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Run-away trim question

 
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Jim Combs



Joined: 24 Jan 2010
Posts: 126
Location: Lexington, Ky

PostPosted: Fri Jun 22, 2018 5:43 am    Post subject: Run-away trim question Reply with quote

I was asked a question recently about runaway trim.
What would I do if it happened?
I have tried flying the -10 with the trim held to see just what happens.  I cruise flight, the out of trim condition happens so fast and the forces on the stick quickly overwhelm the pilots ability to control the aircraft.  Realizing what is going on would be a surprise to the pilot and once it happened, flying the airplane becomes the dominate focus item.  Stopping the runaway by pulling a fuse or some other action would most likely not happen.
This question does not necessarily apply only to the -10.  It could happen on any aircraft.
That being said:
(1) Has anyone ever heard of a runaway condition actually happening?  if so what was the outcome?  
(2) Is there a stand-alone device that could be put into the trim circuit that is powered by the power going to the trim motor that would (A) prevent the motor from running for an extended time and (B) alert the pilot to the runaway condition.  This would be downstream from the switch or controlling electronics.
Jim Combs
N312F (1000+ hours) 


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philperry9



Joined: 23 Nov 2011
Posts: 348

PostPosted: Fri Jun 22, 2018 5:54 am    Post subject: Run-away trim question Reply with quote

You can install the TCW trim controller and it will address the issue of run away trim.  I know it will do more, but here are some basics.

1) It will limit the time that the servo is active to just a few seconds.  Then disconnect the trim requiring to re-engage the switch to activate the servo for a few more seconds.   This prevents a stuck switch to run the servo to full travel and your trim to full defection.
2) It has a sense circuit built into it that senses where there is a short in a wire causing the servo to run.   Then provides a switch that allows you to reverse the travel of the servo through a momentary switch to bring the servo back to its normal spot; then it disconnects the servo from the buss.  Thus locking the servo in a more neutral position.
3) It also has a two-speed option so you don't have to drive your servo at full speed.  This brings the trim adjustments down to a slower and more reasonable speed when you're really scooting through the air.
Phil
On Fri, Jun 22, 2018 at 8:40 AM, Jim Combs <jiminlexky(at)gmail.com (jiminlexky(at)gmail.com)> wrote:
Quote:
I was asked a question recently about runaway trim.
What would I do if it happened?
I have tried flying the -10 with the trim held to see just what happens.  I cruise flight, the out of trim condition happens so fast and the forces on the stick quickly overwhelm the pilots ability to control the aircraft.  Realizing what is going on would be a surprise to the pilot and once it happened, flying the airplane becomes the dominate focus item.  Stopping the runaway by pulling a fuse or some other action would most likely not happen.
This question does not necessarily apply only to the -10.  It could happen on any aircraft.
That being said:
(1) Has anyone ever heard of a runaway condition actually happening?  if so what was the outcome?  
(2) Is there a stand-alone device that could be put into the trim circuit that is powered by the power going to the trim motor that would (A) prevent the motor from running for an extended time and (B) alert the pilot to the runaway condition.  This would be downstream from the switch or controlling electronics.
Jim Combs
N312F (1000+ hours) 



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Jim Combs



Joined: 24 Jan 2010
Posts: 126
Location: Lexington, Ky

PostPosted: Fri Jun 22, 2018 6:04 am    Post subject: Run-away trim question Reply with quote

Thanks, I will check that out.

Jim C
On Fri, Jun 22, 2018 at 9:52 AM, Phillip Perry <philperry9(at)gmail.com (philperry9(at)gmail.com)> wrote:
Quote:
You can install the TCW trim controller and it will address the issue of run away trim.  I know it will do more, but here are some basics.

1) It will limit the time that the servo is active to just a few seconds.  Then disconnect the trim requiring to re-engage the switch to activate the servo for a few more seconds.   This prevents a stuck switch to run the servo to full travel and your trim to full defection.
2) It has a sense circuit built into it that senses where there is a short in a wire causing the servo to run.   Then provides a switch that allows you to reverse the travel of the servo through a momentary switch to bring the servo back to its normal spot; then it disconnects the servo from the buss.  Thus locking the servo in a more neutral position.
3) It also has a two-speed option so you don't have to drive your servo at full speed.  This brings the trim adjustments down to a slower and more reasonable speed when you're really scooting through the air.
Phil
On Fri, Jun 22, 2018 at 8:40 AM, Jim Combs <jiminlexky(at)gmail.com (jiminlexky(at)gmail.com)> wrote:
Quote:
I was asked a question recently about runaway trim.
What would I do if it happened?
I have tried flying the -10 with the trim held to see just what happens.  I cruise flight, the out of trim condition happens so fast and the forces on the stick quickly overwhelm the pilots ability to control the aircraft.  Realizing what is going on would be a surprise to the pilot and once it happened, flying the airplane becomes the dominate focus item.  Stopping the runaway by pulling a fuse or some other action would most likely not happen.
This question does not necessarily apply only to the -10.  It could happen on any aircraft.
That being said:
(1) Has anyone ever heard of a runaway condition actually happening?  if so what was the outcome?  
(2) Is there a stand-alone device that could be put into the trim circuit that is powered by the power going to the trim motor that would (A) prevent the motor from running for an extended time and (B) alert the pilot to the runaway condition.  This would be downstream from the switch or controlling electronics.
Jim Combs
N312F (1000+ hours) 




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Kelly McMullen



Joined: 16 Apr 2008
Posts: 1124
Location: Sun Lakes AZ

PostPosted: Fri Jun 22, 2018 6:31 am    Post subject: Run-away trim question Reply with quote

