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Flaps configuration - G3x

clutch22

Well Known Member
Hey guys. I'm having some trouble configuring my flaps with G3x and POS-12.
Most of the time my G3x system doesn't want to deploy the first notch of flaps. I will have to hold the switch down for several seconds which will bypass the predefined selections until the switch is released. Once I do this, everything works fine. It will go to all my preset flap angles. When I fully retract the flaps, the flap motor will continuously run for about 3-4 seconds until I guess the G3x times out. I'm guessing my problem is that the POS-12 sensor isn't always reaching the required voltage for reflex flap setting and so the motor keeps running until it times out. In fact, I've tried to re-calibrate the POS-12 at the reflex position a few different times. If memory serves me right each time I calibrate that position, the voltage may vary slightly from ~9.64v to ~9.50 volts. I know about the unreliable outputs that the POS-12 delivers at its extremes and I tried to stay away from those ends of the travel. I'm hesitant to try to readjust my POS-12 throw because I'm skeptical that it will fix the problem, because in the reflex position the flap is right up to the aft spar/end of flap motor travel. Therefore, the POS-12 voltage output would have to be dead-on every time for the flap motor to quit running immediately when they are retracted. And the fact that the flap motor keeps running for a few seconds, doesn't bother me, it's that the switch wont deploy them again unless I hold it down to get it to bypass.
 
Andrew,
As I recall, the flap motor will coast after shut off. You need to set the stop position to the point where the motor quits "coasting". Try setting your reflex position to stop just prior to where the flaps are nested. See if that helps. The other thing that could be affecting it is if the POS12 is reaching it's limit prior to the flap reaching the reflex nested position. Watch the voltage on the screen or attach a voltmeter to determine if the arm is set appropriately.
 
I appear to be having the same issue. I am certain my POS-12 doesn't hit its limits before the flaps. Any insight would be much appreciated!
 
I am not using the Vertical Power system. My POS-12 is wired to position inputs in the GEA24 and the flaps wired to the GAD27 as recommended in the manual. I have assumed I am missing something on the configuration pages, but I have searched the installation manual and configuration menus and have yet to find my error.

Thanks!

Mark
 
Hey guys. I'm having some trouble configuring my flaps with G3x and POS-12.
Most of the time my G3x system doesn't want to deploy the first notch of flaps. I will have to hold the switch down for several seconds which will bypass the predefined selections until the switch is released. Once I do this, everything works fine. It will go to all my preset flap angles. When I fully retract the flaps, the flap motor will continuously run for about 3-4 seconds until I guess the G3x times out. I'm guessing my problem is that the POS-12 sensor isn't always reaching the required voltage for reflex flap setting and so the motor keeps running until it times out. In fact, I've tried to re-calibrate the POS-12 at the reflex position a few different times. If memory serves me right each time I calibrate that position, the voltage may vary slightly from ~9.64v to ~9.50 volts. I know about the unreliable outputs that the POS-12 delivers at its extremes and I tried to stay away from those ends of the travel. I'm hesitant to try to readjust my POS-12 throw because I'm skeptical that it will fix the problem, because in the reflex position the flap is right up to the aft spar/end of flap motor travel. Therefore, the POS-12 voltage output would have to be dead-on every time for the flap motor to quit running immediately when they are retracted. And the fact that the flap motor keeps running for a few seconds, doesn't bother me, it's that the switch wont deploy them again unless I hold it down to get it to bypass.

Hello Andrew,

It is probably best to contact us directly via email so we can share information more directly, but it sounds like you may be onto something with the flap position sensor.

You don't mention any issues with using zero flaps and lower, so this tells us the sensor and calibration are working well in that range.

You indicate that this is a "most of the time" problem, so this tells us that perhaps sometimes the pot settles into a location where it provides a voltage (resistance) that is too far outside the calibrated range of the sensor, so the system doesn't know where the flaps are.

When you bump the switch down to command it to move from the Reflex position to the Zero position, it doesn't know where the flap is, so doesn't risk moving it in the wrong direction.

This is just a guess since we haven't seen this before, but if you provide us with your flap position calibration table (screenshot) and show us the voltage readout for the flaps in the reflex position, perhaps we can figure out what is happening.

You might also provide some simulated air loads on the flaps when studying the output voltage in the reflex position to give us a range of observed voltages.

It may be as simple as just re-calibrating under the right conditions, or moving the sensor slightly so it doesn't run out of range before the flaps are parked in the reflex position. Of course, this might cause a full flaps problem.

To others reading, one can always hold the flap switch in the up or down position and force the flaps to move, but having an issue like you describe causes partial loss of the full automation features the GAD27 provides based on the flap position sensor input.

Thanks,
Steve
 
Steve,
That is exactly what is happening. I'll spend some more time messing with it this weekend. Maybe I will adjust the sensor travel some more.

As Bill mentioned, I was thinking maybe there was a chance people were setting their reflex position to have a small (say ~1/16") gap to the aft spar. That would probably be enough to allow the POS to hit the calibrated voltage every time.

So, with that said, I'd be interested to know how many people with a similar setup (preset flap settings via POS-12) have their reflex against the aft spar, or have a small gap.

