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Avery Wedge / Rudder Correction

# of rudder wedges (from Avery) to center the ball at cruise

  • None

    Votes: 7 17.9%

  • .5

    Votes: 2 5.1%

  • 1

    Votes: 13 33.3%

  • 1.5

    Votes: 8 20.5%

  • 2

    Votes: 9 23.1%
  • Total voters
    39
ScottSchmidt

ScottSchmidt

Well Known Member
Hi all, I am wondering how much rudder trim it takes to center the ball at cruise. So part of your answer may be at what speed but I would assume around 110 - 115 kts TAS.
I use the wedge you can purchase from Avery on my -10 and I have seen them on quite a few RV's. On the -10 it typically takes 2 wedges to have it centered at 165kts TAS. Here is a link to the wedge from Avery Tools.

I purchased 2 wedges for the -12 and plan on finding the optimal size and then painting them. I have used Silicon II to hold them on and it looks nice and is removable down the road. Before painting I had 1 on and it needed more. I heard from another that his took 1.5.

So if you use this wedge, how many are you using?
Thanks.
 
Last edited:
Wedge

Hi Scott, we used a piece of scrap aluminum, 3 inches wide x five inches long. Riveted it on with some pro seal under it and a slight bend on it and it centered the ball right up. Mounted it just below the top hinge point of the rudder. Be careful drilling the holes for the rivets. Don
 
I used one Avery Wedge. Seemed to be just right, no trimming needed. Mounted it with double sided tape. Ball is centered when out of the climb.
 
rudder centering

The one question you have not addressed is what side of the rudder to you put the wedge? On the side that the ball is out or opposite? And is there an optimal position on the rudder? Low, middle, or higher up?
My ball is only 1/2 degree off so slight right rudder keeps it centered.
Thanks
 
I started out with one and that was not enough. I cut about 2/3 off of a second and added that and that helped a lot. I flew it that way for several months. One day I decided, just for giggles, to put the last 1/3 of the second wedge on and it helped. I found that 2 worked well.

If I were to do it again I would work backwards and try adding a second full wedge first and then trim some off if that was too much. I think 2 wedges would look more natural than the 3 total pieces I ended up with.
 
Out of Trim

Allan Stern said:
The one question you have not addressed is what side of the rudder to you put the wedge? On the side that the ball is out or opposite? And is there an optimal position on the rudder? Low, middle, or higher up?
My ball is only 1/2 degree off so slight right rudder keeps it centered.
Thanks
Click to expand...

The wedge is applied to the rudder opposite the side requiing the pedal pressure.
 
No one has said that placement of the wedge was crucial. My single wedge is on the pilot side. The bottom of the wedge is a couple of inches above the vertical midpoint of the rudder. Your paint scheme may influence the placement, mine did.
 
Rudder wedge

Before we built out RV-4 I had looked at a lot of RV's at Arlington and most all had trim tabs for right rudder. From my RC model days of pattern competion planes we adjusted right thrust and down thrust to get proper trimming. When we built the 4 I added 1/2 degree of right thrust before installing the cowl. Ball stays centered and no trim tab. Has anyone thought of this for the 12?
TED
Sonerai modified 125 Lyc. 1977
RV-4 2007 280 hobbs
120293 Jabiru 3300 50 percent
 
Not practical for the 12, even if done EAB in my opinion. The motor mounts are not adjustable except by maybe sliding shims under them in a trial and error way. That would affect prop clearance with the cowl and maybe some other stuff. This would be maybe 50 times more difficult than simply sticking on the wedge!
 
Trim tabs

Regarding mounting the trim tab: I used "removable" double side scotch tape while tuning in the size of the tab and then mounted it permanantly with "non-removable" double side scotch tape. Mine's been on there for five years and the guy who suggested it to me has had his on there much longer.
It works for me.
 
pictures of wedge

Could someone post pictures of the Wedge installed on at different locations?
Thanks! Oren
 
Ted Farmin said:
Before we built out RV-4 I had looked at a lot of RV's at Arlington and most all had trim tabs for right rudder. From my RC model days of pattern competion planes we adjusted right thrust and down thrust to get proper trimming. When we built the 4 I added 1/2 degree of right thrust before installing the cowl. Ball stays centered and no trim tab. Has anyone thought of this for the 12?
TED
Sonerai modified 125 Lyc. 1977
RV-4 2007 280 hobbs
120293 Jabiru 3300 50 percent
Click to expand...

I think it would be a good idea and easy to do as long as the cowling is trimmed and fitted after the engine install.
 
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