[GrayHawk]

Suppose a person has been working on control surface alignments, trailing edges, rigging, etc. on a flying RV he bought to gain experience as an RV pilot and also to gain experience in building, maintenance, etc......

This effort so far has been very rewarding, resulting in the plane flying much straighter at higher speeds with improved efficiency (less fuel) & allowing the complete removal of a large metal rudder trim tab, previously held on by 6 rivets, holes now covered with 200 mph tape.

Question #1: How to best repair the holes in the rudder?
A. Build a new rudder?
B. Better answer here?

The last part of this effort will be to correct a built in elevator misalignment (yes, the control horn drilling problem), check the aileron rigging, flaps rigging, and possibly rework one wing tip. Thoughts are to remove the elevators, weld up at least one existing hole, grind, align, redrill, and so forth.
Concern is the thickness of the control horn metal, any changes to the control horn in the welding process, changes in strength.... This done correctly should allow removal of a trim tab on right aileron.

Question #2: How to best correct the misalignment in the elevators?
A. Build new elevators?
B. Better answer here?

Thanks,

 

[GAHco]

Weding 2024 0-no !

Thoughts are to remove the elevators, weld up at least one existing hole, grind, align, redrill, and so forth.
Concern is the thickness of the control horn metal, any changes to the control horn in the welding process, changes in strength.... This done correctly should allow removal of a trim tab on right aileron.

I do not recommend welding the bell cranks and re-drilling them, the aluminum will be permanently made to posses inferior strength and will have lost its heat treating in the areas affected by the heat and most likely fail at some point.

Replacement parts should be available or be able to be made in your shop, depending on your skill, and then drill the holes where you want them.

The necessity of a trim tab for roll is corrected permanently by re-rigging the angle of incidence on one or both wings.

Ailerons without trim tabs balance themselves out with no pressure on the stick, with one re-positioned a little more up or down the other one effectively receives the same effect, it may change the position of your stick but it shouldn't change the right or left roll rigging, that is the wings, or the weight distribution within the aircraft, assuming your vertical surfaces are correct.

 

[GrayHawk]

I do not recommend welding the bell cranks and re-drilling them, the aluminum will be permanently made to posses inferior strength and will have lost its heat treating in the areas affected by the heat and most likely fail at some point.

Replacement parts should be available or be able to be made in your shop, depending on your skill, and then drill the holes where you want them.

The necessity of a trim tab for roll is corrected permanently by re-rigging the angle of incidence on one or both wings.

Ailerons without trim tabs balance themselves out with no pressure on the stick, with one re-positioned a little more up or down the other one effectively receives the same effect, it may change the position of your stick but it shouldn't change the right or left roll rigging, that is the wings, or the weight distribution within the aircraft, assuming your vertical surfaces are correct.

This is not the control bell cranks but the elevator control horns (steel).

 

[GrayHawk]

I do not recommend welding the bell cranks and re-drilling them, the aluminum will be permanently made to posses inferior strength and will have lost its heat treating in the areas affected by the heat and most likely fail at some point.

Replacement parts should be available or be able to be made in your shop, depending on your skill, and then drill the holes where you want them.

The necessity of a trim tab for roll is corrected permanently by re-rigging the angle of incidence on one or both wings.

Ailerons without trim tabs balance themselves out with no pressure on the stick, with one re-positioned a little more up or down the other one effectively receives the same effect, it may change the position of your stick but it shouldn't change the right or left roll rigging, that is the wings, or the weight distribution within the aircraft, assuming your vertical surfaces are correct.

This is not the control bell cranks but the elevator control horns (steel). See the many previous threads on the control horns.

 

[terrykohler]

Small holes in the skin are easy to fix. Just use blind rivets. If the hole is countersunk, the fix is really clean. If not, no big deal. If the rivets were in the aft edge of the rudder (wedge), lightly clean out the c-sinks with your hand chamfer and squeeze in a new rivet.
For the elevator horns, I believe these are made of low carbon, mild (non-heat treated) steel). Your plan to weld and reface is a good one. Remember the horns are powder coated and should get a good coat of primer and finish after you drill the new hole. Make sure the inspection of this horn is part of the annual condition.
Terry
RV9A
N323TP

 

[GrayHawk]

Small holes in the skin are easy to fix. Just use blind rivets. If the hole is countersunk, the fix is really clean. If not, no big deal. If the rivets were in the aft edge of the rudder (wedge), lightly clean out the c-sinks with your hand chamfer and squeeze in a new rivet.
For the elevator horns, I believe these are made of low carbon, mild (non-heat treated) steel). Your plan to weld and reface is a good one. Remember the horns are powder coated and should get a good coat of primer and finish after you drill the new hole. Make sure the inspection of this horn is part of the annual condition.
Terry
RV9A
N323TP

Thanks. That's matching what I've heard before. The only thing different is these control horns are old enough so as to NOT be powder coated; but yes, good corrosion control and a prority item at condition inspection time (as they have been in the past).

 

[GAHco]

Ok!

This is not the control bell cranks but the elevator control horns (steel).

If you are good or know someone who is, go for it, not like you need my permission, its that I have seen some crazy things as an A&P/IA. and I mis-understood your situation.

 

[GrayHawk]

If you are good or know someone who is, go for it, not like you need my permission, its that I have seen some crazy things as an A&P/IA. and I mis-understood your situation.

I am hardly breaking new ground here. The "weld up old hole" method has been 'tested' by many before me. I was just 'fishing' for a better approach.

 

[GAHco]

I am hardly breaking new ground here. The "weld up old hole" method has been 'tested' by many before me. I was just 'fishing' for a better approach.

A better approach is good, a safe landing is better. I see that by being careful that you will get both. Have fun and .........

 

[pierre smith]

Another hole....

Hi Gray,
If your airplane doesn't have an added access hole for a socket to hold the nut on the elevator horn and pushrod connection, then just use a longer drill when drilling the new hole in the elevator horn and continue through the right side skin. Then get a 1" hole saw and enlarge that hole to 1". You now have an easy access for a socket on the bolt when you re-install the pushrod. Most hardware stores sell 1" diameter stainless, snap in plugs to cover the hole........same way with access holes in the pants to inflate the tires without removing wheelpants.

Regards,

 

[GrayHawk]

Hi Gray,
If your airplane doesn't have an added access hole for a socket to hold the nut on the elevator horn and pushrod connection, then just use a longer drill when drilling the new hole in the elevator horn and continue through the right side skin. Then get a 1" hole saw and enlarge that hole to 1". You now have an easy access for a socket on the bolt when you re-install the pushrod. Most hardware stores sell 1" diameter stainless, snap in plugs to cover the hole........same way with access holes in the pants to inflate the tires without removing wheelpants.

Regards,

Thanks for the tip. I hadn't thought of potential problems in removing the bolt or reinstalling it. I can see where the hole on the other side would help.

 

[Rick6a]

........correct a built in elevator misalignment (yes, the control horn drilling problem).......

Many times, there can be two or more acceptable ways to address a non conformance issue. I am used to working with aerospace engineers. I've dealt with engineers who are prone to write up repair specs that are unnecessarily ambitious and complicated. Because I was the guy that had to get in there and actually do the labor, I've always tried to make it as easy on myself as possible. Many times I would propose an alternative (easier) solution for a given repair that the engineering department would sign off on. Good for me.

Saying all that, I would definitely seek endorsement for the following idea with a qualified engineer which I am not. On first blush without actually seeing the condition you describe, this is how I might attempt to address the misalignment issue.....assuming I didn't want to get involved with welding and all that entails.

It "may" be possible to fabricate and rivet a (.071?) steel patch/doubler to the area around the misaligned hole drilled through the elevator control horn. Located to the inboard surface of the horn and using a flush rivet pattern to attach the repair stock, clearance with other parts should not be an issue. The resulting double drilled (figure 8) hole condition that will exist in the control horn after redrilling for the correct hole location through the repair patch should be filed and smoothed to break any sharp edges. Paying special attention to doubler size, edge distance requirements using a suitable rivet pattern and practicing good corrosion control methods should produce an acceptable result.

Run any such ideas through Van's support staff for consideration. Forums can be a nice resource to gather data points for consideration, but it is always best to consult with the guys who actually designed the airplane in the first place. Van's technical support and expertise was included in the price of the kit. Can't hurt to ask.