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AOG RV-10

MConner

Well Known Member
(Temporary fixed to get home, original thread left up for information)


On landing the pitch trim would only run nose down from either stick, not up at all. After landing and fiddling with it I see that the tab on the copilots side is full up and the pilot side is just a little nose up above neutral.

Suggestions?
 
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If

If the tab is full up that means it is commanding full nose down trim. The Rv-10 needs far more up trim than down and the way van designed the trim tabs, only one tab is used for Nose down trim; the other will be about neutral...

Now why it isn’t moving, well that’s another question...
 
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Thanks Bob. Is there only one trim motor? I did not build the plane and am not familiar with the location of the motor or how it is reversed.

Anyone with guidance can call me 941. 730. 5632
 
Thanks Bob. Is there only one trim motor? I did not build the plane and am not familiar with the location of the motor or how it is reversed.

Anyone with guidance can call me 941. 730. 5632

Remove the eppennage fairing and examine the trim motor/cam/control cable arrangement. From there you can trouble shoot your problem.

You will need to provide more information on what you using for trim motor controller, as in Safety Trim, Dynon Autopilot module, etc.

Carl
 
Are you stuck at an airport away from home?


What trim system and control system do you have? What trim switches do you have and where are they located?

I've had to replace the hat switches in my infinity grips already (120hrs)
 
Thanks Bob. Is there only one trim motor? I did not build the plane and am not familiar with the location of the motor or how it is reversed.

Anyone with guidance can call me 941. 730. 5632

There is only one trim motor and it actuates a lever system to control both tabs via cable. If the motor is moving in one direction, but not the other, your problem likely lies with the relays or grip switches/wiring. When using a grip, you must have individual relays for up and down power delivery to the trim motor. These can be home made or on board purchased from providers. Operation in a single direction points to one of those relays failing or it's wiring.

I am guessing that you didn't command the full up trim and that could also point to your grip wiring touching a ground somewhere. The constant stick movement can wear the insulation off the wire if not carefully secured. Turn on the master and see if the trim motor is running against it's stop. Your stick switches typically provide a ground to the relay for activation. In this case, a shorted wire merely activates the relay and doesn't pop a CB. If you did command all that trim via testing, look at the relays as mentioned above.

Larry
 
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We don’t know how you’re wired, but a common failure with the early Ray Allen trim relays was that they’d only run one direction when they start to go. You can tell if you try the trim with teh cokpit silent, and see if you can hear a relay click - in either direction.

They eventually went with a newer relay that hasn’t had reported issues.

Paul
 
Thoughts as a non-RV-10 flyer or builder.

Where are you? Home field in your hangar or AOG on the road? Any RV-10 builders or maintainers nearby?
Is there a hangar available?
Can you get home from there without the plane?

Has the RV-10 been flown with the elevator trim set near nuetral and inop? How can it be secured in a flyable setting and what indications do you have if the pitch trim is depowered?

Assumes Day, VMC, No autopilot or pitch trim inputs powered. What would you lose?

May require flaps retracted or nearly so. Are you and the runways ready for no flaps?

What weight/balance could it be done at? What speed range and control loading?

How much stick force and travel difference will there be for hands free cruise at 110 knots or some other number? Is the no-flap takeoff and no flap landing trim setting the same?


The -10 may be the least suitable RV for this option, so just throwing it out to have darts thrown at the idea.
 
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Update

Ok I appreciate all the support. I can hear the relay clicking in both directions. I did run the trim full forward without meaning to a little at the time while troubleshooting it.

Thank you for being part of this forum and helping me understand how the system worked.
 
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So, it sounds like you got home safely?

The monkey motion of the trim tabs is been discussed here many times, upshot is that it is fine as is.

There is a single servo, two power wires and three for position sensing.

You should be able to run the servo in the other direction by disconnecting/reversing/reconnecting the two motor wires, then use the trim button ------which will now be backwards, i.e. up now is down.

If this works, then almost certain you have bad relay issues.

When I did the trim servo wiring, I used a non polarized Deans connector at the motor, just so I could reverse if needed. And a polorized three pin for the sensor.

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I would suggest you take a good look at the Safety Trim unit, this could have taken care of the issue when it happened. There is a reversing circuit built in for exactly the problem you encountered. http://www.tcwtech.com/Safety-Trim Page.htm

And, the airspeed switched trim rate reduction is nice.
 
Ok I appreciate all the support. I can hear the relay clicking in both directions. I did run the trim full forward without meaning to a little at the time while troubleshooting it.

Thank you for being part of this forum and helping me understand how the system worked.

If you can hear the relay clicking in both directions, but the trim only runs in one, then most likely there is a relay contact failure - I have seen that a couple of time with the old relays.

Paul
 
Mark,
Given all the obvious fault finding there is another scenario that may apply here.
I have seen an RV10 elevator trim fail in a full UP position :eek: it can also fail in full DOWN as yours appears to have done.
The failure I’ve seen still will have the aftermarket relays (if fitted) working, however reversing the wires will not necessarily make the trim motor work in the opposite direction.
The trim motor is a Ray Allen unit with inbuilt limit switches and operates the trim tabs via a bellcrank & cables. Most other RVs have a direct drive setup.
In all cases you can drive the trim motors to their limits with the limit switches normally doing the limiting of travel.
IF the cables/bellcrank travel is not adjusted correctly at installation then you will have a failure like you describe, it’s just a matter of time. What can happen is you drive it fully one way & , because the travel is incorrectly set up, the limit switch does not cut out the motor which is then continuing to load up the gears.
Do this once too often & the gears get stripped & (maybe jammed) the motor is in ‘neutral’ , not doing any driving. I have seen this happen in a full UP position.
IF the other simple checks don’t work then I’d remove the motor, unscrew the motor cover & carefully check the gears as the damage is hard to see.
The simplest fix is to replace the unit - make sure the trim system is adjusted properly.

HTH,
Jake Jansen ( Jake J)
 
RV10 trim fault

What would really help is if the OP gives a report on what they found.

FWIW - a ?safety? trim system will not prevent my description above from happening - nothing is perfectly designed:)
 
Mea Culpa

Ok problem solved.

Remember my post about my steps cracking? Well it seems that when I used a step bit to open the small hole underneath the step?s retaining nut I nicked a wire.

It took hours of troubleshooting and my hat is off to Jesse Saint and his hard working crew. They worked all day and even after sunset to get me back in the air. I commute to work with my -10 and they sure went the extra mile to get me to work early tomorrow morning.

I sure am learning a lot of great lessons about aircraft.

Thank you Jesse.
 
Ok problem solved.

Remember my post about my steps cracking? Well it seems that when I used a step bit to open the small hole underneath the step?s retaining nut I nicked a wire.

It took hours of troubleshooting and my hat is off to Jesse Saint and his hard working crew. They worked all day and even after sunset to get me back in the air. I commute to work with my -10 and they sure went the extra mile to get me to work early tomorrow morning.

I sure am learning a lot of great lessons about aircraft.

Thank you Jesse.

Well done Jesse !
Mark - thnx for the report. Nicking the wire is, mostly, a simple gotcha however I can?t imagine why the wiring was put in such an awkward place.
Hopefully you now get to enjoy flying a wonderful aircraft type for a long time :)
 
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