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Location of lead in the rudder

W

WVM

Well Known Member
Hi,

While browsing through random RV-9 blogs I noticed that some attached the lead close to the spar, while others attached it on the far outside. According to my interpretation of the plans it should be on the far outside. But I found it strange that some builders did it differently.

Some sample pictures:
IMG_7173-X3.jpg

IMG_2901.jpg


What is actually the correct way? Is the other way done with a specific goal?
 
I don't have any input on location but make sure your attach screws are secure. I bought my RV flying and I noticed on a pre flight that the counter balance attach screws were loose and hanging down, had they been any lower they would have jammed the rudder. Pain in the neck to access after the fact.
Good pre flight is mandatory every time !
 
Yes, the counter weight is at the maximum distance from the pivot. Otherwise it is a waste of weight in the tail.

Hints for working with lead - you can drill, but you can also smack it with a hammer to reshape it to fit. Corners, rivet clearance etc apply.

PolySulfide sealant/adhesive (aka proseal) is a good additional bonding agent to prevent small movements.

Ya gotta be really careful with off plan changes in blogs, especially since the plane might not be flying yet, and the blog not updated with issues.
It can be a building time killer just sorting it out too.

Happy Building!
 
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Looks like my photo in the first picture. In this picture there is no lead weight attached, just some dimpled holes (incorrectly).

The plans are pretty clear on DWG-7 to position the lead weights forward like this.
IMG_7175-M.jpg
 
WVM said:
Thank you all for your prompt replies. I was (again) a bit too worried.
Click to expand...

Let's worry about the builder who installed the lead near the spar in the above photo. If you know who it is, send him a note. I recall at least one RV loss attributed to flutter of a rudder assembly.
 
DanH said:
Let's worry about the builder who installed the lead near the spar in the above photo. If you know who it is, send him a note. I recall at least one RV loss attributed to flutter of a rudder assembly.
Click to expand...

You're right, but the builder sold this project and I have no details on to who he sold it.
 
DanH said:
Let's worry about the builder who installed the lead near the spar in the above photo. If you know who it is, send him a note. I recall at least one RV loss attributed to flutter of a rudder assembly.
Click to expand...
If it's the one i'm thinking of, it was also an *unbalanced* rudder assembly. Although it would take more lead to balance the elevator if you're placing it close to the pivot, if it's balanced it should still be okay. Definitely not the optimal solution, though.
 
WVM said:
You're right, but the builder sold this project and I have no details on to who he sold it.
Click to expand...

This thread got resized and I completely missed the right side of the picture with the inboard weight.

You can get the builders number, and report this to Vans. They would be able to locate and contact the builder.
I think they will be motivated to help the new builder and avoid any unsafe condition.
 
Question

After paint and such as per instructions I balanced my elevators by drilling out some lead.
But is the rudder just left with the stock counter weight? I know mine is.
 
I think the source of confusion is the prepunched holes don't line up with the weight.
You have to drill the hole aft of the most forward one to properly position the weight at the forward position.

You can see how the prepunched holes are not spaced out evenly here.
IMG_7173-M.jpg


That is why I mistakenly dimpled the aft two holes, then later realized that the weight doesn't go there.
I left the dimples there. Dimpled the forward hole.
Match drilled the weight and dimpled that new hole and installed the weight forward.
 
That is true Bruce, my confusion started with the wrong dimple.

I use your website regularly as a visual reference to get a better idea on what is exactly described in the plans. Friday I was just checking some random RV-9 blog, and noticed the lead position. I then checked on your website to see how you did that. Noticed the (wrong) dimple and got confused... As the plans are clear on this one, I thought that it had to be some modification of so.

I have informed VAN'S by e-mail for the other builder, but got a delayed message notification in return. The planned maintenance window was already due, so I hope they have got the message.
 
bruceh said:
I think the source of confusion is the prepunched holes don't line up with the weight.
You have to drill the hole aft of the most forward one to properly position the weight at the forward position.

You can see how the prepunched holes are not spaced out evenly here.
IMG_7173-M.jpg


That is why I mistakenly dimpled the aft two holes, then later realized that the weight doesn't go there.
I left the dimples there. Dimpled the forward hole.
Match drilled the weight and dimpled that new hole and installed the weight forward.
Click to expand...

The R-912 rib is supplied to builders with only 2 pre-punch holes.
The fwd most, and aft most holes in the rib that are visable in this photo. They are used as tooling holes while manufacturing/forming the part.
Only the fwd most hole is intended to be used for attachment of the counter weight (depicted in RV-7,9 DWG 7) . The second intermediate hole must be drill by the builder.
In the case shown in this photo, the second hole must have been match drilled with the counter weight positioned in the wrong location.

BTW, in case the builder that this photo belongs to is interested... I can from the reflection in the counterbalance skin that the dimple countersinks are not fully formed. An aesthetics issue, not an airworthiness issue.
 
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