Well, I had a complete elevator trim failure, not runaway, and fortunately I discovered I had the problem shortly after lift-off, so did not allow speed to get much above 120.
Due to some dufus builder error, the cotter pin for the bellcrank bolt on the trim assembly fell out, the nut backed off, and the bolt worked its way out, so the bellcrank did not have any leverage and helped nothing. The resulting trim was somewhere around landing configuration nose up. The stick force was under 10 lbs., easy to hold with one hand for the 15 min flight I had back to home drome. Yes, I suppose you could have runaway trim, that the surprise factor would be main event. Between stick force and throttle, you can control the force involved.
No, I would not want to be IFR.  However, I found that in my case, my Dynon autopilot had no trouble holding the airplane...although I chose not to do that for more than long enough to see if it could. I didn't want to risk failure of the shear pin, and stress the servo.
Yes, I fixed the problem, with just the difficulty of getting my old, creaky body back in the tail cone and reassembling parts that I couldn't get a good view. Now to go punish that doofus builder.............
Quote:
Sent from my IBM-360 main frame


On Fri, Jun 22, 2018 at 6:40 AM, Jim Combs <jiminlexky(at)gmail.com (jiminlexky(at)gmail.com)> wrote:
Quote:
I was asked a question recently about runaway trim.
What would I do if it happened?
I have tried flying the -10 with the trim held to see just what happens.  I cruise flight, the out of trim condition happens so fast and the forces on the stick quickly overwhelm the pilots ability to control the aircraft.  Realizing what is going on would be a surprise to the pilot and once it happened, flying the airplane becomes the dominate focus item.  Stopping the runaway by pulling a fuse or some other action would most likely not happen.
This question does not necessarily apply only to the -10.  It could happen on any aircraft.
That being said:
(1) Has anyone ever heard of a runaway condition actually happening?  if so what was the outcome?  
(2) Is there a stand-alone device that could be put into the trim circuit that is powered by the power going to the trim motor that would (A) prevent the motor from running for an extended time and (B) alert the pilot to the runaway condition.  This would be downstream from the switch or controlling electronics.
Jim Combs
N312F (1000+ hours) 



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Kelly McMullen
A&P/IA, EAA Tech Counselor
KCHD
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stein(at)steinair.com
Guest





PostPosted: Fri Jun 22, 2018 6:38 am    Post subject: Run-away trim question Reply with quote

Also realize that if you’re using either Garmin or Dynon’s integrated autopilots with the Auto Trim wired through their respective A/P’s, you also get trim motor timing limits (which in effect is the same function) along with the trim speed scheduling.  The Safety Trim is an excellent box as a standalone device, but becomes redundant if you have either the Garmin or Dynon integrated A/P (with the respective controllers).

Just my 2 cents as usual.

Cheers,
Stein


From: owner-rv10-list-server(at)matronics.com <owner-rv10-list-server(at)matronics.com> On Behalf Of Jim Combs
Sent: Friday, June 22, 2018 9:03 AM
To: rv10-list(at)matronics.com
Subject: Re: Run-away trim question

Thanks, I will check that out.


Jim C

On Fri, Jun 22, 2018 at 9:52 AM, Phillip Perry <philperry9(at)gmail.com (philperry9(at)gmail.com)> wrote:
Quote:

You can install the TCW trim controller and it will address the issue of run away trim. I know it will do more, but here are some basics.


1) It will limit the time that the servo is active to just a few seconds. Then disconnect the trim requiring to re-engage the switch to activate the servo for a few more seconds. This prevents a stuck switch to run the servo to full travel and your trim to full defection.



2) It has a sense circuit built into it that senses where there is a short in a wire causing the servo to run. Then provides a switch that allows you to reverse the travel of the servo through a momentary switch to bring the servo back to its normal spot; then it disconnects the servo from the buss. Thus locking the servo in a more neutral position.



3) It also has a two-speed option so you don't have to drive your servo at full speed. This brings the trim adjustments down to a slower and more reasonable speed when you're really scooting through the air.



Phil

On Fri, Jun 22, 2018 at 8:40 AM, Jim Combs <jiminlexky(at)gmail.com (jiminlexky(at)gmail.com)> wrote:
Quote:

I was asked a question recently about runaway trim.



What would I do if it happened?



I have tried flying the -10 with the trim held to see just what happens. I cruise flight, the out of trim condition happens so fast and the forces on the stick quickly overwhelm the pilots ability to control the aircraft. Realizing what is going on would be a surprise to the pilot and once it happened, flying the airplane becomes the dominate focus item. Stopping the runaway by pulling a fuse or some other action would most likely not happen.



This question does not necessarily apply only to the -10. It could happen on any aircraft.



That being said:



(1) Has anyone ever heard of a runaway condition actually happening? if so what was the outcome?



(2) Is there a stand-alone device that could be put into the trim circuit that is powered by the power going to the trim motor that would (A) prevent the motor from running for an extended time and (B) alert the pilot to the runaway condition. This would be downstream from the switch or controlling electronics.



Jim Combs

N312F (1000+ hours)










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Jim Combs



Joined: 24 Jan 2010
Posts: 126
Location: Lexington, Ky

PostPosted: Fri Jun 22, 2018 6:52 am    Post subject: Run-away trim question Reply with quote

So I looked into the TCW solution and I still consider this to be a single point of failure.  Note: I am NOT in any way bashing the TCW solution.  It still has power supplied to it and can run the the trim servo IF IT FAILED.  But it does have a separate power switch along with the airspeed speed switch.  Both of which I like, so I will be installing that in the -10.

I have been driving my trim through a DPDT On - Off - On momentary switch and have had no issues with it.  Having the speed select will be a nice addition.  I also like the TCW Flap system.  So I think some upgrades are in order for the -10.
Thanks, 
Jim C
So Kelly, does the IBM 360 heat the house too?  Just wondering.

