install it. I can look at my AP head and see when trim inputs are being sent from the TruTrak to the trim servo. Right now mine are fairly frequently and have experienced a couple if moments  where it was putting inputs in so quickly that be plane never had time to respond before the next input was made. That created and pretty aggressive oscillation of about 30 ft high to 30 ft low as the auto-trim thought it was playing catchup, when in reality  it was behind. 

 Before my next flight, I'm going to make an adjustment to reduce the frequency of the auto-trim inputs. That will (should) give the plane some time to react before the next trim command is issued. 

 Phil

 Sent from my iPhone

 > On Jul 8, 2017, at 5:38 PM, Kelly McMullen <kellym(at)aviating.com (kellym(at)aviating.com)> wrote:

 > 

 > --> RV10-List message posted by: Kelly McMullen <kellym(at)aviating.com (kellym(at)aviating.com)>

 > 

 > I have the Dynon Skyview autopilot system, which shows on screen a trim command, which the autotrim then activates. At cruise the changes are rather minor and infrequent. In the pattern I hand fly anyway and do my own trimming.The Dynon autopilot panel adjusts  trim motor speed automatically to be inverse to airspeed.

 > 

 >> On 7/8/2017 8:15 AM, Marcus Cooper wrote:

 >> --> RV10-List message posted by: Marcus Cooper <cooprv7(at)yahoo.com (cooprv7(at)yahoo.com)>

 >> Phil,

 >> What kind of autopilot do you have? Just curious as I currently have the TruTrak which tells you a trim change is needed but doesn't actuate the trim. However, I am about to do a big panel upgrade which includes going to a Garmin G3X and Garmin autopilot  servos and am wondering if it also ties into the trim?

 >> Thanks,

 >> Marcus

 >>> On Jul 8, 2017, at 9:32 AM, Phillip Perry <philperry9(at)gmail.com (philperry9(at)gmail.com)> wrote:

 >>> Do not archive

 >>> --> RV10-List message posted by: Phillip Perry <philperry9(at)gmail.com (philperry9(at)gmail.com)>

 >>> 

 >>> Last message send too early.

 >>> 

 >>> So I have been disabling auto-trim on my auto pilot. Just to keep it from working up a down until I can learn more about how much input it's putting into the system. I really don't want to go on a 3 hour flight and have the auto-trim running the tab the  whole time when the trim is close enough that servo is close enough to handle the loads.

 >>> 

 >>> So I've been using auto trim to get level and then shutting it down until it's needed.

 >>> 

 >>> I don't know if it helps much, but I'm just hoping to extend the life of the servo by running it when it really doesn't need to be running.

 >>> 

 >>> Phil

 >>> 

 >>> 

 >>> 

 >>> 

 >>> Sent from my iPhone

 >>> 

 >>>> On Jul 8, 2017, at 7:18 AM, Ron Walker <n520tx(at)gmail.com (n520tx(at)gmail.com)> wrote:

 >>>> 

 >>>> --> RV10-List message posted by: Ron Walker <n520tx(at)gmail.com (n520tx(at)gmail.com)>

 >>>> 

 >>>> Doing some T&G last evening in the 10 ... with just me on board, final typically has me full nose up on the trim - even with that, I still need some back pressure ... but that's not the story.

 >>>> 

 >>>> Anyway, on roll-out, I was moving the tab back to neutral and realized it was taking a LOT longer to reset than usual. Eventually I determined that it was not moving at all. The trim had stopped in the full nose up (tab down) position.

 >>>> 

 >>>> Some troubleshooting after shutdown revealed the mechanism is not jammed, it still gets power - when activated, the unit does some "whirring" - but the jack screw does not move. It appears something INTERNAL to the unit has failed.

 >>>> 

 >>>> In all my years flying RV's, I've never heard of a single failure in this manner. Anyone ?

 >>>> 

 >>>> Really wish I had used a DB9 or some other quick connect for this ...

