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  #21  
Old 09-16-2009, 10:55 AM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 8,156
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Quote:
Originally Posted by JBPILOT View Post
As I was told, it was designed to go thru a full stroke in 8 seconds with 12v. Slowing that down causes the internal binding issue to be come serious. Very hard to get the motor to start when it may have stopped in a binding condition. They are sending me another one, with the understand that it needs to operate at the "lower power" settings called for.

John Bender
Ray Allen sells (or used too anyway) a speed control that as far as I know only varies the voltage. This causes much more loss in output torque. If they sell a speed control, they must expect the motor to be able to operate at a reduced speed.

The trim system as designed will appear that the motor is laboring because it is running so slow but this is normal. If yours seems to be laboring so much that it can not be stopped at any point in the travel range and restarted, I would say that your trim motor has a problem.

If the trim is adjusted as described in the manual, it will run from stop to stop in about 20 seconds when the engine is running and buss voltage is at the normal operating level. That is why 25 - 30 seconds is used for the adjustment value when only operating on the aircraft battery.

If you adjust for full travel range in only 8 seconds the pitch trim will be extremly sensitive in cruise flight. This is the case with all the RV models not just the RV-12 and is why most everyone using electric trim on RV's (and many other kit plane models) uses a speed control.
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Scott McDaniels
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
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  #22  
Old 09-16-2009, 11:46 AM
JBPILOT JBPILOT is offline
 
Join Date: Nov 2007
Location: Jesup, Iowa
Posts: 1,630
Default Scott

As I have stated, my motor speeds up then nearly stops until it get past the binding position. I took the top off and watched it. With each revolution of the main 'drive' gear around the threaded rod, it tries to force the threaded rod away from the other reduction gears. With higher 'power' to the servo, it goes right past the tight spot easily. By slowing it down, per the desired requirement, the binding issue becomes a problem. The servo needs to turn very freely thoughout the entire stroke. I think many of us are having the same issue, but since we have not been around these servos in many cases, we have not understood how they should be wokring until the 'problem' shows up.

John Bender
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  #23  
Old 09-16-2009, 06:20 PM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 8,156
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Quote:
Originally Posted by JBPILOT View Post
As I have stated, my motor speeds up then nearly stops until it get past the binding position. I took the top off and watched it. With each revolution of the main 'drive' gear around the threaded rod, it tries to force the threaded rod away from the other reduction gears. With higher 'power' to the servo, it goes right past the tight spot easily. By slowing it down, per the desired requirement, the binding issue becomes a problem. The servo needs to turn very freely thoughout the entire stroke. I think many of us are having the same issue, but since we have not been around these servos in many cases, we have not understood how they should be wokring until the 'problem' shows up.

John Bender
It sounds to me like it is a problem with the trim motor. I have been involved with running a few different motors on the PWM speed control and they typically act as you describe (surging change in speed while it is running) but they all have been able to be slowed down to the specified and run the full range without stalling or getting stuck if stopped in the wrong position. Hopefully a different trim motor will solve your problem.
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Any opinions expressed in this message are my own and not necessarily those of my employer.

Scott McDaniels
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
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  #24  
Old 09-16-2009, 06:40 PM
JBPILOT JBPILOT is offline
 
Join Date: Nov 2007
Location: Jesup, Iowa
Posts: 1,630
Default Thank you Scott

Ray Allen said they would send me another one after a long ( second ) discussion. They said they would try to get one that does not bind too much. Should be here tomorrow or the next day. I'll report back how that goes. I think some of the others are having a similar problem. If it happens to stop at the binding point, sometimes they do not want to start again.

John Bender
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  #25  
Old 01-08-2019, 11:20 PM
pilotyoung pilotyoung is offline
 
Join Date: Jan 2018
Location: Birmingham, AL
Posts: 118
Default Trim Speed Adjustment RV-12

My trim is very sensitive. In cruise, it takes just a quick tap to change the trim pressure, and sometimes that quick tap is too much trim movement.