On Fri, Jun 22, 2018 at 10:29 AM, Kelly McMullen <apilot2(at)gmail.com (apilot2(at)gmail.com)> wrote:
Quote:
Well, I had a complete elevator trim failure, not runaway, and fortunately I discovered I had the problem shortly after lift-off, so did not allow speed to get much above 120.
Due to some dufus builder error, the cotter pin for the bellcrank bolt on the trim assembly fell out, the nut backed off, and the bolt worked its way out, so the bellcrank did not have any leverage and helped nothing. The resulting trim was somewhere around landing configuration nose up. The stick force was under 10 lbs., easy to hold with one hand for the 15 min flight I had back to home drome. Yes, I suppose you could have runaway trim, that the surprise factor would be main event. Between stick force and throttle, you can control the force involved.
No, I would not want to be IFR.  However, I found that in my case, my Dynon autopilot had no trouble holding the airplane...although I chose not to do that for more than long enough to see if it could. I didn't want to risk failure of the shear pin, and stress the servo.
Yes, I fixed the problem, with just the difficulty of getting my old, creaky body back in the tail cone and reassembling parts that I couldn't get a good view. Now to go punish that doofus builder.............
Quote:
Sent from my IBM-360 main frame


On Fri, Jun 22, 2018 at 6:40 AM, Jim Combs <jiminlexky(at)gmail.com (jiminlexky(at)gmail.com)> wrote:
Quote:
I was asked a question recently about runaway trim.
What would I do if it happened?
I have tried flying the -10 with the trim held to see just what happens.  I cruise flight, the out of trim condition happens so fast and the forces on the stick quickly overwhelm the pilots ability to control the aircraft.  Realizing what is going on would be a surprise to the pilot and once it happened, flying the airplane becomes the dominate focus item.  Stopping the runaway by pulling a fuse or some other action would most likely not happen.
This question does not necessarily apply only to the -10.  It could happen on any aircraft.
That being said:
(1) Has anyone ever heard of a runaway condition actually happening?  if so what was the outcome?  
(2) Is there a stand-alone device that could be put into the trim circuit that is powered by the power going to the trim motor that would (A) prevent the motor from running for an extended time and (B) alert the pilot to the runaway condition.  This would be downstream from the switch or controlling electronics.
Jim Combs
N312F (1000+ hours) 




- The Matronics RV10-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

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Jim Combs



Joined: 24 Jan 2010
Posts: 126
Location: Lexington, Ky

PostPosted: Fri Jun 22, 2018 6:53 am    Post subject: Run-away trim question Reply with quote

I have the Advanced Flight System and A/P. No A/P Trim.

Pondering the ADSB upgrade but that is a different thread.

Thanks, Jim C

On Fri, Jun 22, 2018 at 10:34 AM, Stein Bruch <stein(at)steinair.com> wrote:

[quote] Also realize that if you’re using either Garmin or Dynon’s integrated
autopilots with the Auto Trim wired through their respective A/P’s, you
also get trim motor timing limits (which in effect is the same function)
along with the trim speed scheduling. The Safety Trim is an excellent box
as a standalone device, but becomes redundant if you have either the Garmin
or Dynon integrated A/P (with the respective controllers).

Just my 2 cents as usual.

Cheers,

Stein

*From:* owner-rv10-list-server(at)matronics.com <owner-rv10-list-server(at)
matronics.com> *On Behalf Of *Jim Combs
*Sent:* Friday, June 22, 2018 9:03 AM
*To:* rv10-list(at)matronics.com
*Subject:* Re: Run-away trim question

Thanks, I will check that out.

Jim C

On Fri, Jun 22, 2018 at 9:52 AM, Phillip Perry <philperry9(at)gmail.com>
wrote:

You can install the TCW trim controller and it will address the issue of
run away trim. I know it will do more, but here are some basics.

1) It will limit the time that the servo is active to just a few seconds.
Then disconnect the trim requiring to re-engage the switch to activate the
servo for a few more seconds. This prevents a stuck switch to run the
servo to full travel and your trim to full defection.

2) It has a sense circuit built into it that senses where there is a short
in a wire causing the servo to run. Then provides a switch that allows
you to reverse the travel of the servo through a momentary switch to bring
the servo back to its normal spot; then it disconnects the servo from the
buss. Thus locking the servo in a more neutral position.

3) It also has a two-speed option so you don't have to drive your servo at
full speed. This brings the trim adjustments down to a slower and more
reasonable speed when you're really scooting through the air.

Phil

On Fri, Jun 22, 2018 at 8:40 AM, Jim Combs <jiminlexky(at)gmail.com> wrote:

I was asked a question recently about runaway trim.

What would I do if it happened?

I have tried flying the -10 with the trim held to see just what happens.
I cruise flight, the out of trim condition happens so fast and the forces
on the stick quickly overwhelm the pilots ability to control the aircraft


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Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

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rleffler



Joined: 05 Nov 2006
Posts: 645

PostPosted: Fri Jun 22, 2018 7:07 am    Post subject: Run-away trim question Reply with quote

If you add the Dynon module, you can get the trim control as long as you have the Dynon servos.



Get Outlook for iOS


From: owner-rv10-list-server(at)matronics.com <owner-rv10-list-server(at)matronics.com> on behalf of Jim Combs <jiminlexky(at)gmail.com>
Sent: Friday, June 22, 2018 10:51:48 AM
To: rv10-list(at)matronics.com
Subject: Re: Run-away trim question

I have the Advanced Flight System and A/P. No A/P Trim.

Pondering the ADSB upgrade but that is a different thread.


Thanks, Jim C


On Fri, Jun 22, 2018 at 10:34 AM, Stein Bruch <stein(at)steinair.com (stein(at)steinair.com)> wrote:
Quote:

Also realize that if youre using either Garmin or Dynons integrated autopilots with the Auto Trim wired through their respective A/Ps, you also get trim motor timing limits (which in effect is the same function) along with the trim speed scheduling. The Safety Trim is an excellent box as a standalone device, but becomes redundant if you have either the Garmin or Dynon integrated A/P (with the respective controllers).

Just my 2 cents as usual.

Cheers,
Stein


From: owner-rv10-list-server(at)matronics.com (owner-rv10-list-server(at)matronics.com) <owner-rv10-list-server(at)matronics.com (owner-rv10-list-server(at)matronics.com)> On Behalf Of Jim Combs
Sent: Friday, June 22, 2018 9:03 AM
To: rv10-list(at)matronics.com (rv10-list(at)matronics.com)
Subject: Re: Run-away trim question

Thanks, I will check that out.


Jim C



On Fri, Jun 22, 2018 at 9:52 AM, Phillip Perry <philperry9(at)gmail.com (philperry9(at)gmail.com)> wrote:
Quote:

You can install the TCW trim controller and it will address the issue of run away trim. I know it will do more, but here are some basics.


1) It will limit the time that the servo is active to just a few seconds. Then disconnect the trim requiring to re-engage the switch to activate the servo for a few more seconds. This prevents a stuck switch to run the servo to full travel and your trim to full defection.



2) It has a sense circuit built into it that senses where there is a short in a wire causing the servo to run. Then provides a switch that allows you to reverse the travel of the servo through a momentary switch to bring the servo back to its normal spot; then it disconnects the servo from the buss. Thus locking the servo in a more neutral position.



3) It also has a two-speed option so you don't have to drive your servo at full speed. This brings the trim adjustments down to a slower and more reasonable speed when you're really scooting through the air.



Phil



On Fri, Jun 22, 2018 at 8:40 AM, Jim Combs <jiminlexky(at)gmail.com (jiminlexky(at)gmail.com)> wrote:
Quote:

I was asked a question recently about runaway trim.



What would I do if it happened?



I have tried flying the -10 with the trim held to see just what happens. I cruise flight, the out of trim condition happens so fast and the forces on the stick quickly overwhelm the pilots ability to control the aircraft. Realizing what is going on would be a surprise to the pilot and once it happened, flying the airplane becomes the dominate focus item. Stopping the runaway by pulling a fuse or some other action would most likely not happen.



This question does not necessarily apply only to the -10. It could happen on any aircraft.



That being said:



(1) Has anyone ever heard of a runaway condition actually happening? if so what was the outcome?



(2) Is there a stand-alone device that could be put into the trim circuit that is powered by the power going to the trim motor that would (A) prevent the motor from running for an extended time and (B) alert the pilot to the runaway condition. This would be downstream from the switch or controlling electronics.



Jim Combs

N312F (1000+ hours)















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Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

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Kellym



Joined: 10 Jan 2006
Posts: 1548
Location: Sun Lakes AZ

PostPosted: Fri Jun 22, 2018 7:37 am    Post subject: Run-away trim question Reply with quote

Hmm, some Dynon things are compatible, don't know if their autopilot
control panel is among those things. Worth asking.

On 6/22/2018 7:51 AM, Jim Combs wrote:
Quote:
I have the Advanced Flight System and A/P.  No A/P Trim.

Pondering the ADSB upgrade but that is a different thread.

Thanks, Jim C

On Fri, Jun 22, 2018 at 10:34 AM, Stein Bruch <stein(at)steinair.com
<mailto:stein(at)steinair.com>> wrote:

Also realize that if you’re using either Garmin or Dynon’s
integrated autopilots with the Auto Trim wired through their
respective A/P’s, you also get trim motor timing limits (which in
effect is the same function) along with the trim speed scheduling.
The Safety Trim is an excellent box as a standalone device, but
becomes redundant if you have either the Garmin or Dynon integrated
A/P (with the respective controllers).____

__ __

Just my 2 cents as usual.____

__ __

Cheers,____

Stein____

__ __

__ __

*From:* owner-rv10-list-server(at)matronics.com
<mailto:owner-rv10-list-server(at)matronics.com>
<owner-rv10-list-server(at)matronics.com
<mailto:owner-rv10-list-server(at)matronics.com>> *On Behalf Of *Jim Combs
*Sent:* Friday, June 22, 2018 9:03 AM
*To:* rv10-list(at)matronics.com <mailto:rv10-list(at)matronics.com>
*Subject:* Re: Run-away trim question____

__ __

Thanks, I will check that out.____

__ __

Jim C____

__ __

On Fri, Jun 22, 2018 at 9:52 AM, Phillip Perry <philperry9(at)gmail.com
<mailto:philperry9(at)gmail.com>> wrote:____

You can install the TCW trim controller and it will address the
issue of run away trim.  I know it will do more, but here are
some basics.____

__ __

1) It will limit the time that the servo is active to just a few
seconds.  Then disconnect the trim requiring to re-engage the
switch to activate the servo for a few more seconds.   This
prevents a stuck switch to run the servo to full travel and your
trim to full defection.____

__ __

2) It has a sense circuit built into it that senses where there
is a short in a wire causing the servo to run.   Then provides a
switch that allows you to reverse the travel of the servo
through a momentary switch to bring the servo back to its normal
spot; then it disconnects the servo from the buss.  Thus locking
the servo in a more neutral position.____

__ __

3) It also has a two-speed option so you don't have to drive
your servo at full speed.  This brings the trim adjustments down
to a slower and more reasonable speed when you're really
scooting through the air.____

__ __

Phil____

__ __

On Fri, Jun 22, 2018 at 8:40 AM, Jim Combs <jiminlexky(at)gmail.com
<mailto:jiminlexky(at)gmail.com>> wrote:____

I was asked a question recently about runaway trim.____

__ __

What would I do if it happened?____

__ __

I have tried flying the -10 with the trim held to see just
what happens.  I cruise flight, the out of trim condition
happens so fast and the forces on the stick quickly
overwhelm the pilots ability to control the aircraft.
Realizing what is going on would be a surprise to the pilot
and once it happened, flying the airplane becomes the
dominate focus item.  Stopping the runaway by pulling a fuse
or some other action would most likely not happen.____

__ __

This question does not necessarily apply only to the -10.
It could happen on any aircraft.____

__ __

That being said:____

__ __

(1) Has anyone ever heard of a runaway condition actually
happening?  if so what was the outcome? ____

__ __

(2) Is there a stand-alone device that could be put into the
trim circuit that is powered by the power going to the trim
motor that would (A) prevent the motor from running for an
extended time and (B) alert the pilot to the runaway
condition.  This would be downstream from the switch or
controlling electronics.____

__ __

Jim Combs____

N312F (1000+ hours) ____

__ __

__ __

__ __

__ __




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Bob Turner



Joined: 03 Jan 2009
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Location: Castro Valley, CA

PostPosted: Fri Jun 22, 2018 8:14 am    Post subject: Re: Run-away trim question Reply with quote

You absolutely want trim speed control. The stock, full speed, is about right for low (takeoff, landing) speeds but runs way too fast at cruise. I have a Trio Pro autopilot. Not only does it auto-trim when engaged; you can use it to trim manually, too, when the servos are not engaged. It contains a programable with airspeed speed control, too. So my routine is to use the stick switch for takeoff/landing trim (full speed); I use the Trio knob for fine trim adjustments in cruise. I put no top hat on the copilot stick, to prevent accidental trim commands. Right seat pilots have to use a panel mounted rocker switch. I put both AP and trim CBs right in front of the pilot, marked with a colored line. How fast could I pull them, given no warning? I don’t know.
Edit. Forgot to mention, the no top hat on right stick thing is because someone reported a ‘runaway trim’ when their right seat passenger rested a book on the top hat switch.


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PostPosted: Fri Jun 22, 2018 8:55 am    Post subject: Run-away trim question Reply with quote

It is..... I know several people that have it installed. Some features/functions may vary depending if you have Dynon servos versus Trutrak.



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From: owner-rv10-list-server(at)matronics.com <owner-rv10-list-server(at)matronics.com> on behalf of Kelly McMullen <kellym(at)aviating.com>
Sent: Friday, June 22, 2018 11:08:28 AM
To: rv10-list(at)matronics.com
Subject: Re: Run-away trim question


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

Hmm, some Dynon things are compatible, don't know if their autopilot
control panel is among those things. Worth asking.

On 6/22/2018 7:51 AM, Jim Combs wrote:
> I have the Advanced Flight System and A/P. No A/P Trim.
>
> Pondering the ADSB upgrade but that is a different thread.
>
> Thanks, Jim C
>
> On Fri, Jun 22, 2018 at 10:34 AM, Stein Bruch <stein(at)steinair.com
> <mailto:stein(at)steinair.com (stein(at)steinair.com)>> wrote:
>
> Also realize that if youre using either Garmin or Dynons
> integrated autopilots with the Auto Trim wired through their
> respective A/Ps, you also get trim motor timing limits (which in
> effect is the same function) along with the trim speed scheduling.
> The Safety Trim is an excellent box as a standalone device, but
> becomes redundant if you have either the Garmin or Dynon integrated
> A/P (with the respective controllers).____
>
> __ __
>
> Just my 2 cents as usual.____
>
> __ __
>
> Cheers,____
>
> Stein____
>
> __ __
>
> __ __
>
> *From:* owner-rv10-list-server(at)matronics.com
> <mailto:owner-rv10-list-server(at)matronics.com (owner-rv10-list-server(at)matronics.com)>
> <owner-rv10-list-server(at)matronics.com
> <mailto:owner-rv10-list-server(at)matronics.com (owner-rv10-list-server(at)matronics.com)>> *On Behalf Of *Jim Combs
> *Sent:* Friday, June 22, 2018 9:03 AM
> *To:* rv10-list(at)matronics.com <mailto:rv10-list(at)matronics.com (rv10-list(at)matronics.com)>
> *Subject:* Re: Run-away trim question____
>
> __ __
>
> Thanks, I will check that out.____
>
> __ __
>
> Jim C____
>
> __ __
>
> On Fri, Jun 22, 2018 at 9:52 AM, Phillip Perry <philperry9(at)gmail.com
> <mailto:philperry9(at)gmail.com (philperry9(at)gmail.com)>> wrote:____
>
> You can install the TCW trim controller and it will address the
> issue of run away trim. I know it will do more, but here are
> some basics.____
>
> __ __
>
> 1) It will limit the time that the servo is active to just a few
> seconds. Then disconnect the trim requiring to re-engage the
> switch to activate the servo for a few more seconds. This
> prevents a stuck switch to run the servo to full travel and your
> trim to full defection.____
>
> __ __
>
> 2) It has a sense circuit built into it that senses where there
> is a short in a wire causing the servo to run. Then provides a
> switch that allows you to reverse the travel of the servo
> through a momentary switch to bring the servo back to its normal
> spot; then it disconnects the servo from the buss. Thus locking
> the servo in a more neutral position.____
>
> __ __
>
> 3) It also has a two-speed option so you don't have to drive
> your servo at full speed. This brings the trim adjustments down
> to a slower and more reasonable speed when you're really
> scooting through the air.____
>
> __ __
>
> Phil____
>
> __ __
>
> On Fri, Jun 22, 2018 at 8:40 AM, Jim Combs <jiminlexky(at)gmail.com
> <mailto:jiminlexky(at)gmail.com (jiminlexky(at)gmail.com)>> wrote:____
>
> I was asked a question recently about runaway trim.____
>
> __ __
>
> What would I do if it happened?____
>
> __ __
>
> I have tried flying the -10 with the trim held to see just
> what happens. I cruise flight, the out of trim condition
> happens so fast and the forces on the stick quickly
> overwhelm the pilots ability to control the aircraft.
> Realizing what is going on would be a surprise to the pilot
> and once it happened, flying the airplane becomes the
> dominate focus item. Stopping the runaway by pulling a fuse
> or some other action would most likely not happen.____
>
> __ __
>
> This question does not necessarily apply only to the -10.
> It could happen on any aircraft.____
>
> __ __
>
> That being said:____
>
> __ __
>
> (1) Has anyone ever heard of a runaway condition actually
> happening? if so what was the outcome? ____
>
> __ __
>
> (2) Is there a stand-alone device that could be put into the
> trim circuit that is powered by the power going to the trim
> motor that would (A) prevent the motor from running for an
> extended time and (B) alert the pilot to the runaway
> condition. This would be downstream from the switch or
> controlling electronics.____
>
> __ __
>
> Jim Combs____
>
> N312F (1000+ hours) ____
>
> __ __
>
> __ __
>
> __ __
>
> __ __
>
>
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PostPosted: Fri Jun 22, 2018 12:15 pm    Post subject: Run-away trim question Reply with quote

Thanks to those that mentioned our Safety trim controller. One bit of trivia regarding the concept of single point failure. Even though our device is “one box” inside the unit there’s actually three separate series circuits which would have to all fail to provide an uncommanded operation of the servo. As a result after 10 years in the field we have had zero issues resulting in unwanted motion even in the face of a variety of builder mistakes and mis-applications.

Bob NewmanTCW Technologies, LLC
610-928-3420
On Jun 22, 2018, at 10:02 AM, Jim Combs <jiminlexky(at)gmail.com (jiminlexky(at)gmail.com)> wrote:
Quote:
Thanks, I will check that out.

Jim C
On Fri, Jun 22, 2018 at 9:52 AM, Phillip Perry <philperry9(at)gmail.com (philperry9(at)gmail.com)> wrote:
Quote:
You can install the TCW trim controller and it will address the issue of run away trim. I know it will do more, but here are some basics.

1) It will limit the time that the servo is active to just a few seconds. Then disconnect the trim requiring to re-engage the switch to activate the servo for a few more seconds. This prevents a stuck switch to run the servo to full travel and your trim to full defection.
2) It has a sense circuit built into it that senses where there is a short in a wire causing the servo to run. Then provides a switch that allows you to reverse the travel of the servo through a momentary switch to bring the servo back to its normal spot; then it disconnects the servo from the buss. Thus locking the servo in a more neutral position.
3) It also has a two-speed option so you don't have to drive your servo at full speed. This brings the trim adjustments down to a slower and more reasonable speed when you're really scooting through the air.
Phil
On Fri, Jun 22, 2018 at 8:40 AM, Jim Combs <jiminlexky(at)gmail.com (jiminlexky(at)gmail.com)> wrote:
Quote:
I was asked a question recently about runaway trim.
What would I do if it happened?
I have tried flying the -10 with the trim held to see just what happens. I cruise flight, the out of trim condition happens so fast and the forces on the stick quickly overwhelm the pilots ability to control the aircraft. Realizing what is going on would be a surprise to the pilot and once it happened, flying the airplane becomes the dominate focus item. Stopping the runaway by pulling a fuse or some other action would most likely not happen.
This question does not necessarily apply only to the -10. It could happen on any aircraft.
That being said:
(1) Has anyone ever heard of a runaway condition actually happening? if so what was the outcome?
(2) Is there a stand-alone device that could be put into the trim circuit that is powered by the power going to the trim motor that would (A) prevent the motor from running for an extended time and (B) alert the pilot to the runaway condition. This would be downstream from the switch or controlling electronics.
Jim Combs
N312F (1000+ hours)






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Jim Combs



Joined: 24 Jan 2010
Posts: 126
Location: Lexington, Ky

PostPosted: Fri Jun 22, 2018 1:25 pm    Post subject: Run-away trim question Reply with quote

Bob, Thanks for that bit of feedback. I am a retired electrical
engineer. That bit of information should be shared on your website.

I am planning or ordering that and the flap controller in the next few days


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Tim Olson



Joined: 25 Jan 2007
Posts: 2763

PostPosted: Fri Jun 22, 2018 1:47 pm    Post subject: Run-away trim question Reply with quote

Hey Jim, on my RV10 site I have an old write-up from when I put in safety-Trim. There may be more info there that you may want to check out also. I have mine set up with an airspeed switch and also a flap switch which I like very much and did the same on my RV14 as I did the -10.
You’ll be happy with the trim controller and wiring is easier than the relays you probably have now.
Tim

On Jun 22, 2018, at 5:15 PM, Jim Combs <jiminlexky(at)gmail.com (jiminlexky(at)gmail.com)> wrote:
Quote:
Bob, Thanks for that bit of feedback. I am a retired electrical engineer. That bit of information should be shared on your website.

I am planning or ordering that and the flap controller in the next few days.
Jim C
On Fri, Jun 22, 2018 at 4:13 PM, Tcwtech <rnewman(at)tcwtech.com (rnewman(at)tcwtech.com)> wrote:
Quote:
Thanks to those that mentioned our Safety trim controller. One bit of trivia regarding the concept of single point failure. Even though our device is “one box” inside the unit there’s actually three separate series circuits which would have to all fail to provide an uncommanded operation of the servo. As a result after 10 years in the field we have had zero issues resulting in unwanted motion even in the face of a variety of builder mistakes and mis-applications.

Bob NewmanTCW Technologies, LLC
610-928-3420
On Jun 22, 2018, at 10:02 AM, Jim Combs <jiminlexky(at)gmail.com (jiminlexky(at)gmail.com)> wrote:
Quote:
Thanks, I will check that out.

Jim C
On Fri, Jun 22, 2018 at 9:52 AM, Phillip Perry <philperry9(at)gmail.com (philperry9(at)gmail.com)> wrote:
Quote:
You can install the TCW trim controller and it will address the issue of run away trim. I know it will do more, but here are some basics.

1) It will limit the time that the servo is active to just a few seconds. Then disconnect the trim requiring to re-engage the switch to activate the servo for a few more seconds. This prevents a stuck switch to run the servo to full travel and your trim to full defection.
2) It has a sense circuit built into it that senses where there is a short in a wire causing the servo to run. Then provides a switch that allows you to reverse the travel of the servo through a momentary switch to bring the servo back to its normal spot; then it disconnects the servo from the buss. Thus locking the servo in a more neutral position.
3) It also has a two-speed option so you don't have to drive your servo at full speed. This brings the trim adjustments down to a slower and more reasonable speed when you're really scooting through the air.
Phil
On Fri, Jun 22, 2018 at 8:40 AM, Jim Combs <jiminlexky(at)gmail.com (jiminlexky(at)gmail.com)> wrote:
Quote:
I was asked a question recently about runaway trim.
What would I do if it happened?
I have tried flying the -10 with the trim held to see just what happens. I cruise flight, the out of trim condition happens so fast and the forces on the stick quickly overwhelm the pilots ability to control the aircraft. Realizing what is going on would be a surprise to the pilot and once it happened, flying the airplane becomes the dominate focus item. Stopping the runaway by pulling a fuse or some other action would most likely not happen.
This question does not necessarily apply only to the -10. It could happen on any aircraft.
That being said:
(1) Has anyone ever heard of a runaway condition actually happening? if so what was the outcome?
(2) Is there a stand-alone device that could be put into the trim circuit that is powered by the power going to the trim motor that would (A) prevent the motor from running for an extended time and (B) alert the pilot to the runaway condition. This would be downstream from the switch or controlling electronics.
Jim Combs
N312F (1000+ hours)










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johngoodman



Joined: 18 Sep 2006
Posts: 528
Location: GA

PostPosted: Sat Jun 23, 2018 3:49 am    Post subject: Re: Run-away trim question Reply with quote

I have a Vertical Power 200 in my RV-10, and it has runaway trim built in as well as trim speeds. Not sure if the VPX still has it.
John


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rleffler



Joined: 05 Nov 2006
Posts: 645

PostPosted: Sat Jun 23, 2018 4:50 am    Post subject: Run-away trim question Reply with quote

It does. I have a VPX/Pro in my RV-10.



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From: owner-rv10-list-server(at)matronics.com <owner-rv10-list-server(at)matronics.com> on behalf of johngoodman <johngoodman(at)earthlink.net>
Sent: Saturday, June 23, 2018 7:49:59 AM
To: rv10-list(at)matronics.com
Subject: Re: Run-away trim question


--> RV10-List message posted by: "johngoodman" <johngoodman(at)earthlink.net>

I have a Vertical Power 200 in my RV-10, and it has runaway trim built in as well as trim speeds. Not sure if the VPX still has it.
John

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Read this topic online here:

http://forums.matronics.com/viewtopic.php?p=481133#481133






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PostPosted: Sat Jun 23, 2018 5:35 am    Post subject: Run-away trim question Reply with quote

For what it’s worth, I just have the Ray Allen system but with the rates being high for faster airspeed and potential for runaway trim I put in a trim disconnect switch on the panel I can slap before it gets too bad. Not as quick to respond as the systems in this thread, but cheap and effective.
Marcus

On Jun 23, 2018, at 8:48 AM, Bob Leffler <bob(at)thelefflers.com (bob(at)thelefflers.com)> wrote:
Quote:
It does. I have a VPX/Pro in my RV-10.



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From: owner-rv10-list-server(at)matronics.com (owner-rv10-list-server(at)matronics.com) <owner-rv10-list-server(at)matronics.com (owner-rv10-list-server(at)matronics.com)> on behalf of johngoodman <johngoodman(at)earthlink.net (johngoodman(at)earthlink.net)>
Sent: Saturday, June 23, 2018 7:49:59 AM
To: rv10-list(at)matronics.com (rv10-list(at)matronics.com)
Subject: Re: Run-away trim question


--> RV10-List message posted by: "johngoodman" <johngoodman(at)earthlink.net (johngoodman(at)earthlink.net)>

I have a Vertical Power 200 in my RV-10, and it has runaway trim built in as well as trim speeds. Not sure if the VPX still has it.
John

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PostPosted: Sat Jun 23, 2018 5:39 am    Post subject: Run-away trim question Reply with quote

I have VPX. I used use its trim controller. I rewired since then to use the Dynon autopilot control panel's trim feature with auto-trim.
Kelly
40866, 150 hrs in the air.
Quote:
Sent from my IBM-360 main frame


On Sat, Jun 23, 2018 at 5:48 AM, Bob Leffler <bob(at)thelefflers.com (bob(at)thelefflers.com)> wrote:
Quote:
It does.  I have a VPX/Pro in my RV-10.



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From: owner-rv10-list-server(at)matronics.com (owner-rv10-list-server(at)matronics.com) <owner-rv10-list-server(at)matronics.com (owner-rv10-list-server(at)matronics.com)> on behalf of johngoodman <johngoodman(at)earthlink.net (johngoodman(at)earthlink.net)>
Sent: Saturday, June 23, 2018 7:49:59 AM
To: rv10-list(at)matronics.com (rv10-list(at)matronics.com)
Subject: Re: Run-away trim question  


--> RV10-List message posted by: "johngoodman" <johngoodman(at)earthlink.net (johngoodman(at)earthlink.net)>

I have a Vertical Power 200 in my RV-10, and it has runaway trim built in as well as trim speeds. Not sure if the VPX still has it.
John

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PostPosted: Sat Jun 23, 2018 6:55 am    Post subject: Run-away trim question Reply with quote

Sir Tim, Thanks!  