Thanks everyone.
 
I don't know if this will help you but I will share my experience. I have G3x Touch and VPX. Initially I used the position sense and it worked well on the ground. However in flight with full flaps deployed, I would fault the VPX and need to reset flaps before they would retract. In order to complete phase I, I changed the flaps to momentary to avoid a stuck flap in the event I needed to do a go around. At one point I repositioned the POS 12 slightly so it wound not go to either extreme of fully extended or fully retracted POS 12 piston. That made no difference. Now that phase I is completed I revisited the situation. I placed the flaps again in position sense and set the reflex position 6-8 mv shy of fully retracted and the full flap position 6-8 mv shy of fully extended. I now have a reflex, 3 degree, 15 degree and 30 degree position all of which work in flight as well as on the ground.

What I learned;
1) POS 12 sensor arm should not reach either full retraction or full extension
2) mV chosen for reflex or fully extended flaps should be 6-8 mV shy of their respective extremes
3) Don't give up. It's cool when it works.
 
Using the POS12 Sensor

I also have the G3X touch and VPX and the POS12 sensor.

I designed a mechanism to mount the POS12 sensor and I was very deliberate in designing the mechanism for FULL travel of the POS sensor. My thinking was I would have more accuracy by using the full travel of the sensor.

I was having some issues trying to calibrate the flaps in their various positions. From reading this post it looks like I made a mistake to design the full travel.

Other than the fact it is somewhat access limited, should I design a new mechanism to use possibly 80% of the travel?
 
I use a GRT, not Garmin, but perhaps this will help: I positioned the sensor between the flap torque tube and the aft bulkhead, with a small hinge, in such a way that the linear travel between -3 and 0 is maximized. I have had no issues.
 
POS12 install with G3X and VP system in a 9

I am going through the same issues others have in this older post. I have tried 2 different mounting positions for the POS12 and I can either get the flaps to go about 25 degrees down and up tight or not all the way up and to about 30 degrees.

I believe it is the way I have mounted the POS12. Because the flap bar goes up on an arc, the travel is not uniform. I haven't been able to make it work successfully you. Anyone have pictures of how they mounted their POS12? I have seen a hinge used and a ramp. I tried both and still my system does not work properly. Once I get this done, I am ready for the DAR!
 
Maybe

I seem to recall reading in a thread that you want the end points less than full travel. For some reason, 80% seems to be what I recall, leaving 10% on each end unused...
 
I will give that a try. I have been trying to get max travel and that may be a mistake. Making the travel uniform is harder than it should be - at least it has been for me!
 
My POS12 is attached to the arm of the flap actuator as well. The arc of the arm doesn't matter sense the configuration settings in the G3X are for a voltage you set specific to your installation. As was said, don't try to use the full range of the POS12.
 
I just realised I may have made a mistake by not including in my RV7/G3X a GAD27 systems for flaps management: currently my G3X shows the position of the flaps, but I don't think it can be programmed to trigger an alarm (sound+message) if flaps are oversped, which I understand would be possible for sure with the GAD27: however, my G3X has already all the info necessary to create such an alarm function (i.e. flap position+IAS), so maybe it could be included in a next software relase (for G3xpert)??
 
I use a GRT, not Garmin, but perhaps this will help: I positioned the sensor between the flap torque tube and the aft bulkhead, with a small hinge, in such a way that the linear travel between -3 and 0 is maximized. I have had no issues.

Bob,

Are you able to share a picture? I'm interested to see your final configuration.

Thanks!
 
sorry, can't see your picture (I think I'm not he only one to have pb with photobucket), can you describe in words please?
 
Its the dimensions that are important. A hinge is not needed, and the movement is quite linear over the arc desired. Use the 2" dimension, and the 30 degree angle to the vertical brace and it will be fine. Note I had several radii for the attachment if the stroke was too much.

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I'm the OP of this thread, and just saw that this topic is being discussed again. I thought I should update now that everything is working fine now.

I originally had my POS-12 mounted on a piano hinge mounted on the aft spar with the arm connected to a small bracket on an adel clamp. Others have done it this way, although the people I saw weren't using G3x system.
The piano hinge may or may not have been hindering the function of my position sensor. The reason I don't know, is because I later found out that it wasn't the root cause.

Here are some observations that may or may not have played a part in my situation:
  • The play in the hinge pin accounted for several mV of error and would never return to close to the pre-configured mV setting. (yes, the pos-12 was within its accurate range of travel)
  • At one point, I had configured the flaps to stop just shy of being fully retracted. This doesn't work because the flap motor will coast a small amount after power is cut from it.
  • After several emails back & forth to Garmin, we discovered that I never entered a "Partial Flap Max Airspeed". I remembered seeing this during my initial configuration. I had a reason in my head at the time why I felt I should leave it blank, but now I can't remember. I also failed to see the note in the manual that stated that the value must be greater than the full flap airspeed. After entering a value in this field, my predetermined flap settings have worked ever since.

I'm sure the main issue all along was this simple mistake I made in the software configuration. The other changes I made may, or may not have mattered.

Hope this helps someone.
 
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