I just learned about the 30 second rule that it should go from one end extreme to the other end extreme in about 30 seconds. I attempted to time my yesterday. I started timing as I held down the trim switch to get full movement. It moved about half way and stopped. I held down the switch again and the same thing happened, except now is has gone full movement in one direction. I did that several time and each time it stops at approximately the take off position. I have just learned about the trim adjustment procedure contained in the AV-50000 and I am going to work on adjusting to slow it down dramatically. Currently full range is about 16 seconds when you continue after the stop about way. So I have two questions. Is the trim switch and controller supposed to stop 1/2 way when the switch is held down, and if so, is the stop supposed to be in the takeoff position? Second, If I do the test twice to get movement through the full range and double the times, do I then set those two times to equal 30 seconds. Currently, my trim is moving full range, counting the stop, in about 15 seconds. Can anyone advise me on the proper steps to take to solve the problem. Also can someone refer me to the proper place in the KIA to find the adjustment procedure. I have look but so far it has aluded me. Thanks in advance for your help.
__________________
John D. Young, RV-12 Owner
Serial Number 120022, N6812Y
Bought it as a flying airplane in Feb. 2018
Just passed 140 hours flight time in RV-12, and 10,000 hours mostly in corporate jets. I am a CFI; CFII; MEI; and a advancd Ground Instructor, CFIG; and hoping to be able to help new RV-12 owners by doing some transition training for new builders and owners in RV-12's.
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  #26  
Old 01-09-2019, 08:47 AM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 8,156
Default

Quote:
Originally Posted by pilotyoung View Post
My trim is very sensitive. In cruise, it takes just a quick tap to change the trim pressure, and sometimes that quick tap is too much trim movement.

I just learned about the 30 second rule that it should go from one end extreme to the other end extreme in about 30 seconds. I attempted to time my yesterday. I started timing as I held down the trim switch to get full movement. It moved about half way and stopped. I held down the switch again and the same thing happened, except now is has gone full movement in one direction. I did that several time and each time it stops at approximately the take off position. I have just learned about the trim adjustment procedure contained in the AV-50000 and I am going to work on adjusting to slow it down dramatically. Currently full range is about 16 seconds when you continue after the stop about way. So I have two questions. Is the trim switch and controller supposed to stop 1/2 way when the switch is held down, and if so, is the stop supposed to be in the takeoff position? Second, If I do the test twice to get movement through the full range and double the times, do I then set those two times to equal 30 seconds. Currently, my trim is moving full range, counting the stop, in about 15 seconds. Can anyone advise me on the proper steps to take to solve the problem. Also can someone refer me to the proper place in the KIA to find the adjustment procedure. I have look but so far it has aluded me. Thanks in advance for your help.
Since there are a number of instrumentation configurations of the RV-12, it is difficult to offer suggestions without knowing what you have. Your airplane is a rather low serial # which would imply Dynon D180 EFIS but what it actually has depends on when the airplane was finished.

On the Skyview and G3X systems, if they have the optional autopilot control panel, the system has a built in trim runaway prevention. This will not allow the trim to run continuously for more than about 6 seconds. On these airplanes, when testing the trim speed, you need to continuously press and release the trim switch every 4-5 seconds while doing the test. This resets the limit timer and allows the trim to continuously run (except for the fraction of a second that you released it which will have no appreciable effect on the overall time)
It sounds like this is what you are seeing but without knowing how your airplane is equipped it is just a guess.

For additional info, refer to the README document appropriate for what panel equipment you have. They can be found here https://www.vansaircraft.com/public/downloads.htm
__________________
Any opinions expressed in this message are my own and not necessarily those of my employer.

Scott McDaniels
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
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  #27  
Old 01-09-2019, 09:29 AM
pilotyoung pilotyoung is offline
 
Join Date: Jan 2018
Location: Birmingham, AL
Posts: 118
Default Trim

Scott,

Thanks for your reply. My aircraft is a low serial number but last summer I upgraded it to the Skyview HDX and installed the auto-pilot control module and the knob module. Now I know why the trim stopped.