 >>>> 

 >>>> --Ron

 >>>> 

 >>>> 

 >>>> 

 >>> 

 >>> 

 >>> 

 >>> 

 > 

 > 

 > 

 ===========

 -List" x-apple-data-detectors="true" x-apple-data-detectors-type="link" x-apple-data-detectors-result="11"> http://www.matronics.com/Navigator?RV10-List

 ===========

 ta-detectors="true" x-apple-data-detectors-type="link" x-apple-data-detectors-result="12"> http://forums.matronics.com

 ===========

 -detectors="true" x-apple-data-detectors-type="link" x-apple-data-detectors-result="13"> http://wiki.matronics.com

 ===========

 x-apple-data-detectors="true" x-apple-data-detectors-type="link" x-apple-data-detectors-result="14"> http://www.matronics.com/contribution

 ===========

philperry9

Joined: 23 Nov 2011
Posts: 381

Posted: Sun Jul 09, 2017 7:27 am Post subject: Elevator Trim Servo

I suspect the auto-trim is set too high.   I haven't had any issues with the AP rolling out on the wrong heading or failing to intercept an altitude.    

The problem first exhibited itself when I was straight and level and made a power change.   That power change apparently hit a sweet spot where it wanted to ride the roller coaster.    

I let it I for awhile just watching to see if it would ever figure it out; it didn't.   So my next step was to switch my trim speed switch to slow.   It might have helped a bit, but can't say for sure because I couldn't recall if the auto-trim used the trim-speed switch.   Then I disabled auto-trim and the problem went away.   

It was just one of those things you find in Phase 1 where everything works great for 10 hours and then you find some perfect combination of things (a power setting adjustment in my case) where you don't get the results you expect for some freak reason.  

My auto-trim module has the knob on the side and I haven't touched it from the factory.   My next plan is to turn it and slow down the trim inputs a bit.  I'll keep dialing it down until I find a sweet spot or the problem doesn't go away at the end of the knobs travel.  

Phil

Sent from my iPhone

[quote] On Jul 9, 2017, at 4:19 AM, Jesse Saint <jesse(at)saintaviation.com> wrote:

 The overshooting can be gains or auto-trim set too high. If your module has a knob, you can adjust it that way. If it is newer, it is adjusted using the trim switch (pg 9 in the auto trim manual). 

 The Garmin G3X auto pilot does also have auto trim built in. You can adjust setting on it as well. 

 The Dynon lets you set trim speed through the AP Panel, which also provides auto trim. It is not necessarily inverse to airspeed, but that is the correct way to set it. You set a max trim speed and the airspeed for that trim speed, then a minimum trim speed and and airspeed for that trim speed, then it makes a linear correlation between those two airspeeds. This is a very nice feature. 

 In my experience, the trutrak usually trims a lot more than the Dynon and Garmin by default, but you can adjust that. Also, Dynon let's you trim manually even when the AP is on. Garmin turns the auto pilot off if you trim manually (unless fixed in a software update) and the Trutrak disables your trim switch when the AP is on. 

 One other thing is that the Trutrak only offers auto pitch trim. The other two offer auto trim on pitch and roll, although I haven't ever used the roll trim portion more than just to realize it doesn't really need it. 

 Jesse Saint

 Saint Aviation, Inc. 

 jesse(at)saintaviation.com

 C: 352-427-0285

 F: 815-377-3694

 Sent from my iPhone

> On Jul 9, 2017, at 5:34 AM, Bob Leffler <bob(at)thelefflers.com> wrote:

> 

> Phil,

> 

> It sounds like your  vertical gain setting on the AP may be set too high.  The indication of gain being too high is a rapid over correction.

> 

> Have you flown the in the AP mode and tested to see if a manual turn or altitude change is responded to appropriately?  I.e.  Does it turn out within 1 degree of the heading or within a couple feet of the altitude without overshooting?  If the gain is too high you'll see what you are experiencing.   Setting even one or two numbers high and you'll think you are on a roller coaster.   Too low and the AP will seem sluggish and unresponsive.

> 

> I'm not familiar with the Garmin screens, but on the AFS there is additional set of gain controls in the EFIS.   This allowed me to even further fine tune the settings after getting them as close as possible in the manual AP mode.

> 

> In the four years of flying with the Trutrak auto trim, I've never noticed it working.   It made appropriate corrects without any movements that that passenger can notice.

> 

> I don't have my settings handy at the moment, but I have them and can share them with you as a comparison.  There almost identical to Rob Hickman's recommendation on where to start for a RV-10 using a AFS pilot, which is basically the same AP that you have.

