What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Trailing edge of elevators are not even..?

H

hughfi

Well Known Member
Hi there,

So something has bothered me for a while and I am such a perfectionist that I want to resolve it.

The trailing edges of my elevators on either side of the rudder are not even or pitched at the exact same angle. If one is level (the left side), the right is slightly higher. While the plane flys almost perfectly straight, I am pretty sure its the cause of a slight vibration in the controls. Its not something I am worried about, but it is something I would like some advice on. It appears that the right side was riveted to the round bar that goes across the elevator slightly differently to the left.

1.) I am considering replacing the rudder (with trim tab). Am I likely to get any closer with a replacement. I did not build the plane so would get a builder to make me one.

2.) Is it possible to only replace the 'offending' side of the elevator?

3.) Any other advice on this. The rest of the aircraft is perfect and I only require a touch of right rudder when straight and level at cruise speed.

Any advice greatly appreciated.

Thanks,

Hugh.
 
Elevator "Trail"

It's fairly normal for the elevator horns to be in slightly different positions with the elevators "in trail."

My plans call for this procedure:
"Align the [elevator] trailing edge on the extended chord line of the [horizontal] stabilizer. Secure the elevator in this position.

Fabricate a "drill bushing" with an outside diameter of 1/4" and an 3/32" inside diameter....the bushing will protect the VA-146 hinge bearing from the drill bit and act as a drill guide to locate and drill the hole in the WD-605-1-R for the bolt that attaches the horn to the center bracket.

Insert the drill bushing into the HS-411PP hinge bracket/bearing assembly. Using the drill bushing as a drill guide, pilot drill WD-605-1-R to #40.

Remove the elevator from the horizontal stabilizer and carefully drill the hole in the WD-605-1-R horn to final size.

Repeat the above steps for the left elevator assembly."

I'd guess that your elevators aren't lined up due to mis-drilling of the horn weldment(s).

As you can see by the above part numbers, the RV8 uses RV6 elevator horns and the procedure for your plane will be very similar, if not identical.

Assuming one elevator is properly drilled, you could order one new horn weldment (the WD-605-1-R for the right side or WD-605-1-L for the left side) from Vans, remove the old horn weldment, install a new horn weldment and redrill the new one with the elevator "in trail" following the above procedure. This should get your elevators back in alignment and "in trail" as a pair. Not the easiest rework to do, but not impossible.

Mike
 
Fixen stuff.

Hi there,

So something has bothered me for a while and I am such a perfectionist that I want to resolve it.

The trailing edges of my elevators on either side of the rudder are not even or pitched at the exact same angle. If one is level (the left side), the right is slightly higher. While the plane flys almost perfectly straight, I am pretty sure its the cause of a slight vibration in the controls. Its not something I am worried about, but it is something I would like some advice on. It appears that the right side was riveted to the round bar that goes across the elevator slightly differently to the left.



If the left side is level and the right is slightly higher, then if you move the right side to level then the left side would be lower, making up for the difference! JK!!!

What model of RV do you have? Don't know of "round bar" thingy, unless its the pitch horn, weldment, that can be miss drilled so as to miss alighn the elevators.




1.) I am considering replacing the rudder (with trim tab). Am I likely to get any closer with a replacement. I did not build the plane so would get a builder to make me one.

Not sure why you would want to replace the rudder, but you can have a trim tab put on if it flys a little out of trim in cruise.


2.) Is it possible to only replace the 'offending' side of the elevator?


I have found that with enough money most everyting can be replaced, but there are a LOT of RV's out there with elevators a little out of perfict. I don't see how this would cause a vibration, close the throttle in cruise, see if it changes or goes away. Can you feel the vibration in the stick or in your butt?


3.) Any other advice on this. The rest of the aircraft is perfect and I only require a touch of right rudder when straight and level at cruise speed.

Any advice greatly appreciated.

Thanks,

Hugh.
 
Last edited:
SportAvServ said:
3.) Any other advice on this. The rest of the aircraft is perfect and I only require a touch of right rudder when straight and level at cruise speed.
Click to expand...

Does the rudder itself have a fixed trim tab? Most 6's do, because the vertical stabs were not offset like newer models. Mine took some pretty good right pedal, until I put the tab on. I'd even like an elec. trim tab, but most likely won't install one.

L.Adamson --- RV6A
 
That's one I would fix...

As mentioned already, I would bet it is in the Elevator Horn alignment. When the elevators are evenly in trail my horns where off at least 1/8" maybe more from each other to get the elevators to match.
Replacing the horn would require drilling out a good portion of the elevator skin to be able to drill out the rivets on the old horn and reinstall the new one.
Those are steel horns. There might be a way to patch over the hole to allow for redrilling it or weld up the hole.
I would get some expert opinions on an acceptable repair before I did anything.

The instructions assume that the HS and Elevator where built perfectly. The chord line method of alignment is a good double check but I matched my elevators with the rudder off using a straight edge and clamps, then I checked to make sure the chord line was close on both sides.
 
JonJay said:
Those are steel horns. There might be a way to patch over the hole to allow for redrilling it or weld up the hole.
I would get some expert opinions on an acceptable repair before I did anything.
Click to expand...

Another option is to cut off the steel horn section of a new piece, that is opposite of the side of either existing horn, where you want to re-drill the hole. Then butt & rivet these two pieces together, with the flanges away from each other. Drill a new hole that's in alignment this time.
 
Fix for elevator

Weld the horn hole closed on the offending side, grind flush, add and .o63 4130 doubler to the back side of the horn with 1/8" rivets and then re-drill with the elevators in trail, it will be as strong if not stronger and no repainting other then the horn. I have seen this done to fix this problem. My 2 cents CJ
 
You must log in or register to reply here.
Back
Top