I am going to the airport this afternoon to work on this so you reply is very timely.

Thanks.

John
__________________
John D. Young, RV-12 Owner
Serial Number 120022, N6812Y
Bought it as a flying airplane in Feb. 2018
Just passed 140 hours flight time in RV-12, and 10,000 hours mostly in corporate jets. I am a CFI; CFII; MEI; and a advancd Ground Instructor, CFIG; and hoping to be able to help new RV-12 owners by doing some transition training for new builders and owners in RV-12's.
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  #28  
Old 03-23-2019, 09:51 PM
pilotyoung pilotyoung is offline
 
Join Date: Jan 2018
Location: Birmingham, AL
Posts: 118
Default Trim Speed

My trim speed is too fast. It goes full range in about 16 seconds. I have the Dynon Skyview HDX with the auto-pilot controller and the knob module. My understanding is that with the auto-pilot controller, it contains a separate trim controller that has total control of trim feature. I have gone into the setup menu of the Skyview HDX and it has two places to adjust trim speed. One is for high airspeed and the other is for low airspeed. I have set the high airspeed to 40% and the lowspeed is set to 28%. I am hesitant to set them much lower. I tried setting the pot on the Vans 50,000A before I learned that the auto-pilot module controls the trim function. I set the Vans 50,000A all the way counter clockwise and it didn't make any difference.

It is still too fast and too sensitive.

I am wondering if some of you who have similar equipment will tell me what the percentage settings are in your Dynon and if you are happy with them.

Thanks in advance for your help.
__________________
John D. Young, RV-12 Owner
Serial Number 120022, N6812Y
Bought it as a flying airplane in Feb. 2018
Just passed 140 hours flight time in RV-12, and 10,000 hours mostly in corporate jets. I am a CFI; CFII; MEI; and a advancd Ground Instructor, CFIG; and hoping to be able to help new RV-12 owners by doing some transition training for new builders and owners in RV-12's.
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  #29  
Old 03-23-2019, 10:11 PM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 8,156
Default

John,
Have you ever read through the entire read me document that I posted a link to in post # 26?

It references the settings file(s) that can be downloaded from the Van's web site. I am pretty sure that if you load the file into your screen, it will automatically load settings in your HDX that will be pretty close to what you need.

Even though you have HDX, the info you want to select is for Skyview.

BTW, all the way counter clockwise on the AV-50000 is max. speed (think of it as the same as a water valve CCW for wide open.... Fully CW for shut off).
This should still be adjusted to the proper speed because it will revert to using it if there is aver a power failure of the autopilot system.
__________________
Any opinions expressed in this message are my own and not necessarily those of my employer.

Scott McDaniels
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")

Last edited by rvbuilder2002 : 03-23-2019 at 10:16 PM.
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  #30  
Old 03-23-2019, 10:39 PM
pilotyoung pilotyoung is offline
 
Join Date: Jan 2018
Location: Birmingham, AL
Posts: 118
Default Trim Speed

Scott,

I apologize that I did not read the entire file. I just downloaded both files, the pdf readme and the file with the settings. I will install those according to the directions on Tuesday.

I did make a mistake in my last post. I turned the pot all the way clockwise. You are right that counter clockwise is the fastest speed. I just made a mistake when typing the post.

I do appreciate your help on this and other matters. Getting the trim speed right will make flying at cruise much easier.

John
__________________
John D. Young, RV-12 Owner
Serial Number 120022, N6812Y
Bought it as a flying airplane in Feb. 2018
Just passed 140 hours flight time in RV-12, and 10,000 hours mostly in corporate jets. I am a CFI; CFII; MEI; and a advancd Ground Instructor, CFIG; and hoping to be able to help new RV-12 owners by doing some transition training for new builders and owners in RV-12's.
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