> 

> Bob

> 

> 

> Get Outlook for iOS

> _____________________________

> From: Phillip Perry <philperry9(at)gmail.com>

> Sent: Sunday, July 9, 2017 12:11 AM

> Subject: Re: Elevator Trim Servo

> To: <rv10-list(at)matronics.com>

> 

> 

> 

> 

> Marcus,

> 

> Sorry I missed our message. Fortunately I saw it on Kelly's reply. 

> 

> I have the Garmin GX Pilot (TruTrak) with the G3X. It will tell you if you need trim up or down and then you just add it manually. 

> 

> For Auto-Trim, you have to get the Auto-Trim module from TruTrak and install it. I can look at my AP head and see when trim inputs are being sent from the TruTrak to the trim servo. Right now mine are fairly frequently and have experienced a couple if moments where it was putting inputs in so quickly that be plane never had time to respond before the next input was made. That created and pretty aggressive oscillation of about 30 ft high to 30 ft low as the auto-trim thought it was playing catchup, when in reality  it was behind. 

> 

> Before my next flight, I'm going to make an adjustment to reduce the frequency of the auto-trim inputs. That will (should) give the plane some time to react before the next trim command is issued. 

> 

> Phil

> 

> 

> Sent from my iPhone

> 

> > On Jul 8, 2017, at 5:38 PM, Kelly McMullen <kellym(at)aviating.com> wrote:

> > 

> > 

> > 

> > I have the Dynon Skyview autopilot system, which shows on screen a trim command, which the autotrim then activates. At cruise the changes are rather minor and infrequent. In the pattern I hand fly anyway and do my own trimming.The Dynon autopilot panel adjusts trim motor speed automatically to be inverse to airspeed.

> > 

> >> On 7/8/2017 8:15 AM, Marcus Cooper wrote:

> >> 

> >> Phil,

> >> What kind of autopilot do you have? Just curious as I currently have the TruTrak which tells you a trim change is needed but doesn't actuate the trim. However, I am about to do a big panel upgrade which includes going to a Garmin G3X and Garmin autopilot servos and am wondering if it also ties into the trim?

> >> Thanks,

> >> Marcus

> >>> On Jul 8, 2017, at 9:32 AM, Phillip Perry <philperry9(at)gmail.com> wrote:

> >>> Do not archive

> >>> 

> >>> 

> >>> Last message send too early.

> >>> 

> >>> So I have been disabling auto-trim on my auto pilot. Just to keep it from working up a down until I can learn more about how much input it's putting into the system. I really don't want to go on a 3 hour flight and have the auto-trim running the tab the whole time when the trim is close enough that servo is close enough to handle the loads.

> >>> 

> >>> So I've been using auto trim to get level and then shutting it down until it's needed.

> >>> 

> >>> I don't know if it helps much, but I'm just hoping to extend the life of the servo by running it when it really doesn't need to be running.

> >>> 

> >>> Phil

> >>> 

> >>> 

> >>> 

> >>> 

> >>> Sent from my iPhone

> >>> 

> >>>> On Jul 8, 2017, at 7:18 AM, Ron Walker <n520tx(at)gmail.com> wrote:

> >>>> 

> >>>> 

> >>>> 

> >>>> Doing some T&G last evening in the 10 ... with just me on board, final typically has me full nose up on the trim - even with that, I still need some back pressure ... but that's not the story.

> >>>> 

> >>>> Anyway, on roll-out, I was moving the tab back to neutral and realized it was taking a LOT longer to reset than usual. Eventually I determined that it was not moving at all. The trim had stopped in the full nose up (tab down) position.

> >>>> 

> >>>> Some troubleshooting after shutdown revealed the mechanism is not jammed, it still gets power - when activated, the unit does some "whirring" - but the jack screw does not move. It appears something INTERNAL to the unit has failed.

> >>>> 

> >>>> In all my years flying RV's, I've never heard of a single failure in this manner. Anyone ?

> >>>> 

> >>>> Really wish I had used a DB9 or some other quick connect for this ..

n520tx(at)gmail.com
Guest

Posted: Sun Jul 09, 2017 7:49 am Post subject: Elevator Trim Servo

I spent the better part of an hr this morning removing the servo. I hope 

re-install goes as smoothly.

I removed the servo cover and got a look at the innards. One of the 

drive gears had a few teeth missing. In this "dead spot", the shaft will 

not move. Culprit identified.

Pricey little gizmo, too.