I did see that and read your write-up. I don't have a flaps up switch but will add one per your suggestion.  
I do have a flap position potentiometer that is used to show the flap position on the EFIS. 

Thanks, Jim C 

On Fri, Jun 22, 2018 at 5:44 PM, Tim Olson <Tim(at)myrv10.com (Tim(at)myrv10.com)> wrote:
Quote:

Hey Jim, on my RV10 site I have an old write-up from when I put in safety-Trim. There may be more info there that you may want to check out also.  I have mine set up with an airspeed switch and also a flap switch which I like very much and did the same on my RV14 as I did the -10.
You’ll be happy with the trim controller and wiring is easier than the relays you probably have now.
Tim

On Jun 22, 2018, at 5:15 PM, Jim Combs <jiminlexky(at)gmail.com (jiminlexky(at)gmail.com)> wrote:
Quote:
Bob, Thanks for that bit of feedback.   I am a retired electrical engineer.  That bit of information should be shared on your website.  

I am planning or ordering that and the flap controller in the next few days.
Jim C
On Fri, Jun 22, 2018 at 4:13 PM, Tcwtech <rnewman(at)tcwtech.com (rnewman(at)tcwtech.com)> wrote:
Quote:
Thanks to those that mentioned our Safety trim controller.    One bit of trivia regarding the concept of single point failure.   Even though our device is “one box” inside the unit there’s actually three separate series circuits which would have to all fail to provide an uncommanded operation of the servo.      As a result after 10 years in the field we have had zero issues resulting in unwanted motion even in the face of a variety of builder mistakes and mis-applications.     

Bob NewmanTCW Technologies, LLC
610-928-3420
On Jun 22, 2018, at 10:02 AM, Jim Combs <jiminlexky(at)gmail.com (jiminlexky(at)gmail.com)> wrote:
Quote:
Thanks, I will check that out.

Jim C
On Fri, Jun 22, 2018 at 9:52 AM, Phillip Perry <philperry9(at)gmail.com (philperry9(at)gmail.com)> wrote:
Quote:
You can install the TCW trim controller and it will address the issue of run away trim.  I know it will do more, but here are some basics.

1) It will limit the time that the servo is active to just a few seconds.  Then disconnect the trim requiring to re-engage the switch to activate the servo for a few more seconds.   This prevents a stuck switch to run the servo to full travel and your trim to full defection.
2) It has a sense circuit built into it that senses where there is a short in a wire causing the servo to run.   Then provides a switch that allows you to reverse the travel of the servo through a momentary switch to bring the servo back to its normal spot; then it disconnects the servo from the buss.  Thus locking the servo in a more neutral position.
3) It also has a two-speed option so you don't have to drive your servo at full speed.  This brings the trim adjustments down to a slower and more reasonable speed when you're really scooting through the air.
Phil
On Fri, Jun 22, 2018 at 8:40 AM, Jim Combs <jiminlexky(at)gmail.com (jiminlexky(at)gmail.com)> wrote:
Quote:
I was asked a question recently about runaway trim.
What would I do if it happened?
I have tried flying the -10 with the trim held to see just what happens.  I cruise flight, the out of trim condition happens so fast and the forces on the stick quickly overwhelm the pilots ability to control the aircraft.  Realizing what is going on would be a surprise to the pilot and once it happened, flying the airplane becomes the dominate focus item.  Stopping the runaway by pulling a fuse or some other action would most likely not happen.
This question does not necessarily apply only to the -10.  It could happen on any aircraft.
That being said:
(1) Has anyone ever heard of a runaway condition actually happening?  if so what was the outcome?  
(2) Is there a stand-alone device that could be put into the trim circuit that is powered by the power going to the trim motor that would (A) prevent the motor from running for an extended time and (B) alert the pilot to the runaway condition.  This would be downstream from the switch or controlling electronics.
Jim Combs
N312F (1000+ hours) 











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PostPosted: Sat Jun 23, 2018 7:19 am    Post subject: Run-away trim question Reply with quote

The Dynon trim system has runaway protection as well.

Jesse SaintSaint Aviation, Inc.
jesse(at)saintaviation.com (jesse(at)saintaviation.com)
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On Jun 23, 2018, at 8:36 AM, Kelly McMullen <apilot2(at)gmail.com (apilot2(at)gmail.com)> wrote:
Quote:
I have VPX. I used use its trim controller. I rewired since then to use the Dynon autopilot control panel's trim feature with auto-trim.
Kelly
40866, 150 hrs in the air.
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On Sat, Jun 23, 2018 at 5:48 AM, Bob Leffler <bob(at)thelefflers.com (bob(at)thelefflers.com)> wrote:
Quote:
It does. I have a VPX/Pro in my RV-10.



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From: owner-rv10-list-server(at)matronics.com (owner-rv10-list-server(at)matronics.com) <owner-rv10-list-server(at)matronics.com (owner-rv10-list-server(at)matronics.com)> on behalf of johngoodman <johngoodman(at)earthlink.net (johngoodman(at)earthlink.net)>
Sent: Saturday, June 23, 2018 7:49:59 AM
To: rv10-list(at)matronics.com (rv10-list(at)matronics.com)
Subject: Re: Run-away trim question


--> RV10-List message posted by: "johngoodman" <johngoodman(at)earthlink.net (johngoodman(at)earthlink.net)>

I have a Vertical Power 200 in my RV-10, and it has runaway trim built in as well as trim speeds. Not sure if the VPX still has it.
John

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#40572 Phase One complete in 2011




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