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more aileron deflection to the right side

fl9500

Active Member
Hi,
I have a 20 year old 1300 hours flight time used RV6A and I noticed, that the aileron deflection is one inch more to the right side than to left.
When the stick is in the middle position, the aileron are aligned.

Can this be a problem ?

Thanks, Achim
 
Hi,
I have a 20 year old 1300 hours flight time used RV6A and I noticed, that the aileron deflection is one inch more to the right side than to left.
When the stick is in the middle position, the aileron are aligned.

Can this be a problem ?

Thanks, Achim

Is this because the aileron stops were installed differently? What is causing the "stop" on each aileron? Could be that the stop on one side was either installed in a different location, or has failed/fallen off...
 
Achim, yes, it can be a problem, the more so if the difference in deflection is new. As Mickey states, check for the presence and secure positioning of each aileron stop. Also check if nothing else restricts the travel one side, such as reduced stick travel by foreign object, as in crotch belt buckle, forgotten tool, etc.

Below the stop as shown in plan sheet #16, and described in the build manual.
 

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Check the deflection angles to see which one, if either, has the correct deflection per the plans. Too much deflection can cause you to exceed structural load limits.
 
Just to note, having excessive travel (missing or incorrect stop) can be a critical safety issue. With the bell crank arrangement on the -6, it is possible for the bell crank to travel over-center if improperly rigged. This could result in a locked aileron and loss of control.
 
when I got my 6A, the pushrod lengths were not correct and the aileron throws were off because that put the bellcranks out of design neutral position.
Check that it is rigged properly.
 
Also check that the bellcrank in one wing was installed in the right orientation. If one was installed upside down, deflection angles would be different between the two wings. Consult the plans sheet# 20 for guidance.
 
Just to note, having excessive travel (missing or incorrect stop) can be a critical safety issue. With the bell crank arrangement on the -6, it is possible for the bell crank to travel over-center if improperly rigged. This could result in a locked aileron and loss of control.

I agree that proper rigging should always be confirmed, but it actually isn't possible for the aileron control system on an RV-6 to be jammed by an over center condition.
The reason is that in an over center condition, the force applied from the stick (and the opposite aileron wanting to move back in trail) will be pulling on the bell crank to remove if from the over center condition.
 
I had the same problem on my purchased -6a, and it also took me a while to figure it out, since the plane flew just fine.

Bellcranks of that vintage were manufactured in the field, and mine were not done very precisely, which made for interesting geometry. For personal peace of mind, I ended up installing factory new parts per current builder's plans from end to end. That fixed it.

Edit: Thanks for making me go back and find my post about it, allowed me to edit it and restore photos that got orphaned with Dropbox, sure hope Imgur stays free!
 
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...
Edit: Thanks for making me go back and find my post about it, allowed me to edit it and restore photos that got orphaned with Dropbox, sure hope Imgur stays free!

Use the paperclip for your images - it's free, and it means that your post will keep working until the end of time...
 
I would go along with the bell crank alignment suggestion. When I was assembling the RV6 I purchased I struggled to get the aileron throws the same. The local RV expert explained that with the control column in the centre align both cranks to be the same distance from the rib alongside and then set the pushrods out to the ailerons. It’s surprising how small an adjustment makes a big difference. Could be worth checking.
 
I agree that proper rigging should always be confirmed, but it actually isn't possible for the aileron control system on an RV-6 to be jammed by an over center condition.
The reason is that in an over center condition, the force applied from the stick (and the opposite aileron wanting to move back in trail) will be pulling on the bell crank to remove if from the over center condition.


Good to know, and makes sense. Something that could maybe happen on the ground with no aerodynamic loads only. I know i was able to cause that condition while assembling the control system, but of course no flight loads in that situation.
 
Bellcrank flipped

I had a similar problem with my old RV-4.

On the ground, full right stick and the aileron would hit the stop, with a nice solid feel, before the stick ran out of travel...

but...full left stick and the stick would run out of travel before the ailerons hit the stop...felt like something was binding rather than a clean "stop". Also left aileron had measurably less "up" travel, despite the control stick having more left travel.

...it also had a very heavy right wing that I couldn't cure.

So after carefully measuring the bellcranks, and comparing them to the plans, the left bellcrank was found to be installed upside down (easy to do, the bellcrank's pivot lengths difference is only 3/8" and the plans don't explicitly state which way to install it--shorter throw could either go to the aileron or control stick pushrod--and it fits either way.)

Flipping the bellcrank:
  • cured the heavy wing;
  • both ailerons hit the stops;
  • and, the stick/aileron travel became symmetrical.

By the way, I was 3rd owner, the airplane had been flying for over 20 years and 600 hours with the left bellcrank upside down!
 

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I had a similar problem with my old RV-4.

On the ground, full right stick and the aileron would hit the stop, with a nice solid feel, before the stick ran out of travel...

but...full left stick and the stick would run out of travel before the ailerons hit the stop...felt like something was binding rather than a clean "stop". Also left aileron had measurably less "up" travel, despite the control stick having more left travel.

...it also had a very heavy right wing that I couldn't cure.

So after carefully measuring the bellcranks, and comparing them to the plans, the left bellcrank was found to be installed upside down (easy to do, the bellcrank's pivot lengths difference is only 3/8" and the plans don't explicitly state which way to install it--shorter throw could either go to the aileron or control stick pushrod--and it fits either way.)

Flipping the bellcrank:
  • cured the heavy wing;
  • both ailerons hit the stops;
  • and, the stick/aileron travel became symmetrical.

By the way, I was 3rd owner, the airplane had been flying for over 20 years and 600 hours with the left bellcrank upside down!

This is what I would be checking! :):)
 
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