--Ron

On 07/08/2017 08:28 AM, Phillip Perry wrote:

 	  Quote: 	

 We just replaced one on a -10 on our field.  Exactly the same failure after some T&G's in the evening.  There was noise but no movement as a gear broke inside the unit.

 It was ~10 years old, FYI.

 I suspect this servo gets more use (and high pressures on the mechanisms) than any other servo (Aileron and rudder for those who have rudder trim).

 Sent from my iPhone

> On Jul 8, 2017, at 7:18 AM, Ron Walker <n520tx(at)gmail.com> wrote:

>

> 

>

> Doing some T&G last evening in the 10 ... with just me on board, final typically has me full nose up on the trim - even with that, I still need some back pressure ... but that's not the story.

>

> Anyway, on roll-out, I was moving the tab back to neutral and realized it was taking a LOT longer to reset than usual. Eventually I determined that it was not moving at all. The trim had stopped in the full nose up (tab down) position.

>

> Some troubleshooting after shutdown revealed the mechanism is not jammed, it still gets power - when activated, the unit does some "whirring" - but the jack screw does not move. It appears something INTERNAL to the unit has failed.

>

> In all my years flying RV's, I've never heard of a single failure in this manner. Anyone ?

>

> Really wish I had used a DB9 or some other quick connect for this ...

>

> --Ron

>

philperry9

Joined: 23 Nov 2011
Posts: 381

Posted: Sun Jul 09, 2017 8:28 am Post subject: Elevator Trim Servo

Curious how old it was?   The one we replaced had the same failure at 10 years.  



Sent from my iPhone



 	  Quote: 	
		   On Jul 9, 2017, at 9:49 AM, Ron Walker <n520tx(at)gmail.com> wrote:

 

 

 

 I spent the better part of an hr this morning removing the servo. I hope re-install goes as smoothly.

 

 I removed the servo cover and got a look at the innards. One of the drive gears had a few teeth missing. In this "dead spot", the shaft will not move. Culprit identified.

 

 Pricey little gizmo, too.

 

 --Ron

 

> On 07/08/2017 08:28 AM, Phillip Perry wrote:

> 

> We just replaced one on a -10 on our field.  Exactly the same failure after some T&G's in the evening.  There was noise but no movement as a gear broke inside the unit.

> It was ~10 years old, FYI.

> I suspect this servo gets more use (and high pressures on the mechanisms) than any other servo (Aileron and rudder for those who have rudder trim).

>  Sent from my iPhone

>> On Jul 8, 2017, at 7:18 AM, Ron Walker <n520tx(at)gmail.com> wrote:

>> 

>> 

>> 

>> Doing some T&G last evening in the 10 ... with just me on board, final typically has me full nose up on the trim - even with that, I still need some back pressure ... but that's not the story.

>> 

>> Anyway, on roll-out, I was moving the tab back to neutral and realized it was taking a LOT longer to reset than usual. Eventually I determined that it was not moving at all. The trim had stopped in the full nose up (tab down) position.

>> 

>> Some troubleshooting after shutdown revealed the mechanism is not jammed, it still gets power - when activated, the unit does some "whirring" - but the jack screw does not move. It appears something INTERNAL to the unit has failed.

>> 

>> In all my years flying RV's, I've never heard of a single failure in this manner. Anyone ?

>> 

>> Really wish I had used a DB9 or some other quick connect for this ...

>> 

>> --Ron

>>

n520tx(at)gmail.com
Guest

Posted: Sun Jul 09, 2017 10:41 am Post subject: Elevator Trim Servo

I bought the emp kit in 2005, so I would guess at least 12 yrs old. 

However, it's only been flying since Oct 2016 (9 mths). Perhaps it just 

went brittle while sitting idle all those years.

--Ron

On 07/09/2017 11:28 AM, Phillip Perry wrote:

 	  Quote: 	

 Curious how old it was?   The one we replaced had the same failure at 10 years.

 Sent from my iPhone

> On Jul 9, 2017, at 9:49 AM, Ron Walker <n520tx(at)gmail.com> wrote:

>

> 

>

> I spent the better part of an hr this morning removing the servo. I hope re-install goes as smoothly.

>

> I removed the servo cover and got a look at the innards. One of the drive gears had a few teeth missing. In this "dead spot", the shaft will not move. Culprit identified.

>

> Pricey little gizmo, too.

>

> --Ron

Display posts from previous:

	Matronics Email Lists Forum Index -> RV10-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum